May 16, 2025

Seven New Meta-analyses Suggest Wide Range of Benefits from Exercise for Persons with ADHD

ADHD is associated with deficits in executive functions. These are mental processes that enable individuals to plan, focus attention, manage tasks, and regulate emotions. These skills encompass working memory, cognitive flexibility, and inhibitory control, which are crucial for goal-directed behavior and decision-making. 

Working memory, which temporarily stores and processes information, contributes to language development by helping individuals make sense of what they read or hear.  

Cognitive flexibility refers to the ability to change perspectives, adapt thinking strategies, adjust to changing needs and priorities, recognize errors, and grasp opportunities.  

Inhibition switching involves intentional control of attention and emotions, suppressing automatic responses when necessary to prevent inappropriate behavior.  

These elements are critical to academic, social, and professional success. 

An international study team (Li et al.) conducted a meta-analysis of randomized controlled trials (RCTs) to explore the efficacy of physical activity for improving executive functions among children with ADHD aged 6 to 12. 

Meta-analysis of eleven RCTs encompassing 388 children reported a medium-to-large effect size improvement in cognitive flexibility. However, it found no benefit from aerobic exercise (such as running, jumping). When limited to the nine studies with 301 children that focused on cognitively engaging exercise (such as soccer and water sports that require constant monitoring of other players and strategizing), it found a large effect size improvement. Correcting for possible publication bias had no effect on the outcome. 

Meta-analysis of nine RCTs totaling 398 children reported a large effect size improvement in working memory. Once again, it found no benefit from aerobic exercise. Focusing on the seven RCTs with 288 children that used cognitively engaging exercise, it found a very large effect size improvement. There was no sign of publication bias. 

Meta-analysis of fourteen RCTs combining 579 children reported a small-to-medium effect size improvement in inhibition switching. But whereas it found a medium effect size improvement for shorter interventions of less than an hour (eight RCTs, 334 children), it found no benefit from interventions lasting an hour or more (six RCTs, 245 children. Again, there was no sign of publication bias. 

The team concluded, “Our study shows that physical activity interventions have a positive effect on improving executive function in school-age children with ADHD, with cognitive-engaging exercises showing greater benefits across three executive function measures.” 

A Chinese study team (Yang et al.) performed a related meta-analysis on the effect of exercise on inhibitory control in adults. Combining eight RCTs with a total of 372 participants, it reported a very large effect size improvement in inhibitory control, primarily from regular exercise. However, the effects were heavily influenced by a couple of outliers. The team claimed to have performed a sensitivity analysis but offered no evidence. Likewise, they noted signs of publication bias but did not use the standard trim-and-fill analysis to correct for it. 

Another Chinese study team (Xiangqin Song et al.) examined the effect of exercise on working memory in children and adolescents.  

Meta-analysis of 17 RCTs encompassing 419 participants found a medium effect size improvement in working memory. The large effect size improvement for cognitive aerobic exercise (4 RCTs, 233 participants) was twice the effect size for simple aerobic exercise (8 RCTs, 397 participants), though this meta-analysis still found a small-to-medium effect size gain from the latter. There was no sign of publication bias.  

The team concluded, “The results indicate that cognitive-aerobic exercise and ball sports are significantly more effective than other types of exercise interventions in improving working memory. This difference may be attributed to the varying cognitive load, task complexity, and the degree of activation of executive functions across different exercise types. The findings suggest that when designing exercise interventions for children with ADHD, priority should be given to exercise types with higher cognitive load in order to more effectively enhance working memory.” 

A joint Australian-U.S. team (Singh et al.) conducted a meta-meta-analysis on the effect of exercise on executive functions, that is, a meta-analysis of previous meta-analyses of RCTs.  

Combining ten separate meta-analyses with well over 2,800 children and adolescents with ADHD, it reported large effect size improvements in executive functions overall. There was no further breakdown by type of executive function and type of physical activity.  

The team concluded, “While exercise was seen to have a moderate and similar positive impact across all populations with respect to general cognition and memory, benefits for executive function were particularly marked in individuals with ADHD. This subgroup was unique in demonstrating a large effect size. This could be attributed to the task selection and the fact that many ADHD studies involved children. While the exact reason for this finding is unclear, there is evidence to suggest that impairments in executive function are common among individuals with ADHD. As such, it is plausible that this population may have a greater capacity for improvement due to starting from a lower baseline, compared with those with ‘normal’ executive function.” 

Another Chinese study team (Yagang Song et al.) performed a meta-analysis of RCTs examining the effects of physical exercise on anxiety, depression, and emotion regulation among children and adolescents with ADHD.  

Meta-analysis of eleven studies with a combined total of 384 participants reported a medium effect size reduction in symptoms of anxiety, with a dose-effect response. Physical exercise once a week had no significant effect, while twice a week was associated with a medium effect size reduction, and three or more times a week with a very large effect size improvement. Moderate intensity exercise was three times more effective than low intensity exercise.  

Meta-analysis of seven studies encompassing 187 individuals similarly reported a medium effect size reduction in symptoms of depression. Once again, moderate intensity was far more effective than low intensity exercise. 

Meta-analysis of seven studies totaling 429 children and adolescents reported a very large effect size improvement in emotion regulation, especially for physical exercise conducted at least twice a week

There was no sign of publication bias in the anxiety, depression, or emotion regulation findings. 

The team concluded, “Physical exercise demonstrated a substantial overall impact on enhancing anxiety, depression, and emotional regulation in children with ADHD, exhibiting a dose-response effect correlated with the period, frequency, duration, and intensity of the exercise. This investigation ... presents an additional evidence-based therapeutic approach for the considerable number of children with ADHD who are not appropriate candidates for pharmacological intervention.” 

A joint U.S.-Hong Kong study team (Liu et al.) performed a meta-analysis exploring the effect of physical exercise on motor proficiency. Motor proficiency includes both gross motor skills (like walking and running) and fine motor skills (like writing and buttoning).  

Meta-analysis of ten studies encompassing 413 children and adolescents with ADHD reported a very large effect size improvement in motor proficiency from physical exercise. The gains for object control, fine manual control, and manual coordination were roughly twice the gains for body coordination. There was no sign of publication bias. 

Finally, a Spanish research team (González-Devesa et al.) conducted a meta-analysis examining the effect of exercise on objectively measured sleep status among persons with ADHD. 

Meta-analysis of three RCTs with a combined total of 131 individuals that used accelerometers to measure sleep duration reported no significant effect one way or the other from exercise

The team concluded, “The existing evidence regarding the use of exercise to manage sleep problems in individuals with ADHD remains inconclusive. Preliminary findings from this review suggest a potential positive effect of exercise on self-reported sleep quality; however, its efficacy in improving sleep duration could not be confirmed.” 

The Take-Away:

An ideal exercise regimen for children with ADHD should focus on cognitively engaging physical activities rather than simple aerobic exercise. Sports and activities that require strategic thinking, attention to others’ actions, and rapid decision-making—such as soccer, martial arts, or water-based team sports—gave the best results, especially for working memory and cognitive flexibility. These types of exercise also show strong benefits for emotional regulation, reducing anxiety and depression, and enhancing motor proficiency.

To maximize benefits, the regimen should include moderate-intensity sessions at least two to three times per week, each lasting less than an hour, as longer durations appear less effective for improving inhibitory control. This structured, cognitively demanding approach offers an evidence-based, non-pharmacologic treatment option for children with ADHD, particularly for those who cannot or prefer not to use medication.  We need, however, more work to determine if exercise will provide the same symptom reduction and protection from adverse outcomes as has been shown for medications.

Daniel González-Devesa, Miguel Adriano Sanchez-Lastra, José Carlos Diz-Gómez, and Carlos Ayán-Pérez, “Effectiveness of Exercise on Sleep Quality in Attention Deficit Hyperactivity Disorder: A Systematic Review and Meta-Analysis,” Children (2025) 12, 119, https://doi.org/10.3390/children12020119

Dong Li, Chuyuan Miao, Deng Wang, and Chenmu Li, “Effect of physical activity interventions on executive functions in school-age children with ADHD: A meta-analysis of randomized controlled trials,” Journal of Affective Disorders (2025), https://doi.org/10.1016/j.jad.2025.01.155

Hok Ling Venus Liu, Fenghua Sun, David I. Anderson, and Choi Yeung Andy Tse, “The Effect of Physical Activity Intervention on Motor Proficiency in Children and Adolescents with ADHD: A Systematic Review and Meta-analysis,” Child Psychiatry & Human Development (2025) 56:177–191, https://doi.org/10.1007/s10578-023-01546-5

Ben Singh, Hunter Bennett, Aaron Miatke, Dorothea Dumuid, Rachel Curtis, Ty Ferguson, Jacinta Brinsley, Kimberley Szeto, Jasmine M Petersen, Claire Gough, Emily Eglitis, Catherine EM Simpson, Christina L Ekegren, Ashleigh E Smith, Kirk I Erickson, and Carol Maher, “Effectiveness of exercise for improving cognition, memory and executive function: a systematic umbrella review and meta-meta-analysis,” British Journal of Sports Medicine (2025) 0:1-11, https://doi.org/10.1136/bjsports-2024-108589

Xiangqin Song, Yaoqi Hou, Wenying Shi, Yan Wang, Feifan Fan, and Liu Hong, “Exploring the impact of different types of exercise on working memory in children with ADHD: a network meta-analysis,” Frontiers in Psychology (2025) 16:1522944, https://doi.org/10.3389/fpsyg.2025.1522944

Yagang Song, Shuqi Jia, Xing Wang, Aiwei Wang, Tao Ma, Shufan Li, Jiwei Che, Zhaohui Guo, Feng Ding, Yuxi Ren, and Man Qin, “Effects of physical exercise on anxiety, depression, and emotion regulation in children with attention deficit hyperactivity disorder: a systematic review and meta-analysis,” Frontiers in Pediatrics (2025) Vol. 12, https://doi.org/10.3389/fped.2024.1479615

Yi Yang, Chang-Hong Wu, Liang Sun, Ting-Ran Zhang, and Jiong Luo, “The impact of physical activity on inhibitory control of adult ADHD: a systematic review and meta-analysis,” Journal of Global Health (2025) Vol. 15, 10.7189/jogh.15.04025

 

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Immediate and Long-term Effects of Exercise on ADHD Symptoms and Cognition

Immediate and Longer-term Effects of Exercise on ADHD Symptoms and Cognition

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

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

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

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

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

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

July 18, 2021

How Effective Is Exercise in Treating ADHD?

New meta-analysis explores effectiveness of physical exercise as treatment for ADHD

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

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

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

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

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

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

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

February 21, 2022

Myths About the Treatment of ADHD

Myths About The Treatment of ADHD

Myth:  ADHD medications "anesthetize" ADHD children.
 
The idea here is that the drug treatment of ADHD is no more than a chemical straightjacket intended to control a child's behavior to be less bothersome to parents and teachers. After all, everyone knows that if you shoot up a person with tranquilizers, they will calm down.

Fact:  ADHD medications are neither anesthetics nor tranquilizers.

The truth of the matter is that most ADHD medications are stimulants. They don't anesthetize the brain; they stimulate it. By speeding up the transmission of dopamine signals in the brain, ADHD medications improve brain functioning, which in turn leads to an increased ability to pay attention and control behavior.  The non-stimulant medications improve signaling by norepinephrine. They also improve the brain's ability to process signals. They are not sedatives or anesthetics. When taking their medication, ADHD patients can focus and control their behavior to be more effective in school, work, and relationships.  They are not "drugged" into submission.

Myth: ADHD medications cause drug and alcohol abuse
We know from many long-term studies of ADHD children that when they reach adolescence and adulthood, they are at high risk for alcohol and drug use disorders. Because of this fact, some media reports have implied that their drug use was caused by treatment of their ADHD with stimulant medications.

Fact: ADHD medications do not cause drug and alcohol abuse
Some ADHD medications indeed use the same chemicals that are found in street drugs, such as amphetamine.  But there is a very big difference between these medications and street drugs. When street drugs are injected or snorted, they can lead to addiction, but when they are taken in pill form as prescribed by a doctor, they do not cause addiction. When my colleagues and I examined the world literature on this topic, we found that rather than causing drug and alcohol abuse, stimulant medicine protected ADHD children from these problems later in life. One study from researchers at Harvard University and the Massachusetts General Hospital found that the drug treatment of ADHD reduced the risk for illicit drug use by84 a percent. These findings make intuitive sense. These medicines reduce the symptoms of the disorder that lead to illicit drug use. For example, an impulsive ADHD teenager who acts without thinking is much more likely to use drugs than an ADHD teen whose symptoms are controlled by medical drug treatment. After we published our study, other work appeared. Some of these studies did not agree that ADHD medications protected ADHD people from drug abuse, but they did not find that they caused drug abuse.

Myth:  Psychological or behavioral therapies should be tried before medication.  
Many people are cautious about taking medications, and that caution is even stronger when parents consider treatment options for their children.  Because medications can have side effects, shouldn't people with ADHD try to talk therapy before taking medicine?

Fact:  Treatment guidelines suggest that medication is the first-line treatment.
The problem with trying talk or behavior therapy before medication is that medication works much better.  For ADHD adults, one type of talk therapy(cognitive behavioral therapy) is recommended, but only when the patient is also taking medication.  The multimodal treatment of ADHD (MTA) study examined this issue in ADHD children from several academic medical centers in the United States. That study found that treating ADHD with medication was better than treating it with behavior therapy. Importantly, behavior therapy plus medication was no more effective than medication alone. That is why treatment guidelines from the American Academy of Pediatrics and the American Academy of Children and Adolescents recommend medicine as a first-line treatment for ADHD, except for preschool children. ADHD medications indeed have side effects, but these are usually mild and typically do not interfere with treatment.  And don't forget about the risks that a patient faces when they do not use medications for ADHD.  These untreated patients are at risk for worsening ADHD symptoms and complications.

Myth: Brain abnormalities of ADHD patients are caused by psychiatric medications
A large scientific literature shows that ADHD people have subtle problems with the structure and function of their brains.  Scientists believe that these problems are the cause of ADHD symptoms. Critics of ADHD claim that these brain problems are caused by the medications used to treat ADHD.  Who is right?

Fact: Brain abnormalities are found in never medicated ADHD patients.
Alan Zametkin, a scientist at the US National Institute of Mental Health, was the first to show brain abnormalities in ADHD patients who had never been treated for their ADHD.  He found that some parts of the brains of ADHD patients were underactive. His findings could not be due to medication because the patients had never been medicated. Since his study, many other researchers have used neuroimaging to examine the brains of ADHD patients. This work confirmed Dr. Zametkin’s observation of abnormal brain findings in unmediated patients. Reviews of the brain imaging literature have concluded that the brain abnormalities seen in ADHD cannot be attributed to ADHD medications.

May 15, 2021

U.S. Nationwide Study Finds Down Syndrome Associated with 70% Greater Odds of ADHD

The Background:

Down syndrome (DS) is a genetic disorder resulting from an extra copy of chromosome 21. It is associated with intellectual disability. 

Three to five thousand children are born with Down syndrome each year. They have higher risks for conditions like hypothyroidism, sleep apnea, epilepsy, sensory issues, infections, and autoimmune diseases. Research on ADHD in patients with Down syndrome has been inconclusive. 

The Study:

The National Health Interview Survey (NHIS) is a household survey conducted by the National Center for Health Statistics at the CDC. 

Due to the low prevalence of Down syndrome, a Chinese research team used NHIS records from 1997 to 2018 to analyze data from 214,300 children aged 3 to 17, to obtain a sufficiently large and nationally representative sample to investigate any potential association with ADHD. 

DS and ADHD were identified by asking, “Has a doctor or health professional ever diagnosed your child with Down syndrome, Attention Deficit Hyperactivity Disorder (ADHD), or Attention Deficit Disorder (ADD)?” 

After adjusting for age, sex, and race/ethnicity, plus family highest education level, family income-to-poverty ratio, and geographic region, children and adolescents with Down syndrome had 70% greater odds of also having ADHD than children and adolescents without Down syndrome. There were no significant differences between males and females. 

The Take-Away:

The team concluded, “in a nationwide population-based study of U.S. children, we found that a Down syndrome diagnosis was associated with a higher prevalence of ASD and ADHD. Our findings highlight the necessity of conducting early and routine screenings for ASD and ADHD in children with Down syndrome within clinical settings to improve the effectiveness of interventions.” 

June 27, 2025

Meta-analysis Explores Link Between ADHD and Homelessness Among Children and Adolescents

An estimated 150 million children and adolescents live on the streets worldwide. In the U.S., roughly 1.5 million experience homelessness annually. Homelessness increases the risk of health issues, violence, early pregnancy, substance use, vaccine-preventable diseases, mental disorders, suicidal behavior, and early death. 

Rates of anxiety, major depression, conduct disorders, and post-traumatic stress disorder are higher among school-age homeless children compared to their housed peers.  

However, there has been limited attention to ADHD, leading a French research team to conduct a systematic review and meta-analysis of its prevalence among homeless children and adolescents.  

The inclusion criteria required that participants be homeless, under 19 years of age at baseline, and have ADHD identified through a screening tool, self-report, or clinical assessment. 

Results:

Meta-analysis of 13 studies with a combined total of 2,878 individuals found indications of ADHD in almost one in four homeless children and adolescents. There was no sign of publication bias, but considerable variation in estimates across studies. 

The team found a dose-response effect. Meta-analysis of six studies with 1,334 participants under 12 years old reported 13% with indications of ADHD. Meta-analysis of five studies encompassing 991 individuals, 12 through 18 years old, found an ADHD rate of 43%. The ADHD rate among adolescents was 3.3 times greater than among children

There were no significant differences among countries. 

Moreover, limiting the meta-analysis to the seven studies with 1,538 participants that relied on clinical ADHD diagnoses, the gold standard,  resulted in an ADHD prevalence of 23%

The team concluded, “The review of 13 studies revealed that ADHD is common in homeless children and adolescents, suggesting that homelessness may contribute to the development or exacerbation of ADHD symptoms. Conversely, ADHD with other comorbidities may increase the likelihood of homelessness. Reintegrating these children and adolescents into care systems and ensuring access to public health interventions tailored for homeless families and youth is imperative for breaking the cycle of homelessness and improving long-term trajectories.” 

In other words, this review not only confirmed a strong link between homelessness and ADHD in children and youth, but also suggested a complex, cyclical relationship. Providing tailored health care and support for these vulnerable groups is crucial to interrupt this cycle and help improve their future outcomes.

June 23, 2025

Nationwide Population Study Reports Increased Risk of Hospitalization for Psychosis or Mania Following Initiation of ADHD Medication

Background:

In Iceland, treatment with ADHD medication can only be initiated by psychiatrists or pediatricians with experience in diagnosing neurodevelopmental disorders. The diagnostic evaluation is most often carried out by a psychologist or psychiatrist, and must be confirmed by a psychiatrist. 

Some previous studies have suggested a small but significant increased risk of psychosis or mania associated with ADHD medication, while others have not. 

Iceland has a single-payer national healthcare insurance system that tracks virtually its entire population. An Icelandic research team accessed two administrative databases with nationwide coverage – the Icelandic Prescription Medicines Register and the Icelandic Hospital Discharge Register – to explore this relationship among all adults from 2010 through 2022. 

They included three categories of ADHD medications prescribed in Iceland: amphetamines, including dexamphetamine and lisdexamphetamine; methylphenidate; and atomoxetine. In Iceland, methylphenidate or atomoxetine must be prescribed and tried first before switching to lisdexamphetamine or dexamphetamine. 

Method:

Diagnoses of mania or psychosis recorded in electronic health records were used to identify individuals who were admitted to a psychiatric ward within one year of starting treatment with a specific class of ADHD medication. First-onset psychosis or mania was defined as the emergence of these conditions in individuals with no prior history, diagnosis, or hospitalization for psychosis or mania. 

A total of 16,125 adults began using an ADHD medication for the first time during the 13-year study period. 

Methylphenidate was the most used ADHD medication among those admitted for psychosis or mania (25 out of 61; 41%), reflecting its status as the most frequently prescribed stimulant during the study period. It was followed by amphetamines (21 out of 61; 34.4%) and atomoxetine (15 out of 61; 24.6%). 

Half of those hospitalized had previously received a diagnosis of substance use disorder. One in nine (11%) of those hospitalized acknowledged misuse of the type of ADHD medication they had been prescribed. 

Within a year of discharge, 42 out of the 61 patients (68.9%) had been prescribed an ADHD medication again. Among those, one in four (11 out of 42; 26%) were readmitted for psychosis or mania within the following year.  

The team noted, “It is concerning that most patients (68.9%) in our study resumed ADHD drug treatment within a year of hospital discharge … However, some studies have reported that the use of psychostimulants or atomoxetine to treat ADHD in individuals with psychotic disorders did not increase the risk of hospitalisation for psychosis if used concurrently with antipsychotic medication or that such use might even reduce this risk.”  

Findings: 

By comparison with the general population, adults initiating ADHD medications had eight times the relative risk of being admitted for psychosis or mania within the first year.  

The absolute risk was low: 0.38% overall for those initiating ADHD medication.  Adjusting for the general population risk of hospitalization for first-onset psychosis or mania, more than 300 patients would need to be initiated to ADHD medication to generate one hospital admission for psychosis or mania

The team conceded, “Confounders of real-life clinical settings, such as non-disclosed ADHD drug abuse or misuse or some degree of substance abuse, may have influenced our findings.” 

A further, unmentioned, limitation is that the team did not perform any of the usual adjustments for confounding variables, critically including co-occurring (comorbid) psychiatric disorders known to be common with ADHD, and likely to have a major effect on the relative risk of hospitalization. 

Given the very small increase in risk along with the methodological flaws, the team’s suggestion of a “potential causal role of ADHD drugs in the development of first-onset psychosis or mania” is unsubstantiated and speculative.  This is especially so given other studies suggesting no increased risk for psychosis due to these medications.  

In any event, causation cannot be established through observational studies.

June 19, 2025