title: Prevalence of substance misuse in first-episode psychosis.
abstract: BACKGROUND
  Reports suggest a high prevalence of substance misuse in psychotic disorders but few studies examine comorbidity at onset of psychosis.
  
  
  OBJECTIVE
  To identify the prevalence and pattern of substance use and misuse in first-episode psychosis, and relationships with diagnosis, mode of presentation and demographic variables.
  
  
  METHODS
  Consensus diagnoses for 168 subjects presenting with first-episode psychosis were made using ICD-10 diagnostic criteria. Information on substance use and misuse was obtained from multiple sources. We examined associations between substance misuse, diagnosis and demographic factors.
  
  
  RESULTS
  Criteria for drug use, drug misuse or alcohol misuse were met by 37% of the sample. One-year prevalence rates were 19.5% (drug misuse) and 11.7% (alcohol misuse). Thirteen subjects (8.4%) received a primary diagnosis of substance-related psychotic disorder; a significant increase compared with an earlier cohort from the same catchment area. Drug misuse was associated with younger age of onset of psychosis, male gender and non-African-Caribbean ethnicity.
  
  
  CONCLUSIONS
  This study confirms high rates of substance misuse at onset of psychosis. There is evidence for an increase in diagnosis of substance-related psychotic disorders over time. Those most at risk of substance misuse are young males.
authors.affiliation: Department of Psychological Medicine, University of Glasgow. r.cantwell@clinmed.gla.ac.uk
authors.forename: R
authors.initials: R
authors.lastname: Cantwell
authors.forename: J
authors.initials: J
authors.lastname: Brewin
authors.forename: C
authors.initials: C
authors.lastname: Glazebrook
authors.forename: T
authors.initials: T
authors.lastname: Dalkin
authors.forename: R
authors.initials: R
authors.lastname: Fox
authors.forename: I
authors.initials: I
authors.lastname: Medley
authors.forename: G
authors.initials: G
authors.lastname: Harrison
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D017831:Diagnosis, Dual (Psychiatry); D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011618:Psychotic Disorders / Q000453:epidemiology*; D019966:Substance-Related Disorders / Q000453:epidemiology*