title: Non-psychotic psychiatric disorder and subsequent risk of schizophrenia. Cohort study.
abstract: BACKGROUND
  Those with schizophrenia often give a history of premorbid non-psychotic psychiatric disorder.
  
  
  OBJECTIVE
  To investigate the association between non-psychotic psychiatric disorders and the later development of schizophrenia.
  
  
  METHODS
  Men aged 18 or 19 years, conscripted to the Swedish army in 1970 (n=50 054) were linked to the Swedish National Psychiatric Case Register.
  
  
  RESULTS
  There was an increased risk of schizophrenia in those with ICD-8 diagnoses of neurosis (OR=4.6,95% Cl 3.2-6.9), personality disorder (OR=8.2, 95% Cl 5.4-12.3), alcohol abuse (OR=5.5, 95% Cl 1.7-17.5) or substance abuse (OR=14.0, 95% Cl 7.8-25.0) at age 18. Of those who developed schizophrenia, 38% (95% Cl 32-45) received a diagnosis of non-psychotic psychiatric disorder at age 18. Only those with personality disorder had a significantly increased risk of schizophrenia (OR=2.4, 95% Cl 1.1-5.2) with onset after age 23.
  
  
  CONCLUSIONS
  Personality factors could represent an underlying vulnerability to schizophrenia. Other diagnoses occurring before schizophrenia may reflect a prodromal phase of the illness.
authors.affiliation: Division of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK. wpcghl@cardiff.ac.uk
authors.forename: G
authors.initials: G
authors.lastname: Lewis
authors.forename: A S
authors.initials: AS
authors.lastname: David
authors.forename: A
authors.initials: A
authors.lastname: Malmberg
authors.forename: P
authors.initials: P
authors.lastname: Allebeck
mesh_terms: D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000150:complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009497:Neurotic Disorders / Q000150:complications; D010554:Personality Disorders / Q000150:complications*; D012042:Registries; D012307:Risk Factors; D012559:Schizophrenia / Q000209:etiology*; D012565:Schizophrenic Psychology; D019966:Substance-Related Disorders / Q000150:complications