Exploring non-clinical inattention in adults: prevalence, and links to working memory and self-regulation.

Abstract

Inattention is a symptom related to several mental health disorders, most notably ADHD. Recent work has suggested that a) inattention is a symptom worth studying in it’s own right regardless of co-occurring pathology, b) it persists beyond childhood and may be more relevant to adults than the other ADHD symptoms (hyperactivity and impulsivity), and c) it is dimensional so investigation of it should consider the full spectrum of symptom expression. The approach of this thesis is based on these points. A preliminary study addressed the prevalence of inattention. Findings validated the approach of the thesis and suggested that inattention is highly prevalent in a general population sample of adults (over 30% when broadly defined), more so than hyperactivity-impulsivity. Across four further studies we used behavioural and pupillometry measures to investigate the cognitive underpinnings of inattention with a view to differentiating it from hyperactivity and impulsivity. Research suggests a role for executive functions (EFs) and self-regulatory processes in ADHD, although there is conflicting theory on what aspects of these relate to which symptoms. Various EF and self-regulatory components, with consideration for “hot” and “cool” cognitive distinctions, were tested in relation to ADHD symptoms using a model based on an interpretation of the literature. Findings across studies were mixed, but make several notable contributions to literature in this area. Firstly we demonstrated a unique and robust relationship between inattention and working memory. Secondly, we show strong evidence against a relationship between inattention and norepinephrine activity as indexed by changes in pupil diameter. There were also notable distinctions between inattention and the other symptoms of ADHD across the research. We discuss how these findings relate to theory on “hot” and “cool” cognition, along with their application to both general population and clinical groups.