Objectives: To assess pre-treatment, baseline, and outcome differences of patients with early- (onset<age 18) and adult-onset (onset>or=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<.001). After controlling for relevant confounders, no significant outcome differences including CGI-S, GAF, remission of positive symptoms, or employment status were detected between early- and adult-onset psychoses.
Conclusions: Patients with early-onset psychosis may require a different approach to early detection. Outcome differences between early- and adult-onset were minor, but need to be replicated in future (long-term) prospective epidemiological studies in other services.