October 21, 2025

Meta-analysis Suggests Motor Competence Deficits Associated with ADHD, But With Methodological Shortcomings

Children and adolescents with ADHD tend to be less active and more sedentary than their typically developing peers. This is concerning, since physical activity benefits mental, physical, and social development. For youth with ADHD, being active can improve symptoms like inattention, working memory, and inhibitory control. 

A major barrier to physical activity for children and adolescents with ADHD is limited motor competence. This stems from challenges in developing basic motor skills and more complex abilities needed for sports and advanced movements. 

Difficulties in developing fundamental movement skills – such as locomotor (running, jumping), object-control (throwing, catching), and stability skills (balancing, turning) – can reduce motor competence and limit physical activity. These basic movements are learned and refined with practice and age, not innate abilities. 

To date, research on the link between ADHD and motor competence has remained inconclusive. This systematic review and meta-analysis by a Spanish research team therefore aimed to determine whether children and adolescents with ADHD differ in motor competence from those with typical development (TD). 

Studies had to include children and adolescents diagnosed with ADHD. They had to involve a full motor assessment battery, not just one test, and present motor competence data for both ADHD and TD groups. 

The team excluded studies involving participants with other neurodevelopmental disorders or cognitive impairments, unless separate data for the ADHD subgroup were reported. 

Meta-analysis of six studies combining 323 children and adolescents found that typically developing individuals were twelve times more likely to score in the 5th percentile of the Movement Assessment Battery for Children as their peers diagnosed with ADHD. They were also three times more likely to score in the 15th percentile (five studies, 289 participants). Results were consistent across the studies (low heterogeneity). All included studies were randomized. 

Meta-analysis of five studies totaling 198 participants using the Test of Gross Motor Development reported significant deficits in both locomotor skills and object control skills among children and adolescents diagnosed with ADHD relative to their typically developing peers. In this case, however, results were inconsistent across studies (very high heterogeneity), and one of the studies was unrandomized. Because the team published only unstandardized mean differences, there was no indication of effect sizes. 

Meta-analysis of two studies encompassing 164 participants using the Bruininks-Oseretsky Test of Motor Proficiency similarly yielded significant deficits among children and adolescents diagnosed with ADHD relative to their typically developing peers, but in this case with low heterogeneity. Notably, one of the two studies was not randomized. 

Moreover, the team made no assessment of publication bias. 

The team concluded, “The findings of this review indicate that children and adolescents with ADHD show significantly lower levels of motor competence compared to their TD peers. This trend was evident across a range of validated assessment tools, including the MABC, BOT, TGMD, and other standardized test batteries. Future research should aim to reduce methodological heterogeneity and further investigate the influence of factors such as ADHD subtypes and comorbid conditions on motor development trajectories.” 

However, without a publication bias assessment, reliance on unrandomized studies in two of the tests, no indication of effect size in the same two tests, and small sample sizes, these results are at best suggestive, and will require further research to confirm. 

Nerea Blanco-Martínez, Daniel González-Devesa, Carlos Ayán-Pérez, and José Carlos Diz-Gómez, “Differences in Motor Competence Between Children and Adolescents With and Without ADHD: Findings from a Systematic Review and Meta-analysis,” Journal of Autism and Developmental Disorders (2025), https://doi.org/10.1007/s10803-025-07033-1

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Meta-analysis finds limited benefits from computerized cognitive training

Meta-analysis Finds Limited Benefits from Computerized Cognitive Training

Computerized cognitive training (CCT) uses computers to try to strengthen cognitive skills and processes, reduce ADHD symptoms, and improve executive functioning. Executive functions are cognitive processes and mental skills that help individuals plan, monitor, and successfully execute their goals.

CCT programs target one or more cognitive processes such as motor inhibition, interference inhibition, sustained attention, and working memory. They ramp up task difficulty as performance improves. The goal is to harness the brain’s inherent adaptability (neuroplasticity) to boost performance. 

A European study team that previously probed the efficacy of CCT through meta-analysis had been unable to provide a robust estimate of effect size due to an insufficient number of high-quality trials with probably blinded outcomes. Noting that “there have been a considerable number of new RCTs [randomized controlled trials] published, many with larger samples, well-controlled designs and blinded outcomes,” the team performed an updated systematic review and meta-analysis.

They included RCTs with participants of any age who either had a clinical diagnosis of ADHD or were above cut-off on validated ADHD rating scales. RCTs had to have been peer-reviewed and published in an academic journal, and to have reported a validated outcome measure of ADHD symptoms, neuropsychological processes, and/or academic outcomes.

Fourteen RCTs with a combined total of 631 participants had probably blinded outcomes. Meta-analysis of these studies yielded no significant effect on either overall ADHD symptoms or hyperactivity/impulsivity symptoms. There was a marginally significant reduction in inattention symptoms, but the effect size was small. Between-study variation (heterogeneity) was negligible and there was no sign of publication bias.

Regarding academic outcomes, meta-analyses revealed no gain in arithmetic ability or reading fluency. There was a small but not statistically significant improvement in reading comprehension. Heterogeneity was minimal, with no indication of publication bias.

With two related exceptions, meta-analyses of RCTs measuring executive functions likewise reported no significant improvements in attention, interference inhibition (initial stage in controlling impulsive behavior), motor inhibition (follow-up stage in controlling impulsive behavior), non-verbal reasoning, processing speed, and set shifting (the ability to unconsciously shift attention between one task and another).

The exceptions were for working memory tasks. Meta-analysis of 15 RCTs with a combined 753 participants reported a highly significant small-to-medium effect size improvement in verbal working memory. A separate meta-analysis of nine RCTs with a total of 441 participants similarly reported a highly significant improvement in visuospatial working memory, this time with medium effect size.

The team concluded, “There was no empirical support for the use of CCT as a stand-alone intervention for ADHD symptoms based on the largest and most comprehensive meta-analysis of RCTs conducted to date. Small effects, of likely limited clinical importance, on inattention symptoms were found – but these were limited to the setting in which the intervention was delivered. Robust evidence of small- to-moderate improvements in visual-spatial and verbal STM/WM tasks did not transfer to other domains of executive functions or academic outcomes.”

Meta-analysis Finds Little Evidence in Support of Game-based Digital Interventions for ADHD

ADHD treatment usually involves a combination of medication and behavioral therapy. However, medication can cause side effects, adherence problems, and resistance from patients or caregivers. 

Numerous systematic reviews and meta-analyses have evaluated the effects of non-pharmacological interventions on ADHD. With little research specifically examining game-based interventions for children and adolescents with ADHD or conducting meta-analyses to quantify their treatment effectiveness, a Korean study team performed a systematic search of the peer-reviewed medical literature to do just that.  

The Study: 

To be included, studies had to be randomized controlled trials (RCTs) that involved children and adolescents diagnosed with ADHD. The team excluded RCTs that included participants with psychiatric conditions other than ADHD.  

Eight studies met these standards. Four had a high risk of bias.  

Meta-analysis of four RCTs with a combined total of 481 participants reported no significant improvements in either working memory or inhibition from game-based digital interventions relative to controls. 

Likewise, meta-analysis of three RCTs encompassing 160 children and adolescents found no significant improvement in shifting tasks relative to controls. 

And meta-analysis of two RCTs combining 131 participants reported no significant gains in initiating, planning, organizing, and monitoring abilities, nor in emotional control

The only positive results were from two RCTs with only 90 total participants that indicated some improvement in visuospatial short-term memory and visuospatial working memory.  

There was no indication of effect size, because the team used mean differences instead of standardized mean differences.  

Conclusion:

The team concluded, “The meta-analysis revealed that game-based interventions significantly improved cognitive functions: (a) visuospatial short-term memory … and (b) visuospatial working memory … However, effects on behavioral aspects such as inhibition and monitoring … were not statistically significant, suggesting limited behavioral improvement following the interventions.” 

Simply put, the current evidence does not support the effectiveness of game-based interventions in improving behavioral symptoms of ADHD in children and adolescents. The only positive results were from two studies with a small combined sample size, which does not qualify as a genuine meta-analysis. All the other meta-analyses performed with larger sample sizes reported no benefits. 

Meta-analysis Finds Narrative Language Impairment in Youths with ADHD

Meta-analysis Finds Narrative Language Impairment in Youths with ADHD

Youths with ADHD are known to be more prone to language problems when compared with typically developing peers. To what extent does that affect their ability to share a narrative with others?

A Danish research team conducted a systematic review and meta-analysis of the peer-reviewed medical literature to explore this question. They stressed that this ability is important because "a narrative is a genre of discourse - a form of social communication used to derive meaning from experiences and to construct a shared understanding of events. In other words, it is the fundamental ability of orally producing a coherent story." They focused on the production of narratives rather than comprehension.

Studies had to have a minimum of 10 participants. They had to compare aspects of oral narrative production in children and adolescents with either a formal ADHD diagnosis or a score above a clinical cut-off on a validated ADHD rating scale to a control group of typically developing youths. Youths with confirmed autism spectrum disorder (ASD) or language impairment diagnoses were excluded. There were no constraints on IQ.

The team found sixteen studies with a combined total of 1,015 youths that met these criteria and were suitable for meta-analysis.

They examined seven aspects of oral narrative production:

·        Coherence: A story structure that is logical and easy to follow in cause and sequence. There is a clear beginning, middle, and end. There are goals, attempts, and outcomes. A meta-analysis of nine studies with a combined total of 750 participants found youths with ADHD less coherent than their typically developing peers, with a medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Cohesion: This ensures referencing of events and characters in a manner that enables the listener to grasp how characters, events, and ideas in a story are related. Ambiguous or contradictory references get in the way of this. A meta-analysis of eight studies with a combined total of 501 participants found youths with ADHD showed less cohesion than their typically developing peers, with a medium effect size. Again, with virtually no between-study heterogeneity, and no sign of publication bias.
·        Disruptions: These can be sequence errors, misinterpretations, embellishments, or confabulations - fabricating imaginary experiences as compensation for loss of memory. A meta-analysis of six studies with 389 participants found youths with ADHD had more disruptions than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bias.
·        Fluency: Best explained in terms of errors that interfere with this quality, such as false starts, repeating words or sentences, and abandoning sentences without completing them. A meta-analysis of four studies with 220 participants found no difference in fluency between youths with ADHD and their typically developing peers.
·        Production: This is a measure of output -overall length of the story, number of sentences, number of words. After adjusting for evidence of publication bias, a meta-analysis of twelve studies with 645 participants found no difference here.
·        Syntactic complexity: This includes the extent of vocabulary and the use of proper grammar. A meta-analysis of six studies with 272 participants found youths with ADHD displayed less syntactic complexity than their typically developing peers, with a small-to-medium effect size. There was virtually no between-study heterogeneity and no sign of publication bi
·        Internal state language: References to perceptions, thoughts, beliefs, and feelings. There were only two studies with 130 participants, so no meta-analysis was performed.

The authors concluded, "the results from the current meta-analysis suggest that children with ADHD have impairments in their narrative language. In particular, children with ADHD produce narratives that are less coherent, less cohesive, less syntactically complex, and include more disruptive errors than typically developing children do."

December 4, 2023

Taiwan Nationwide Population Study Concludes Dopaminergic ADHD Medications Reduce Risk of Myopia

The Background:

Myopia is a growing global health concern linked to conditions like macular degeneration, glaucoma, and retinal detachment. Its prevalence has surged in recent decades; by 2050, an estimated 5 billion people will have myopia. The increase is especially marked in Asia – a survey in Taiwan reports that 84% of students aged 15 to 18 are myopic, with 24% severely affected. 

Dopamine is an important neurotransmitter in the retina, involved in eye development, visual signaling, and refractive changes. The dopamine hypothesis, suggesting that retinal dopamine release helps prevent myopia, has emerged as a leading theory of myopia control. 

Most studies show ADHD is highly heritable, often involving dopamine system genes. ADHD is strongly associated with dopaminergic abnormalities, especially in dopamine transporter function and release dynamics. 

Medications for ADHD, like methylphenidate, atomoxetine, and clonidine, help regulate dopamine to reduce symptoms.  

The Study:

Given dopamine’s critical involvement in both ADHD and myopia, a Taiwanese research team hypothesized that medications for ADHD that influence dopaminergic pathways may have a significant effect on myopia risk.  

To evaluate this hypothesis, the team conducted a nationwide cohort study using data from Taiwan’s National Health Insurance (NHI) program, which covers 99% of the nation’s 23 million residents and provides access to comprehensive eye care and screenings. Taiwan requires visual acuity screenings beginning at age four, with annual examinations for school-aged children to promote the early detection of visual anomalies such as myopia.  

Furthermore, ADHD medication and diagnosis are tracked through compulsory diagnostic codes. This permits an accurate assessment of the effects of dopaminergic medications on myopia risk. 

Propensity score allocation using a multivariable logistic regression model was applied to reduce bias from confounding influences, pairing cohorts based on similar scores. 

The Results: 

Comparing 133,945 individuals with ADHD with an equal number without ADHD, untreated ADHD was associated with a 22% greater risk of myopia.  

However, after adjusting for covariates (gender, age, insured premium, comorbidities, location, and urbanization level), the ADHD cohort receiving medication treatment showed a 39% decreased risk of myopia relative to the untreated ADHD cohort. 

Narrowing this further to the ADHD cohort receiving dopaminergic medications reduced the risk of myopia by more than half (52%) relative to the untreated ADHD cohort.  

Treatment with two dopaminergic medications reduced the risk by well over two-thirds (72%) relative to the untreated ADHD cohort. 

There were no significant differences between methylphenidate, atomoxetine, and clonidine. Each reduced risk by about 50%. 

The team did not directly compare the ADHD cohort receiving dopaminergic medications with the non-ADHD cohort. But if there were 122 cases of myopia in the ADHD cohort for every 100 cases in the non-ADHD cohort, and dopaminergic medications halved the cases in the ADHD cohort to about 60, that would represent a roughly 40% reduction in myopia risk relative to the non-ADHD cohort. 

The team concluded, “our research indicates that pharmacologically treated ADHD children have a reduced risk of myopia. Conversely, untreated ADHD children are at a heightened risk relative to those without ADHD. Moreover, the cumulative effects of ADHD medications were found to notably decrease myopia incidence, emphasizing the protective influence of dopaminergic modulation in these interventions.” 

The Take-Away:

Children with untreated ADHD are more likely to develop myopia, but those receiving dopaminergic medications had a substantially lower risk. The findings suggest that ADHD medications may help protect against myopia by boosting dopamine signaling. More research is needed before firmly drawing this conclusion, but this research could open the door to new approaches for preventing myopia in at-risk children.

December 8, 2025

Two New Meta-analyses Point to Benefits of Transcranial Direct Current Stimulation

Background: 

ADHD treatment includes medication, behavioral therapy, dietary changes, and special education. Stimulants are usually the first choice but may cause side effects like appetite loss and stomach discomfort, leading some to stop using them. Cognitive behavioral therapy (CBT) is effective but not always sufficient on its own. Research is increasingly exploring non-drug options, such as transcranial direct current stimulation (tDCS), which may boost medication effectiveness and improve results. 

What is tDCS?

tDCS delivers a weak electric current (1.0–2.0 mA) via scalp electrodes to modulate brain activity, with current flowing from anode to cathode. Anodal stimulation increases neuronal activity, while cathodal stimulation generally inhibits it, though effects vary by region and neural circuitry. The impact of tDCS depends on factors such as current intensity, duration, and electrode shape. It targets cortical areas, often stimulating the dorsolateral prefrontal cortex for ADHD due to its role in cognitive control. Stimulation of the inferior frontal gyrus has also been shown to improve response inhibition, making it another target for ADHD therapy. 

There is an ongoing debate about how effective tDCS is for individuals with ADHD. One study found that applying tDCS to the left dorsolateral prefrontal cortex can help reduce impulsivity symptoms in ADHD, whereas another study reported that several sessions of anodic tDCS did not lead to improvements in ADHD symptoms or cognitive abilities.  

New Research:

Two recent meta-analyses have searched for a resolution to these conflicting findings. Both included only randomized controlled trials (RCTs) using either sham stimulation or a waitlist for controls. 

Each team included seven studies in their respective meta-analyses, three of which appeared in both. 

Both Wang et al. (three RCTs totaling 97 participants) and Wen et al. (three RCTs combining 121 participants) reported very large effect size reductions in inattention symptoms from tDCS versus controls. There was only one RCT overlap between them. Wang et al. had moderate to high  variation (heterogeneity) in individual study outcomes, whereas Wen et al. had virtually none. There was no indication of publication bias. 

Whereas Wen et al.’s same three RCTs found no significant reduction in hyperactivity/impulsivity symptoms, Wang et al. combined five RCTs with 221 total participants and reported a medium effect size reduction in impulsivity symptoms. This time, there was an overlap of two RCTs between the studies. Wen et al. had no heterogeneity, while Wang et al. had moderate heterogeneity. Neither showed signs of publication bias.  

Turning to performance-based tasks, Wang et al. reported a medium effect size improvement in attentional performance from tDCS over controls (three RCTs totaling 136 participants), but no improvement in inhibitory control (five RCTs combining 234 persons). 

Wang et al. found no significant difference in adverse events (four RCTs combining 161 participants) between tDCS and controls, with no heterogeneity. Wen et al. found no significant difference in dropout rates (4 RCTs totaling 143 individuals), again with no heterogeneity.  

Wang et al. concluded, “tDCS may improve impulsive symptoms and inattentive symptoms among ADHD patients without increasing adverse effects, which is critical for clinical practice, especially when considering noninvasive brain stimulation, where patient safety is a key concern.” 

Wen et al. further concluded, “Our study supported the use of tDCS for improving the self-reported symptoms of inattention and objective attentional performance in adults diagnosed with ADHD. However, the limited number of available trials hindered a robust investigation into the parameters required for establishing a standard protocol, such as the optimal location of electrode placement and treatment frequency in this setting. Further large-scale double-blind sham-controlled clinical trials that include assessments of self-reported symptoms and performance-based tasks both immediately after interventions and during follow-up periods, as well as comparisons of the efficacy of tDCS targeting different brain locations, are warranted to address these issues.” 

The Take-Away: 

Previous studies have shown mixed results on the benefits of this therapy on ADHD. These new findings suggest that tDCS may hold some real promise for adults with ADHD. While the technique didn’t meaningfully shift hyperactivity or impulsivity, it was well-tolerated and showed benefit, especially in self-reported symptoms. However, with only a handful of trials to draw from, it would be a mistake to suggest tDCS as a standard treatment protocol. Larger, well-designed studies are the next essential step to clarify where, how, and how often tDCS works best.

Meta-analysis Reports Executive Function Gains from Exercise Interventions for ADHD

Background:

The development of ADHD is strongly associated with functional impairments in the prefrontal cortex, particularly the dorsolateral prefrontal cortex, which plays a key role in maintaining attention and controlling impulses. Moreover, imbalances in neurotransmitters like dopamine and norepinephrine are widely regarded as major neurobiological factors contributing to ADHD. 

Executive functions are a group of higher-order cognitive skills that guide thoughts and actions toward goals. “Executive function” refers to three main components: inhibitory control, working memory, and cognitive flexibility. Inhibitory control helps curb impulsive actions to stay on track. Working memory allows temporary storage and manipulation of information for complex tasks. Cognitive flexibility enables switching attention and strategies in varied or demanding situations. 

Research shows that about 89% of children with ADHD have specific executive function impairments. These difficulties in attention, self-control, and working memory often result in academic and social issues. Without timely intervention, these issues can lead to emotional disorders like depression, anxiety, and irritability, further affecting both physical health and social development. 

Currently, primary treatments for executive function deficits in school-aged children with ADHD include medication and behavioral or psychological therapies, such as Cognitive Behavioral Therapy (CBT). While stimulant medications do improve executive function, not all patients are able to tolerate these medications. Behavioral interventions like neurofeedback provide customized care but show variable effectiveness and require specialized resources, making them hard to sustain. Safer, more practical, and long-lasting treatment options are urgently needed. 

Exercise interventions are increasingly recognized as a safe, effective way to improve executive function in children with ADHD. However, systematic studies on school-aged children remain limited.  

Moreover, there are two main scoring methods for assessing executive function: positive scoring (higher values mean better performance, such as accuracy) and reverse scoring (lower values mean better performance, such as reaction time). These different methods can affect how results are interpreted and compared across studies. This meta-analysis explored how different measurement and scoring methods might influence results, addressing important gaps in the research. 

The Study:

Only randomized controlled trials (RCTs) involving school-aged children (6–13 years old) diagnosed with ADHD by DSM-IV, DSM-5, ICD-10, ICD-11, or the SNAP-IV scale were included. Studies were excluded if the experimental group received non-exercise interventions or exercise combined with other interventions. 

Cognitive Flexibility 

Using positive scoring, exercise interventions were associated with a narrowly non-significant small effect size improvement relative to controls (eight RCTs, 268 children). Using reverse scoring, however, they were associated with a medium effect size improvement (eleven RCTs, 452 children). Variation (heterogeneity) in individual RCT outcomes was moderate, with no sign of publication bias in both instances. 

Inhibitory Control 

Using positive scoring, exercise interventions were associated with a medium effect size improvement relative to controls (ten RCTs, 421 children). Using reverse scoring, there was an association with a medium effect size improvement (eight RCTs, 265 children). Heterogeneity was moderate with no sign of publication bias in either case. 

Working Memory 

Using positive scoring, exercise interventions were associated with a medium effect size improvement relative to controls (six RCTs, 321 children). Using reverse scoring, the exercise was associated with a medium effect size improvement (five RCTs, 143 children). Heterogeneity was low with no indication of publication bias in both instances. 

Conclusion:

The team concluded, “Exercise interventions can effectively improve inhibitory control and working memory in school-aged children with ADHD, regardless of whether positive or reverse scoring methods are applied. However, the effects of exercise on cognitive flexibility appear to be limited, with significant improvements observed only under reverse scoring. Moreover, the effects of exercise interventions on inhibitory control, working memory, and cognitive flexibility vary across different measurement paradigms and scoring methods, indicating the importance of considering these methodological differences when interpreting results.” 

Although this work is intriguing, it does not show that exercise significantly improves the symptoms of ADHD in children. This means that exercise, although beneficial for many reasons, should not be viewed as a replacement for evidence-based treatments for the disorder.

December 3, 2025