Cannabis and Young Users-A Brief Intervention to Reduce Their Consumption (CANABIC): A Cluster Randomized Controlled Trial in Primary Care

Abstract

Purpose: Brief intervention to reduce cannabis is a promising technique that could be adapted for use in primary care, but it has not been well studied in this setting. We tested the efficacy of a brief intervention conducted by general practitioners among cannabis users aged 15 to 25 years.

Methods: We performed a cluster randomized controlled trial with 77 general practitioners in France. The intervention consisted of an interview designed according to the FRAMES (feedback, responsibility, advice, menu, empathy, self-efficacy) model, while the control condition consisted of routine care.

Results: The general practitioners screened and followed up 261 young cannabis users. After 1 year, there was no significant difference between the intervention and control groups in the median number of joints smoked per month among all users (17.5 vs 17.5; P = .13), but there was a difference in favor of the intervention among nondaily users (3 vs 10; P = .01). After 6 months, the intervention was associated with a more favorable change from baseline in the number of joints smoked (-33.3% vs 0%, P = .01) and, among users younger than age of 18, smoking of fewer joints per month (12.5 vs 20, P = .04).

Conclusions: Our findings suggest that a brief intervention conducted by general practitioners with French young cannabis users does not affect use overall. They do, however, strongly support use of brief intervention for younger users and for moderate users.

Trial registration: ClinicalTrials.gov NCT01433692.

Keywords: addiction; brief intervention; general practice; marijuana; practice-based research; primary care; public health.

© 2017 Annals of Family Medicine, Inc.

Figures

Figure 1

Flowchart of general practitioners and patients. Note: Following Consolidated Standard Reporting Trials (Consort) 2010 flow diagram.

Figure 2

Median number of joints smoked per month at baseline and at 3, 6, and 12 months. aValues are median number of joints smoked per month (interquartile range).

Figure 3

Median number of joints smoked per month at baseline and at 3, 6, and 12 months, according to age-group. aValues are median number of joints smoked per month (interquartile range).