EARLY INTERVENTION IN PSYCHOSIS - THE CRITICAL PERIOD HYPOTHESIS

Background We consider the evidence for the proposition that the early phase of psychosis (including the period of untreated psychosis) is a 'critical period' in which (a) long-term outcome is predictable, and (b) biological, psychological and psychosocial influences are developi ng and show maximum plasticity. Method First-episode prospective studi es. predictors of outcome and the genesis of patients' key appraisals of their psychosis are reviewed. Results The data support the notion o f the 'plateau effect', first coined by Tom McGlashan, which suggested that where deterioration occurs. it does so aggressively in the first 2-3 years; and that critical psychosocial influences, including famil y and psychological reactions to psychosis and psychiatric services, d evelop during this period. Conclusions The early phase of psychosis pr esents important opportunities for secondary prevention. We outline a prototype of intervention appropriate to the critical period.The data challenge the widely held assumption that first-episode psychosis is a benign illness posing little risk.