title: Stimulant and other substance use disorders in schizophrenia: prevalence, correlates and impacts in a population sample.
abstract: OBJECTIVE
  Stimulants may worsen psychotic symptoms but there is limited evidence about the impact of stimulant abuse in people with schizophrenia. This study examined the prevalence and correlates of stimulant and other drug disorders in a population-based sample of people with schizophrenia, examining associations with frequent service use, physical health comorbidities and accommodation instability.
  
  
  METHODS
  New South Wales (NSW) hospital, community mental health and emergency department data were used to examine health service contact over 5 years in 13,624 people with a diagnosis of schizophrenia. Associations of stimulant disorders were examined with multinomial logistic regression, comparing people with no substance disorders to those with cannabis disorders, stimulant disorders or both.
  
  
  RESULTS
  Of people with schizophrenia, 51% had substance disorders, including 14% with stimulant disorders. Stimulant disorders were more common in young adults and in urban areas, less common in migrants, and unrelated to initial social disadvantage. More than 80% of those with stimulant disorders also had cannabis disorders. Service use and harms were most common in this group, including frequent mental health admissions (59%), frequent emergency department presentations (52%), admissions with injury or self-harm (44%), infectious disease diagnoses (22%), multiple changes of residence (61%), movement to more disadvantaged locations (42%) and periods of homelessness (18%). People with stimulant disorders alone had higher rates of self-harm, infectious disease and non-mental health admissions than people with cannabis disorders alone.
  
  
  CONCLUSIONS
  Stimulant disorders occur in people with schizophrenia and in first-episode psychosis at rates more than 10 times that of the broader population. Stimulant disorders are likely to worsen the burden of psychosis, and strategies are needed to engage and support the highly disadvantaged group of people with schizophrenia who have cannabis and stimulant disorders.
authors.affiliation: InforMH, Mental Health and Drug and Alcohol Office, NSW Ministry of Health, North Ryde, Australia Discipline of Psychiatry, Sydney Medical School, University of Sydney, Sydney, Australia School of Population Health, University of Queensland, Brisbane, Australia Grant.Sara@health.nsw.gov.au.
authors.forename: Grant E
authors.initials: GE
authors.lastname: Sara
authors.affiliation: School of Population Health, University of Queensland, Brisbane, Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Burgess
authors.affiliation: CADE Clinic, Department of Academic Psychiatry, Royal North Shore Hospital, Sydney, Australia.
authors.forename: Gin S
authors.initials: GS
authors.lastname: Malhi
authors.affiliation: Psychiatry and Population Health, Queensland Centre for Mental Health Research, University of Queensland, Brisbane, Australia.
authors.forename: Harvey A
authors.initials: HA
authors.lastname: Whiteford
authors.affiliation: Centre for Youth Substance Abuse Research, University of Queensland, Brisbane, Australia.
authors.forename: Wayne C
authors.initials: WC
authors.lastname: Hall
mesh_terms: D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000453:epidemiology* / Q000523:psychology; D015897:Comorbidity; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology; D008605:Mental Health Services / Q000706:statistics & numerical data; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D012559:Schizophrenia / Q000453:epidemiology*; D012565:Schizophrenic Psychology; D016728:Self-Injurious Behavior / Q000453:epidemiology / Q000523:psychology; D012959:Socioeconomic Factors; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Amphetamine; cannabis; cocaine; psychosis; schizophrenia