title: New directions in the conceptualization of psychotic disorders.
abstract: OBJECTIVE
  Recent studies raise controversies about the nature of psychotic illnesses, and the role of life experiences and drug abuse as causative agents in the onset of psychoses.
  
  
  RESULTS
  Evidence from studies across many geographic locales and cultures finds increased risk of psychoses in first- and second-generation immigrant populations. Trauma incurred in war and civil unrest, trauma of child abuse, and the experience of being bullied in childhood are correlated with increased rates of psychoses in the populations at risk. The risk of onset of psychoses is increased by maternal and infant starvation, and by substance misuse (marijuana, khat) in late childhood and adolescence. These studies question the validity of a categorical distinction between the schizophrenic and affective illnesses.
  
  
  CONCLUSIONS
  A variety of extrinsic factors, such as in-utero and infant malnutrition, substance abuse, and traumatic experiences, appear to be significant risk factors for the development of schizophrenia-like and psychotic affective disorders. These findings raise the issue of whether the present classification of the psychoses is in urgent need of reconceptualization.
authors.affiliation: Department of Psychiatry, University of Minnesota Medical School and the Community-University Health Care Clinic, Minneapolis, MN 55404, USA. kroll001@umn.edu
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Kroll
mesh_terms: D001714:Bipolar Disorder / Q000145:classification; D054242:Emigrants and Immigrants; D048070:Fetal Nutrition Disorders / Q000523:psychology; D006801:Humans; D008960:Models, Psychological; D011618:Psychotic Disorders / Q000145:classification / Q000209:etiology*; D012036:Refugees; D012307:Risk Factors; D012559:Schizophrenia / Q000145:classification / Q000209:etiology; D013313:Stress Disorders, Post-Traumatic / Q000523:psychology; D019966:Substance-Related Disorders / Q000523:psychology