ABSTRACT
OBJECTIVE: The aim of this study was to demonstrate changes of clinical benefit and subjective wellbeing after once-daily extended release quetiapine furmate (quetiapine XR) in patients with schizophrenia. METHODS: In a naturalistic, observational, and multicentric study, 1,494 patients with schizophrenia who switched to quetiapine XR (flexible dosing) due to insufficient efficacy or intolerance were recruited. Clinical Global Impressions-Clinical Benefit (CGI-CB), CGI-Severity (CGI-S), CGI-Improvement (CGI-I) and Subjective Wellbeing under Neuroleptic Treatment Scale (SWN-K) were assessed at baseline and after 8 weeks treatment. We also examined factors related to changes of CGI-CB and SWN-K scores using linear regression analysis. RESULTS: Among 1,494 patients, 1,342 patients (89.8%) completed this study and 1,204 patients (80.6%) without protocol violation were included in the analysis. The mean dose of quetiapine XR was 416.9+/-205.8 mg/day at the initiation and continuously increased to 591.6+/-228.3 mg/day until week 5. At the endpoint, the mean dose of quetiapine XR was 580.24+/-382.24 mg/day. Both CGI-CB and CGI-S scores were significantly decreased after 8 weeks (both p<0.0001) and 745 patients (61.9%) achieved clinical benefit. Mean CGI-I scores were 2.49+/-0.80 and the response rate defined as CGI-I< or =2 was 51.6%. Subjective wellbeing scores were increased after 8 weeks (p<0.0001). Improvements of CGI-CB and subjective wellbeing were associated with quetiapine XR dosages as well as age and baseline scores. CONCLUSION: After switching to quetiapine XR, 61.9% of patients with schizophrenia who had a history of unsatisfactory treatment (efficacy or tolerance) showed clinical benefit and subjective wellbeing was significantly increased. Regarding that dosages of quetiapine XR were associated with improvements of clinical benefit and subjective wellbeing, active treatment strategies with higher dosages of quetiapine XR could be suggested in the real field.