Cognitive and electrophysiological markers of adult full syndrome and subthreshold attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) has been often referred to as an executive function deficit disorder with a specific electrophysiological signature. Although previous research suggests that individuals with subthreshold symptoms also suffer from severe impairments in daily life, only few studies have investigated cognitive and neural alterations in this group. Here, we explored impairments in executive functions and their electrophysiological correlates in a sample of adults with full syndrome (N = 113) and subthreshold (N = 46) ADHD compared to controls (N = 42). Results suggest that adults with full syndrome ADHD exhibit more executive function deficits than controls, while there were no electrophysiological differences found between groups. Also, we observed only small differences in neuropsychological variables between subthreshold ADHD and controls and no evidence for altered neural activity in the resting state. While subthreshold ADHD was not associated with altered executive functions or abnormal electrophysiological activity, this group reported significant psychological impairments and comorbidity.