Early intervention in psychosis. The critical period hypothesis

Br J Psychiatry Suppl. 1998;172(33):53-9.


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 developing and show maximum plasticity.

Method: First-episode prospective studies, predictors of outcome and the genesis of patients' key appraisals of their psychosis are reviewed.

Results: The data support the notion of 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 family and psychological reactions to psychosis and psychiatric services, develop during this period.

Conclusions: The early phase of psychosis presents 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.

Publication types

  • Review

MeSH terms

  • Adaptation, Psychological
  • Age Distribution
  • Age of Onset
  • Antipsychotic Agents / therapeutic use
  • Depression / psychology
  • Episode of Care
  • Follow-Up Studies
  • Humans
  • Interpersonal Relations
  • Prognosis
  • Prospective Studies
  • Psychotic Disorders / prevention & control
  • Psychotic Disorders / psychology
  • Psychotic Disorders / therapy*
  • Recurrence
  • Social Isolation
  • Social Support
  • Substance-Related Disorders / psychology
  • Suicide
  • Time Factors


  • Antipsychotic Agents