Duration of untreated psychosis and its relationship to clinical outcome

Background: A major reason for interest in early intervention for psychotic disorders is the hypothesised relationship between longer duration of untreated psychosis (DUP) and poorer outcome of treatment. Aims: To critically examine the evidence concerning DUP being related to treatment outcome and possible mediators of any such relationship. Method: A systematic review of studies in which DUP is assessed and its relationship to treatment outcome is examined. In addition, studies relevant to possible neurotoxic effects of DUP were reviewed. Results: The research is entirely of a correlational nature and, therefore, firm conclusions regarding causation are not possible. There is, however, substantial evidence of DUP being an independent predictor of treatment outcome, particularly remission of positive symptoms, over the first year or so of treatment. Findings regarding the possible neurotoxic effects of DUP are inconsistent. Conclusions: There continues to be evidence consistent with DUP influencing aspects of treatment outcome. Non-correlational studies, such as quasi-experimental designs, could provide stronger evidence regarding causality.