Background and objectives: Aripiprazole is a first-line agent in the treatment of bipolar disorder (BD) and available data demonstrates its efficacy on clinical symptoms in serotonin reuptake inhibitors-resistant obsessive-compulsive disorder (OCD) patients. Therefore, aripiprazole augmentation to mood stabilizers could represent a promising treatment in BD patients with comorbid OCD. The study examined the efficacy and safety of aripiprazole added to lithium or valproate for the treatment of obsessive-compulsive (OC) symptoms in euthymic BD patients with comorbid OCD. Materials and methods: This is a 12-week prospective observational study. The efficacy of aripiprazole on OC symptoms was assessed through the mean change of Yale–Brown Obsessive-Compulsive (YBOCS) total score. Tolerability was assessed with the Utvalg for Kliniske Undersogelser (UKU) side effect scale and by reporting adverse events. Results: A total of 70 patients were included in the analyses. The withdrawal rate was 21.4%, mainly due to adverse events. Mean ± SD final aripipra-zole dose was 15.2 ± 5.3 in the completer sample (N = 55). The Y-BOCS mean score decreased from 24.0 ± 4.1 at baseline to 17.1 ± 4.3 at 12 weeks. Treatment response rate (Y-BOCS reduction ≥ 35%) was 41.8%, while partial response rate (Y-BOCS reduction greater than 25% but less than 35% from baseline) accounted for the other 18.2% of patients. Overall, 91.4% of completers had at least 1 adverse effect (tremor, tension/inner unrest, reduced duration of sleep, akathisia). No significant differences emerged comparing aripiprazole efficacy and tolerability between patients treated with lithium or valproate. Conclusion: Our findings show that aripiprazole addition to lithium or valproate can reduce OC symptoms in real-world BD euthymic patients.
