Objective: Adolescent onset psychosis was reported to be associated with a lower level of premorbid functioning and a longer duration of untreated psychosis (DUP). If replicated this is an important finding, since both variables were reported to be independent predictors of outcome. The aim of this study was (i) to confirm that early onset psychosis would be associated with lower premorbid functioning, longer DUP, as well as poorer outcome compared to adult onset psychosis.
Method: The Early Psychosis Prevention and Intervention Centre admitted 786 first-episode psychosis (FEP) patients from 1998-2000. Data on DUP, premorbid, baseline, and outcome characteristics were collected from patients'medical records (MR) of 637 patients who met inclusion criteria.Age at onsetwas dichotomized in 'belowand above 19 years of age'consistent other studies.
Results: The mean age at onset in the complete sample was 21.3 years (SD 3.6) with 27.3% (n = 174) experiencing their first psychotic symptoms below age 19 (range 8.2 - 18.9). Subjects were treated for a mean duration of 63.4 weeks (SD 34.2). Subjects with adolescent onset psychosis had achieved a significantly lower level of premorbid functioning, and suffered from a longer DUP. The rate of bipolar disorder at baseline in the adult onset group was twice as high as in the adolescent onset group. The longer DUP in the adolescent onset group was not accounted for by differences in premorbid functioning or rate of bipolar disorder. Sequential logistic regression with premorbid functioning, DUP, gender, time in treatment, and severity of illness at baseline as covariates revealed that the adolescent onset group were less likely to achieve remission of positive symptoms (OR = 1.44; CI = 0.98 - 2.13; p = 0.067).Age at onset (as a continuous variable) significantly predicted remission controlling for the same set of covariates (OR = 1.07; CI = 1.01 - 1.12, p = 0.013).
Conclusions: Our results confirm previous reports that premorbid functioning is worse and DUP longer in adolescent compared to adult onset psychosis. The lower rate of remission of positive symptoms in adolescent onset psychosis was partly but not completely explained by the longer DUP and worse premorbid functioning.