Visuospatial working memory underlies choice-impulsivity in boys with attention-deficit/hyperactivity disorder

• The directional relationship between choice-impulsivity and separate indices of phonological and visuospatial working memory performance in boys with and without ADHD was examined.
• Overall ADHD, inattention, and hyperactivity were associated with increased impulsivity and poorer phonological and visuospatial working memory.
• Mediation analyses revealed a significant indirect effect of visuospatial working memory performance, through choice-impulsivity, on measures of overall ADHD, inattention, and hyperactivity/impulsivity.
• Findings suggest that deficits of visuospatial working memory underlie choice-impulsivity, which in turn contributes to the ADHD phenotype.

The present study examined the directional relationship between choice-impulsivity and separate indices of phonological and visuospatial working memory performance in boys (aged 8–12 years) with (n = 16) and without ADHD (n = 19). Results indicated that high ratings of overall ADHD, inattention, and hyperactivity were significantly associated with increased impulsivity and poorer phonological and visuospatial working memory performance. Further, results from bias-corrected bootstrapped mediation analyses revealed a significant indirect effect of visuospatial working memory performance, through choice-impulsivity, on overall ADHD, inattention, and hyperactivity/impulsivity. Collectively, the findings suggest that deficits of visuospatial working memory underlie choice-impulsivity, which in turn contributes to the ADHD phenotype. Moreover, these findings are consistent with a growing body of literature that identifies working memory as a central neurocognitive deficit of ADHD.