Open Access Study protocol

CANABIC: CANnabis and Adolescents: effect of a Brief Intervention on their Consumption – study protocol for a randomized controlled trial

Catherine Laporte12*, Hélène Vaillant-Roussel1, Bruno Pereira3, Olivier Blanc14, Gilles Tanguy1, Paul Frappé5, David Costa6, Yoann Gaboreau7, Mélanie Badin6, Laurent Marty18, Gilles Clément1, Claude Dubray9, Bruno Falissard10, Pierre-Michel Llorca4 and Philippe Vorilhon111

Author Affiliations

1 Department of General Medicine, Faculty of Medicine of Clermont-Ferrand, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France

2 EA 7280 NPsy-Sydo, University of Auvergne, Faculty of Medicine of Clermont-Ferrand, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France

3 Office for Clinical Research and Innovation, Clermont-Ferrand University Hospital, 58 Rue Montalembert, 63000 Clermont-Ferrand, France

4 Adult Psychiatry Department – B, Clermont-Ferrand University Hospital, 58 Rue Montalembert, 63000 Clermont-Ferrand, France

5 Department of General Medicine, Saint-Etienne Faculty of Medicine, 15 Rue Ambroise Paré, 42023 St Etienne Cedex 2, France

6 Department of General Medicine, Montpellier Faculty of Medicine, 2 Rue de l'École de Médecine, 34000 Montpellier, France

7 Department of General Medicine, Grenoble Faculty of Medicine, Domaine de la Merci, BP 170 La Tronche, 38042 Grenoble Cedex 9, France

8 Health anthropologist, 7 rue de l'église, 63450 St Amant Tallende, France

9 Clinical Investigation Centre (Inserm CIC -501), Clermont-Ferrand University Hospital, 58 Rue Montalembert, 63000 Clermont-Ferrand, France

10 Faculty of Medicine, Paris South, INSERM 669 Unit, Maison de Solenn, 97 Bld de Port Royal, 75679 Paris cedex 14, France

11 EA 4681PEPRADE, University of Auvergne, Faculty of Medicine of Clermont-Ferrand, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France

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Trials 2014, 15:40  doi:10.1186/1745-6215-15-40

Published: 30 January 2014

Abstract

Background

Cannabis is the most consumed illegal substance in France. General practitioners (GPs) are the health professionals who are most consulted by adolescents. Brief intervention (BI) is a promising care initiative for the consumption of cannabis, and could be a tool for GPs in caring for adolescents who consume cannabis. The aim of the CANABIC study is to measure the impact of a BI carried out by a GP on the consumption of cannabis by adolescents of 15 to 25 years of age.

Methods

A randomized clustered controlled trial, stratified over three areas (Auvergne, Languedoc-Roussillon, and Rhône - Alpes), comparing an intervention group, which carries out the BI in consultation, and a control group, which ensures routine medical care. The main assessment criterion is the consumption of cannabis by amount of joints per month, at 12 months. The amount necessary to highlight a significant difference between the two groups of 30% of consumption at 12 months is 250 patients (50 GPs, 5 patients per GP; risk α = 5%; power = 90%; intra-cluster correlation coefficient ρ = 0.2; Hawthorne effect = 15%; lost to follow-up rates for GPs = 10% and for patients = 20%). This plan is replicated for the three areas, and therefore a total of 750 patients are expected.

The secondary criteria for judgment are the associated consumption of tobacco and alcohol, the perception of the consequences of consumption, and the driving of a vehicle following consumption.

Discussion

Research about BI for young cannabis users is underway. The aim of the CANABIC study is to validate a BI suited to adolescents who consume cannabis, which may be performed in the general practice. This would provide a tool for their treatment by a GP, which could be widely distributed during initial or further medical training.

Trial registration

CANABIC is a randomized clustered trial (NCT01433692, registered 2011 Sept 12), PHRC funded: Clinical Research Hospital Program (Governmental Fund, Health Ministry). Date first patient randomized: March 2012.

Keywords:
Adolescents and young adults; Brief intervention; Cannabis; General medicine