Early- and Delayed Antipsychotic Response and Prediction of Outcome in 528 Severely Impaired Patients with Schizophrenia Treated with Amisulpride

Introduction: 'Early-onset' studies have shown that symptomatic response often occurs early and that early symptomatic response is predictive for later outcome. Limiting factors of these studies include the restriction on symptomatic outcome, the inclusion of mostly moderately ill patients, and the use of various antipsychotics. Methods: Response and remission rates were assessed in 528 severely ill patients with schizophrenia at baseline, week 2,4 and 12 using PANSS, SWN-K, CGI-S, and SOFAS. The clinical measures were combined to one outcome criterion (Com-bOut). Predicitive validity was analyzed for Com-bOut using linear regression models. Results: Rate and time to response differed markedly between outcome measures. 32% reached positive symptom response at week 2, 58% at week 4 and 85% at week 12. Non-response at week 4, but not at week 2 was predictive for later non-response. The combined outcome criterion was best predicted by early response in subjective wellbeing (T=-7.88, p < 0.001) and social functioning(T=-7.43, p < 0.001). Discussion: Rate and time to response might depend on sample characteristics and outcome measure. In severely ill patients early antipsychotic response is possibly delayed from the first 2 to the first 4 weeks. Early response in subjective wellbeing and social functioning are strong predictors for overall outcome, which make them a useful supplementation to the assessment of symptomatic response.