Patients with schizophrenia often experience comorbid obsessive-compulsive syndromes (OCSs). Within these patients, a significant subgroup developed secondary OCS during treatment with antiserotonergic, atypical antipsychotic agents such as clozapine. Although cognitive behavioral therapy and antiobsessive antidepressants brought up inconsistent results, in some cases, dose reductions of clozapine in combination approaches were able to alleviate OCS. One suggestive agent for antiobsessive add-on treatment is aripiprazole, a partial agonist at dopamine and serotonin receptors.Here, we summarize the courses of 7 patients (6 men; mean age, 37 years; mean duration of psychotic illness, 17 years). They had been treated with clozapine for 9 years. The distressing and treatment-resistant comorbidity with OCS emerged approximately 4 years after the start of clozapine therapy. During combined treatment with mean doses of 22.9 mg of aripiprazole for 9.7 weeks, we assessed a small yet statistically not significant improvement of the psychotic disorder, whereas a marked reduction of obsessions and significant improvements of compulsions could be observed. The mean total Yale Brown Obsessive Compulsive Rating Scale decreased from 18.7 to 12.4 (P = 0.003).These data support the findings of 2 previous case reports and point toward an antiobsessive potency of aripiprazole. The relevant disabling comorbidities of psychosis and OCS need further investigation with multimodal neurobiological approaches. The proposed strategy should be further evaluated in prospective controlled trials with severity of comorbid OCS as a primary end point.