Application of the dual-component model of working memory to ADHD

Attention deficit/hyperactivity disorder (ADHD) has been associated with a deficit in working memory across both verbal and spatial domains, but the precise nature of this deficit is poorly understood. The dual-component model postulates that working memory capacity consists of two dissociable components: maintenance in primary memory (PM) and recall from secondary memory (SM). Participants diagnosed with ADHD (n=32) and age-matched controls (n=31) performed both verbal and spatial free-recall tasks, and subsets of these two samples were selected for further comparison based on their use of a "recency" order-of-report strategy. The primary results showed that maintenance in PM appears to be largely intact whereas recall from SM appears to be deficient in ADHD relative to age-matched controls. Similar outcomes were observed across both task domains. Implications for understanding both the underlying pathology and treatment of ADHD are discussed.