title: Effectiveness of a self-guided web-based cannabis treatment program: randomized controlled trial.
abstract: BACKGROUND
  Self-help strategies offer a promising way to address problems with access to and stigma associated with face-to-face drug and alcohol treatment, and the Internet provides an excellent delivery mode for such strategies. To date, no study has tested the effectiveness of a fully self-guided web-based treatment for cannabis use and related problems.
  
  
  OBJECTIVE
  The current study was a two-armed randomized controlled trial aimed at testing the effectiveness of Reduce Your Use, a fully self-guided web-based treatment program for cannabis use disorder consisting of 6 modules based on cognitive, motivational, and behavioral principles.
  
  
  METHODS
  225 individuals who wanted to cease or reduce their cannabis use were recruited using both online and offline advertising methods and were randomly assigned to receive: (1) the web-based intervention, or (2) a control condition consisting of 6 modules of web-based educational information on cannabis. Assessments of cannabis use, dependence symptoms, and abuse symptoms were conducted through online questionnaires at baseline, and at 6-week and 3-month follow-ups. Two sets of data analyses were undertaken--complier average causal effect (CACE) modeling and intention to treat (ITT).
  
  
  RESULTS
  Two thirds (149) of the participants completed the 6-week postintervention assessment, while 122 (54%) completed the 3-month follow-up assessment. Participants in the intervention group completed an average of 3.5 of the 6 modules. The CACE analysis revealed that at 6 weeks, the experimental group reported significantly fewer days of cannabis use during the past month (P=.02), significantly lower past-month quantity of cannabis use (P=.01), and significantly fewer symptoms of cannabis abuse (P=.047) relative to controls. Cannabis dependence symptoms (number and severity) and past-month abstinence did not differ significantly between groups (Ps>.05). Findings at 3 months were similar, except that the experimental group reported significantly fewer and less severe cannabis dependence symptoms (Ps<.05), and past-month quantity of cannabis consumed no longer differed significantly between groups (P=.16). ITT analyses yielded similar outcomes.
  
  
  CONCLUSIONS
  Findings suggest that web-based interventions may be an effective means of treating uncomplicated cannabis use and related problems and reducing the public health burden of cannabis use disorders.
  
  
  BACKGROUND
  ACTRN12609000856213, Australian New Zealand Clinical Trials Registry.
authors.affiliation: University of New South Wales, Randwick, Australia. s.rooke@unsw.edu.au
authors.forename: Sally
authors.initials: S
authors.lastname: Rooke
authors.forename: Jan
authors.initials: J
authors.lastname: Copeland
authors.forename: Melissa
authors.initials: M
authors.lastname: Norberg
authors.forename: Donald
authors.initials: D
authors.lastname: Hine
authors.forename: Jim
authors.initials: J
authors.lastname: McCambridge
mesh_terms: D000328:Adult; D001315:Australia; D005260:Female; D015438:Health Behavior; D006801:Humans; D020407:Internet; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology / Q000628:therapy*; D017063:Outcome Assessment, Health Care; D012648:Self Care; D017216:Telemedicine / Q000379:methods*; D013813:Therapy, Computer-Assisted; D016896:Treatment Outcome; D055815:Young Adult