A new study highlights the benefits of physical exercise in improving cognitive function in children with attention deficit/hyperactivity disorder (ADHD), according to a report published in the Journal of Psychiatric Research. The findings support the inclusion of nonpharmaceutical interventions in conjunction with commonly used medications for the treatment of ADHD.

According to the investigators, this is the first meta-analysis that reviewed behavioral and cognitive interventions for ADHD and examined their effect on cognitive interventions. The researchers collated studies published between 1980 and 2017, extracting data from studies that used objective cognitive measures. Multiple meta-analyses were conducted to compare the effectiveness across all interventions. 

The analysis included 18 studies with interventions that were categorized into 4 groups: neurofeedback, cognitive-behavioral therapy (CBT), cognitive training, and physical exercise. Physical exercise interventions were the most effective in targeting and reducing cognitive symptoms, with a homogenous effect size of 0.93. Cognitive training interventions demonstrated the lowest effect size of 0.45, indicating a less than medium effect, but only 2 studies were included in the analysis. CBT and neurofeedback interventions both had moderate effect sizes of 0.70 and 0.61, respectively.

“All the interventions showed moderate to large effect sizes, indicating their success in reducing cognitive symptoms, as compared to control or less effective interventions,” the researchers noted.

A separate meta-analysis of cognitive functions yielded 49 effect sizes for 4 categories including attention, inhibition, flexibility, and working memory. Inhibition demonstrated the largest average effect size (0.69) and working memory demonstrated the lowest (0.4). Measures on attention and flexibility demonstrated small to medium effect sizes (0.41 and 0.6, respectively).

“When all the interventions were considered, inhibition and flexibility were the functions most affected,” the investigators said. “They demonstrated the ability to undergo a significant change following the interventions and thus could be considered the most malleable.”

The researchers conducted 2 meta-analyses reviewing medicated and unmedicated patients. In that review, improvement in cognitive function was significantly improved in unmedicated patients, with a homogenous effect size 0.67. The effect size was similar in medicated patients, “indicating only a slightly higher effect of non-pharmaceutical treatments when combined with medication,” they wrote.

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“According to this study, although all behavioral interventions designed to aid ADHD seem to have a positive effect on cognitive symptomology, physical exercise, especially aerobic exercise that included targeting executive functions, appears to be the most effective,” concluded the investigators.

Reference

Lambez B, Harwood-Gross A, Golumbic EZ, Rassovsky Y. Non-pharmacological interventions for cognitive difficulties in ADHD: a systematic review and meta-analysis [published online October 9, 2019]. J Psychiatr Res. doi:10.1016/j.jpsychires.2019.10.007