Comparing illness presentation, treatment and functioning between patients with adolescent- and adult-onset psychosis

Studies have shown that early- and adult-onset schizophrenia patients differ in pre-morbid traits, illness presentation, psychopathology, and prognosis. We aimed to compare adult-onset patients (age range 26-55 years) with an adolescent-onset cohort (15-25 years) in demographics, illness presentation and functioning at baseline. Participants were from two territory-wide early intervention services for adolescent-onset (n=671) and adult-onset psychosis patients (n=360) in Hong Kong. The adolescent-onset cohort had their initial psychotic episode from 2001-2003; retrospective data collection was done through systematic case note review. The adult-onset cohort was recruited for a larger interventional study from 2009-2011; information was collected via face-to-face interviews. Adult-onset psychosis was significantly associated with more females, more smokers, more non-local birth, more full-time employment, better functioning, poorer medication adherence, more psychiatric hospitalization and fewer with schizophrenia than adolescent-onset psychosis (mean age: 20.4). The effect sizes were small, except for medication adherence where a robust effect was found. No group difference in DUP was found. The finding that adult-onset patients had better functioning challenges the view that adolescent- and adult-onset psychoses share a similar prognostic trajectory. Implications for adapting intervention processes for adolescent- and adult-onset psychosis are discussed.