Differentiation of ADHD and Depression Based on Cognitive Performance

Objective: The aim of this study was to assess whether self-report scales and neuropsychological tests used for adult patients with ADHD can help to distinguish between ADHD-specific and depressive symptoms. Method: In a cross-sectional design, differences in self-report questionnaires and neuropsychological tests among clinical subgroups and healthy controls (HC) were evaluated. Patients in clinical groups were diagnosed with major depressive disorder (MDD) or ADHD with or without depressive symptoms according to Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) guidelines. Results: The Hyperactivity subscales of the Conners’ Adult ADHD Rating Scale (CAARS) differed between MDD and ADHD, whereas self-concept and inattention scales even distinguished comorbidity subgroups within the ADHD population. A reduced alertness and higher variations in reaction times measured by performance tests indicated problems in sustained attention in ADHD patients compared with HC. Conclusion: The diagnostic process of ADHD, and thereby the distinction from other symptom-overlapping, comorbid mental disorders, might be improved by utilizing ADHD-specific self-report questionnaires and neuropsychological tests, which are short, cost-effective, and standardized screening methods.