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Randomized controlled trial of a novel cannabis use intervention delivered by telephone
Peter J Gates1, Melissa M Norberg, Jan Copeland
1National Cannabis Prevention and Information Centre, University of New South Wales, Randwick, NSW, Australia. p.gates@unsw.edu
Aims:
To evaluate the efficacy of a telephone-based intervention consisting of four sessions of motivational interviewing (MI) and cognitive behavioural therapy (CBT) designed to assist individuals to reduce their cannabis use and related problems.
Design:
Random allocation to intervention or delayed treatment control with 4- and 12-week follow-up assessments.
Setting:
Counsellors from the Cannabis Information and Helpline (CIH), an Australian reactive telephone service, delivered the intervention to callers seeking treatment.
Participants:
A total of 160 participants were recruited by the CIH, with 110 participants completing the final follow-up assessment (69% retention).
Measurements:
Cannabis use, dependence and related problems and other substance use were assessed at baseline and follow-up.
Findings:
Intervention participants reported greater reductions in dependence symptoms [P < 0.001, d = 0.9 (0.5-1.3)] and related problems [P < 0.001, d = 0.5 (0.1-0.9)] compared with control participants at both follow-up assessments. Compared with control, intervention participants reported greater confidence to reduce cannabis use at 4 weeks [P = 0.002, d = 0.5 (0.1-0.9)], and in turn reported a greater percentage of abstinent days at 12 weeks [P = 0.019, d = 0.6 (0.2-1.0)].
Conclusions:
A brief course of motivational interviewing plus cognitive behavioural therapy delivered by telephone can help to reduce cannabis dependence and promote abstinence in the short term.
