The long-term outcome of first-episode schizophrenia needs improvement. Here, we evaluate the effectiveness of 5 years sustained specialist treatment (ST), ST including Parent groups (ST + P) or treatment as usual (TAU) on psychotic relapse and social functioning.

A three condition randomized, parallel assigned, single-blind efficacy trial, in which 198 first-episode psychosis (FEP) patients aged 15–28 years were included. The effect on time to first relapse, first relapse rates, mean number of relapses per patient, and time to the improvement of social functioning were analyzed using Cox regression or ANOVA.

We found no significant differences between treatment conditions in the ITT analysis concerning time to first relapse, nor first relapse rate. Mean number of relapses per patient differed at a trend level between ST, ST + P or TAU conditions, respectively: 0.72; 0.62 or 1.02 (p = 0.069). No evidence was found for differential effect of treatment conditions on social functioning.

Five years sustained ST of FEP nor addition of parent groups increased time to first relapse or reduced first relapse rate, compared to sustained TAU. Indications for favorable effects of parent groups were found on relapses per patient.