Back to overview

Efficacy of a brief motivational intervention to reduce cannabis use in early psychosis

English title Efficacy of a brief motivational intervention to reduce cannabis use in early psychosis
Applicant Bonsack Charles
Number 108454
Funding scheme Project funding (Div. I-III)
Research institution Section accueil et interventions brèves - Consultation générale et consilium
Institution of higher education University of Lausanne - LA
Main discipline Neurology, Psychiatry
Start/End 01.09.2005 - 29.02.2008
Approved amount 211'241.00
Show all

All Disciplines (3)

Neurology, Psychiatry
Addictive Diseases
Medico-Social Problems of Youth

Keywords (6)

Motivational interviewing; brief intervention; psychosis; schizophrenia; cannabis; substance abuse

Lay Summary (English)

Lay summary
BackgroundCannabis use has a negative impact on psychosis. Studies are needed to explore efficacy of psychological interventions to reduce cannabis harm in psychosis.AimsTo study the efficacy of a specific motivational intervention with 60 cannabis users suffering from psychosis.MethodsParticipants (aged less than 35 years) were randomly assigned to treatment as usual plus motivational intervention or treatment as usual only. Assessments were completed at baseline and at 3, 6 and12-months follow-up.ResultsCannabis use decreased in both groups at follow up. Patients who received motivational intervention in addition to usual treatment were found to have transient greater reduction of number of joints and more increase in confidence at 3 and 6 months follow up, but their was no difference between groups at 12 months. ConclusionsSpecific motivational intervention was associated with a better short term reduction on cannabis use among subjects suffering from psychosis, but this advantage was not maintained at one year follow-up.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
118347 Efficacy of transitional case management following psychiatric hospital discharge: a randomized trial 01.03.2008 Project funding (Div. I-III)