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February 21, 2024
Noting that “little is known about whether school-level stimulant therapy for ADHD is associated with NUPS [nonmedical use of prescription stimulants] among US secondary school students,” a team of American researchers searched for answers in a nationally representative sample of 3,284 U.S. secondary schools with well over 150,000 high school students.
“Previous studies,” the authors continued, “have largely neglected school-level factors associated with NUPS among US secondary school students, including school size, school geographical location, school-level racial composition, school-level rates of substance use (eg, binge drinking), and school-level stimulant therapy for ADHD.”
In surveys, students were asked if they had ever taken stimulant medications for ADHD under a physician’s or health professional’s supervision, with three possible answers: no, yes but only in the past, and yes, currently. Responses for use in the past, and separately for current use, were combined and aggregated to the school level to reflect the percentage of the study body who used prescription stimulants for ADHD.
The surveys explored NUPS by asking, “On how many occasions (if any) have you taken amphetamines or other prescription stimulant drugs on your own—that is, without a doctor telling you to take them... in your lifetime?...during the last 12 months?...during the last 30 days?”
The study team controlled for sex, race and ethnicity, parental education, GPA, binge drinking, cigarette smoking, cannabis use, cohort year, school type, grade level, urbanicity, school size, US Census region, % of student body with low grades, % female, % with at least one parent with a college degree, % White, % binge drinking during past 2 weeks, % cigarette smoking in past 30 days, and % cannabis use during the past 30 days. The analysis also included individual-level medical use of stimulant therapy for ADHD history to estimate individual-level past-year NUPS. Finally, it included both individual-level and school-level risk factors to assess individual-level past-year NUPS.
With all these adjustments, at the individual level, both high school students presently on prescribed stimulant therapy for ADHD and those who had previously been on such prescribed therapy were more than twice as likely to engage in past-year NUPS as those who were never on prescribed stimulant medication.
Turning to the school level, in schools where 12% or more of students were on prescribed stimulant therapy for ADHD, students in general were 36% more likely to engage in past-year NUPS than in schools where none of the students were on prescribed stimulant therapy for ADHD.
This is not surprising, as it confirms that students who use prescription drugs for nonmedical often get their supply from fellow students who are prescribed those drugs.
While at the individual level, binge drinking, cigarette smoking, and cannabis use were strong predictors of NUPS, at the whole-school level they had no significant effect. A poor grade point average mildly increased risk in the individual, but high percentages of students with low grades had no effect on peer NUPS. Race and ethnicity made a difference at the individual level (NUPS significantly more likely among White students than Blacks and Hispanics), but made no difference at the school level.
The team concluded, “These findings suggest that school-level stimulant therapy for ADHD and other school-level risk factors were significantly associated with NUPS and should be accounted for in risk-reduction strategies and prevention efforts.”
Sean Esteban McCabe, John E. Schulenberg, Timothy E. Wilens, Ty S. Schepis, Vita V. McCabe, and Philip T. Veliz, “Prescription Stimulant Medical and Nonmedical Use AmongUS Secondary School Students, 2005 to 2020,” JAMA Network Open (2023), https://doi.org/10.1001/jamanetworkopen.2023.8707.
The Background:
ADHD and epilepsy are the two most common neurological disorders in children and adolescents. Additionally, they appear as co-diagnoses more often than chance would predict. Roughly a quarter of children with epilepsy also have ADHD, and children with ADHD face a 2.5-times greater risk of developing epilepsy than their peers.
Clinicians have long suspected that carrying both diagnoses compounds cognitive difficulties, but no rigorous quantitative review has mapped out exactly how much, or in what ways. This new meta-analysis now fills that gap.
The Study:
The team pooled data from peer-reviewed studies that included children and adolescents diagnosed with both conditions alongside at least one comparison group: children with neither condition, children with epilepsy alone, or children with ADHD alone. To capture the breadth of thinking skills, they constructed a general intelligence factor drawing on six cognitive domains:
The Results:
Across eleven studies (995 participants), children and adolescents with both conditions scored moderately lower on general intelligence than those with epilepsy alone. The same pattern held across all six cognitive domains. Seven studies (785 participants) comparing the dual-diagnosis group with those who had ADHD alone found an equally consistent moderate deficit, replicated in every domain.
The clearest signal emerged when researchers compared children and adolescents carrying both diagnoses to typically-developing peers. Seven studies covering 427 individuals revealed a substantially larger gap in general intelligence, with the effects of the two conditions appearing to be roughly additive, meaning the combined burden was approximately equal to the sum of each condition's individual impact. This pattern held across five of the six domains.
The Interpretation:
The results come with meaningful caveats. Variability across individual studies was moderate in the first two comparisons and high in the third, reflecting real differences in how studies were designed, which populations they sampled, and how they measured cognition. While there was no sign of publication bias in the first group, it was not assessed in two of the three analyses.
The authors describe “a widespread profile of cognitive dysfunction” in children and adolescents with both epilepsy and ADHD, while underscoring that the substantial variability between studies warrants caution in drawing overly precise conclusions. The findings nonetheless carry practical weight: children managing both conditions may need more intensive cognitive screening and support than current clinical practice routinely provides.
The focus on children and adolescents with ADHD often revolves around behavioral issues and academic difficulties, but the social struggles are real. Around 60% of youth with ADHD experience meaningful difficulties in social skills, reading social cues, and forming reciprocal relationships with peers. Over time, these struggles can raise the risk of anxiety and depression.
Medication remains the primary treatment for ADHD, with stimulants like methylphenidate (Ritalin) being the most commonly prescribed. While effective at reducing core symptoms such as inattention and impulsivity, medication has not been shown to improve social behavior or peer relationships.
The Background:
Exercise has recently emerged as a promising adjunctive therapy. A newly published meta-analysis examined whether structured physical activity can specifically improve social functioning in young people with ADHD. It builds on a previous review from 2015, addressing gaps that earlier work left open: social outcomes were rarely treated as a primary focus, and no prior analysis had systematically compared exercise types or asked how much exercise is actually needed to see benefits.
The Study:
The analysis included 13 randomized controlled trials involving 703 participants aged 6 to 18, all clinically diagnosed with ADHD. Only exercise programs lasting at least four weeks were considered. Studies that combined exercise with other therapies, such as psychotherapy, were excluded to isolate exercise's specific effects.
The researchers used a technique called network meta-analysis, which allows different interventions to be compared against one another even when they haven't been tested head-to-head, alongside dose-response modeling to identify how much exercise produces the greatest benefit.
Results:
The most striking results came from closed-skill exercise: across four studies involving 92 participants, it was associated with a very large reduction in social dysfunction. Open-skill exercise, by contrast, showed no measurable improvement across four studies with 91 participants. Multicomponent exercise (the group combining elements of both open- and closed-skill) reported large gains in two smaller studies with 33 participants.
Mind-body exercise showed a moderate benefit across three studies involving 44 participants.
The dose-response analysis offered a practically useful finding: 30 to 60 minutes of moderate-intensity exercise per day appeared to produce the best outcomes, with a minimum of roughly 15 to 30 minutes daily needed to achieve any meaningful benefit.
The Take-Away:
The results are encouraging but should be interpreted carefully. The number of studies in each category was small (two to three studies each), and sample sizes were modest, meaning the findings may not hold up as more evidence accumulates. The absence of publication bias is reassuring, as is the use of rigorous methodology, but this remains an early-stage evidence base. Larger, well-designed trials are needed before firm clinical recommendations can be made.
For now, the findings position structured physical activity (particularly closed-skill and multicomponent exercise) as a plausible complement to existing ADHD treatment, specifically targeting the social difficulties that medication tends not to address. The practical dose guidance is a useful starting point: around half an hour of moderate daily exercise as a minimum, with an hour as the apparent sweet spot. As low-risk additions to a treatment plan go, that’s a relatively accessible bar for most families to consider alongside professional guidance.
Exercise has attracted growing attention as an intervention for ADHD. As a potential treatment option for ADHD, it is, of course, highly appealing because it can be low- to no-cost, widely accessible, and free of the side effects that can accompany medication. From previous studies, we know that certain types of exercise may be more effective than others, but do we actually know enough for clinicians to prescribe physical activity as a treatment for ADHD?
The First Study: Effects on Core ADHD Symptoms
Despite encouraging findings in individual studies, researchers have lacked clear guidance on which types of exercise work best, at what intensity, and for how long. A meta-analysis by Chen et al. set out to address this by pooling data from 20 randomized controlled trials (RCTs) involving 841 children and adolescents aged 4–18, all of which compared exercise interventions against non-exercising control groups.
The results were cautiously optimistic. Across standardized symptom scales, exercise produced a small improvement in ADHD symptoms overall. Objective cognitive tests showed a moderate improvement. Emotional and behavioral outcomes, however, showed no significant change.
To understand what was driving differences between studies, the researchers broke results down by exercise type. Therapeutic and alternative exercises (targeted movements and specific techniques such as those prescribed by physical therapists) were associated with moderate symptom improvements. Mind-body practices (such as yoga or tai chi) showed small-to-moderate gains. Conventional aerobic exercise yielded smaller effects, while skill-based competitive sports showed no measurable benefit. Notably, the variability between individual studies remained high throughout, meaning these categories should be interpreted with some caution.
Results:
The authors recommend that clinicians and parents consider incorporating therapeutic or alternative exercise sessions twice a week, each lasting 60–90 minutes, as a supplemental strategy alongside existing ADHD treatment. They stop short of calling this definitive, noting that future research should clarify how exercise produces its effects and how it might best be combined with medication or behavioral therapy.
The Second Study: Effects on Inhibitory Control
A second meta-analysis, by Zhang et al., zoomed in on a specific and particularly relevant cognitive challenge in ADHD: inhibitory control. Inhibitory control refers to the ability to suppress impulsive responses and tune out irrelevant distractions. This capacity underlies much of the restlessness, interrupting, and difficulty staying on task that characterize the condition.
This analysis drew on 34 studies with over 1,300 participants spanning all age groups, making it broader in scope than the Chen et al. review. Overall, exercise was associated with a moderate improvement in inhibitory control. When the analysis was restricted to RCTs alone, this finding held up. When studies with a high risk of bias were excluded, however, the effect size dropped to small-to-moderate.
One notable null result: three studies that used EEG to measure brain activity during inhibitory tasks found no significant effects on the neural signatures most closely tied to this process. This suggests exercise may influence behavior without necessarily changing the underlying brain mechanisms researchers expected, or that current methods aren't yet sensitive enough to detect such changes.
The dosing question produced some of the more practically useful findings. Single exercise sessions yielded only borderline small improvements. Sustained exercise programs, by contrast, showed moderate improvements, and programs with sessions three times per week produced large gains and had the strongest effect between the two meta-analyses. Exercise intensity and total program duration, perhaps interestingly, were not significant factors.
Results:
The authors are measured in their conclusions: exercise shows a real but modest benefit for inhibitory control, and frequency appears to matter more than intensity. They caution against overstating the case for exercise as treatment for ADHD overall, as it did not significantly affect hyperactivity or impulsivity as standalone outcomes, and its neural effects remain unclear.
The Broader Picture :
Ultimately, these two meta-analyses support exercise as a meaningful supplemental intervention for ADHD, particularly for attention and cognitive control, while urging realistic expectations. Neither suggests exercise should replace established treatments. Both are limited by high variability across the underlying studies, and both call for better-designed research to sharpen the guidance available to clinicians and families.
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