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A comprehensive meta-analysis has shed light on the enduring cognitive benefits of ADHD medications, specifically methylphenidate and atomoxetine.

The study, conducted by researchers at King's College London, marks the first extensive review of chronic medication effects on cognitive functions in individuals with Attention Deficit/Hyperactivity Disorder (ADHD).

ADHD affects an estimated 4-7% of the population, characterized by symptoms of inattention, hyperactivity, and impulsiveness that often persist into adulthood. Executive functions such as sustained attention, working memory, and inhibitory control are particularly impaired in those with ADHD, impacting academic and occupational performance.

Lead study author Katya Rubia emphasized the significance of understanding the long-term cognitive impacts of ADHD medications, stating, "Both drugs commonly used for ADHD do not just improve ADHD behaviors but also improve cognitive functions. This is important as it suggests they will be useful to improve school performance or occupational performance."

The meta-analysis published in Neuroscience and Biobehavioral Reviews encompassed 28 studies, evaluating the effects of methylphenidate and atomoxetine on attention, inhibition, reaction time, and working memory. Methylphenidate, a stimulant that increases dopamine and norepinephrine levels in the brain, demonstrated medium to large improvements in attention (Hedges' g = 0.59) and inhibition (Hedges' g = 0.37). Atomoxetine, a non-stimulant that inhibits norepinephrine reuptake, showed slightly larger effects on attention (Hedges' g = 0.64) and inhibition (Hedges' g = 0.47).

Both medications also enhanced reaction time, though to a lesser extent: methylphenidate (Hedges' g = 0.34) and atomoxetine (Hedges' g = 0.36). PsyPost reported, methylphenidate significantly improved working memory (Hedges' g = 0.36), whereas atomoxetine showed promising results without statistical significance (Hedges' g = 0.30), possibly due to fewer studies included.

Rubia said the findings suggest both methylphenidate and atomoxetine are equally effective in enhancing cognitive performance in individuals with ADHD. The study's rigorous analysis included only randomized, double-blind, placebo-controlled trials involving children, adolescents, and adults diagnosed with ADHD.

Despite the robust evidence supporting these medications' cognitive benefits, the study noted limitations, such as the relatively smaller number of atomoxetine studies compared to methylphenidate. Further research is needed to explore the effects of other ADHD medications on cognition comprehensively.

"We are also testing currently the effects of newer licenced drugs for ADHD such as lisdexamfetamine and guanfacine on ADHD cognition and brain function using fMRI," Rubia added.