Objective: Psychotic disorders often start in adolescence. We aim to investigate premorbid and baseline differences characterizing patients with an onset of psychosis in adolescence versus adulthood.
Method: We compare first-episode, DSM-IV non-affective psychosis with onset before (n = 43) and after (n = 189) 18 years on duration of untreated psychosis (DUP), level of symptoms, suicidal behaviour, and other baseline clinical and demographic characteristics.
Results: Adolescent onset patients had poorer premorbid functioning, a longer DUP, higher suicidality, and more depressive symptoms. They also had better cognition, fewer psychotic symptoms, and were more likely to be treated on an out-patient basis.
Conclusion: Adolescents with first-episode psychosis may have a slower and more silent, i.e. insidious onset, and are at risk of experiencing longer treatment delays than adults. They fit the description of what used to be labeled process (versus reactive) schizophrenia.