Prediction of acute clinical response following a first episode of non affective psychosis: results of a cohort of 375 patients from the Spanish PAFIP study.

Objective: Predicting response to antipsychotic treatment might optimize treatment strategies in early phases of schizophrenia. We aimed to investigate sociodemographic, premorbid and clinical predictors of response to antipsychotic treatment after a first episode of non-affective psychosis.

Method: 375 (216 males) patients with a diagnosis of non affective psychosis entered the study. The main outcome measure was clinical response at 6 weeks and variables at baseline were evaluated as predictors of response. ANOVA for continuous and chi-square for categorical data were used to compare responders and non-responders. Multivariate logistic regression was used to establish a prediction model.

Results: 53.3% of study subjects responded to antipsychotic treatment. The following variables were associated with an unfavorable response: 1.--lower severity of symptoms at baseline; 2.--diagnosis of schizophrenia; 3.--longer DUI and DUP; 4.--poorer premorbid adjustment during adolescence and adulthood; 5.--family history of psychosis, and 6.--hospitalization. Patients with a family history of psychosis, longer DUP, poor premorbid functioning and lower severity of psychotic symptoms at intake have a reduced likelihood of responding to antipsychotic treatment.

Conclusion: Helping clinicians to identify those first episode patients with a lower probability of having a favorable clinical response is meant as a first step to achieve a successful initial treatment.