title: Leisure time activities that predict initiation, progression and reduction of cannabis use: a prospective, population-based panel survey.
abstract: OBJECTIVE
  Frequent cannabis consumption can lead to severe physical and mental harm. As cannabis is often consumed in leisure time, this study aimed at identifying differences in leisure time activities that predicted the severity of cannabis use.
  
  
  METHODS
  In a prospective population-based survey on cannabis use a cohort of 5025 subjects aged 13-29 years were assessed by telephone interview and followed up 3 years later. Different leisure time activities and the persons (e.g. partner, friend, sibling) the activities were spent with were analysed for the initiation, progression and reduction/cessation of cannabis use over time using multinomial and ordered logistical regression models.
  
  
  RESULTS
  The persons the leisure time was spent with at baseline led to a higher probability of initiation and progression of cannabis use over time than the type of leisure time activity. There also was a tendency for tobacco use to increase during the progression phase and to remain high after a reduction/cessation of cannabis use.
  
  
  CONCLUSIONS
  The influence of persons the leisure time was spent with was of higher relevance to most phases of cannabis use than the type of leisure time activity.
authors.affiliation: Research Institute for Public Health and Addiction, Konradstrasse 32, Zurich, Switzerland. michael.schaub@isgf.uzh.ch
authors.forename: Michael
authors.initials: M
authors.lastname: Schaub
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gmel
authors.forename: Beatrice
authors.initials: B
authors.lastname: Annaheim
authors.forename: Max
authors.initials: M
authors.lastname: Mueller
authors.forename: David
authors.initials: D
authors.lastname: Schwappach
mesh_terms: D000293:Adolescent; D000328:Adult; D002188:Cannabis; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007407:Interviews as Topic / Q000379:methods; D007899:Leisure Activities / Q000523:psychology; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology / Q000628:therapy*; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D011897:Random Allocation; D012931:Social Environment; D013997:Time Factors; D055815:Young Adult