The present study investigated whether schizophrenic, unipolar depressive, and obsessive–compulsive psychiatric patients show a distinguishable profile in tasks considered sensitive to frontal lobe functioning. Three psychiatric samples, each comprising 25 patients with little symptomatic overlap, were compared to 70 healthy controls. Participants completed several executive tasks (Wisconsin Card Sorting Test (WCST), verbal fluency, digit span, Stroop, and Trail-Making). Except for age, which was entered as a covariate, subjects did not differ in any sociodemographic background variable. Healthy controls showed superior performance relative to depressive and schizophrenic patients who exhibited comparable deficits in all tasks. Obsessive–compulsive disorder (OCD) patients revealed dysfunctions in the Trail-Making Tests A and B and in the fluency task. Dysfunctions in the domains of working memory, verbal fluency, distractibility, and concept formation were not confined to a specific psychiatric population.