title: Perceived functions predict intensity of use and problems in young polysubstance users.
abstract: OBJECTIVE
  To model consumption patterns and problems associated with alcohol, cannabis, ecstasy, amphetamine and cocaine hydrochloride use in a non-treatment sample of young polysubstance users.
  
  
  METHODS
  A cross-sectional survey of 364 16-22-year-old (56.3% male) polysubstance users recruited and interviewed by peer interviewers.
  
  
  METHODS
  Structured questionnaires were used to gather identical datasets on the five target psychoactive substances, recording patterns of substance use; adverse consequences from use; negative effects; functions for substance use; and perceived peer use.
  
  
  RESULTS
  Functions for substance use strongly predicted intensity of use in all five substances when peer use, age of first use and demographics were controlled, explaining an additional 11-19% of the variance in scores. Functions also explained an average of 22% of the variance in problem scores over and above the effects of background variables and current intensity of use. In particular, functions concerned with relief from negative mood states were strong predictors of problem scores in alcohol, cannabis and cocaine.
  
  
  CONCLUSIONS
  The potential implications of using a functional approach to explaining and responding to substance use are considerable. This could help to enhance our understanding of how experimental substance use becomes regular and how regular use becomes problematic, and could thus inform prevention, education and intervention efforts.
authors.affiliation: National Addiction Centre, Institute of Psychiatry, King's College London, London, UK. a.boys@iop.kcl.ac.uk
authors.forename: Annabel
authors.initials: A
authors.lastname: Boys
authors.forename: John
authors.initials: J
authors.lastname: Marsden
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects; D000437:Alcoholism / Q000453:epidemiology / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010379:Peer Group; D011619:Psychotropic Drugs / Q000008:administration & dosage / Q000009:adverse effects; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology*; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D011619:Psychotropic Drugs