This systematic review aimed to establish whether the duration of untreated psychosis is associated with prognosis in patients with schizophrenia.[Marshall et al., 2005] A total of 26 studies were identified that reported the relationship between duration of untreated psychosis and outcome, in prospective cohorts of patients with schizophrenia, recruited during their first episode of psychosis.[Marshall et al., 2005] The results demonstrate a convincing, albeit modest, association between the duration of untreated psychosis and a range of clinical outcomes, including remission.[Marshall et al., 2005] The authors are keen to point out that the association does not prove a direct cause – it does not prove that untreated psychosis causes poor outcomes.[Marshall et al., 2005] Rather, the two factors could be related via a third variable.[Marshall et al., 2005]
Reference:
Marshall M, Lewis S, Lockwood A, et al. Association between duration of untreated psychosis and outcome in cohorts of first-episode patients: a systematic review. Arch Gen Psychiatry 2005; 62 (9): 975–983.