title: Duration of untreated psychosis and its relationship to clinical outcome.
abstract: 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.
  
  
  OBJECTIVE
  To critically examine the evidence concerning DUP being related to treatment outcome and possible mediators of any such relationship.
  
  
  METHODS
  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.
authors.affiliation: Department of Psychiatry, University of Western Ontario, Room 113B, WMCH Building, 392 South Street, London, Ontario N6A 4G5, Canada. rnorman@uwo.ca
authors.forename: Ross M G
authors.initials: RM
authors.lastname: Norman
authors.forename: Shôn W
authors.initials: SW
authors.lastname: Lewis
authors.forename: Max
authors.initials: M
authors.lastname: Marshall
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome