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ADHD has long been associated with higher rates of criminal behavior, but most studies have relied heavily on self-reported data and small, non-representative samples. A new Swedish study addresses these limitations, providing a more comprehensive and reliable picture using data from nationwide registers. It sheds light on the role of ADHD medication in reducing the risk of criminal convictions, offering insights for clinicians, policymakers, and families.
Earlier research, such as a 2019 Danish study, found that ADHD diagnosed in children and adolescents ages 4 to 15 was associated with a 1.6-fold increased risk of future criminal conviction. However, these findings were limited by a smaller sample size and a focus on just one nation’s context. Like Denmark, Sweden’s single-payer universal healthcare system allows for the collection of extensive data on health and crime records, providing an ideal environment for large-scale, population-based research.
To investigate ADHD’s connection to criminal behavior, the Swedish research team analyzed records from a cohort of 1,646,645 individuals born between 1986 and 1997. They excluded those who died or emigrated before age 15 (the age of criminal responsibility in Sweden) and those who immigrated to Sweden, resulting in a final study group of 1,235,939 individuals. Slightly more than half of the cohort was male.
ADHD diagnoses were based on clinical records and prescriptions for approved ADHD medications, while criminal convictions—both violent and nonviolent—were identified using Sweden’s National Crime Register, covering the years 2001 to 2013. The study adjusted for various potential confounding factors, including sex, birth year, parental education, and other psychiatric conditions. They also used the Swedish Multi-Generation Register to control for unmeasured familial factors to compare outcomes among full siblings.
The study found that ADHD is strongly associated with increased rates of criminal convictions. Compared to individuals without ADHD, those with an ADHD diagnosis were roughly:
Interestingly, when comparing conviction rates among males and females with ADHD, the rates of nonviolent convictions were similar, but females with ADHD were about 25% more likely to be convicted of a violent crime than males with ADHD.
The research also highlighted the importance of ADHD medication in reducing criminal behavior. When individuals with ADHD who were taking medication were excluded from the analysis, the data showed significantly higher rates of criminal convictions:
These findings suggest that ADHD medications can significantly reduce the risk of both violent and nonviolent criminal behavior in individuals with ADHD, emphasizing the value of pharmacological treatment for those with the condition.
The researchers concluded that “ADHD is a strong risk factor for both violent and non‐violent criminal convictions in males and females even after adjustments for psychiatric comorbidities and unmeasured familial factors.” The study also found that untreated ADHD poses a particularly high risk for criminal behavior, highlighting the protective role of medication.
These findings are clinically relevant for several reasons. First, they reinforce the importance of ensuring that individuals with ADHD have access to effective treatment options, especially during the transition from adolescence into adulthood, which is statistically a period of higher risk for criminal behavior. Additionally, the study provides critical data for shaping public policy and interventions aimed at supporting individuals with ADHD, with a focus on reducing criminality through proper management of the disorder.
This study offers new insights into the complex relationship between ADHD, medication, and criminal behavior, emphasizing the crucial role of treatment in mitigating risks. It provides a compelling case for prioritizing access to ADHD medication as part of a broader strategy for supporting those with ADHD.
Anna-Karin Ångström, Anneli Andersson, Miguel Garcia-Argibay, Zheng Chang, Paul Lichtenstein, Brian M. D’Onofrio, Catherine Tuvblad, Laura Ghirardi, and Henrik Larsson, “Criminal convictions in males and females diagnosed with attention deficit hyperactivity disorder: A Swedish national registry study,” JCPP Advances (2024), e12217, https://doi.org/10.1002/jcv2.12217.
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 ..."
A team of German researchers explored five million member records from a database that tracks more than sixty nationwide statutory health insurance programs. The database closely tracks the characteristics of the overall German population.
This was a longitudinal cohort study, tracking individuals first diagnosed with adult ADHD between 2013 and 2017. Anyone who was not continuously insured during this period was excluded, as were those who died, plus anyone older than 55 to prevent bias from high morbidity in the top age brackets.
The study team used the database to add up direct healthcare costs, including inpatient care, outpatient care, psychotherapy, medical aids and remedies, medication, and sickness benefits. In Germany, sickness benefits kick in after more than six weeks of continuous inability to work.
The study tracked data within a window extending both four years back and four years forward from the initial adult ADHD diagnosis.
The resulting study cohort consisted of 2,380 persons between 18 and 55, initially diagnosed with ADHD at an average age of 35. Sixty percent were male.
One-third were prescribed ADHD medication upon diagnosis. Four years later, only one-eighth were still on medication.
Almost two-thirds received psychotherapy, dropping to under a third in succeeding years.
During the year following diagnosis, average healthcare costs totaled about €4,000 per individual. For those who initiated ADHD medication, the average cost was just over €5,400, and for those who did not it was almost €3,500.
The authors concluded, "An important finding of the present investigation is that in the year of initial diagnosis, less than one-third of individuals received any prescription of ADHD-specific medication, and only a fourth got at least two prescriptions. At the same time, almost two-thirds of individuals received psychotherapy in the year of ADHD[adult ADHD] diagnosis. In about one-third of individuals, psychotherapy had been initiated already before a diagnosis of ADHD, presumably for treatment of comorbid disorders. ... In current German guidelines, ADHD-specific medication is recommended as the first choice ... Apparently, despite the vast body of evidence for the beneficial effects of ADHD-specific medication, at least in the short-term, and in contrast to the recommendations of previous and current guidelines, stimulant medication is only reluctantly prescribed in newly identified adults with ADHD. ... Overall, our findings suggest that significant deficiencies may currently exist concerning the reality of healthcare for ADHD in Germany, and that guideline recommendations are not yet comprehensively implemented in everyday routine care."
Older adults are at greater risk for cardiovascular disease. Psychostimulants may contribute to that risk through side effects, such as elevation of systolic blood pressure, diastolic blood pressure, and heart rate.
On the other hand, smoking, substance abuse, obesity, and chronic sleep loss - all of which are associated with ADHD - are known to increase cardiovascular risk, and stimulant medications are an effective treatment for ADHD.
So how does this all shake out? A Dutch team of researchers sets out to explore this. Using electronic health records, they compared all 139 patients 55 years and older at PsyQ outpatient clinic, Program Adult ADHD, in The Hague. Because a principal aim of the study was to evaluate the effect of medication on cardiovascular functioning after first medication use, the 26 patients who had previously been prescribed ADHD medication were excluded from the study, leaving a sample size of 113.
The ages of participants ranged from 55 from 79, with a mean of 61. Slightly over half were women. At the outset, 13 percent had elevated systolic and/or diastolic blood pressure, 2 percent had an irregular heart rate, 15 percent had an abnormal electrocardiogram, and 29 percent had some combination of these (a "cardiovascular risk profile"), and 21 percent used antihypertensive medication.
Three out of four participants had at least e comorbid disorder. The most common are sleep disorders, affecting a quarter of participants, and unipolar mood disorders (depressive or more rarely manic episodes, but not both), also affecting a quarter of participants.
Twenty-four patients did not initiate pharmacological treatment. Of the 89 who received ADHD medication, 58 (65%) reported positive effects, and five experienced no effect. Thirty-eight (43%) discontinued ADHD medication while at the clinic due to lack of effect or to side effects. The most commonly reported positive effects were enhanced concentration, more overview, less restlessness, more stable mood, and having more energy. The principal reasons for discontinuing medication were anxiety/depression, cardiovascular complaints, and lack of effect.
Methylphenidate raised heart rate and lowered weight, but had no significant effect on systolic and diastolic blood pressure. Moreover, there was no significant correlation between methylphenidate dosage and any of these variables, nor between methylphenidate users taking hypertensive medication and those not taking such medication. There was no significant difference in systolic or diastolic blood pressure and heart rate before and after the use of methylphenidate among patients with the cardiovascular risk profiles.
Systolic blood pressure rose in ten out of 64 patients, with two experiencing an increase of at least 20 mmHg. It descended in five patients, with three having a decrease of at least 20 mmHg. Diastolic blood pressure rose by at least 10 mmHg in four patients, while dropping at least 10 mmHg in five others.
The authors concluded "that the use of a low dose of ADHD-medication is well tolerated and does not cause clinically significant cardiovascular changes among older adults with ADHD, even among those with an increased cardiovascular risk profile. Furthermore, our older patients experienced significant and clinically relevant improvement of their ADHD symptoms using stimulants, comparable with what is found among the younger age group," and that "the use of methylphenidate may be a relatively safe and effective treatment for older adults with ADHD, under the condition that all somatic complaints and especially cardiovascular parameters are monitored before and during pharmacological treatment."
Yet they cautioned that "due to the observational nature of the study and the lack of a control group, no firm conclusions can be drawn as to the effectiveness of the stimulants used. ... Important factors that were not systematically reported were the presence of other risk factors, such as smoking, substance (ab)use, aspirin use, and level of physical activity. In addition, the response to medication was not systematically measured"
Executive function impairment is a key feature of ADHD, with its severity linked to the intensity of ADHD symptoms. Executive function involves managing complex cognitive tasks for organized behavior and includes three main areas: inhibitory control (suppressing impulsive actions), working memory (holding information briefly), and cognitive flexibility (switching between different mental tasks). Improving executive functions is a critical objective in the management of ADHD.
Recent studies show that exercise interventions can enhance executive function in individuals with ADHD. Unlike traditional medications, which are costly and may cause side effects such as headaches, nausea, or growth issues, exercise can be incorporated into daily routines of children and adolescents without negative reactions.
Some studies report that aerobic exercise does not significantly improve executive function. However, most past reviews of aerobic exercise effects on executive function have focused on people without ADHD, with few examining interventions for children or adolescents with ADHD.
The Study:
A Chinese and South Korean study team conducted a systematic search of the peer-reviewed published literature to perform meta-analyses on randomized controlled trials (RCTs) specifically focused on aerobic exercise interventions for children and adolescents with ADHD.
All studies included were randomized controlled trials involving participants aged 6 to 18 years who had been clinically diagnosed with ADHD. The interventions consisted of various forms of aerobic exercise, while the control groups engaged in either non-exercise activities or daily routines. Each study was required to report at least one outcome measure with usable data for calculating the effect size on executive functioning.
The Results:
Meta-analysis of fifteen RCTs combining 653 children and adolescents with ADHD reported a medium to large effect size improvement in inhibitory control. There was no sign of publication bias, but wide heterogeneity (variation) in outcomes among studies.
Six to eight weeks of aerobic exercise produced modest improvements, with much greater gains seen after twelve weeks. Hour-long sessions were as effective as longer ones. Moderate intensity exercise proved more beneficial than vigorous intensity.
Meta-analysis of eight RCTs combining 399 children and adolescents with ADHD produced a medium effect size improvement in working memory. There was no sign of publication bias, and heterogeneity was moderate.
Once again, six to eight weeks of aerobic exercise produced modest improvements, with much greater gains seen after twelve weeks. Hour-long sessions were as effective as longer ones. But in this case moderate-to-vigorous intensity yielded the best results.
Meta-analysis of ten RCTs combining 443 children and adolescents with ADHD was associated with a medium to large effect size improvement in cognitive flexibility. There was no sign of either publication bias or heterogeneity. Neither the length of treatment, session time, or intensity affected the outcome.
The Take-Away:
The team concluded, “Our study indicates that aerobic exercise interventions have a positive impact with a moderate effect size on inhibitory control, working memory, and cognitive flexibility in children and adolescents with ADHD. However, the effectiveness of the intervention is influenced by factors such as the intervention period, frequency, session durations, intensity, and the choice between acute or chronic exercise. Specifically, chronic aerobic exercise interventions lasting 12 weeks or longer, with a frequency of 3 to 5 sessions per week, session durations of 60 min or more, and intensities that are moderate or moderate-to-vigorous, have the greatest overall effect… caution should be exercised when interpreting these findings due to the significant heterogeneity in inhibitory control and working memory.”
Vitamins play important roles in metabolism, immune regulation, and neurodevelopment. Recent studies show that deficiencies in vitamins like D, B6, B12, and folate are common in people with ADHD and ASD (autism spectrum disorder), and are associated with behavioral, cognitive, and brain development issues.
The Study:
A study team based in China has just performed a systematic search of the peer-reviewed medical literature to perform meta-analyses of clinical trials exploring vitamin interventions in the treatment of ADHD and ASD.
ADHD trials included participants with an official diagnosis. The primary intervention was vitamin supplements, while other treatments, including medications, remained unchanged or were excluded during the study period. ADHD outcomes included measurable changes in ADHD symptoms using validated rating scales and executive function measures.
Eligible studies included standard or sham control groups, crossover, parallel, or other clinical trial designs. In crossover studies, only first-phase data were analyzed to prevent carryover effects.
Ten trials with 852 participants met the standards, but meta-analysis showed no significant results. The outcomes varied widely, suggesting a need to distinguish among vitamins.
Results:
Of the five trials involving 347 participants that specifically evaluated vitamin D supplementation, results indicated a large effect size improvement in ADHD symptoms and executive function measures. The other five studies did not show any observable improvement.
Key limitations include:
The team concluded, “This meta-analysis supports the use of vitamin supplementation as a promising adjunctive treatment for ASD and ADHD. Vitamin B showed greater benefits in improving symptoms of ASD, while vitamin D was more effective in managing ADHD-related behaviors. These findings suggest that specific vitamins may target disorder-specific symptoms. Despite limitations such as the lack of trials on other vitamins and limited understanding of underlying mechanisms, vitamin therapy remains a low-cost, accessible option.”
An important limitation of this work is that the positive results for vitamin D were due to two studies from Iran. So far, no positive study has emerged from a non-Iranian study.
Interpretation:
The vitamin D findings are intriguing and could be important if replicated outside of Iran. Since supplementation is already widely recommended to those with limited sunlight exposure, clinicians may want to consider monitoring their patients’ vitamin D intake, especially in the winter months. It should be noted, however, that due to the limitations of this study, the results are by no means conclusive, and vitamin D should not be taken as a stand-alone treatment for ADHD.
Claims-based real-world data can reveal population-level trends in health among people with neurodevelopmental disorders. This new study examined the prevalence, demographics, and chronic comorbidities of adults and of children and adolescents with ADHD in a large national health plan. It also compared healthcare use and costs between those with and without ADHD.
A research team in the United States conducted an observational cohort study using claims data from more than 1.9 million adults and nearly 500,000 children and adolescents, comparing individuals diagnosed with ADHD to those without the diagnosis.
ADHD was diagnosed in 4% of adults and in 5% of children and adolescents.
Comorbidities By The Numbers:
Disruptive childhood disorders are behavioral problems marked by ongoing defiance, uncooperativeness, and aggression that affect a child's daily life and relationships. The main types, oppositional defiant disorder (ODD) and conduct disorder (CD), involve persistent anger and argumentativeness in ODD, and more severe actions like aggression, cruelty, and criminal behavior in CD. Without treatment, these common childhood disorders can continue into adulthood and raise the risks of substance use, violence, incarceration, and early death.
Disruptive childhood disorders were twenty times more frequent among children and adolescents with ADHD than among those without ADHD diagnosis, and fifteen times more frequent among adults with ADHD.
Bipolar disorder was twelve times more common among children and adolescents with ADHD than those without ADHD, and seven times more common among adults with ADHD.
Schizophrenia was eleven times more prevalent among children and adolescents with ADHD than those without ADHD, and three-and-a-half times more common among adults with ADHD.
Anxiety was nine times more frequent among children and adolescents with ADHD than among those without ADHD diagnosis, and more than five times more frequent among adults with ADHD.
Depression was eight times more common among children and adolescents with ADHD than those without ADHD, and more than five times more common among adults with ADHD.
Suicidal ideation was eight times more prevalent, and suicide attempt seven times more prevalent, among children and adolescents with ADHD than those without ADHD. Both suicidal ideation and suicide attempt were five times more common among adults with ADHD.
Gender dysphoria was almost six times more frequent among children and adolescents with ADHD than among those without ADHD diagnosis, and five times more frequent among adults with ADHD.
Eating disorders were over four times more common among children and adolescents with ADHD than those without ADHD, and five times more common among adults with ADHD.
Substance-related disorders were over six times more prevalent, and alcohol use disorder was six times more prevalent among children and adolescents with ADHD than those without ADHD, and four and three times more prevalent among adults with ADHD.
Increased Costs of Medical Care:
These comorbidities and ADHD led to higher medical costs. Children and adolescents with ADHD spent $610 more annually on healthcare than those without, while adults with ADHD had $1,684 higher average yearly expenditures than non-ADHD adults.
The Take-Away:
This large claims-based analysis of a national commercial insurer found ADHD diagnoses in roughly 4% of adults and 5% of children. It documented substantially higher rates of co-occurring behavioral-health conditions and markedly greater healthcare utilization and expenditures among those with ADHD. The authors report increased odds for several co-occurring diagnoses, as well as higher per-member-per-month (PMPM) spending and per-thousand-per-month (PTPM) utilization, largely driven by greater use of behavioral health services.
Importantly, these results come from cross-sectional, claims data within a commercially insured population: they describe associations, not causal relationships, and may not generalize to uninsured, publicly insured, or otherwise different populations. These findings, therefore, warrant cautious interpretation and highlight the need for longitudinal and more representative studies to clarify drivers of the increased burden and to inform care and policy.
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