Predictors of response to second generation antipsychotics in drug naïve patients with schizophrenia: a 1 year follow-up study in Shanghai.

Response and remission are of great importance to patients with first-episode schizophrenia. Although previous researches have revealed characteristics related to medication response, there is rarely data over remission-related factors. We presume that factors correlated to response may also influence remission in 1 year treatment for first-episode schizophrenia. 398 drug-naïve patients met the criteria of schizophrenia using ICD-10 criteria were recruited from Shanghai Mental Health Center and treated with one of three second generation antipsychotics (risperidone, olanzapine or quetiapine). Patients were followed up for 1 year and assessed at 2 weeks, and then 2, 3, 6, 8 and 12 months. Severity of symptom was evaluated using the Chinese version of the Positive and Negative Syndrome Scale (PANSS). Response was defined as a reduction of 50% or more PANSS scores. The 8-item criteria of remission (proposed by the Remission of Schizophrenia Working Group) were used. Logistic regression analysis revealed that shorter duration of untreated psychosis (DUP), longer treatment time, higher baseline PANSS positive score and higher PANSS general pathological scores predicted response, and acute prodromal phase was the independent factor for remission. These results indicate baseline characters that related to response and those related to remission may be different for patients with schizophrenia.