Attention regulation in women with ADHD and women with bipolar disorder: an ex-Gaussian approach

Abstract Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) show certain overlapping features, such as increased reaction time variability. Here, we tested whether more detailed ex-Gaussian measures identify shared or disorder-specific impairments in ADHD and BD. The sample consisted of 60 women (20 each in ADHD, BD and control groups). We compared the groups on ex-Gaussian measures of mu, sigma, and tau from a flanker task (congruent and incongruent conditions), an oddball task, and a four-choice reaction time task (baseline and fast-incentive conditions of the ‘fast task’). The ex-Gaussian measures mu and sigma reflect the speed and variability of typical responses, while tau captures infrequent slow responses. Compared to controls, both ADHD and BD groups showed a significantly increased tau in the fast task baseline condition. Participants with BD further showed a significantly increased sigma compared to ADHD and control groups in the flanker task incongruent condition. Our findings indicate that the ex-Gaussian approach is informative in detecting shared and disorder-specific cognitive impairments in ADHD and BD that may represent objective markers of these two disorders.