Clinical predictors of response to olanzapine or risperidone during acute episode of schizophrenia

The study attempted to identify clinical variables which could predict the response to a second-generation antipsychotic treatment during acute episodes among schizophrenic patients. Socio-demographic, premorbid and clinical variables were studied in a population of 95 diagnosed with schizophrenia, as defined in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSMIV), during an acute treated phase, in a multicentre prospective study. Patients were assigned to olanzapine or risperidone treatment in an open design. Clinical evaluations were performed at D0, D42 and D180. Good response to treatment was defined as a Positive and Negative Syndrome Scale (PANSS) reduction greater than 20% and a Brief Psychiatric Rating Scale (BPRS) score lower than 35. Univariate analysis revealed earlier age at onset of schizophrenia and earlier age at first prescription of antipsychotic among non-responders compared with good responders at D42. Non-responders also had a clinical profile at the onset of antipsychotic treatment characterised by more severe forms of the acute episode as shown by higher scores at the positive, general and overall PANSS scale and on CGI-S and BPRS scores. With a multivariate logistic regression model, age at onset and overall duration of illness remained the only clinical criteria identified as predictors of response to antipsychotic treatment at D42. Clinical variables do not clearly appear to be good predictors of treatment efficacy.