Consecutive patients who presented with first-episode psychosis (n=242) were obtained from a larger database on early intervention in psychosis (Malla et al., 2003). All subjects who were admitted to the first-episode program were eligible for this study. The sample was assessed for demographic and illness characteristics, such as duration of untreated psychosis; diagnosis; length of prodromal (warning symptoms) period; premorbid adjustment; level of psychotic, negative, depressive, anxiety, and extrapyramidal symptoms; and alcohol and drug use. A total of 82 of the patients (40.8 percent) had an onset of psychosis during adolescence and 119 (59.2 percent) had an onset during young adulthood. The adolescent group had longer delays in treatment of psychosis (duration of untreated psychosis), showed moderately worse premorbid functioning during late adolescence, and were more likely to present with bizarre behavior and primary negative symptoms. Given the finding of delayed treatment for adolescents with psychosis, primary care physicians should be alert for symptoms in adolescent patients, even though the disorder has a relatively low incidence. More effective methods for reducing delay in treatment through early case identification and more specific treatment of negative symptoms should be more rigorously applied to adolescent patients with psychosis. 3 tables and 49 references