title: Reasons for substance use among people with mental disorders.
abstract: BACKGROUND
  Comorbidity of mental disorders and substance use continues to be a major problem. To inform the development of more effective interventions for these co-existing disorders, this paper aimed to determine if there are clear variations in the reasons for tobacco, alcohol or cannabis use across people with different mental disorders.
  
  
  METHODS
  Data from five randomized controlled trials on co-existing disorders that measured reasons for tobacco, alcohol or cannabis use using the Drug Use Motives Questionnaire, Reasons for Smoking Questionnaire or via free response are reported and combined. Two studies involved participants with depression, two involved participants with a psychotic disorder and one involved participants with a range of mental disorders. A series of logistic regressions were conducted to examine differences in reasons for tobacco, alcohol or cannabis use and to compare these reasons between people with psychotic disorders or depression.
  
  
  RESULTS
  Participants had a mean age of 38 (SD=12) and just over half (60%) were male. Forty-six percent of participants had a psychotic disorder and 54% experienced depression. Data from 976 participants across the five studies were included in the analyses. Tobacco and alcohol were primarily used to cope, while cannabis was primarily used for pleasure. People with psychotic disorders were more likely than people with depression to use tobacco for coping, pleasure and illness motives. People with depression, in contrast, were more likely to use alcohol for these reasons and social reasons.
  
  
  CONCLUSIONS
  It may be important to tailor interventions for co-existing mental disorders and substance use by substance type and type of mental disorder. For example, interventions might be improved by including alternative coping strategies to tobacco and/or alcohol use, by addressing the social role of alcohol and by helping people with mental disorders using cannabis to gain pleasure from their lives in other ways.
authors.affiliation: Centre for Brain and Mental Health Research, Faculty of Health, University of Newcastle, Callaghan, NSW 2308, Australia. Louise.Thornton@newcastle.edu.au
authors.forename: Louise K
authors.initials: LK
authors.lastname: Thornton
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Baker
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Lewin
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Kay-Lambkin
authors.forename: David
authors.initials: D
authors.lastname: Kavanagh
authors.forename: Robyn
authors.initials: R
authors.lastname: Richmond
authors.forename: Brian
authors.initials: B
authors.lastname: Kelly
authors.forename: Martin P
authors.initials: MP
authors.lastname: Johnson
mesh_terms: D000223:Adaptation, Psychological; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking / Q000523:psychology*; D001294:Attitude to Health; D003866:Depressive Disorder / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000523:psychology*; D008875:Middle Aged; D009042:Motivation; D011618:Psychotic Disorders / Q000523:psychology*; D016032:Randomized Controlled Trials as Topic; D012737:Sex Factors; D012907:Smoking / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult