Early Psychosis Prevention and Intervention Centre long-term follow-up study of first-episode psychosis: methodology and baseline characteristics

Aim: This paper reports the rationale, methodology and baseline characteristics of a large long‐term follow‐up study of first‐episode psychosis from a geographically defined catchment area. Method: A total of 723 first‐episode psychosis patients were recruited from a specialized early psychosis service between 1989 and 2001 and prospectively followed up at a median of 7.4 years after initial presentation. Participants’ baseline demographic, clinical and functional characteristics are described. Sampling bias at study recruitment was assessed by comparison with a more complete sample of Early Psychosis Prevention and Intervention Centre (EPPIC) cases rated directly from the medical records. Results: At baseline, 57% of the sample were diagnosed with schizophrenia or schizophreniform disorder, whereas the full range of psychotic disorders was represented. Statistical analysis confirmed that the sample recruited was representative of total EPPIC‐treated incident cases. Conclusions: The EPPIC long‐term follow‐up study is a large and epidemiologically representative first‐episode psychosis cohort that has been subsequently prospectively followed up over a long period. Such a sample provides a rare opportunity to study the course and outcome of psychotic disorders.