New Global Estimate of Adult ADHD Prevalence: A Comprehensive Review

Adult ADHD has long been a subject of debate in the field of mental health, with previous estimates of its prevalence varying widely. To achieve a more precise understanding, an international team of researchers conducted a new umbrella review and meta-analysis, offering an updated estimate of adult ADHD rates worldwide.

A Comprehensive Approach: Reviewing 57 Studies

This large-scale analysis combined five systematic reviews and meta-analyses, incorporating data from 57 unique primary studies. Altogether, the research synthesized findings from a pooled total of over 21 million participants. This comprehensive approach provided a more accurate estimate of the global prevalence of ADHD in adults.

Key Findings: 3.1% Global Prevalence

The study concluded that the worldwide prevalence of adult ADHD is 3.1%, with a 95% confidence interval ranging from 2.6% to 3.6%. This estimate falls within the range of earlier reports but provides a more targeted understanding of the rate at which ADHD affects adults globally.

Putting the Numbers in Context

The researchers described this prevalence rate as “relatively high.” They noted that it is only slightly lower than the estimated prevalence of major mental health conditions like schizophrenia (4%) and major depressive disorder (5%)—disorders that have historically received significant attention and resources worldwide.

Moreover, the prevalence of adult ADHD is higher than that of several other well-known mental health conditions, including bipolar disorder (1%), as well as anxiety disorders such as PTSD (Post-Traumatic Stress Disorder), OCD (Obsessive-Compulsive Disorder), GAD (Generalized Anxiety Disorder), and panic disorders.

Implications for Awareness and Treatment

This updated estimate emphasizes that ADHD is a significant global mental health concern in adults, comparable to or exceeding the prevalence of other disorders that are often more widely recognized. These findings underscore the need for greater awareness, research, and treatment options for adult ADHD, which is still frequently misunderstood or overlooked in the broader discourse of mental health.

Conclusion

By providing a clearer picture of how prevalent ADHD is in adult populations around the world, this study contributes valuable data that could shape future research, policy, and clinical approaches.

November 8, 2024

Population Study: Stimulants Shown to Reduce Hospitalization and Suicidality

Swedish Population Study Suggests Stimulants Reduce Hospitalization and Suicidality, Have No Significant Effect on Work Disability

A meta-analysis of short-term, placebo-controlled, randomized clinical trials (Cortese et al. 2018), looking at both efficacy and safety, supported prescribing stimulants – methylphenidate use in children and adolescents and amphetamine use in adults – as first-choice medications. 

However, these were short-term studies, and they focused on relieving ADHD symptoms. What about longer-term outcomes, especially looking more broadly at functional impairment and overall quality of life? 

Sweden has a single-payer health insurance system that encompasses virtually every resident and is linked to national registers that enable researchers to conduct nationwide population studies. 

A joint Finnish-Swedish research team used Sweden’s registers to study outcomes for all individuals of working age, 16 to 65 years old, living in Sweden who had received a diagnosis of ADHD from 2006 through 2021. The resulting study cohort encompassed 221,714 persons with ADHD. 

The team adjusted for the following confounding variables: Genetics, baseline severity of symptoms, baseline comorbidities, temporal order of treatments (which medication was used as first, second, third, and so forth, including also nonuse of ADHD medications), time since cohort entry, and time-varying use of psychotropic drugs, including antidepressants, anxiolytics, hypnotics, mood stabilizers (carbamazepine, valproic acid, and lamotrigine), lithium, antipsychotics, and drugs for addictive disorders. 

With these adjustments, they discovered that amphetamine treatment was associated with a roughly 25% reduction in psychiatric hospitalization relative to unmedicated ADHD. Lisdexamphetamine was associated with a roughly 20% reduction, dexamphetamine with a 12% reduction, and methylphenidate with a 7% reduction. All four medications are stimulants

None of the non-stimulant medications – atomoxetine, guanfacine, clonidine – had any significant effect on psychiatric hospitalization. Nor did modafinil a drug that is not FDA approved for ADHD but is sometimes used when other drugs fail. 

Amphetamine was also associated with the greatest reduction in suicide attempts or deaths, with a roughly 40% decline relative to unmedicated ADHD. Dexamphetamine was associated with a roughly 30% decline and lisdexamphetamine with a roughly 25% decline. The stimulant methylphenidate was only associated with an 8% reduction, and modafinil had no significant effect. 

Surprisingly, non-stimulant medications were associated with significant increases in suicide attempts or deaths: 20% for atomoxetine, 65% for guanfacine, and almost double for clonidine

Amphetamine and lisdexamphetamine also reduced the risk of nonpsychiatric hospitalization by more than a third compared to unmedicated ADHD. Dexamphetamine was associated with a risk reduction of more than 25%, methylphenidate with 20% lesser risk.  

The non-stimulant atomoxetine was associated with a roughly 15% reduction in risk of nonpsychiatric hospitalization. But neither guanfacine nor clonidine had any significant effect. 

Turning to work disability, atomoxetine was the only ADHD medication associated with a reduction – a roughly 10% improvement. All other medications had no significant effect

The team concluded, “In this cohort study of adolescents and adults with ADHD, the use of medications for ADHD, especially lisdexamphetamine and other stimulants, was associated with decreased risk of psychiatric hospitalizations, suicidal behavior, and nonpsychiatric hospitalizations during periods when they were used compared with periods when ADHD medication was not used. Non-stimulant atomoxetine use was associated with decreased risk of work disability.” 

September 13, 2024

Two new meta-analyses evaluate digital interventions for treating ADHD

Two New Meta-analyses Evaluate Digital Interventions for Treating ADHD

There is increasing interest in digital interventions to treat ADHD symptoms and to overcome deficits in executive functioning that are associated with this disorder. Executive functions such as working memory and cognitive speed originate in the frontal lobes of the brain, and guide voluntary goal-directed behavior.

There is increasing interest in digital interventions to treat ADHD symptoms and to overcome deficits in executive functioning that are associated with this disorder. Executive functions such as working memory and cognitive speed originate in the frontal lobes of the brain, and guide voluntary goal-directed behavior. They affect reading speed and accuracy, reading comprehension, attention, and impulse control, among other behaviors important to the ability to function in social, educational, and professional environments.

A Swedish study team based at Umeå University recently conducted a systematic search of the medical literature to explore the efficacy of computerized cognitive training (CCT) to improve executive functioning in adults with ADHD.

They included published randomized controlled trials (RCTs) involving adults 18 to 65 years old with a primary diagnosis of ADHD. The controls were participants with either a passive (wait-list) or active (modified simple training) intervention.

Nine RCTs with a combined total of 285 participants met inclusion criteria. Lumping together all cognitive outcome types, meta-analysis reported a small effect size improvement that was just barely statistically significant (p = .048, with p < .05 as the boundary).

However, when separated out by individual outcome types – executive functioning, cognitive speed, general short-term memory, or ADHD symptom severity – the meta-analyses found no improvements that reached statistical significance. 

Moreover, all RCTs except one were judged as high risk of bias.

While it is possible that additional studies enlarging the pool of participants could lead to statistical significance, all effect sizes were small to begin with, which is not encouraging.

The team concluded, “Considering the small positive effect in this meta-analysis for overall cognitive outcomes, together with the lack of evidence for far transfer, practitioners and individuals with ADHD should weigh the costs (resources and time) against the benefits of training.”

A South Korean study team recently concluded the first RCT-only meta-analysis of game-based digital therapeutics (DTx).

Combining 14 RCTs with a total of 1,183 participants, they found a small effect size improvement in parent-rated attention symptoms for game-based DTx interventions over controls. Nine RCTs combining 424 participants likewise found a small effect size improvement in teacher-rated attention symptoms. Between-study variation (heterogeneity) was negligible, and there was no indication of publication bias.

Combining five RCTs with a total of 256 participants, they reported small effect size improvements in both parent and teacher-rated hyperactivity/impulsivity symptoms. But they found no improvement in hyperactivity symptoms alone, whether evaluated by parents or teachers. Heterogeneity was in all instances negligible, with no sign of publication bias. 

The team then compared game-based DTx interventions with pharmaceutical treatment. 

ADHD medications outperformed game-based DTx interventions for improvement of attention symptoms in both parent (four RCTs with a total of 128 participants) and teacher (three RCTs with 92 participants) ratings, with small-to-medium effect sizes. Medications likewise prevailed in improving hyperactivity/impulsivity symptoms, whether rated by parents or teachers, with small-to-medium effect sizes.

The team concluded, “This study is the first direct and indirect meta-analysis to compare the efficacy of game-based DTx between control and medication according to the assessor in an RCT. In conclusion, game-based DTx had a more significant effect than the control. Additionally, between medication treatment versus DTx, medication was more effective.”

March 15, 2024

Siblings of Those With ADHD at Higher Risk for ADHD & Other Disorders

Israel-wide population study:siblings of individuals with ADHD have highly elevated risk of ADHD, slightly elevated risk of anxiety and personality disorders, no greater risk for other disorders or low IQ

Israel has a military draft that applies to males and females alike, except orthodox women and orthodox male seminary(yeshiva) students, who are exempt. Upon turning 17 every Israeli undergoes a medical review, including both a physical and psychiatric assessment, in preparation for the draft. The Draft Board Registry maintains comprehensive health information on all unselected Israelis until they turn 21. The registry also tracks all family members of draft registrants, including full siblings.

An Israeli study team used registry records from 1998 through2014 to obtain data for a total of over a million individuals (1,085,388). Because of the exemption for orthodox women, 59% were male.

The team identified 903,690 full siblings in the study population (58% males), including 166,359 male-male sibling pairs, 104,494 female-female sibling pairs, and 197,571 opposite-sex sibling pairs.

Next, the team identified all cases in the study population with a diagnosis of a psychiatric disorder, low IQ (≥2 standard deviations below the population mean), Type-1 diabetes, hernia, or hematological malignancies. It matched each case with ten age- and sex-matched controls selected at random from the study population. Then, for each case and case-matched controls, it identified all siblings.

There were 3,272 cases receiving treatment for ADHD, 2,128 with autistic spectrum disorder, 9,572 with severe/profound intellectual disability, 7,902 with psychotic disorders, 9,704 with mood disorders, 10,606with anxiety disorders, 24,815 with personality disorders, 791 with substance abuse disorders, 31,186 with low IQ, 2,770 with Type-1 diabetes, 30,199 with a hernia, and 931 with hematological malignancies.

Draftees with ADHD were five and a half times more likely to have a sibling with ADHD than controls.

There were no significant associations between ADHD and any of the somatic disorders - Type-1 diabetes, hernia, or hematological malignancies - nor between ADHD and low IQ.

There were also no significant associations between ADHD and autism spectrum disorder, severe/profound intellectual disability, mood disorders, and substance use disorders.

On the other hand, draftees with ADHD were more than 40% more likely to have siblings with anxiety or personality disorders than controls.

Surprisingly, draftees with ADHD were less than half as likely to have siblings with psychotic disorders than controls.

There were some limitations. The psychiatric classification system used by the Israeli military did not permit assessing the risk of bipolar disorder and depression separately. That meant having to use a broader category of mood disorders, including both disorders. In addition, the military diagnostic system does not allow diagnosis of comorbid psychiatric disorders in the same individual, instead of assigning only the most severe diagnosis.

March 27, 2022

What We Know About ADHD in Female Populations

A new consensus statement updates what is known about ADHD in girls and women, and offers professional advice

Boys are three times as likely as girls to be diagnosed with ADHD, and anywhere from three to sixteen times more likely to be referred for treatment.

An international team of experts recently published a consensus statement addressing this discrepancy and offering guidance to rectify the imbalance and improve diagnosis and care for girls and women with ADHD. Here are some key conclusions.

ADHD symptoms:

-Experts caution that ADHD behaviors typically express themselves differently in boys than in girls.
-That in turn leads to gender-based biases in teachers and parents. In two studies in which teachers were shown vignettes of individuals with typical ADHD behaviors, switching from female to male names and pronouns led to higher rates of referral for support and treatment.

Comorbidity:

-A major reason for this different expression of ADHD in boys is that they have much higher rates of comorbid externalizing disorders, such as the conduct disorder and oppositional defiant disorder, leading them to break rules and get into fights in school. This no doubt contributes to lower rates of referral for girls.
-On the other hand, females are more likely to have comorbid internalizing disorders, such as emotional problems, anxiety, and depression. These may be interpreted as primary conditions, and the link to ADHD is missed altogether.
-Because ADHD has come to be associated with many externalizing disorders, it is then easy to fail to identify it when it is associated with internalizing disorders such as eating disorders.
-Untreated ADHD in girls can increase the risk of substance use disorders.

Associated vulnerabilities:

Children with ADHD are more likely to be unpopular with their peers and to experience rejection. Whereas boys are more likely to experience that rejection in physical ways, girls are more likely to experience it in social ways and through cyberbullying. That, in turn, contributes to lower self-esteem, which could explain some comorbid internalizing disorders.

Symptoms of hyperactivity/impulsivity, one of the two key components of ADHD, are associated with higher rates of risk-taking behavior:

- Like males with ADHD, females with ADHD have higher injury rates.
-Both males and females with ADHD are more likely to underachieve in school or drop out altogether.
-Overall, adolescents with ADHD become sexually active earlier, have more sexual partners, and are more frequently treated for sexually transmitted diseases than their normally developing peers. That also leads to higher rates of teenage and unplanned pregnancies.
-As with males with ADHD, females with ADHD have higher rates of criminal behavior than normally developing peers. While females with ADHD are still half as likely to be convicted of a crime than males with ADHD, one study showed they nevertheless are eighteen times more likely to be convicted of a crime than normally developing females.

Compensatory or coping behaviors:

- Girls may turn to drink alcohol, smoking cannabis, smoking cigarettes, or vaping nicotine to cope with emotional anguish, social isolation, and rejection.
-Some girls may seek to build social support through high-risk activities such as joining a gang, becoming promiscuous, and engaging in criminal behavior.

Triggers for possible referral

Ages 5-11:

-Bedwetting, nail-biting

Ages 5-16:

-Early sexualized behavior

Ages 5-18:

-Suspensions, expulsions, frequent detentions
-Poor attendance/truancy
-Consistent lateness, poor organization
-Academic difficulties, low academic self-esteem
-Conduct problems, conflicts with parents and peers
-Bullying (usually as victims)
-Regular tobacco and alcohol use
- Obesity and other eating disorders
- Repeated injuries
- Sleep difficulties
- Executive function difficulties
- Extreme emotional meltdowns

Ages 12 and above:

- Relationship problems, anxiety about relationships
- Social rejection, isolation
- Substance abuse, including alcohol
- Risky sexual behavior
- Underage or unwanted pregnancy
- Delinquency or criminal behavior (including shoplifting, vandalism)
- Low self-esteem
- Self-harm, suicidality

Ages 16 and above:

- Dropping out of school
- Losing jobs
- Parenting problems
- Criminality
- Financial difficulties
- Traffic crashes
- Internalizing conditions: depression, anxiety

Ages 18 and above:

- Gambling problems, compulsive shopping
- Personality disorder
- Chronic fatigue syndrome
- Fibromyalgia

The key message is not to disregard females because they do not present with the externalizing behavioral problems, or the disruptive, hard-to-manage boisterous, or loud behaviors typically associated with males with ADHD.

Diagnosis

The authors emphasize that "comprehensive assessment should be completed to accurately capture the symptoms of ADHD across multiple settings, their persistence over time, and associated functional impairments. High rates of comorbidity are typically present. The assessment process is typically tripartite, involving the use of rating scales, a clinical interview, and ideally objective information from informants or school reports."

Rating scales: Ideally rely on those that provide female norms, making them more sensitive to female presentation.

Clinical interviews:

-Be mindful of age-appropriate, common-occurring conditions in females with ADHD, including autistic spectrum disorder, tics, mood disorders, anxiety, eating disorders, fibromyalgia, and chronic fatigue syndrome.
- Be alert to signs of self-harming behaviors(especially cutting), which peak in adolescence and early adulthood.
-Given that heritability of ADHD is high, ranging between 70-80% in both children and adults, be mindful that informants who are family members may also have ADHD (possibly undiagnosed) which may affect their judgment of "typical" behavior. The assessor should obtain specific examples of behavior from the informant and use these to make clinically informed judgments, rather than relying upon the informants' perception of what is typical or atypical.

Treatment

Pharmacological:

- Recommendations for medication do not differ by sex, except that pharmacological treatment is generally not advised during pregnancy or breastfeeding.
- A systematic review and network meta-analysis recommended methylphenidate for children and adolescents and amphetamines for adults, taking into account both efficacy and safety. Larger confidence intervals about the tolerability and efficacy of bupropion, clonidine, and guanine were reported, indicating less conclusive results about the efficacy and tolerability of these oral medications. The use of medication should be followed up over time to verify if medications are effective and well-tolerated, and to manage the effects of related conditions(e.g. anxiety, depression) if they emerge.

Non-pharmacological:

- Cognitive behavioral therapy (CBT) together with psychoeducation (which can be provided to both patients and parent/guardians together or independently) are the best forms of psychological treatment.
- Parents and other guardians of teenage girls need to be shown how to identify deliberate self-harming or risky behavior.
- Adolescent girls may require assistance in addressing risky behavior (sexual risk, substance misuse) and improving self-management. Girls with ADHD are more vulnerable to sexual exploitation and have higher rates of early and unwanted pregnancy.
- Adults are more likely to require interventions to address employment problems, child-rearing, and parenting. Women with ADHD are also more vulnerable to sexual exploitation, including physical and sexual violence.
- Interventions should support attendance and engagement with education to avoid early school-leaving, diminished educational attainment, and associated vulnerabilities. While externalizing conditions have a greater impact on classroom behavior, internalizing conditions affect motivation and thus the ability to benefit from education.

Institutional outreach

- Educational, social care, occupational, and criminal justice system professionals should be trained to improve the detection and referral of ADHD in girls and women.
- Flexible learning systems and support with childcare can help women with ADHD return to education after having a baby.
- Depending on the country of residence, women who disclose their disability to their employer may be entitled to reasonable adjustments to the workplace to accommodate their condition.
- Low to no-cost apps are available to assist persons with ADHD with itineraries, lists, and reminders.
- Career planning should take into account that some occupations may provide a better fit for women with ADHD: "some individuals with ADHD show a preference for more stimulating environments, active, hands-on, or busy and fast-paced jobs."
- Persons with ADHD, both male and female, make up roughly a quarter of the prison population: "Evidence indicates that ADHD treatment is associated with reduced rates of criminality, is tolerated and effective in prison inmates, and improves their quality of life and cognitive function. This has led to speculation that effective identification and treatment of ADHD may help to reduce re-offending."

The authors concluded, "To facilitate identification, it is important to move away from the previously predominating disruptive boy stereotype of ADHD and understand the more subtle and internalized presentation that predominates in girls and women."

March 1, 2022

Assessing Co-occuring Disorders in Relatives of Those With ADHD

Taiwan Population Study Assesses Comorbidity of Psychiatric Disorders among First-degree Relatives of Those with ADHD

ADHD patients were found to be seven times more likely than controls to have first-degree relatives with ADHD.

Taiwan's National Health Insurance program is a single-payer system that covers 99.6% of the island's 23 million residents. It includes family relationships.

This enabled a Taiwanese study team to examine the comorbidity of psychiatric disorders among close relatives in the entire population over eleven years, beginning at the start of 2001 and concluding at the end of2011.

For greater certainty of diagnosis, only persons twice diagnosed with the same psychiatric disorder were included as index individuals. There were 431,887 index patients, 152,443 of whom were ADHD index patients.

These index patients were then compared with all of their first-degree relatives (FDRs): parents, children, siblings, and twins. This produced 1,017,430 patient-FDR pairs, of which 401,301 were ADHD patient-FDR pairs.

Next, four controls were matched by age, gender, and type relative to each case, resulting in 4,069,720 control pairs.

After adjusting for age, gender, urbanization, and income level, ADHD patients were seven times more likely than controls to have first-degree relatives with ADHD. They were also seven times more likely to have FDRs with major depressive disorder, four times more likely to have FDRs with autism spectrum disorder, twice as likely to have FDRs with bipolar disorder, and 80%more likely to have FDRs with schizophrenia.

February 3, 2023

ADHD medication and risk of suicide

ADHD medication and risk of suicide

A Chinese research team performed two types of meta-analyses to compare the risk of suicide for ADHD patients taking ADHD medication as opposed to those not taking medication.

The first type of meta-analysis combined six large population studies with a total of over 4.7 million participants. These were located on three continents - Europe, Asia, and North America - and more specifically Sweden, England, Taiwan, and the United States.

The risk of suicide among those taking medication was found to be about a quarter less than for unmediated individuals, though the results were barely significant at the 95 percent confidence level (p = 0.49, just a sliver below the p = 0.5 cutoff point). There were no significant differences between males and females, except that looking only at males or females reduced sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications produced divergent outcomes. A meta-analysis of four population studies covering almost 900,000 individuals found stimulant medications to be associated with a 28 percent reduced risk of suicide. On the other hand, a meta-analysis of three studies with over 62,000 individuals found no significant difference in suicide risk for non-stimulant medications. The benefit, therefore, seems limited to stimulant medication.

The second type of meta-analysis combined three within-individual studies with over 3.9 million persons in the United States, China, and Sweden. The risk of suicide among those taking medication was found to be almost a third less than for unmediated individuals, though the results were again barely significant at the 95 percent confidence level (p =0.49, just a sliver below the p = 0.5 cutoff point). Once again, there were no significant differences between males and females, except that looking only at males or females reduced the sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications once again produced divergent outcomes. Meta-analysis of the same three studies found a 25 percent reduced risk of suicide among those taking stimulant medications. But as in the population studies, a meta-analysis of two studies with over 3.9 million persons found no reduction in risk among those taking non-stimulant medications.

A further meta-analysis of two studies with 3.9 million persons found no reduction in suicide risk among persons taking ADHD medications for 90 days or less, "revealing the importance of duration and adherence to medication in all individuals prescribed stimulants for ADHD."

The authors concluded, "exposure to non-stimulants is not associated with a higher risk of suicide attempts. However, a lower risk of suicide attempts was observed for stimulant drugs. However, the results must be interpreted with caution due to the evidence of heterogeneity ..."

December 13, 2021

Meta-analyses Suggest Physical Exercise is Effective Tool in Treating ADHD

Two meta-analyses suggest physical exercise is an effective tool in treating ADHD

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."

December 5, 2021

Associations Between ADHD and Suicidality in Canadian Cohort Study

Ambiguous associations between ADHD and suicidality in a Canadian cohort study

The National Longitudinal Survey of Children and Youth is a prospective cohort of Canadian children followed from childhood to early adulthood. It is considered nationally representative, except for children living on First Nations (indigenous) reserves, in institutions, and in remote regions. Keep in mind that suicide rates among indigenous youth are way higher than in the general population.

The initial cohort included 8,698 participants aged 7- 11 years, of which 6,465 had to be excluded for lack of answers to questions on suicide attempts, leaving 2,233 participants. Again, by comparison with the excluded group, these participants were less likely to be from higher-risk backgrounds, including having a mother who did not complete high school or coming from low-income families.

The share of adolescents who attempted suicide in the previous year increased from 3.6% at ages 12-13 years to 5.6% at ages 14-15 years, then gradually declined to 1% of young adults at ages 22-23 years.

The overwhelming majority (96%)reported never attempting suicide. One in fifty (2%) reported suicide attempts limited to adolescence, and another one in fifty reported suicide attempts persisting into adulthood.

The study team performed a multivariable regression model examining the contributions of sex and ten risk factors, including various psychiatric disorders, for suicidality. One of those risk factors was ADHD, split into two subcategories: symptoms at 10-11 years, and symptoms at 12-13 years. Those in the former group were twice as likely -for each standard deviation increase in symptoms - as those without such symptoms to report suicide attempts persisting into adulthood versus never attempted. But they were no more likely to report adolescence-limited attempts versus never-attempted, or attempts persisting into adulthood versus adolescence-limited. Furthermore, there were no significant associations between ADHD symptoms at 12-13 years and any of the three foregoing categories.

The authors acknowledged, "despite the large sample size, the number of individuals who attempted suicide was low, limiting the statistical power ..."

September 29, 2023

ADHD symptoms and suicidal ideation in college

ADHD symptoms and suicidal ideation in college

The mechanisms underlying the association between ADHD symptoms and suicidal ideation are poorly understood. A team of researchers from France and Montreal set out to explore this relationship with 2,331 French college students.

The students were participants in the internet-based student Health Research Enterprise project, a prospective population-based cohort study of students in higher education institutions in France. The i-Share study includes a longitudinal collection of data on childhood and family history, lifestyle, health information, and psychosocial examinations during the college years and beyond. 15,528 participants were included in the initial cohort, of which 2,331 completed all the questionnaires and did not have any missing data at the one-year follow-up. The mean age was 21, and four out of five were women. ADHD symptoms were assessed at the initiation of the study. Suicidal ideation was evaluated through a questionnaire completed a year later. Before that, three months after initiation, participants filled out a mental health survey that inquired about two potential mediators of suicidal ideation: depressive symptoms and self-esteem.

After adjusting for potential confounding factors (e.g., sex, childhood adversity, living conditions, and substance use) and taking into account the role of the mediators, the effect of ADHD symptoms on suicidal ideation (i.e., the direct effect) was no longer statistically significant, whereas pathways through depressive symptoms and self-esteem were both statistically significant. The pathway through depressive symptoms accounted for 25% of the total effect, while the pathway through self-esteem accounted for 64% of the total effect. Most of this indirect effect of self-esteem was in turn explained by the unique effect of self-esteem (not explained by depression), which accounted for 45% of the association, whereas a smaller part was explained by the effect of self-esteem through depression (accounting for 19% of the total effect). Ultimately, both mediators had the same effect (45% vs. 44%). Patterns were similar for males and females.

The authors caution that the study sample was not representative of the population of college students. It relied on volunteers, females were overrepresented, and the dropout ratio was very high. Participants in the final sample were more satisfied with their financial resources during their college years and during childhood, and less frequently consumed tobacco, than those in the initial cohort. The researchers recommend that ADHD patients be screened for self-esteem, and point out that other studies have indicated that exercise, Internet support groups, and interpersonal group therapy can build self-esteem in young people.

October 19, 2021

Meta-analysis Finds Association Between ADHD and Suicidal Behaviors

Meta-analysis finds association between ADHD and suicidal behaviors

A newly published meta-analysis of 57 studies encompassing almost a third of a million participants has uncovered a very strong association between ADHD and suicide, a strong association with suicidal ideation, and a small-to-medium association with suicide attempts.

The population examined included children, adolescents, and adults. Only persons formally diagnosed were considered to have ADHD. Studies that included self-injuries without suicidal intent were excluded. Most of the studies focused on European and American populations, with one in six from other locations, mostly Asian.

The most striking result was for actual suicides. The odds ratio (OR) for four datasets encompassing roughly one hundred forty thousand participants was 6.69 (95% CI 3.24 to 17.39, p <.0001). As a frame of reference, an OR of 1.5 is a small effect size, 2.5 is a medium one, and 4.3 is a large one. That means the effect size, in this case, is very large.

For suicidal ideation, 23 datasets with a combined total of just over 73,000 participants produced a medium-to-large OR of 3.5 (95% CI 2.94 to 4.25, p < .0001). In three datasets with more than nine thousand participants that adjusted for confounders, the adjusted OR was 4.5 (95% CI 1.72 to 11.63, p < .0001), indicating a large effect size.

For suicide attempts, 44 datasets encompassing over 228,000 participants produced an OR of 2.4 (95% CI1.64 to 3.43, p < .0001). In six datasets with over 65,000 participants that adjusted for confounders, the adjusted OR dropped to 2.1 (95% CI 1.27 to 3.47,p = .005).

There was no evidence of publication bias for studies on suicides or suicidal ideation, but significant evidence of bias for studies on suicide attempts (Eager's p = .03). This means that studies with positive findings were more likely to be published than negative studies.

There was, however, strong statistical evidence for differences between studies in the size of their ORS.  This indicates that the pooled OR cannot summarize results from all datasets, and more work is needed to clarify why the ORS differs among studies.

The authors appropriately caution that their meta-analysis is not informative on cause-effect relationships, but offer as a hypothesis that ADHD contributes to suicidal spectrum behaviors (SSBs) through Impulsivity, a core symptom of ADHD, along with impaired decision-making and risk-taking, that characterize several individuals with ADHD Additionally, a sizeable portion of individuals with ADHD present with deficits in executive functions. As executive functions are implicated in the regulation of impulse control and emotions, executive dysfunctions may contribute to SSBs.

Given the large to very large effect sizes for suicide and suicidal ideation, the authors advise: Awareness of this association should prompt practitioners to systematically screen for SSBs in patients with ADHD at the first assessment and at each follow-up, which in turn should contribute to decreasing the risk of SSB's. This is particularly noteworthy considering that questionnaires/scales commonly used to screen/assess ADHD symptoms generally do not include suicide-related items.

August 29, 2021

Is prenatal antidepressant exposure a risk factor for ADHD?

Is prenatal antidepressant exposure a risk factor for ADHD?

A systematic review of the literature found seven studies examining this question. Significantly, six were large cohort studies with a combined total of almost three million individuals. The other was a large case-control study with 7,874 participants.
The largest cohort study, with more than a million and a half children, found that prenatal antidepressant exposure increased the risk for ADHD.  The adjusted odds ratio was 1.6forany antidepressant and for selective serotonin reuptake inhibitors (SSRI). But sibling comparison models, which better adjust for confounds shared by siblings(e.g., poverty, stress in the home), this study found no increased risk of ADHD.
The second-largest cohort study, with over 875 thousand children, found a small adjusted risk of 1.2 for all antidepressants, with little variation by class of antidepressant. The fourth-largest study, with over 140 thousand children, likewise found a small adjusted risk of 1.2, which barely achieved statistical significance (95% CI 1.0-1.4).
The third-largest study, with over 190 thousand children, obtained an adjusted risk of 1.4 for all antidepressants. But it also pointed to a possible explanation for the small association found in this and other studies, suggesting that the apparent association with antidepressant use was due to ADHD's known genetic association with psychiatric conditions treated by antidepressants.
The fifth-largest study, with more than 55 thousand children, similarly found an adjusted risk of 1.7 for SSRIs and an adjusted risk of 1.7 for an unmediated maternal psychiatric disorder. Again, the underlying psychiatric disorder appears to be confounding the effect of antidepressants.
The sixth-largest study, with over 38 thousand children, found no evidence of any effect from SSRIs. Yet it found evidence of a large effect from bupropion, with an odds ratio of 3.6, and only one in 50 odds of obtaining such a result by chance (p = 0.02). However, it offered no comparison with untreated depression and made no adjustments for potential confounders.
The case-control study found an odds ratio of 2.3 for maternal use of any antidepressant, which dropped to a statistically non-significant 1.6 when adjusted for a maternal psychiatric disorder (95% CI0.66-3.71).

July 10, 2021

ADHD and Adulthood Unhappiness

ADHD is Associated with Significantly Higher Probability of Unhappiness in Adults

An international team of researchers sets out to measure the association between ADHD symptoms and self-evaluations of happiness among adults in the general population of the U.K. A nationally representative sample of 7,274 adults was asked to rate their happiness on a three-point scale. They also used the Adult ADHD Self-Report Scale (ASRS) Screener to assess ADHD symptom levels.
Higher ADHD symptom levels were found to be inversely associated with self-assessments of happiness. Adults with the lowest ADHD symptoms (0-9 on theaters) were roughly twice as likely to report being happy as those scoring10-13, five times as happy as those scoring 14-17, and ten times as happy as those with the highest ADHD symptom scores (18-24). These results were highly significant.
That did not mean that most adults with high ADHD symptom scores were unhappy. Even among those with the highest ADHD symptom scores (18-24), a majority (58 percent) reported being either "fairly happy" or "very happy." Butonly11 a percent of that group reported being "very happy," as opposed to 44 percent of those scoring the lowest on ADHD symptoms.
While the association is clear and strong, establishing causation is trickier. As the authors acknowledge, "as the symptoms associated with ADHD are similar to, and sometimes overlap, with those that are commonly observed in individuals with other psychiatric disorders ... a screening instrument to identify ADHD symptoms may have had limited power to distinguish 'pure' ADHD and cases with ADHD symptoms related to other psychiatric disorders." Emotional instability and anxiety disorder each mediated more than a third of the association between ADHD and unhappiness, and depression almost a third. These could have been brought about by ADHD and could also have been produced by other psychiatric disorders.  Because the ASRS is not a diagnostic instrument, the authors concluded that "the results of this study should be considered provisional, until if, and when, they are replicated in those with a clinical diagnosis of ADHD with and without comorbid disorders."

July 6, 2021

The State of the Art on Identifying and Treating Persons with Comorbid ADHD and Substance Use Disorders

The State of the Art on Identifying and Treating Persons with Comorbid ADHD and Substance Use Disorders

An international group of twelve experts recently published a consensus report examining the state of the evidence and offering recommendations to guide the screening, diagnosis, and treatment of individuals with ADHD-SUD comorbidity.[1]

In a clear sign that we are still in the early stages of understanding this relationship, five of the thirteen recommendations received the lowest recommendation grade (D), eight received the next-lowest (C), and none received the highest (A and B). The lower grades reflected the absence of the highest level of evidence, obtained from meta-analyses or systematic reviews of relevant randomized controlled trials (RCTs).

Nevertheless, with these limitations in mind, the experts agreed on the following points:

Diagnosis

  •  The strongest recommendation, the only one based on a 2+ level of evidence (well-conducted case-control or cohort studies with allowing risk of confounding or bias and a moderate probability that the relationship is causal) is that the "Short Version of the Adult ADHD Self-Report Scale (ASRS-SV) screener is currently the most widely used and investigated screening tool in individuals with ADHD and comorbid SUD, with good sensitivity and specificity across studies."
  • Two other recommendations were graded C: The diagnostic process should include current and past substance abuse, and seek to involve partners and relatives in evaluating symptoms and functional impairments.
  • Four recommendations got the lowest grade, D. The experts suggested starting the diagnostic process as soon as possible and focusing on drug- and alcohol-free periods in the patient's life during history taking. They also recommended that physicians and clinical psychologists should only make diagnoses if they have extensive training in diagnosing ADHD, as well as experience with adults with ADHD and with addiction care, and that they should consider treating adults with sufficiently severe ADHD symptoms.

Treatmen

  •  In general, evidence was stronger in this area, and only one of the six recommendations was graded D. The other five recommendations were graded C, with the highest level of evidence being 2(cohort or case and control studies with undetermined risk of bias), although in three cases it was level 3 (non-analytical studies, such as case reports and case series).
  • The grade D recommendation was to always consider a combination of psychotherapy and pharmacotherapy.

The grade C recommendations included considering adequate medical treatment of both ADHD and SUD; integrating ADHD treatment with SUD treatment as soon as possible;

June 2, 2021

Everything You Need to Know About ADHD

Everything You Need to Know About ADHD

You've heard all sorts of misinformation about Attention-Deficit/Hyperactivity Disorder(ADHD), whether from friends, the internet, or uninformed press articles:

"ADHD is not real."

"Pharmaceutical companies invented ADHD to make money."

"I'm just a little ADD."

"Natural solutions are the best for ADHD treatment."

ADHD symptoms were first described in the late 1700s, primarily among hyperactive boys. It was described variously over 200 years as "fidgeting," "defects of moral control," "hyperkinetic reaction," "minimal brain damage" and eventually ADD (Attention Deficit Disorder) in the 1980s and ADHD today.

Because the natural tendency toward hyperactivity decreased with age, ADHD was originally thought to be a developmental disorder that disappeared in mid-to-late adolescence. When medicines were developed and used in ADHD treatment for young boys, physicians stopped prescribing them around mid-adolescence, because it was presumed the condition had been remediated. They were wrong. We know now that ADHD persists into adulthood for about two-thirds of ADHD youth.

ADHD was not widely recognized in girls until the mid-1990s when it became clear that girls with ADHD were less disruptive than boys with ADHD and were not being appropriately diagnosed. Girls with ADHD show less of the physical hyperactivity of boys, but suffer from "dreaminess," "lack of focus" and "lack of follow-through."

It was also in the 1990s that ADHD' pervasive comorbidity with depression, anxiety, mood, and autism spectrum disorders was established. At the same time, researchers were beginning to describe deficits in executive functioning and emotional dysregulation that became targets of substantial research in the 21st century.

Even with the 1990s recognition that ADHD is a lifetime disorder, equally present (in different forms) in both men and women, medical schools and continuing medical education courses (required for realizing sure of health professionals) have only begun to teach the most up-to-date evidence-based knowledge to the medical community. There still is much misinformation and a lack of knowledge among primary care professionals and the public.

ADHD Throughout the Lifespan
Most cases of ADHD start in Otero before the child is born. As a fetus, the future ADHD person carries versions of genes that increase the risk for the disorder. At the same time, they are exposed to toxic environments. These genetic and environmental risks change the developing brain, setting the foundation for the future emergence of ADHD.

In preschool, early signs of ADHD are seen in emotional lability, hyperactivity, disinhibited behavior and speech, and language and coordination problems. The full-blown ADHD syndrome typically occurs in early childhood, but can be delayed until adolescence. In some cases, the future ADHD person is temporarily protected from the emergence of ADHD due to factors such as high intelligence or especially supportive family and/or school environments. But, as the challenges of life increase, this social, emotional, and intellectual scaffolding is no longer sufficient to control the emergence of disabling ADHD symptoms.

Throughout childhood and adolescence, the emergence and persistence of the disorder are regulated by additional environmental risk factors such as family chaos, as well as the age-dependent expression of risk genes that exert different effects at different stages of development. During adolescence, most cases of ADHD persist and by the teenage years, many youths with ADHD have onset with a mood, anxiety, or substance use disorder. Indeed, parents and clinicians need to monitor ADHD youth for early signs of these disorders. Prompt treatment can prevent years of distress and disability.

By adulthood, the number of comorbid conditions increases, including obesity, which likely impacts future medical outcomes. Emerging data shows people with ADHD to be at increased risk for hypertension and diabetes. ADHD adults tend to be very inattentive but show fewer symptoms of hyperactivity and impulsivity. They remain at risk for substance abuse, low self-esteem, injuries due to accidents, occupational failure, and social disability, especially if they are not treated for the disorder.

Seven Important Concepts About ADHD


There are approximately 10 million U.S. adults with ADHD, 9 million of whom are undiagnosed. But with diligent research by the medical profession, we have learned seven important concepts about ADHD:
1.    ADHD has been documented worldwide in 5% of the population.
2.    Sixty-seven percent of ADHD children grow into ADHD adults and seniors. ADHD is heritable, runs in families, and is impacted by the physical environment and familial lifestyle.
3.    In youth, rates of ADHD are higher in males than females as males, but these rates even out by adulthood.
4.    ADHD coexists and is often masked by several other disorders: anxiety, depression, spectrum bipolar and autism disorder, substance abuse, alcoholism, obesity, risky behaviors, disorganized lives, working memory deficits, and significant executive dysfunctions that affect personal, social, and work success.
5.    ADHD medications(stimulants and non-stimulants) are the most effective treatments for ADHD symptoms. Psychological support/training designed for ADHD, and lifestyle modifications, are important adjuncts to medicine.
6.    ADHD costs the U.S. economy more than $100 million annually in lost productivity, accidents, hospitalizations with comorbidities, and family and professional support for ADHD patients.
7.    ADHD is diagnosable and safely treatable in trained primary care practices.

How do you know if you or someone you love has ADHD? Evaluate your life against the seven concepts above. Then get screened and diagnosed by a health care professional. The diagnosis of ADHD should be done only by a licensed clinician who has been trained in ADHD. That clinician should have one goal in mind: to plan a safe and effective course of evidence-based treatment.

When diagnosing adults, it is also useful to collect information from a significant other, which can be a parent for young adults or a spouse for older adults. But when such individuals are not available, diagnosing ADHD based on the patient's self-report is valid. Just remember that personal, work, and family lives are improved with treatment. Research and technology related to ADHD improve all the time.

ADHD in Adults is a great resource for anyone interested in learning more about ADHD, with evidence-based information and education for both healthcare professionals and the public. The website also features a new ADHD screener for predicting the presence of ADHD in adults.

Stephen V. Faraone, Ph.D., is a Distinguished Professor of Psychiatry and Neuroscience & Physiology at SUNY Update Medical University and a global expert on Adult ADHD.

March 12, 2021