Predictors of antipsychotic treatment response in patients with first-episode schizophrenia, schizoaffective and schizophreniform disorders.

Background: Duration of untreated psychosis (DUP) may contribute to the observed heterogeneity of the treatment response in first-episode schizophrenia.

Aims: To examine the relationship of DUP and premorbid function with clinical outcomes following up to 2 years of antipsychotic treatment.

Method: For a subsample (n=191) of subjects participating in a clinical trial, DUP and premorbid function were prospectively compared with clinical response to olanzapine or haloperidol.

Results: Shorter DUP and good premorbid function each independently are associated with better clinical response, including improvement in overall psychopathology and negative symptoms. Premorbid function also is associated with positive symptom, social and vocational outcomes.

Conclusions: Earlier antipsychotic treatment is associated with better outcomes in first-episode schizophrenia. Poor premorbid function could indicate an illness subtype less likely to respond to antipsychotic treatment regardless of when it is instituted.