Executive and Non-Executive Functions in Attention Deficit Hyperactivity Disorder of the Inattentive Type (ADHD-I): A Cognitive Profile

Objective: This study examined the hypothesis that individuals with attention deficit hyperactivity disorder, predominantly inattentive type (ADHD-I), show both executive function (EF) deficits and non-EF deficits. Method: A group with ADHD-I (n = 16) and a paired control group (n = 21) completed a battery of tasks covering the major domains of EF (planning, working memory, flexibility and inhibition) and non-EF (alertness, divided attention, flexibility, sustained attention, visual field and visual scanning). Results: EF impairments in planning, spatial working memory, flexibility, and inhibition as well as non-EF impairments in divided attention, flexibility, sustained attention and visual scanning were observed in the ADHD-I group. Conclusion: Our results do not support the traditional model of ADHD. Given that neither EF nor non-EF tests typically distinguish ADHD-I from ADHD-C, alternative methodologies are required to confirm the validity of ADHD subtypes in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.