An early improvement in depressive symptoms predicts symptomatic remission of schizophrenia treated with quetiapine: A multicenter, 4-week case-control study

The aim of this study was to determine whether an early improvement in depressive symptoms is a predictor of symptomatic remission in schizophrenia. Patients with DSM-IV schizophrenia diagnosis who received antipsychotic treatment but did not fulfill Andreasen's symptomatic remission criteria were recruited. Each patient received quetiapine with a flexible dose strategy of 300-800 mg daily for 4 weeks after a 1-week washout period of previous antipsychotics. Remission was defined by Andreasen's criteria, which includes eight items of the Positive and Negative Symptom Scale with scores of less than three in each item. Seventy-five patients completed the study. Of these, 27 (36%) achieved symptomatic remission after treatment with quetiapine. A significant improvement in depressive symptoms was found in both the remission and the nonremission groups, although the improvement was less pronounced in the nonremission group at the endpoint. Binary logistic regression analysis showed that age (β=-0.07, P=0.02) and early improvement in depressive symptoms within the first 3 days were predictive of symptomatic remission (β=-0.27, P=0.01) for the treatment of schizophrenia. Our data suggest that an early improvement in depressive symptoms in the treatment of schizophrenia is crucial for symptomatic remission.