Activities of daily living and working memory in pediatric attention-deficit/hyperactivity disorder (ADHD)

Most children with ADHD have impaired working memory abilities. These working memory deficits predict impairments in activities of daily living (ADLs) for adults with ADHD. However, our understanding of the relation between pediatric ADHD and ADLs is limited. Thus, this study aimed to examine (1) the extent to which pediatric ADHD is associated with ADL difficulties; and if so (2) the extent to which these difficulties are related to their well-documented working memory difficulties and/or core ADHD inattentive and hyperactive/impulsive symptom domains. A well-characterized, clinically evaluated sample of 141 children ages 8-13 years (M = 10.36, SD = 1.46; 51 girls; 70% White/non-Hispanic) were administered a battery of well-validated working memory tests and assessed for ADHD symptoms (teacher-ratings) and ADL difficulties (parent-ratings); cross-informant reports were used to control for mono-informant bias. Children with ADHD exhibited medium magnitude difficulties with ADLs (d = 0.61, p <0.005, 38% impaired). Results of the bias-corrected, bootstrapped conditional effects model indicated that lower working memory predicted reduced performance of age-expected ADLs (beta =0.28) and greater ADHD inattentive (beta = -0.40) and hyperactive/impulsive symptoms (beta = -0.16). Greater inattentive, but not hyperactive/impulsive, symptoms predicted greater ADL difficulties (beta = -0.36) even after controlling for working memory. Interestingly, working memory exerted a significant indirect effect on ADLs via inattentive (indirect effect: beta =0.15, effect ratio =0.54) but not hyperactive/impulsive symptoms. These findings implicate ADHD inattentive symptoms as a potential mechanism underlying ADL difficulties for children with ADHD, both independently and via working memory's role in regulating attention.