Factors influencing relapse during a 2-year follow-up of first-episode psychosis in a specialized early intervention service

Background: Differential association of risk factors associated with relapse following treatment of first-episode psychosis (FEP) have not been studied adequately, especially for patients treated in specialized early intervention (SEI) services, where some of the usual risk factors may be ameliorated. Method: Consecutive FEP patients treated in an SEI service over a 4-year period were evaluated for relapse during a 2-year follow-up. Relapse was based on ratings on the Scale for Assessment of Positive Symptoms (SAPS) and weekly ratings based on the Life Chart Schedule (LCS). Predictor variables included gender, duration of untreated psychosis (DUP), total duration of untreated illness (DUI), age of onset, pre-morbid adjustment, co-morbid diagnosis of substance abuse during follow-up and adherence to medication. Univariate analyses were followed by logistic regression for rate of relapse and survival analysis with the Cox proportional-hazards regression model for time to relapse as the dependent variables. Results: Of the 189 eligible patients, 145 achieved remission of positive symptoms. A high rate of medication adherence (85%) and relatively low relapse rates (29.7%) were observed over the 2-year follow-up. A higher relapse rate was associated with a co-morbid diagnosis of substance abuse assessed during the follow-up period [odds ratio (OR) 2.84, 95% confidence interval (CI) 1.24-6.51]. The length of time to relapse was not associated with any single predictor. Conclusions: Specialized treatment of substance abuse may be necessary to further reduce risk of relapse even after improving adherence to medication.