The objectives of this 12-week multicenter open-label switching study were to evaluate the overall clinical efficacy, safety, and tolerability of aripiprazole in stable patients with schizophrenia or schizoaffective disorder, and to assess, in a naturalistic setting, whether such patients experience symptom worsening when switched from D2 receptor antagonists to aripiprazole (a D2 receptor partial agonist). Patients with schizophrenia or schizoaffective disorder in a symptomatically stable state were randomized to aripiprazole or standard-of-care antipsychotics. The Clinical Global Impression (CGI), Positive and Negative Syndrome Scale, and Investigator's Assessment Questionnaire were used monthly. The Udvalg for Kliniske Undersogelser side-effect rating scale scores and treatment emergent adverse events were recorded to assess the safety and tolerability of switching to aripiprazole from other antipsychotics. A total of 292 patients were randomly assigned to receive aripiprazole (N = 245) or non-aripiprazole antipsychotics (N = 47). Mean CGI-Improvement score at 12 weeks was 3.56+/-1.29 (95% confidence interval: 3.39-3.73) in the aripiprazole group, indicating that aripiprazole was effective in treating schizophrenic patients. Aripiprazole treatment resulted in improvement from baseline on all efficacy outcome measures, including Positive and Negative Syndrome Scale total, positive, negative, and general subscale, and CGI-Severity scores. In addition, after aripiprazole treatment, the remission rate was increased from 43.9% at baseline to 51.7% at 12 weeks. The proportion of patients with symptom worsening at 12 weeks was low (12.4%). Both Investigator's Assessment Questionnaire and Udvalg for Kliniske Undersogelser scores showed that there were fewer prolactin-related adverse events in the aripiprazole group than in the standard-of-care antipsychotics group (P<0.05). There were no significant between-group differences in time to failure to maintain remission and time to dropout. In the naturalistic setting, symptomatically stable outpatients with schizophrenia who were switched to aripiprazole showed clinically meaningful treatment benefits. The majority of patients was successfully switched from other antipsychotics without serious symptom exacerbation or adverse events over a course of 12 weeks.
