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"
There has been consistent evidence of an association between ADHD and subjectively reported sleep problems even in patients not medicated for the disorder. There have also been studies using wrist-worn actigraphy (a wrist watch-like device that measures gross motor activity) and sleep lab-based polysomnography that measure objective sleep parameters.
What has been missing are large population-based cohort studies to explore the prevalence rates of different sleep disorders and medical prescriptions in ADHD.
Methods Used:
Sweden has a single-payer health insurance system and a series of national population registers that track virtually its entire population. Using the Swedish Total Population Register, a local research team created a cohort of all 6,470,658 persons born between 1945 and 2008. They linked this to the Swedish National Patient Register, which includes inpatient hospitalizations from 1975 to 2013, and outpatient specialist diagnoses from 2001 to 2013, to identify diagnoses of sleep disorders. They also linked to the Prescribed Drug Register, covering 2005 to 2013, to identify prescriptions for sleep medications.
Summary of Findings:
Overall, persons with ADHD were eight times more likely to be diagnosed with any sleep disorder relative to normally developing peers. Broken down by age, adolescents with ADHD were 16 times more likely to receive such diagnoses, young adults (18-30) twelve times more likely, children and mid-age adults (31-45) eight times more likely, and older adults six times more likely.
Broken down by specific sleep disorder diagnoses, relative to normally developing peers, persons with ADHD were:
As for sleep medication, relative to normally developing peers, persons with ADHD were:
Conclusion:
The team concluded, “Our findings also suggest that greater clinical attention should be directed towards addressing sleep problems in individuals with ADHD. This entails implementing proactive measures through sleep education programmes and providing both pharmacological and non-pharmacological approaches such as cognitive behavioural therapy and parental sleep training.”
Attention is a critical determinant of academic achievement, influencing domains such as language, literacy, and mathematics. To explore whether physical activity can improve attention in children with ADHD, an international team conducted a meta-analysis of peer-reviewed studies. The goal was to evaluate the impact of various physical activity regimens on attention-related outcomes in this population.
The researchers performed a comprehensive search of the medical literature to identify studies examining the effects of physical activity on attention in schoolchildren with ADHD. They included 10 studies with a total of 474 participants in their meta-analysis. The studies evaluated two main types of physical activity:
Additionally, they examined variations based on the frequency, duration, and type of control groups used in the studies. To assess consistency, they also analyzed heterogeneity (variability of outcomes) and checked for potential publication bias.
Key findings from the meta-analysis include:
The authors concluded that mentally engaging exercise is more effective than aerobic exercise in improving attention problems in schoolchildren with ADHD. Furthermore, higher frequency and longer duration of physical activity do not necessarily yield better outcomes.
This research underscores the importance of tailoring physical activity interventions to emphasize cognitive engagement over intensity or duration. By refining strategies, educators and parents can better support children with ADHD in achieving academic success. But take note: given the results from controlled studies, it seems clear that if there is a positive effect of exercise, it is very small so should not replace standard treatments for ADHD.
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Previous studies have examined how stimulant medications affect the brain in controlled settings, but less is known about their impact in real-world conditions, where children may not always take their medication consistently or may combine it with other treatments. A new study leverages data from the Adolescent Brain Cognitive Development (ABCD) study to explore how real-world stimulant use impacts brain connectivity and ADHD symptoms over two years.
Changes in Brain Connectivity Researchers used brain imaging data from the ABCD study to examine the functional connectivity—communication between brain areas—of six regions within the striatum, a brain area involved in motivation and movement control. They focused on how stimulant use influenced connectivity between the striatum and other networks involved in executive functioning and visual-motor control.
The study found that stimulant exposure was linked to reduced connectivity between key striatal areas (such as the caudate and putamen) and large brain networks, including the frontoparietal and visual networks. These changes were more pronounced in children taking stimulants compared to those who were not medicated, as well as compared to typically developing children. Importantly, this reduction in connectivity seemed to regulate certain brain networks that are typically altered in children with ADHD.
Symptom Improvement In addition to brain changes, 14% of children taking stimulants experienced a significant reduction in ADHD symptoms over the two-year period. These children showed the strongest connectivity reductions between the right putamen and the visual network, suggesting that stimulant-induced connectivity changes may contribute to improvements in visual attentional control, which is a common challenge for children with ADHD.
Why This Matters This study is one of the first to examine how stimulant use in real-world conditions affects brain networks in children with ADHD over time. The findings suggest that stimulants may help normalize certain connectivity patterns associated with ADHD, particularly in networks related to attention and control. These insights could help clinicians better understand the potential long-term effects of stimulant treatment and guide personalized approaches to ADHD management.
Conclusion Stimulant medications appear to alter striatal-cortical connectivity in children with ADHD, with some changes linked to symptom improvement. This research highlights the potential for stimulant medications to impact brain networks in ways that support attention and control, highlighting the importance of understanding how real-world medication use influences ADHD treatment outcomes.
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