Symptomatic remission in schizophrenia: Results from a risperidone maintenance treatment study.

This study aimed to investigate remission following the treatment of schizophrenia patients with risperidone. Clinically stabilized patients with schizophrenia (n = 374) were randomly assigned to 4-week, 26-week, or no-dose-reduction groups, in which the baseline risperidone dose was continued for 4, 26, or all weeks during 1-year period. The 'Positive and Negative Syndrome Scale' (PANNS) was assessed at baseline and monthly for six months, followed by every two months until the last recruited patient completed 1-year follow-up. Symptomatic remission was defined according to criteria established by the Schizophrenia Working Group. A Generalized Linear Mixed Model indicated significant variation in remission over time, which increased after baseline in the entire group (F = 49.32, df = 1, 3114, P < 0.001). The overall length of risperidone treatment (F = 4.34, df = 1, 416, P = 0.038) and the duration of illness (F = 8.51, df = 1, 359, P = 0.004) had significantly negative effects upon remission. Baseline remission patients were associated with a significantly increased time to relapse compared with the baseline of non-remission patients over a one year follow up period (F = 5.74, df = 1, 367, P = 0.017). One-year risperidone maintenance treatment increased remission rates in schizophrenia. A shorter illness duration, risperidone treatment length, and a lower total PANSS score were clinically useful predictors of remission. Achieving remission may postpone relapse.