Fatigue in an adult attention deficit hyperactivity disorder population: A trans-diagnostic approach.

Objectives: Trans-diagnostic approaches suggest that key cognitive and behavioural processes maintain symptoms across a wide range of mental health disorders. Fatigue is a common clinical feature of attention deficit hyperactivity disorder (ADHD) in adulthood; however, empirical data supporting its prevalence are lacking. This study aimed to collate outcomes from outpatient services to (1) investigate the prevalence of fatigue in adults with ADHD, (2) examine symptoms of ADHD in adults with chronic fatigue syndrome (CFS), and (3) consider secondary clinical characteristics common to both disorder groups.