title: Routes of administration of cannabis used for nonmedical purposes and associations with patterns of drug use.
abstract: OBJECTIVE
  Little is known regarding cannabis administration routes for nonmedical use-that is, its delivery methods (e.g., joints, water pipe, food). Therefore, we examined the prevalence rates of different cannabis delivery methods and assessed the relationship of the distinct administration routes with problematic drug use. Subgroups of cannabis users were also investigated (i.e., "pure" cannabis users, previously described as employing a harmless route of administration, and water pipe users, previously described as using a harmful route of administration).
  
  
  METHODS
  As part of the Cohort Study on Substance Use Risk Factors, 1,763 cannabis users answered questions concerning their drug use (i.e., routes of administration, problematic cannabis use, other illicit drug use). Descriptive statistics, latent class analysis, correlations and t-tests were assessed.
  
  
  RESULTS
  The main administration route was "joints with tobacco"; other routes of administration had prevalence rates from 23.99% to 38.23%. In addition, increasing the number of administration routes was associated with more problematic cannabis use, as well as heavier illicit drug use. Water pipes without tobacco were especially linked to heavy drug use patterns, whereas "pure" cannabis use seemed less harmful.
  
  
  CONCLUSIONS
  Our findings highlighted that diversification in routes of administration can be associated with heavier illicit drug use. This was especially true for water pipe users, whereas "pure" cannabis users, who did not mix cannabis with tobacco, were an exception. Indeed, these results may be useful for future preventive programs, which may need to focus on those who have diversified routes of administration for cannabis.
authors.affiliation: Alcohol Treatment Centre, Lausanne University Hospital CHUV, Lausanne, Switzerland. Electronic address: Stephanie.Baggio@chuv.ch.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Baggio
authors.affiliation: Alcohol Treatment Centre, Lausanne University Hospital CHUV, Lausanne, Switzerland.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Deline
authors.affiliation: Alcohol Treatment Centre, Lausanne University Hospital CHUV, Lausanne, Switzerland.
authors.forename: Joseph
authors.initials: J
authors.lastname: Studer
authors.affiliation: Institute of Social and Preventive Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Meichun
authors.initials: M
authors.lastname: Mohler-Kuo
authors.affiliation: Alcohol Treatment Centre, Lausanne University Hospital CHUV, Lausanne, Switzerland.
authors.forename: Jean-Bernard
authors.initials: JB
authors.lastname: Daeppen
authors.affiliation: Alcohol Treatment Centre, Lausanne University Hospital CHUV, Lausanne, Switzerland; Addiction Switzerland, Lausanne, Switzerland; Centre for Addiction and Mental Health, Toronto, Ontario, Canada; University of the West of England, Frenchay Campus, Bristol, United Kingdom.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gmel
mesh_terms: D002188:Cannabis; D015331:Cohort Studies; D004333:Drug Administration Routes; D004435:Eating; D006801:Humans; D008297:Male; D002189:Marijuana Abuse; D008385:Marijuana Smoking; D055815:Young Adult
keywords: Cannabis administration routes; Patterns of drug use; Problematic cannabis use; Water pipe; “Pure” cannabis use