Association between the duration of untreated psychosis and short- and long-term outcome in schizophrenia within the Northern Finland 1966 Birth Cohort

Abstract

Background: Long duration of untreated psychosis (DUP) may relate to poor outcome in schizophrenia. However, the associations between DUP and outcomes, particularly in later course of illness, remain unclear. Our aim was to explore the associations between DUP and short- and long-term outcomes in schizophrenia.

Methods: Data was collected for subjects with schizophrenia (n=89) in the population-based Northern Finland 1966 Birth Cohort. DUP was obtained from medical records, and its associations with short- (under 2years) and long-term clinical and social outcomes were assessed extending to 20years after the onset of the illness.

Results: Longer DUP predicted longer length of first hospitalisation and increased the risk of rehospitalisation during the first two years. Longer DUP associated with decreased probability of disability pension, smaller amount of time spent in hospital, and higher proportion of time at work during the first 10years of the follow-up.

Conclusions: Regarding early outcome, long DUP may be a modest marker and proxy measure of a more severe clinical phenotype. The divergent results of earlier studies and the association between long DUP and better long-term outcome in our study, indicate that the length of DUP does not necessarily predict poor outcome in long-term follow-up. This may also be due to methodical difficulties, e.g. insufficient power and residual confounding linked to long follow-up studies.