Meta-analysis finds vocal emotion recognition accuracy is significantly lower in ADHD

Emotion dysregulation (ED) refers to the difficulty someone has in managing their emotions. People with ED might experience strong reactions like anger, irritability, emotional outbursts, or even excessive happiness. This issue affects 25% to 45% of children with ADHD and 30% to 70% of adults with ADHD. ED may come from challenges in recognizing emotions—like anger, sadness, fear, or happiness—based on facial expressions or tone of voice. People with ADHD struggle to control their emotions in a similar way that they have trouble controlling their attention and behavior.

Emotion Recognition in ADHD

One way researchers study ED in people with ADHD is by testing how well they recognize emotions. In these studies, participants are shown faces or hear voices expressing different emotions, and they are asked to identify which emotion is being shown. This helps measure how accurately people with ADHD recognize emotions compared to people without ADHD (referred to as typically developing, or TD, individuals).

Research Findings

A group of psychologists from the UK reviewed many studies that compared how well people with ADHD and TD individuals performed on emotion recognition tasks. They focused on studies that looked specifically at how well participants could recognize emotions through vocal expressions (such as changes in tone of voice).

They combined the results of 20 different studies, which together included 1,651 participants, and found that people with ADHD had more difficulty recognizing emotions than those without ADHD. The overall difference between the two groups was moderate, meaning the ADHD group consistently had more trouble, but the differences weren’t extreme. Only two of the 20 studies showed slightly different results, and there was no sign that the studies were biased. Whether or not participants were taking medication for ADHD didn’t change the outcomes.

Recognizing Positive and Negative Emotions

The study found that people with ADHD had more trouble recognizing both positive and negative emotions compared to the TD group:

• Anger and sadness: People with ADHD showed a moderate level of difficulty in recognizing these emotions.
• Happiness: There was a small-to-moderate level of difficulty in recognizing happiness.
• Overall: There was no clear pattern showing that ADHD participants struggled more with certain types of emotions; instead, their errors seemed random. This suggests that their difficulties in recognizing emotions may be linked to their general attention problems.

Age Differences

The study found that emotion recognition difficulties were more pronounced in children with ADHD than in adults. Among children, the deficit was large, while among adults, the difference was moderate.

Conclusion

The psychologists concluded that their analysis provides strong evidence that people with ADHD struggle with recognizing emotions, particularly through vocal expressions. They also found that these difficulties aren’t specific to certain emotions (like only anger or sadness), but rather seem to affect emotion recognition in general. This supports the idea that ED in ADHD is partly due to the same attention problems that make it difficult for people with ADHD to focus or control their behavior. The findings highlight that emotion dysregulation in ADHD may be a secondary problem caused by these underlying attention issues.

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ADHD is associated with deficits in cognitive functions. These include such executive functions as reaction time, motor and interference inhibition, sustained attention, and working memory. 

To what extent can ADHD medications compensate for such deficits? A recent meta-analysis by a European study team has explored this question. It suggests that while medication cannot completely reverse deficits in executive functions, it can lead to significant improvements. 

Based on consistent evidence from many randomized double-blind controlled trials (RCTs) measuring behavioral improvements, first line treatment for ADHD is with stimulant medication while second-line treatment (for stimulant non-responders, or poor tolerability) is with non-stimulant medication (atomoxetine, viloxazine, guanfacine and clonidine). 

This systematic literature search yielded eighteen RCTs, not all of which covered the same executive functions or medicines. 

Meta-analyses yielded the following results: 

Reaction Time 

Eleven RCTs, encompassing 925 participants, found a small-to-medium effect size improvement with methylphenidate. Variation (heterogeneity) among these studies was moderate, and there was no sign of publication bias. 

Four RCTs with a total of 286 participants similarly reported a small-to-medium effect size improvement with atomoxetine. Again, heterogeneity was moderate, with no indication of publication bias. 

Attention 

Sixteen RCTs, with a combined 1,335 participants, found a medium effect size improvement with methylphenidate. Heterogeneity was moderate, and there was some indication of publication bias. No effort was made to correct for publication bias. 

Three RCTs, encompassing 254 persons, found a medium effect size improvement with atomoxetine. Heterogeneity was moderate, with no evidence of publication bias. 

Inhibition 

Thirteen RCTs, with a total of 1,201 participants, found a small-to-medium effect size improvement with methylphenidate. Heterogeneity was moderate, with marginal indication of publication bias. 

Six RCTs with a combined 753 individuals, reported a medium effect size improvement with atomoxetine. Heterogeneity was high, but there was no evidence of publication bias. 

Working Memory 

Nine RCTs, with a total of 1,025 participants, found a small-to-medium effect size improvement with methylphenidate. Heterogeneity was moderate, with no indication of publication bias. 

Three RCTs with a combined 132 individuals, reported a statistically nonsignificant small-to-medium effect size improvement with atomoxetine. Heterogeneity was moderate, with no indication of publication bias. The nonsignificant outcome may have been due to the much smaller number of participants. 

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The team concluded, “these meta-analyses of chronic effects of stimulants and non-stimulants on executive functions in ADHD showed significant improvements with both methylphenidate and with atomoxetine in all cognitive domains tested with relatively similar effect sizes, and no statistical differences between them. The findings hence suggest comparable positive effects of both ADHD medication types on the most relevant executive functions in ADHD, suggesting for the first time that stimulant and non-stimulant ADHD medications, when taking [sic] longer-term, not only improve behavioural symptoms of ADHD, but also improve executive function performance, and to a similar degree.” 

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Children and adolescents with ADHD are known to have difficulties in relating to family members, peers, and teachers. Over the long run this can contribute to anxiety or even delinquency. 

Several cognitive functions that allow individuals to process social information and interact with others contribute to shaping everyday social interactions. These include: 

• Theory of mind (ToM): Being able to attribute mental states to others, and thus explain and predict their behaviors. 

• Empathy: Being able to feel an appropriate emotion in response to another person’s mental state, and thereby understand others’ feelings. 

• Emotion recognition: Being able to identify emotions in facial expressions and other communication cues, such as voice and body position. 

A European research team performed a systematic search of the peer-reviewed medical literature to conduct meta-analyses of ToM, Empathy, Facial and Non-Facial Emotion Recognition in children and adolescents with ADHD when compared to typical development. As a comparison measure, they also included Everyday Social Skills (using self, parent, teacher, or clinician questionnaires/interviews of social skills) as an outcome. 

The search yielded 142 case-control studies (including dissertations) with a total of 16,283 participants. 

Meta-analysis of 82 studies with a combined total of 10,770 participants found a very large effect size impairment in everyday social skills among children and adolescents with ADHD when compared with typically developing peers. Adjusting for covariates only strengthened the finding. There was no sign of publication bias. 

This was mirrored in three out of five measures of social cognition: 

• Theory of mind (ToM): Meta-analysis of 49 studies with a total of 2,449 participants identified a large effect size impairment among children and adolescents with ADHD when compared with typically developing peers. Adjusting for covariates made no difference in the outcome. There was no sign of publication bias. 

• Empathy: Meta-analysis of twelve studies combining 916 individuals yielded a medium effect size impairment among children and adolescents with ADHD. But there were strong signs of publication bias, and the outcome lost significance after adjusting for covariates (perhaps because it became under-powered with three studies pooling only 151 persons). 

• Facial emotion recognition: Meta-analysis of 43 studies with a total of 3,369 participants reported a medium effect size impairment among children and adolescents with ADHD after adjusting for covariates. There was absolutely no indication of publication bias. 

• Non-facial emotion recognition: Meta-analysis of eight studies encompassing 707 persons reported a small effect size impairment with signs of publication bias that became insignificant after adjusting for covariates. 

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The team concluded, “Our findings show that children and adolescents with ADHD have deficits in ToM, Facial Emotion Recognition, and Everyday Social Skills, three domains that warrant clinical attention.” 

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A Chinese study team performed a systematic search of peer-reviewed journal literature to identify randomized controlled trials (RCTs) examining the efficacy of cognitive training as a treatment for youths with ADHD.

Seventeen RCTs with a combined total of 1,075 participants met standards for inclusion in a series of meta-analyses. Seven RCTs used waitlist controls, seven used placebo training, two used treatment-as-usual, and one used active knowledge training. Participants were unmediated in four RCTs, with varying proportions of medicated participants in the remaining thirteen.

A meta-analysis of 15 RCTs, with a combined 789 participants, assessed changes in inattention symptoms following treatment, as rated by parents or clinicians. It found a small-to-medium effect size improvement in symptoms of inattention. There was no indication of publication bias, but between-study heterogeneity was very high.

But that gain vanished altogether when combining only the six RCTs that were blinded, meaning the symptom evaluators had no idea which participants had received cognitive treatment and which participants had not. There was zero difference between the treatment and control groups. Significantly, between-study heterogeneity also diminished markedly, becoming low to moderate.

A second meta-analysis, of 15 RCTs with a combined 723 participants, assessed changes in hyperactivity/impulsivity symptoms following treatment, as rated by parents or clinicians. It found no significant difference between participants who received cognitive training and controls. There was no sign of publication bias, and between-study heterogeneity was moderate-to-high.

The three remaining meta-analyses looked for improvements in executive functions, using the Behavior Rating Inventory of Executive Function (BRIEF).

A meta-analysis of 13 RCTs, with a combined 748 participants, found a small-to-medium effect size improvement in the global executive composite index of BRIEF, as evaluated by parents. There was no sign of publication bias, and between-study heterogeneity was moderate-to-high.

But that improvement again disappeared altogether when considering only the five RCTs that were blinded. Between-study heterogeneity also became insignificant.

A meta-analysis of 6 RCTs with 401 participants found no significant improvement in the behavioral regulation index of BRIEF. Heterogeneity was negligible.

Finally, a meta-analysis of 7 RCTs with 463 participants also found no significant improvement in the metacognition index of BRIEF. In this case, between-study heterogeneity was high.

While acknowledging that "when analyses were set in blinded measures, effect sizes were not statistically significant," the author nevertheless concluded, "In summary, multiple cognitive training alleviates the presentation of inattention and improves general executive function behaviors in children with ADHD." This suggests an underlying bias on the part of the study team in favor of treatment even when not supported by best (i.e., blinded) methodological practices.

Noting that "Growing evidence shows that moderate physical activity (PA) can improve psychological health through enhancement of neurotransmitter systems," and "PA may play a physiological role similar to stimulant medications by increasing dopamine and norepinephrine neurotransmitters, thereby alleviating the symptoms of ADHD," a Chinese team of researchers performed a comprehensive search of the peer-reviewed journal literature for studies exploring the effects of physical activity on ADHD symptoms.

They found nine before-after studies with a total of 232 participants, and fourteen two-group control studies with a total of 303 participants, that met the criteria for meta-analysis.

The meta-analysis of before-after studies found moderate reductions in inattention and moderate-to-strong reductions in hyperactivity/impulsivity. It also reported moderate reductions in emotional problems and small-to-moderate reductions in behavioral problems.

The effect was even stronger among unmediated participants. There was a very strong reduction in inattention and a strong reduction in hyperactivity/impulsivity.

The meta-analysis of two-group control studies found strong reductions in inattention, but no effect on hyperactivity/impulsivity. It also found no significant effect on emotional and behavioral problems.

There was no sign of publication bias in any of the meta-analyses.

The authors concluded, "Our results suggest that PA intervention could improve ADHD-related symptoms, especially inattention symptoms. However, due to a lot of confounders, such as age, gender, ADHD subtypes, the lack of rigorous double-blinded randomized-control studies, and the inconsistency of the PA program, our results still need to be interpreted with caution."

ADHD is hypothesized to arise from 1) poor inhibitory control resulting from impaired executive functions which are associated with reduced activation in the dorsolateral prefrontal cortex and increased activation of some subcortical regions; and 2)hyperarousal to environmental stimuli, hampering the ability of the executive functioning system, particularly the medial frontal cortex, orbital and ventromedial prefrontal areas, and subcortical regions such as the caudate nucleus, amygdala, nucleus accumbens, and thalamus, to control the respective stimuli.

These brain anomalies, rendered visible through magnetic resonance imaging, have led researchers to try new means of treatment to directly address the deficits. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that uses a weak electrical current to stimulate specific regions of the brain.

Efficacy:

A team of researchers from Europe and ran performed a systematic search of the literature and identified fourteen studies exploring the safety and efficacy of tDCS. Three of these studies examined the effects on ADHD symptoms. They found a large effect size for the inattention subscale and a medium effect size for the hyperactivity/impulsivity. Yet, as the authors cautioned, "a definite conclusion concerning the clinical efficacy of tDCS based on the results of these three studies is not possible."

The remaining studies investigated the effects on specific neuropsychological and cognitive deficits in ADHD:

•  Working memory was improved by anodal stimulation - but not cathodal stimulation - of the left dorsolateral prefrontal cortex. Anodal stimulation of the right inferior frontal gyrus had no effect.
•  Response inhibition: Anodal stimulation of the left or right dorsolateral prefrontal cortex was more effective than anodal stimulation of the bilateral prefrontal cortex.
• Motivational and emotional processing was improved only with stimulation of both the dorsolateral prefrontal cortex and orbitofrontal cortex.

The fact that heterogeneity in the methodology of these studies made meta-analysis impossible means these results, while promising, cannot be seen as in any way definitive.

Safety:

Ten studies examined childhood ADHD. Three found no adverse effects either during or after tDCS. One study reported a feeling of "shock" in a few patients during tDCS. Several more reported skin tingling and itching during tDCS. Several also reported mild headaches.

The four studies of adults with ADHD reported no major adverse events. One study reported a single incident of acute mood change, sadness, diminished motivation, and tension five hours after stimulation. Another reported mild instances of skin tingling and burning sensations.

To address side effects such as tingling and itching, the authors suggested reducing the intensity of the electrical current and increasing the duration. They also suggested placing electrodes at least 6 cm apart to reduce current shunting through the ski. For children, they recommended the use of smaller electrodes for better focus in smaller brains.

The authors concluded, "The findings of this systematic review suggest at least a partial improvement of symptoms and cognitive deficits in ADHD by tDCS. They further suggest that stimulation parameters such as polarity and site are relevant to the efficacy of tDCS in ADHD. Compared to cathodal stimulation, Anodal tDCS seems to have a superior effect on both the clinical symptoms and cognitive deficits. However, the routine clinical application of this method as an efficient therapeutic intervention cannot yet be recommended based on these studies ..."

Two recent meta-analyses, one by an Asian team, and the other by a European team, have reported encouraging results on the efficacy of physical exercise in treating ADHD among children and adolescents.

One, a Hong Kong-based team (Liang et al. 2021) looked at the effect of exercise on executive functioning.

The team identified fifteen studies with a combined total, of 493 participants that met the criteria for inclusion. As the authors noted, "only a few studies successfully blinded participants and therapists, due to the challenges associated with executing double-blind procedures in non-pharmacological studies."

After adjusting for publication bias, the meta-analysis of the fifteen studies found a large improvement in overall executive functioning.

The studies varied in which aspects of executive functioning were addressed. A meta-analysis of a subset of eleven studies encompassing 406 participants found a large improvement in inhibitory control. A meta-analysis of another subset, of eight studies with a total of 311 participants, found a large improvement in cognitive flexibility. Finally, a meta-analysis of a subset of five studies encompassing 198 participants found a small-to-medium improvement in working memory.

Nine studies involved acute (singular) exercise interventions lasting 5 to 30 minutes, while twelve studies involved chronic (regular) exercise interventions ranging from 6 to 12 weeks, with a total duration of 12 to 75 hours. The chronic exercise was more than twice as effective as acute exercise. The former resulted in large improvements in overall executive functioning, the latter in small-to-medium improvements.

No significant differences were found between aerobic exercises (such as running and swimming) and cognitively engaging exercises(such as table tennis and other ball games, and exergaming ... video games that are also a form of exercise, relying on technology that tracks body movements).

The authors concluded that "Chronic sessions of exercise interventions with moderate intensity should be incorporated as a treatment for children with ADHD to promote executive functions."

Meanwhile, a German study team (Seiffer et al. 2021) looked at the effects of regular, moderate-to-vigorous physical activity on ADHD symptoms in children and adolescents.

They found eleven studies meeting their criteria, with a combined total of 448 participants. A meta-analysis of all eleven studies found a small-to-moderate decline in ADHD symptoms. However, the three studies with blinded outcome assessors found a large and statistically highly significant decline in symptoms, whereas the eight studies with blinded outcome evaluators found only a small decline that was not statistically significant.

When compared with active controls using pharmacotherapy in a subgroup of two studies with 146 participants, pharmacotherapy held a small-to-moderate advantage that fell just short of statistical significance, most likely because of the relatively small sample size.

The authors concluded that moderate to vigorous physical activity (MVPA) "could serve as an alternative treatment for ADHD," but that additional randomized controlled trials "are necessary to increase the understanding of the effect regarding frequency, intensity, type of MVPA interventions, and differential effects on age groups."

Sweden has a national single-payer health insurance system that includes virtually the entire population. It also has a system of national registers that track every resident from birth to death. That makes it possible to conduct nationwide population studies with a very high degree of precision and reliability.

In addition, one of the national registers is the Swedish Twin Register. Tracking all twins in the population enables studies to evaluate the degree to which observed associations may be attributable to genetic influences and to familial confounding. The twin method relies on the different levels of genetic relatedness between monozygotic ("identical") twins, who are genetically identical, and dizygotic ("fraternal") twins, who share on average half of their genetic variation (as do ordinary full siblings).

A Swedish team of researchers identified 42,582 Swedish twins born between 1959 and 1985, and who were, therefore, adults by the time of the study (20-47 years old). Of these, 24,872 (three out of five) completed a web-based survey with 1,300 questions covering lifestyle and mental and physical health. Out of this group, 17,999 provided information on ADHD symptoms and food frequency.

Self-reported ADHD symptoms came from nine inattention components and nine hyperactivity/impulsivity components, covering the 18 DSM- IV symptoms of ADHD.

The food frequency questionnaire included 94 food items, with the following frequency categories: never, 1-3 times/month, 1-2 times/week, 3-4 times/week, 5-6 times/week, 1 time/day, 2 times/day, 3 times/day.

In the raw data, the two subtypes of ADHD exhibited very similar associations. Both had significant associations with unhealthy diets. Both were more likely to be eating foods high in added sugar, and neglecting fruits and vegetables while eating more meat and fats.

After adjusting for the degree of relatedness of twins (whether monozygotic or dizygotic) and controlling for the other ADHD subtype, the associations remained statistically significant for inattention, but diminished to negligible levels or became statistically non-significant for hyperactivity/impulsivity.

Even for persons with inattention symptoms, adjusted correlations were small (never exceeding r = 0.10), with the strongest associations being for overall unhealthy eating habits (r = 0.09), eating foods high in added sugar (r = 0.10) or high in fat (r = 0.05), and neglecting fruits and vegetables (r = 0.06). All other associations became statistically non-significant.

For persons with hyperactivity/impulsivity symptoms, the only associations that remained statistically significant ­- but at tiny effect sizes - were unhealthy dietary patterns (r = 0.04) and consumption of foods high in added sugar (r = 0.03).

The further genetic analysis, therefore, focused on the strongest associations, between ADHD subtypes on the one hand, and unhealthy dietary patterns and eating foods high in added sugar on the other hand. The heritability estimates (the fraction of phenotypic covariance explained by genetic influences) were 44%, 40%, and 37% for inattention and high-sugar food, inattention and unhealthy dietary patterns, and hyperactivity/impulsivity and high-sugar food, respectively.

 When examining only differences between pairs of monozygotic("identical") twins, the correlations became stronger for inattention, rising to r = 0.12 for unhealthy eating habits and r = 0.13 for consumption of foods high in added sugar. For hyperactivity/impulsivity symptoms, the association with unhealthy eating habits was weaker, and the association with consumption of foods high in added sugar became statistically insignificant.

The authors concluded, "we identified positive associations between self-reported trait dimensions of ADHD and intake of seafood, high-fat food, high-sugar food, high-protein food, and an unhealthy dietary pattern, and negative associations with consumption of fruits, vegetables, and a healthy dietary pattern. However, all the associations are small in magnitude. These associations were stronger for inattention compared to hyperactivity/ impulsivity. This pattern of associations was also reflected at the etiological level, where we found a slightly stronger genetic correlation between inattention with dietary habits and hyperactivity/impulsivity with dietary habits. Non-shared environmental influences also contributed to the overlap between ADHD symptom dimensions and consumption of high-sugar food and unhealthy dietary pattern. However, shared environmental influences probably contributed relatively little to the associations between ADHD symptoms and dietary habits. ... significant MZ twin intraplate differences also provided support for a potential causal link between inattention and dietary habits.

Youths with ADHD are known to be more prone to language problems when compared with typically developing peers. To what extent does that affect their ability to share a narrative with others?

A Danish research team conducted a systematic review and meta-analysis of the peer-reviewed medical literature to explore this question. They stressed that this ability is important because "a narrative is a genre of discourse - a form of social communication used to derive meaning from experiences and to construct a shared understanding of events. In other words, it is the fundamental ability of orally producing a coherent story." They focused on the production of narratives rather than comprehension.

Studies had to have a minimum of 10 participants. They had to compare aspects of oral narrative production in children and adolescents with either a formal ADHD diagnosis or a score above a clinical cut-off on a validated ADHD rating scale to a control group of typically developing youths. Youths with confirmed autism spectrum disorder (ASD) or language impairment diagnoses were excluded. There were no constraints on IQ.

The team found sixteen studies with a combined total of 1,015 youths that met these criteria and were suitable for meta-analysis.

They examined seven aspects of oral narrative production:

·        Coherence: A story structure that is logical and easy to follow in cause and sequence. There is a clear beginning, middle, and end. There are goals, attempts, and outcomes. A meta-analysis of nine studies with a combined total of 750 participants found youths with ADHD less coherent than their typically developing peers, with a medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Cohesion: This ensures referencing of events and characters in a manner that enables the listener to grasp how characters, events, and ideas in a story are related. Ambiguous or contradictory references get in the way of this. A meta-analysis of eight studies with a combined total of 501 participants found youths with ADHD showed less cohesion than their typically developing peers, with a medium effect size. Again, with virtually no between-study heterogeneity, and no sign of publication bias.
·        Disruptions: These can be sequence errors, misinterpretations, embellishments, or confabulations - fabricating imaginary experiences as compensation for loss of memory. A meta-analysis of six studies with 389 participants found youths with ADHD had more disruptions than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Fluency: Best explained in terms of errors that interfere with this quality, such as false starts, repeating words or sentences, and abandoning sentences without completing them. A meta-analysis of four studies with 220 participants found no difference in fluency between youths with ADHD and their typically developing peers.
·        Production: This is a measure of output -overall length of the story, number of sentences, number of words. After adjusting for evidence of publication bias, a meta-analysis of twelve studies with 645 participants found no difference here.
·        Syntactic complexity: This includes the extent of vocabulary and the use of proper grammar. A meta-analysis of six studies with 272 participants found youths with ADHD displayed less syntactic complexity than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bi
·        Internal state language: References to perceptions, thoughts, beliefs, and feelings. There were only two studies with 130 participants, so no meta-analysis was performed.

The authors concluded, "the results from the current meta-analysis suggest that children with ADHD have impairments in their narrative language. In particular, children with ADHD produce narratives that are less coherent, less cohesive, less syntactically complex, and include more disruptive errors than typically developing children do."

To what extent does sex matter in the expression of ADHD symptoms and associated cognitive deficits among youths with ADHD?

A recently published meta-analysis of 54 studies by a Canadian team of researchers at the University of Quebec at Montreal suggests it makes little to no difference. A meta-analysis of 26 studies with over 5,900 youths found no significant difference in inattention symptoms, and a meta-analysis of 24 studies with over 5,500 youths likewise found no difference in hyperactivity-impulsivity symptoms. Separating out hyperactivity and impulsivity made no difference.

Given these results, it's no surprise that a meta-analysis of 15 studies with over 3,500 youths again found no significant divergence between the sexes for total ADHD symptoms. Parents and teachers differed, however, in their ratings of symptoms. Whereas parents observed no differences, teachers reported boys had slightly more inattention and hyperactive-impulsive behaviors than girls. Turning to cognitive functions, a series of meta-analyses found no significant sex differences for interference control, working memory, and planning scores. But boys performed slightly worse on inhibition and motor response inhibition. While the raw data also showed boys slightly under-performing girls on cognitive flexibility, strong evidence of publication bias made this unreliable.

The team also compared youths with ADHD and youths without ADHD. Both for females and for males, those differences in ADHD symptoms were - as would be expected - extremely large, whether for total symptoms, inattention, or hyperactivity-impulsivity. All cognitive function scores were moderately better for normally developing boys compared with boys with ADHD, and for normally developing girls compared with girls with ADHD. Yet once again, when comparing these effect sizes between girls and boys, there were no significant differences for any of the symptom and cognitive function effects.

"In other words," the authors wrote, "boys and girls with ADHD presented significantly more primary symptoms and executive and attention deficits than did their peers without ADHD, and effect sizes were not significantly different between the sexes." They concluded, "girls with ADHD do not differ from boys with ADHD in many domains of cognitive functioning, and they have significantly more severe difficulties across the executive and attentional functions measured relative to girls without ADHD. This meta-analysis is the first to examine sex differences in cognitive flexibility, working memory, and planning."

Methylphenidate (MPH) is one of the most widely-prescribed medications for children. Given that ADHD frequently persists over a large part of an individual's lifespan, any side effects of medication initiated during childhood may well be compounded over time. With funding from the European Union, a recently released review of the evidence looked for possible adverse neurological and psychiatric outcomes.

From the outset, the international team recognized a challenge: ADHD severity may be an important potential confounder, as it may be associated with both the need for long-term MPH therapy and high levels of underlying neuropsychiatric comorbidity. Their searches found a highly heterogeneous evidence base, which made meta-analysis inadvisable. For example, only 25 of 39 group studies reported the presence or absence of comorbid psychiatric conditions, and even among those, only one excluded participants with comorbidities. Moreover, in only 24 of 67 studies was the type of MPH used (immediate or extended-release) specified. The team, therefore, focused on laying out an evidence map to help determine priorities for further research.

The team found the following breakdown for specific types of adverse events:

·        Low mood/depression. All three non-comparative studies found MPH safe. Two large cohort studies, one with over 2,300 participants, and the other with 142,000, favored MPH over the non-stimulant atomoxetine. But many other studies, including a randomized controlled trial (RCT), had unclear results. Conclusion: the evidence base regarding mood outcomes from long-term MPH treatment is relatively strong, includes two well-powered comparative studies, and tends to favor MPH.

·        Anxiety. Here again, all three non-comparative studies found MPH safe. But only two of seven comparative studies favored MPH, with the other five having unclear results. Conclusion: while the evidence about anxiety as an outcome of long-term MPH treatment tends to favor MPH, the evidence base is relatively weak.

·        Irritability/emotional reactivity. A large cohort study with over 2,300 participants favored MPH over atomoxetine. Conclusion: the evidence base is limited, although it includes one well-powered study that found in favor of MPH over atomoxetine.

·        Suicidal behavior/ideation. There were no non-comparative studies, but all five comparative studies favored MPH. That included three large cohort studies, with a combined total of over a hundred thousand participants, that favored MPH over atomoxetine. Conclusion: the evidence base is relatively strong, and tends to favor MPH.

·        Bipolar disorder. A very large cohort study, with well over a quarter-million participants, favored MPH over atomoxetine. A much smaller cohort study comparing MPH with atomoxetine, with less than a tenth the number of participants, pointed toward caution. Conclusion: the evidence base is limited and unclear, although it includes two well-powered studies.

·        Psychosis/psychotic-like symptoms. By far the largest study, with over 145,000 participants, compared MPH with no treatment, and pointed toward caution. A cohort study with over 2,300 participants favored MPH over atomoxetine. Conclusion: These findings indicate that more research is needed into the relationship between ADHD and psychosis, and into whether MPH moderates that risk, as well as research into individual risk factors for MPH-related psychosis in young people with ADHD.

·        Substance use disorders. A cohort study with over 20,000 participants favored MPH over anti-depressants, anti-psychotics, and no medication. Other studies looking at dosages and durations of treatment, age at treatment initiation, or comparing with no treatment or alternative treatment, all favored MPH except a single study with unclear results. Conclusion: the evidence base is relatively strong, includes one well-powered study that compared MPH with antipsychotic and antidepressant treatment, and tends to favor MPH.

·        Tics and other dyskinetic. Of four non-comparative studies, three favored MPH, the other, with the smallest sample size, urged caution. In studies comparing with dexamphetamine, pemoline, Adderall, or no active treatment, three had unclear results and two pointed towards caution. Conclusion: more research is needed regarding the safety and management of long-term MPH in those with comorbidities or tic disorder.

·        Seizuresor EEG abnormalities. With one exception, the studies had small sample sizes. The largest, with over 2,300 participants, compared MPH with atomoxetine, with inconclusive results. Two small studies found MPH safe, one had unclear results, and two others pointed towards caution. Conclusion: While the evidence is limited and unclear, the studies do not indicate evidence for seizures as an AE of MPH treatment in children with no prior history more research is needed into the safety of long-term MPH in children and young people at risk of seizures.

·        Sleep Disorders. All three non-comparative studies found MPH safe, but the largest cohort study, with over 2,300 participants, clearly favored atomoxetine. Conclusion: more research is needed into the relationship between ADHD, sleep, and long-term MPH treatment.

·        Other notable psychiatric outcomes. Two noncomparative studies, with 118 and 289participants, found MPH safe. A cohort study with over 700 participants compared with atomoxetine, with inconclusive results. Conclusion: there is limited evidence regarding long-term MPH treatment and another neuropsychiatric outcome, and that further research may be needed into the relationship between long-term MPH treatment and aggression/hostility.

Although this landmark review points to several gaps sins in the evidence base, it mainly supports prior conclusions of the US Food antidrug Administration (FDA) and other regulatory agencies (based on short-term randomized controlled trials) that MPH is safe for the treatment of ADHD in children and adults.  Given that MPH has been used for ADHD for over fifty years and that the FDA monitors the emergence of rare adverse events, patients, parents, and prescribers can feel confident that the medication is safe when used as prescribed.

Drivers with ADHD are far more likely to be involved in crashes, to be at fault in crashes, to be in severe crashes, and to be killed in crashes. The more severe the ADHD symptoms, the higher the risk. Moreover, ADHD is often accompanied by comorbid conditions such as oppositional-defiant disorder, depression, and anxiety that further increase the risk.

What can be done to reduce this risk? A group of experts has offered the following consensus recommendations:

·        Use stimulant medications. While there is no reliable evidence on whether-stimulant medications are of any benefit for driving, there is solid evidence that stimulant medications are effective in reducing risk. But there is also a “rebound effect” in many individuals after the medication wears off, in which performance becomes worse than it had been before medication. It is therefore important to time the taking of medication so that its period of effectiveness corresponds with driving times. If one has to drive right after waking up, it makes sense to take a rapid-acting form. The same holds for late-night driving that may require a quick boost.
·        Use a stick shift vehicle wherever possible. Stick shifts make drivers pay closer attention than automatic transmissions. The benefits of alertness are most notable in city traffic. But using a stick shift is far less beneficial in highway driving, where shifting is less frequent.
·        Avoid cruise control. Highways can be monotonous, making drivers more prone to boredom and distraction. That is even more true for those with ADHD, so it is best to keep cruise control turned off.
·        Avoid alcohol. Drinking and driving is a bad idea for everyone, but, once again, it’s even worse for those with ADHD. Parents should consider the no-questions-asked policy of either picking up their teenager anytime and anywhere or setting up an account with a ride-sharing service.
·        Place the smartphone out of reach and hearing. Cell phone use is as about as likely to impair as alcohol. Hands-free devices only reduce this risk moderately, because they continue to distract. Texting can be deadly. Sending a short text or emoticon can be the equivalent of driving 100 yards with one’s eyes closed. Either turn on Do Not Disturb mode or, for even greater effectiveness, place the smartphone in the trunk.
·        Make use of automotive performance monitors. These can keep track of maximum speeds and sudden acceleration and braking, to verify that a teenager is not engaging in risky behaviors.
·        Take advantage of “graduated driver’s licensing laws” wherever available. These laws forbid the presence of peers in the vehicle for the first several (for example, six) months of driving. Parents can extend that period for teenagers with ADHD, or set it as a condition in states that lack such laws.
·        Encourage practicing after obtaining a learner’s permit. Teenagers with ADHD generally require more practice than those without. A “pre-drive checklist” can be a good place to start. For example: check the gas, check the mirrors, make sure the view through the windows is unobstructed, put your cell phone in Do not disturb mode and place it out of reach, put on a seatbelt, and scan for obstacles.
·        Consider outsourcing. Look for a driving school with a professional to teach good driving skills and habits.

Experts do not agree on whether to delay licensing for those with ADHD. On the one hand, teenagers with ADHD are 3-4 years behind in the development of brain areas responsible for executive functions that help control impulses and better guide behavior. Delaying licensing can reduce risk by about 20 percent. On the other hand, teens with ADHD are more likely to drive without a license, and no one wants to encourage that, however inadvertently. Moreover, graduated driver’s licensing laws only have a legal effect on teens who get their licenses at the customary age.

An international team of mental health professionals used a nationally representative sample of English adults over age 16 to explore this question. Of 13,671 households selected, 7,461 were a little more than half participated.

Participants used the Adult ADHD Self-Report Scale (ASRS) Screener to assess symptoms of ADHD on a scale ranging from 0 to 24. Those scoring ≥ 14 were considered as having high levels of ADHD symptoms. They also responded to a computer-assisted self-interview that asked, "Have you been unfairly treated in the last 12 months … because of your mental health," requiring a yes or no answer.

The raw data showed an exponential relationship between levels of ADHD symptoms and mental health discrimination. Respondents scoring0-9 on the ASRS reported negligible discrimination (prevalence of 0.3%).  Among those scoring 10-13, the prevalence was 2.3%, rising to 5.5% of those with scores in the 14-17 range, and 18.8% among those in the 18-24 range.

After adjusting for sociodemographic variables (sex, age, ethnicity, marital status, educational attainment, and income), those with high levels of ADHD symptoms were nearly 10 times more likely to have experienced discrimination than others.  After adjusting for other psychopathology and stressful life events, this increased risk fell to 2.8.

The authors concluded, "This is an important finding given that mental health discrimination has been associated with detrimental consequences in individuals with mental health disorders and therefore might also be a factor in the negative outcomes that have been noted in adults with ADHD/ADHD symptomatology. As ADHD continues to be underdiagnosed and untreated in adults, the results of this study highlight the importance of identifying and treating these individuals and suggest that interventions to inform the public about ADHD may be important for reducing the stigma and discrimination associated with this condition."

What are we to make of adults who exhibit the diagnostic criteria for ADHD, but are nevertheless high-functioning and successful? A trio of British investigators has just published six case studies that explore this question.  It would have been better for them to have conducted a much larger, controlled research study but, in the absence of such data in the area, these case studies are intriguing and may help guide more informative research.
The authors recruited six successful men between the ages of30 and 65 from a National Health Service tertiary service in London. Four were in long-term relationships, with children. All had good jobs.

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In open-ended taped interviews of up to an hour in length, each was asked three questions:
1.     What do you think are the advantages and disadvantages of having ADHD?
2.     Please describe a time when you felt that your ADHD helped you to achieve something?
3.     What aspects of your ADHD would you miss if it went away?

Hyper-focus in ADHD is generally considered a deficit, inset-shifting, and task-switching. But the authors report that participants associated it with productivity. One said, "I think the energy that the ADHD brain seems to have....it's unfocused, quite scattered, chaotic and a bit random...but give that brain something that you can tune into, and it's your interest, then all that random stuff just goes boom... I get this incredible intense concentration and that's great for work."
Participants also saw advantages in divergent thinking, with one stating, "I'm an artist.... a creative type... a Bohemian.... you are most likely to be a creative person if you are a divergent thinker....and not convergent... I am very creative and that's through and through... I'm a fine art graduate, a musician, a published poet, an entrepreneur, a performer."
All the participants reported being seen as nonconformists. Depending on a viewpoint, that can be seen as either detrimental or advantageous.
Impulsivity is a core symptom of ADHD. Participants however related it to bravery, and more specifically adventurousness, spontaneity, and thrill-seeking. One said, "thrill-seeking is an ADHD thing... I can list in my life have done white water rafting, bungee jumping, hand-glider pilot ... I have done a lot in my life and achieved a lot and experienced a lot...... Furthermore, I would see a lot of that as being quite positive, and a lot of that is ADHD drive."
Another common theme was high energy and "spirit." One participant said, "I've got all this energy.... a lot of energy.... whatever it's to do with.... nature/nurture/spiritual stuff."
These testimonials are useful as a check on the usual narrative of impairment. ADHD does not predestine all it afflicts to an unfulfilling life. Many, often assisted by medication, still lead exciting, successful, rewarding lives.   Yet, we must be cautious in concluding that these individuals were successful because of their ADHD.  It is possible, even likely, that they had other strengths such as high intelligence that compensated for their ADHD symptoms.  We can not know from this report if their lives had been even more fulfilling or successful in the absence of ADHD.   See, for example, my blog about highly intelligent people with ADHD:  https://www.linkedin.com/pulse/20141126141502-65669938-smart-people-can-have-adhd-too/.
While the authors concede that "generalizing the findings of this study is not easy to do," they inexplicably "also argue that the positive aspects we found are relevant to other adults with ADHD regardless of sample size, age, gender or ethnicity."   It is not possible to draw such a definitive conclusion without a much larger sample.
On a hopeful note, they conclude, "This is a study that reaches out to people with lived experience of ADHD: service users, patients, family members, carers, partners, to say that not all symptoms of ADHD are maleficent. Recovery, high functionality, and flourishing with ADHD are possible. Too often people with lived experience hear about ADHD deficits, functional impairments, and associations with substance misuse, criminality, or other disadvantages on almost every level of life (school, work, relationships). ... This study affirms the positive human qualities, assets, and attributes in ADHD that can promote and sustain high functioning and flourishing."   I fully endorse the idea that those with ADHD can have wonderful lives, especially if they receive appropriate treatment, both medical and psychological.

A team of Spanish researchers has published a systematic review of 16 studies with a total of 728 participants exploring the effects of physical exercise on children and adolescents with ADHD. Fourteen studies were judged to be of high quality, and two of medium quality.

Seven studies looked at the acute effects of exercise on eight to twelve-year-old youths with ADHD. Acute means that the effects were measured immediately after periods of exercise lasting up to 30 minutes. Five studies used treadmills and two used stationary bicycles, for periods of five to 30 minutes. Three studies "showed a significant increase in the speed of reaction and precision of response after an intervention of 20-30 min, but at moderate intensity (50-75%)." Another study, however, found no improvement in mathematical problem-solving after 25 minutes using a stationary bicycle at low (40-50%) or moderate intensity (65-75%). The three others found improvements in executive functioning, planning, and organization in children after 20- to 30-minute exercise sessions.

Nine studies examined longer-term effects, following regular exercise over many weeks. One reported that twenty consecutive weekly yoga sessions improved attention. Another found that moderate to vigorous physical activity (MVPA) led to improved behavior beginning in the third week, and improved motor, emotional and attentional control, by the end of five weeks. A third study reported that eight weeks of starting the school day with 30 minutes of physical activity led to improvement in Connor's ADHD scores, oppositional scores, and response inhibition. Another study found that twelve weeks of aerobic activity led to declines in bad mood and inattention. Yet another reported that thrice-weekly 45-minute sessions of MVPA over ten weeks improved not only muscle strength and motor skills, but also attention, response inhibition, and information processing.

Two seventy-minute table tennis per week over twelve weeks improved executive functioning and planning, in addition to locomotor and object control skills.

Two studies found a significant increase in brain activity. One involved two hour-long sessions of rowing per week for eight weeks, the other three 90-minute land-based sessions per week for six weeks. Both studies measured higher activation of the right frontal and right temporal lobes in children, and lower theta/alpha ratios in male adolescents.

All 16 studies found positive effects on cognition. Five of the nine longer-term studies found positive effects on behavior. No study found any negative effects. The authors of the review concluded that physical activity "improves executive functions, increases attention, contributes to greater planning capacity and processing speed and working memory, improves the behavior of students with ADHD in the learning context, and consequently improves academic performance." Although the data are limited by a lack of appropriate controls, they suggest that, in addition to the well-known positive effects of physical activity, one may expect to see improvements in ADHD symptoms and associated features, especially for periods of sustained exercise.

A Dutch study compared the efficacy of mindfulness-based cognitive therapy (MBCT) combined with treatment as usual (TAU), with TAU-only as the control group. MBCT consisted of an eight-week group therapy consisting of meditation exercises (body scan, sitting meditation, mindful movement), psychoeducation about ADHD, and group exercises. TAU consisted of usual treatment in the Netherlands, including medications and other psychological treatments. Sixty individuals were randomly assigned to each group. MBCT was taught in subgroups of 8 to 12 individuals. Patients assigned to TAU were not brought together in small groups. Baseline demographic and clinical characteristics were closely matched for both groups.

Outcomes were evaluated at the start, immediately following treatment, and again after 3 and 6 months using well-validated rating scales. Following treatment, the MBCT + TAU group outperformed the TAU group by an average of 3.4points on the Conner's Adult Rating Scale, corresponding to a standardized mean difference of .41. Thirty-one percent of the MBCT + TAU group made significant gains, versus 5% of the TAU group. 27% of MBCT +TAU patients scored a symptom reduction of at least 30 percent, as opposed to only 4% of TAU patients. Three and six-month follow-up effects were stable, with an effect size of .43.

The authors concluded, "that MBCT has significant benefits to adults with ADHD up to 6 months after post-treatment, about both ADHD symptoms and positive outcomes." Yet in their section on limitations, they overlook a potentially important one. There was no active placebo control. Those who were undergoing TAU-only were aware that they were not doing anything different from what they had been doing before the study. Hence, no substantial placebo response would be expected from this group during the intervention period (post-treatment they were offered an opportunity to undergo MBCT). Moreover, MBCT + TAU participants were gathered into small groups, whereas TAU participants were not. We, therefore, have no way of knowing what effect group interaction had on the outcomes because it was not controlled for. So, although these results are intriguing and suggest that further research is worthwhile, the work is not sufficiently rigorous to definitively conclude that MBCT should be prescribed for adults with ADHD.

Though there have been numerous studies on the efficacy of cognitive-behavioral therapy (CBT) for ADHD symptoms in children, adolescents, and adults, few have examined efficacy among adults over 50. A new study begins to fill that void.

Psychiatric researchers from the New York University School of Medicine, Massachusetts General Hospital, and Pfizer randomly assigned 88 adults diagnosed with elevated levels of ADHD to one of two groups. The first group received 12 weeks of CBT targeting executive dysfunction - a deficiency in the ability to properly analyze, plan, organize, schedule, and complete tasks. The second group was assigned to a support group, intended to serve as a control for any effects arising from participating in group therapy. Each group was split into subgroups of six to eight participants. One of the CBT subgroups was run concurrently with one of the support-only subgroups and matched on the percent receiving ADHD medications.

Outcomes were obtained for 26 adults aged 50 or older (12 in CBT and 14 in support) and compared with 55 younger adults (29 in CBT and 26 in support). The mean age of the younger group was 35 and of the older group 56. Roughly half of the older group, and 3/5ths of the younger group, were on medication. Independent("blinded") clinicians rated symptoms of ADHD before and after treatment.

In the blind structured interview, both inattentive scores and executive function scores improved significantly and almost identically for both older and younger adults following CBT. When compared with the controls(support groups), however, there was a marked divergence. In younger adults, CBT groups significantly outperformed support groups, with mean relative score improvements of 3.7 for inattentive symptoms and 2.9 for executive functioning. In older adults, however, the relative score improvements were only 1.1 and0.9 and were not statistically significant.

Given the non-significant improvements over placebo, the authors' conclusion that "The results provide preliminary evidence that CBT is an effective intervention for older adults with ADHD" is premature. As they note, a similar large placebo effect was seen in adults over 50 in a meta-analysis of CBT for depression, rendering the outcomes non-significant. Perhaps structured human contact is the key ingredient in this age group. It may also be, as suggested by the positive relative gains on six of seven measures, that CBT has a small net benefit over placebo, which cannot be validated with such a small sample size. Awaiting results from studies with larger sample sizes, it is, for now, impossible to reach any definitive conclusions about the efficacy of CBT for treating adults over 50.

A two-year study examined the effect of digital media use on ADHD symptoms in over 2500 adolescents. An earlier meta-analysis found that traditional media use (TV and video console games) was modestly associated with ADHD-like behaviors (Nikkelen et al 2014). The current study extends the examination to a large sample, with modern digital media delivery of high-intensity stimuli, including mobile platforms.

The authors used the Current Symptom Self-Report Scale (Barkley R 1998) to establish ADHD symptoms at baseline and six-month assessments over 24 months. None of the subjects reported having ADHD, study entry. Subjects were considered to be ADHD symptom-positive (the primary binary outcome) if they had greater than or equal to six inattentive and/or hyperactive-impulsive symptoms rated on this frequency-based scale (0-3). Modern digital media use was surveyed on a frequency basis for 14 media activities(including checking social media sites, texting, browsing, downloading or streaming music, posting pictures, online chatting, playing games, online shopping, and video chatting). The most common media activity was the high-frequency checking of social media. Of note, high-frequency engagement in each of the digital media activities was significantly, but moderately, associated with having ADHD symptoms at each six-month follow-up (OR 1.10), even after adjusting for covariates. High-frequency media use at baseline seemed to be associated with the development of ADHD symptoms.

Among the 495 students who reported no high-frequency media use at baseline, 4.6% met ADHD symptom criteria at follow-up. Among 114 students scoring 7 for high-frequency media use at baseline, 9.5% met the symptoms criteria. For the 51 students with a score of 14 for high-frequency media use at baseline, the rate was 10.5% (both comparisons were statistically significant).

This study is important in that it notes that an association between high-frequency digital media use (in current platforms and modalities) may be associated with the development of ADHD-like symptoms. A significant limitation of the study, as noted by the authors, is that ADHD-like symptoms do not establish a diagnosis of ADHD and do not assess impairment; therefore, these results must be interpreted with some caution. It does highlight that even with the current level of understanding, it might be prudent for clinicians to recommend limiting high-frequency media use for adolescent patients.

It sounds like science fiction, but scientists have been testing computerized methods to train the brains of ADHD people to reduce both ADHD symptoms and cognitive deficits such as difficulties with memory or attention.  

Two main approaches have been used: cognitive training and neurofeedback. Cognitive training methods ask patients to practice tasks aimed at teaching specific skills, such as retaining information in memory or inhibiting impulsive responses.

Currently, results from ADHD brain studies suggest that the ADHD brain is not very different from the non-ADHD brain, but that ADHD leads to small differences in the structure, organization, and functioning of the brain. The idea behind cognitive training is that the brain can be reorganized to accomplish tasks through a structured learning process. Cognitive retraining helps people who have suffered brain damage, so it was logical to think it might help the types of brain differences seen in ADHD people. Several software packages have been created to deliver cognitive training sessions to ADHD people.

Neurofeedback was applied to ADHD after it had been observed, in many studies, that people with ADHD have unusual brain waves as measured by the electroencephalogram (EEG). We believe that these unusual brain waves are caused by the different ways that the ADHD brain processes information. Because these differences lead to problems with memory, attention, inhibiting responses, and other areas of cognition and behavior, it was believed that normalizing the brain waves might reduce ADHD symptoms.

In a neurofeedback session, patients sit with a computer that reads their brain waves via wires connected to their heads. The patient is asked to do a task on the computer that is known to produce a specific type of brain wave.  The computer gives feedback via sound or a visual on the computer screen that tells the patient how 'normal' their brainwaves are. By modifying their behavior, patients learn to change their brain waves. The method is called neurofeedback because it gives patients direct feedback about how their brains are processing information.

Both cognitive training and neurofeedback have been extensively studied. If you've been reading my blogs about ADHD, you know that I play by the rules of evidence-based medicine. My view is that the only way to be sure that a treatment works is to see what researchers have published in scientific journals. The highest level of evidence is a meta-analysis of randomized controlled clinical trials. This ensures that many rigorous studies have been conducted and summarized with a sophisticated mathematical method.  

Although both cognitive training and neurofeedback are rational methods based on good science, meta-analyses suggest that they do not help reduce ADHD symptoms. They may be helpful for specific problems, such as problems with memory, but more work is needed to be certain if that is true. The future may bring better news about these methods if they are modified and become more effective. You can learn more about non-pharmacologic treatment for ADHD from a book I recently edited: Faraone, S. V. &Antshel, K. M. (2014). ADHD: Non-Pharmacologic Interventions. Child Adolesc Psychiatr Clin N Am 23, xiii-xiv.

I recently came across a paper from Tom Brown that adds to the growing scientific literature about smart people with ADHD. Dr. Brown's study measured executive functions in 157 ADHD adults with an intelligence quotient (IQ) in the top 9 percent of the population. The executive functions of the brain regulate cognitive processes in a manner that allows for the effective planning and execution of behaviors.

We know from many studies that both children and ADHD have deficits in executive functions, which impair their ability to manage time and keep themselves organized. Dr. Brown extends that literature by showing that three out of four ADHD adults with high IQ scores were significantly impaired on tests of executive functioning. They had problems in many areas: working memory, processing speed, and auditory-verbal working memory relative.

The lesson from this literature is clear. Smart people can have ADHD. Their high IQs will help them do better than the average person with ADHD, but they may not achieve their potential without appropriate diagnosis and treatment.

For more evidence-based info about adult ADHD, go to www.adhdinadults.com.

Research on ADHD has extensively explored various aspects of the condition, yet surprisingly little attention has been devoted to its impact on romantic relationships. Despite over 25,000 articles on ADHD listed in PubMed, only a small number examine topics such as love, sex, and relationship dynamics.

One study by Brunner and colleagues analyzed ADHD symptoms and romantic relationship quality in 189 college students. The findings indicated that students with high levels of hyperactivity-impulsivity and inattentiveness reported lower relationship quality compared to peers with fewer ADHD symptoms. Similarly, a study of 497 college students revealed that ADHD symptoms were linked to the use of maladaptive coping strategies in relationships, resulting in reduced romantic satisfaction.

In research involving young adults, ADHD symptoms were associated with greater negativity and reduced positivity during conflict resolution tasks within romantic partnerships. Higher levels of ADHD symptoms were predictive of lower relationship satisfaction. However, couples where the ADHD partner displayed only inattentive symptoms experienced fewer relational challenges, suggesting that the severity and type of symptoms significantly influence outcomes.

Regarding sexual behavior, studies highlight distinct patterns among individuals with ADHD. Adolescents with ADHD, regardless of gender, report nearly double the number of lifetime sexual partners compared to their non-ADHD peers. These findings align with research by Barkley and colleagues, who observed that ADHD predicted earlier sexual activity and parenthood. Similarly, Flory and colleagues, in a retrospective study, found that childhood ADHD was associated with earlier sexual initiation, more sexual partners, casual relationships, and unintended pregnancies.

A broader study of over 1,000 adults found that ADHD was associated with less stability in romantic relationships, difficulty providing emotional support, higher rates of sexual dysfunction, and increased divorce rates.

Although the body of research on ADHD and romantic relationships is relatively small, it consistently highlights the significant impact of ADHD on love, sex, and relational dynamics, often presenting unique challenges for those affected.

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Many myths have been manufactured about attention deficit hyperactivity disorder (ADHD).  Facts that are clear and compelling to most scientists and doctors have been distorted or discarded from popular media discussions of the disorder.   Sometimes, the popular media seems motivated by the maxim "Never let the facts get in the way of a good story."  That's fine for storytellers, but it is not acceptable for serious and useful discussions about ADHD.

Myths about ADHD are easy to find.  These myths have confused patients and parents and undermined the ability of professionals to appropriately treat the disorder.   When patients or parents get the idea that the diagnosis of ADHD is a subjective invention of doctors, or that ADHD medications cause drug abuse, that makes it less likely they will seek treatment and will increase their chances of having adverse outcomes. 

Fortunately, as John Adams famously said of the Boston Massacre, "Facts are stubborn things."  And science is a stubborn enterprise; it does not tolerate shoddy research or opinions not supported by fact.   ADHD scientists have addressed many of the myths about the disorder in the International Consensus Statement on ADHD, a published summary of scientific facts about ADHD endorsed by 75 international ADHD scientists in2002.  The statement describes evidence for the validity of ADHD, the existence of genetic and neurobiological causes for the disorder, and the range and severity of impairments caused by the disorder.   

The Statement makes several key points:

• The     U.S. Surgeon General, the American Medical Association, the American     Psychiatric Association, the American Academy of Child and Adolescent Psychiatry, the     American Psychological Association, and the American Academy of Pediatrics recognize ADHD as a valid disorder.
• ADHD     involves a serious deficiency in a set of psychological abilities, and these deficiencies pose serious harm to most individuals possessing the disorder.
• Many studies show that the psychological deficits in people with ADHD are associated with abnormalities in several specific brain regions.
• The genetic contribution to ADHD is routinely found to be among the highest for any psychiatric disorder.
• ADHD     is not a benign disorder. For those it afflicts, it can cause devastating problems.

The facts about ADHD will prevail if you take the time to learn about them. This can be difficult when faced with a media blitz of information and misinformation about the disorder. In future blogs, I'll separate the fact from the fiction by addressing several popular myths about ADHD.

The stimulants methylphenidate and amphetamine are well known for their efficacy in treating symptoms of ADHD in both youth and adults.   Although these medications have been used for several decades, relatively little is known about the mechanisms of action that lead to their therapeutic effect.    

New data about the mechanism comes from a meta-analysis by Katya Rubia and colleagues. They analyzed 14 functional magnetic resonance imaging (fMRI) data sets comprising 212 youth with ADHD.  Each of these data sets assessed the short-term effects of stimulants on fMRI-assessed brain activations. In the fMRI paradigm, ADHD and control participants are asked to do a neurocognitive task while the activity of their brains is being measured. Dr. Rubia and colleagues analyzed data from fMRI assessments of time discrimination, inhibition, and working memory, each of which is known to be deficient in ADHD patients.    

The meta-analysis found that the most consistent brain activations were seen in a region comprising the right inferior frontal cortex(IFC) and insula, even when the analysis was limited to previously medication-naïve patients. The implicated region of the brain is known to mediate cognitive control, time estimation, and attention.  Dr.Rubia also notes that other studies show that the IFC/Insula is needed for updating information and allocating attention to relevant stimuli.  

Another region implicate by the meta-analysis was the right putamen, a region that is rich in dopamine transporters. This finding is consistent with the fact that the dopamine transporter is the main target of stimulant medications.    

What is the potential clinical implication of these findings?  As Dr. Rubia and colleagues note, it is possible that the fMRI anomalies they identified could be used as a biomarker for ADHD or a biomarker to select patients who should respond optimally to stimulant medication. Although fMRI cannot be used as a clinical tool at this time, research of this sort is opening up new horizons for how we understand the etiology of ADHD and the mechanisms whereby medications exert their effects.

Cognitive Behavioral Therapy (CBT) is a one-to-one therapy, for adolescents or adults, where a therapist teaches an ADHD patient how thoughts, feelings, and behaviors are all interrelated and how each of these elements affects the others.  CBT emphasizes cognition or thinking because a major goal of this therapy is to help patients identify thinking patterns that lead to problem behaviors.  For example, the therapist might discover that the patient frequently has negative automatic thoughts such as "I'm stupid" in challenging situations. We call the thought 'automatic' because it invades the patient's consciousness without any effort. Thinking "I'm stupid" can cause anxiety and depression, which leads to failure. Thus, stopping the automatic thought will modify this chain of events and, hopefully, improve the outcome from failure to success.

CBT also educates patients about their ADHD and how it affects them in important daily activities.

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For example, most ADHD patients need help with activity schedules, socializing, organizing their workspace, and controlling their distractibility. By teaching specific cognitive and behavioral skills, the therapist helps the patient deal with their ADHD symptoms productively. For example, some ADHD patients are very impulsive when conversing with others. They don't wait their turn during conversations and may blurt out irrelevant ideas. This can be annoying to others, especially in the context of school or business relationships. The CBT therapist helps the patient identify these behaviors and creates strategies for avoiding them.

So, does CBT work for ADHD? The evidence base is small, but when CBT has been used for adult ADHD, it has produced positive results in well-designed studies.   These studies typically compare patients taking ADHD medications with those taking ADHD medications and receiving CBT.  

So for now, it is best to consider CBT as an adjunct rather than a replacement for medication. There are even fewer studies of CBT for adolescents with ADHD.  These initial studies also suggest that CBT will be useful for adolescents with ADHD who are also taking ADHD medications.  Some data suggest that CBT can be successfully applied in the classroom, but the evidence base is very small.

How can this information be used by doctors and patients for treatment planning?  Current treatment guidelines suggest starting with an ADHD medication.  After a suitable medication and dose are found, the patient and doctor should determine if any problems remain.  If so, CBT should be considered an adjunct to ADHD medications.

The term "cognitive behavior therapy (CBT)" refers to a type of talk therapy that seeks to change the way patients think about themselves, their disorder, and the world around them in a manner that will help them overcome symptoms and achieve life goals.

Because CBT is typically administered by a psychologist or other mental health professionals, CBT services are not available in primary care. Nonetheless, it is useful for primary care practitioners to know about CBT so that they can refer appropriately as needed. So, what can we say about the efficacy of CBT for treating adults with ADHD?

Based on a meta-analysis by Young and colleagues, we know for certain that the number of published trials of CBT for adult ADHD is small; only nine trials are available. Five of these compared CBT with waiting list controls; three compared CBT with appropriate placebo control groups. In all of these studies, patients in the CBT and control groups were also being treated with ADHD medications.

Thus, they speak to the efficacy of CBT when given as an adjunctive treatment. The meta-analysis examined the waiting list controlled studies and the placebo-controlled studies separately. For both types of study, the effect of CBT in reducing ADHD symptoms was statistically significant, with a standardized mean effect size of 0.4.

This effect size, albeit modest, is large enough to conclude that CBT will be useful for some patients being treated with ADHD medications. Given these results, a reasonable guideline would be to refer adults with ADHD to a CBT therapist if they are being maintained on an ADHD medication, but that medication is not leading to a complete remission of their symptoms and impairments. So listen to your patients. If, while on an appropriately titrated medication regime, they still complain about unresolved symptoms or impairments, you need to take action.  In some cases, changing their dose or shifting to another medication will be useful. If such approaches fail or are not feasible, you should consider referral to a CBT therapist.

I have too often seen on the Internet or media the statement that ADHD is a recent invention of psychiatrists and/or pharmaceutical companies. Such statements ignore the long history of ADHD that my colleague and I reviewed in our "Primer" about ADHD.  

ADHD has a long history. The first ADHD syndrome was described in a German medical textbook by Weikard in 1775. That's not a typo. The ADHD syndrome had been identified before the birth of the USA. Dr.Weikard did not use the term ADD or ADHD, yet he described a syndrome of hyperactivity and inattention that corresponds to what we call ADHD today.  

ADHD-like syndromes were described in Scotland in 1798 and in France in the late 19th century. The first description of an ADHD-like syndrome in a medical journal was by Dr. George Still in 1901 who described what he called a 'defect of moral control' in The Lancet. The discovery that stimulant drugs are effective in treating ADHD occurred in 1937 when Dr. Charles Bradley discovered that Benzedrine (an amphetamine compound) improved the behavior of children diagnosed with behavioral disorders. In subsequent years, several terms were used to describe children with ADHD symptoms. Examples are Kramer-Pollnow syndrome, minimal brain damage, minimal brain dysfunction, and hyperkinetic reaction.  

,It was not until the 1980s that the term Attention Deficit Disorder (ADD) came into widespread use with the publication of the American Psychiatric Association's Diagnostic and Statistical Manual (DSM).   During the ensuing decades, several changes were made to the diagnostic criteria and the term ADD was replaced with ADHD so as not to overemphasize either inattention or hyperactivity when diagnosing the disorder. And, as the graphic below describes, these new and better diagnostic criteria led to many breakthroughs in our understanding of the nature of the disorder and the efficacy of treatments. So, if you think that ADHD is an invention of contemporary society, think again. It has been with us for quite some time.

We know from many studies that ADHD is associated with a slightly lower intelligence quotient (IQ) and with problems in thinking known as executive function deficits. If that's the case, you might think that people with a high IQ cannot have ADHD.  You would be wrong. Data on groups sometimes mislead us about individuals. Although on average, ADHD people have IQ scores that are about 9 points lower than others, there is a wide spread of IQs in both ADHD and non-ADHD people. So many people with ADHD have higher IQs than those without ADHD and vice-versa. Moreover, studies of people with high IQs support the idea that ADHD can be validly diagnosed among very intelligent individuals.

A series of studies using Antshel and colleagues showed that the clinical profile of high IQ ADHD was very similar to what has been observed for ADHD in general. For example, like their less intelligent counterparts, high IQ ADHD children have an increased risk for mood, anxiety, and disruptive behavior disorders. Children with a high IQ and ADHD showed a pattern of familial transmission as well as cognitive, psychiatric, and behavioral impairments consistent with the diagnosis of ADHD. The degree to which ADHD persisted into adulthood was also similar between the two groups.

In studies of adults with ADHD, the same group concluded that "adults with ADHD and a high IQ display patterns of functional impairments, familiarity and psychiatric co-morbidities that parallel those found in the average-IQ adult ADHD population." Of particular interest, despite their high intelligence, High-IQ adults with ADHD show impaired executive functioning, and their performance on tests of executive functioning predicted life impairments.

Why are these data important? Milioni and colleagues argue that among higher IQ adults with ADHD, a higher degree of intellectual efficiency may compensate for deficits in executive functions. This ability to compensate allows them to succeed in many tasks, which otherwise might have been impaired by their ADHD symptoms. But, in many cases, such compensation is not sufficient or is too burdensome. When compensation fails, ADHD symptoms and other impairments emerge. When this occurs later in life, some clinicians are reluctant to diagnose ADHD. Caution is warranted, but clinicians need to know that the diagnosis of ADHD among high IQ is valid.

Over the past few decades, a consensus has emerged among psychopathologists that some patients exhibit a well-defined syndrome referred to as sluggish cognitive tempo or SCT.

There are no diagnostic criteria for SCT because it has not yet been accepted as a separate disorder by the American Psychiatric Association. People with SCT are slow-moving, indolent, and mentally muddled. They often appear to be lost in thoughts, daydreaming, drowsy or listless. In reviewing these symptoms and the literature, Barkley suggested that SCT be referred to as Concentration Deficit Disorder (CDD). This term is less pejorative, but is not yet commonly used.

Becker and colleagues recently evaluated the internal and external validity of SCT via a meta-analysis of 73 studies. Internal validity addresses the consistency of SCT symptoms as a measure of an underlying construct. Based on factor analytic studies using more than 19,000 participants, the authors concluded that the items purported to measure SCT are sufficiently correlated with one another to justify the idea that they measure the same underlying construct.

Further support for internal validity was found in studies reporting high test-retest and interrater reliability. As regards ADHD, the authors found that SCT correlated significantly with both inattentive (r = 0.72) and hyperactive-impulsive (r = 0.46) symptoms in adults. The greater correlation with inattentive symptoms makes sense given the nature of SCT symptoms. So these data confirm two key points about SCT: 1) it is associated with ADHD symptoms, and 2) it is a meaningful construct in its own right. Very little is known about the implications of SCT for the treatment of ADHD.  

In a naturalistic study of 88 children and adolescents with ADHD, Ludwig and colleagues examined the effect of SCT on the response of ADHD symptoms to methylphenidate. They found no significant differences in treatment response between subjects with and without SCT. McBurnett and colleagues tested the effects of atomoxetine on SCT in children with ADHD and dyslexia (ADHD+D) or dyslexia only. Atomoxetine treatment led to significant reductions in both ADHD symptoms and SCT outcomes.

Because controlling for changes in ADHD symptoms did not predict changes in SCT outcomes, the authors concluded that change in SCT in response to atomoxetine is mostly independent of change in ADHD. Although these data are preliminary and in need of replication, they do provide some guidance for clinicians dealing with ADHD patients who also have SCT.

Methylphenidate(MPH) is one of the most widely-prescribed medications for children. Given that ADHD frequently persists over a large part of an individual’s lifespan, any side effects of medication initiated during childhood may well be compounded over time. With funding from the European Union, a recently released review of the evidence looked for possible adverse neurological and psychiatric outcomes.

From the outset, the international team recognized a challenge: “ADHD severity may be an important potential confounder, as it may be associated with both the need for long-term MPH therapy and high levels of underlying neuropsychiatric comorbidity.” Their search found a higy heterogeneous evidence base, which made meta-analysis inadvisable. For example, only 25 of 39 groups studies reported the presence or absence of comorbid psychiatric conditions, and even among those, only one excluded participants with comorbidities. Moreover, in only 24 of 67 studies was the type of MPH used (immediate or extended-release)specified. The team, therefore, focused on laying out an “evidence map” to help determine priorities for further research.

The team found the following breakdown for specific types of adverse events:

·      Low mood/depression. All three non-comparative studies found MPH safe. Two large cohort studies, one with over 2,300 participants, and the other with 142,000, favored MPH over the non-stimulant atomoxetine . But many other studies, including a randomized controlled trial(RCT), had unclear results. Conclusion: “the evidence base regarding mood outcomes from long-term MPH treatment is relatively strong, includes two well-powered comparative studies, and tends to favor MPH.”

·      Anxiety. Here again, all three non-comparative studies found MPH safe. But only two of seven comparative studies favored MPH, with the other five having unclear results. Conclusion: “while the evidence about anxiety as an outcome of long-term MPH treatment tends to favor MPH, the evidence base is relatively weak.”

·      Irritability/emotional reactivity. A large cohort study with over 2,300 participants favored MPH over atomoxetine . Conclusion: “the evidence base … is limited, although it includes one well-powered study that found in favor of MPH over atomoxetine.”

·      Suicidal behavior/ideation. There were no non-comparative studies, but all five comparative studies favored MPH. That included three large cohort studies, with a combined total of over a hundred thousand participants, that favored MPH over atomoxetine. Conclusion: “the evidence base … is relatively strong, and tends to favor MPH.”

·      Bipolar disorder. A very large cohort study, with well over a quarter-million participants, favored MPH over atomoxetine. A much smaller cohort study comparing MPH with atomoxetine , with less than a tenth the number of participants, pointed toward caution. Conclusion: “the evidence base … is limited and unclear, although it includes two well-powered studies.”

·      Psychosis/psychotic-like symptoms. By far the largest study, with over 145,000 participants, compared MPH with no treatment, and pointed toward caution. A cohort study with over 2,300participants favored MPH over atomoxetine. Conclusion: “These findings indicate that more research is needed into the relationship between ADHD and psychosis, and into whether MPH moderates that risk, as well as research into individual risk factors for MPH-related psychosis in young people with ADHD.”

·      Substance use disorders. A cohort study with over 20,000 participants favored MPH over anti-depressants, anti-psychotics, and no medication. Other studies looking at dosages and durations of treatment, age at treatment initiation, or comparing with no treatment or “alternative” treatment, all favored MPH except a single study with unclear results. Conclusion: “the evidence base … is relatively strong, includes one well-powered study that compared MPH with antipsychotic and antidepressant treatment, and tends to favor MPH.”

·      Tics and other dyskinesias. Of four noncomparative studies, three favored MPH, the other, with the smallest sample size, urged caution. In studies comparing with dexamphetamine, pemoline, Adderall, or no active treatment, three had unclear results and two pointed towards caution. Conclusion: “more research is needed regarding the safety and management of long-term MPH in those with comorbid tics or a tic disorder.”

·      Seizures or EEG abnormalities. With one exception, the studies had small sample sizes. The largest, with over 2,300 participants, compared MPH with atomoxetine, with inconclusive results. Two small studies found MPH safe, one had unclear results, and two others pointed towards caution. Conclusion: “While the evidence is limited and unclear, the studies do not indicate evidence for seizures as an AE of MPH treatment in children with no prior history … more research is needed into the safety of long-term MPH in children and young people at risk of seizures.”

·      Sleep Disorders. All three noncomparative studies found MPH safe, but the largest cohort study, with over 2,300 participants, clearly favored atomoxetine. Conclusion: “more research is needed into the relationship between ADHD, sleep, and long-term MPH treatment.”

·      Other notable psychiatric outcomes. Two noncomparative studies, with 118 and 289 participants, found MPH safe. A cohort study with over 700 participants compared with atomoxetine, with inconclusive results. Conclusion: “there is limited evidence regarding long-term MPH treatment and other neuropsychiatric outcomes, and that further research may be needed into the relationship between long-term MPH treatment and aggression/hostility.”

Although this landmark review points to several gaps in the evidence base, it mainly supports prior conclusions of the US Food and Drug Administration (FDA) and other regulatory agencies (based on short-term randomized controlled trials) that MPH is safe for the treatment of ADHD in children and adults. Given that MPH has been used for ADHD for over fifty years and that the FDA monitors the emergence of rare adverse events, patients, parents and prescribers can feel confident that the medication is safe when used as prescribed.

Drivers with ADHD are far more likely to be involved in crashes, to be at fault in crashes,to be in severe crashes, and to be killed in crashes. The more severe the ADHD symptoms, the higher the risk. Moreover, ADHD is often accompanied by comorbid conditions such as oppositional-defiant disorder, depression, and anxiety that further increase the risk.

What can be done to reduce this risk? A group of experts has offered the following consensus recommendations:

·   Use stimulant medications. While there is no reliable evidence on whether non-stimulant medications are of any benefit for driving, there is solid evidence that stimulant medications are effective in reducing risk. But there is also a rebound effect in many individuals after the medication wears off, in which performance actually becomes worse than if had been prior to medication. It is therefore important to time the taking of medication so that its period of effectiveness corresponds with driving times. If one has to drive right after waking up, it makes sense to take a rapid acting form. The same holds for late night driving that may require a quick boost.

·   Use a stick shift vehicle wherever possible. Stick shifts make drivers pay closer attention than automatic transmissions. The benefits in alertness are most notable in city traffic. But using a stick shift is far less beneficial in highway driving, where shifting is less frequent.

·  Avoid cruise control. Highways can be monotonous, making drivers more prone to boredom and distraction. That is even more true for those with ADHD, so it is best to keep cruise control turned off.

·   Avoid alcohol. Drinking and driving is a bad idea for everyone, but, once again, it's even worse for those with ADHD. Parents should consider a no-questions-asked policy of either picking up their teenager anytime and anywhere, or setting up an account with a ride-sharing service.·   Place the smartphone out of reach and hearing. Cell phone use is as about as likely to impair as alcohol. Hands-free devices only reduce this risk moderately, because they continue to distract. Texting can be deadly. Sending a short text or emoticon can be the equivalent of driving 100 yards with one's eyes closed. Either turn on Do Not Disturb mode, or, for even greater effectiveness, place the smart phone in the trunk.

·   Make use of automotive performance monitors. These can keep track of maximum speeds and sudden acceleration and braking, to verify that a teenager is not engaging in risky behaviors.

·   Take advantage of graduated driver's licensing laws wherever available. These laws forbid the presence of peers in the vehicle for the first several (for example, six) months of driving. Parents can extend that period for teenagers with ADHD, or set it as a condition in states that lack such laws.

·  Encourage practicing after obtaining a learner's permit. Teenagers with ADHD generally require more practice than those without. A pre-drive checklist can be a good place to start. For example:check the gas, check the mirrors, make sure the view through the windows is unobstructed, put cell phone in Do Not Disturb mode and place it out of reach, put on seat belt, scan for obstacles.

·   Consider outsourcing. Look for a driving school with a professional to teach good driving skills and habits.

Experts do not agree on whether to delay licensing for those with ADHD. On the one hand, teenagers with ADHD are 3-4 years behind in the development of brain areas responsible for executive functions that help control impulses and better guide behavior. Delaying licensing can reduce risk by about 20 percent. On the other hand, teens with ADHD are more likely to drive without a license, and no one wants to encourage that, however inadvertently. Moreover, graduated driver's licensing laws only have legal effect on teens who get their licenses at the customary age.

The ENIGMA-ADHD Working Group published their second large study on the brains of people with ADHD in the American Journal of Psychiatry this month. In this second study, the focus was on the cerebral cortex, which is the outer layer of the brain.

ADHD symptoms include inattention and/or hyperactivity and acting impulsively. The disorder affects more than one in 20 (5.3%) children, and two-thirds of those diagnosed continue to experience symptoms as adults.

In this study, researchers found subtle differences in the brain’s outer layer - the cortex - when they combined brain imaging data on almost 4,000 participants from 37 research groups worldwide. The differences were only significant for children and did not hold for adolescents or adults. The childhood effects were most prominent and widespread for the surface area of the cortex. More focal changes were found in the thickness of the cortex. All differences were subtle and detected only at a group level, and thus these brain images cannot be used to diagnose ADHD or guide its treatment.

These subtle differences in the brain’s cortex were not limited to people with the clinical diagnosis of ADHD: they were also present - in a less marked form - in youth with some ADHD symptoms. This second finding results from a collaboration between the ENIGMA-ADHD Working Group and the Generation-R study from Rotterdam, which has brain images on 2700 children aged 9-11 years from the general population. The researchers found more symptoms of inattention to be associated with a decrease in cortical surface area. Furthermore, siblings of those with ADHD showed changes to their cortical surface area that resembled their affected sibling. This suggests that familial factors such as genetics or shared environment may play a role in brain cortical characteristics.

This is the largest study to date to look at the cortex of people with ADHD. It included 2246 people with a diagnosis of ADHD and 1713 people without, aged between four and 63 years old. This is the second study published by the ENIGMA-ADHD Working Group; the first examined structures that are deep in the brain. The ADHD Working Group is one of over 50 working groups of the ENIGMA Consortium, in which international researchers pull together to understand the brain alterations associated with different disorders and the role of genetic and environmental factors in those alterations.

The authors say the findings could help improve understanding of the disorder. ‘We identify cortical differences that are consistently associated with ADHD by combining data from many different research groups internationally. We find that the differences extend beyond narrowly-defined clinical diagnoses and are seen, in a less marked manner, in those with some ADHD symptoms and in unaffected siblings of people with ADHD. This finding supports the idea that the symptoms underlying ADHD may be a continuous trait in the population, which has already been reported by other behavioral and genetic studies.’. In the future, the ADHD Working Group hopes to look at additional key features in the brain- such as the structural connections between brain areas – and to increase the representation of adults affected by ADHD, in whom limited research has been performed to date. 

See: https://ajp.psychiatryonline.org/doi/10.1176/appi.ajp.2019.18091033