OBJECTIVES: To assess pre-treatment, baseline, and outcome differences of patients with early- (onsetor=age 18) psychosis in an epidemiological cohort of first-episode patients. METHODS: The Early Psychosis Prevention and Intervention Centre (EPPIC) in Australia admitted 786 FEP patients from January 1998 to December 2000. Data were collected from patients' files using a standardized questionnaire. Seven hundred four files were available, 61 of which were excluded owing to non-psychotic diagnoses or a psychotic disorder due to a general medical condition and 7 owing to missing data on age at onset. 636 patients were analyzed. RESULTS: The mean age at onset was 21.3 years (SD 3.6); the prevalence of early-onset psychosis was 18.6% (onset range 8.2-17.9). Patients with early-onset were likely to have a slightly, but significantly worse premorbid functioning and a significantly longer duration of untreated psychosis (Median 26.3 weeks) compared to patients with adult-onset (Median 8.7 weeks; p
