title: Motivational intervention to reduce cannabis use in young people with psychosis: a randomized controlled trial.
abstract: BACKGROUND
  Cannabis use has a negative impact on psychosis. Studies are needed to explore the efficacy of psychological interventions to reduce cannabis use in psychosis. Our aim is to study the efficacy of a specific motivational intervention on young cannabis users suffering from psychosis.
  
  
  METHODS
  Participants (aged less than 35 years) were randomly assigned to treatment as usual (TAU) alone, or treatment as usual plus motivational intervention (MI + TAU). TAU was comprehensive and included case management, early intervention and mobile team when needed. Assessments were completed at baseline and at 3, 6 and 12 months follow-up.
  
  
  RESULTS
  Sixty-two participants (32 TAU and 30 MI + TAU) were included in the study. Cannabis use decreased in both groups at follow-up. Participants who received MI in addition to TAU displayed both a greater reduction in number of joints smoked per week and greater confidence to change cannabis use at 3 and 6 months follow-up, but differences between groups were nonsignificant at 12 months.
  
  
  CONCLUSIONS
  MI is well accepted by patients suffering from psychosis and has a short-term impact on cannabis use when added to standard care. However, the differential effect was not maintained at 1-year follow-up. MI appears to be a useful active component to reduce cannabis use which should be integrated in routine clinical practice.
authors.affiliation: CHUV Lausanne, Site de Cery, Unité de réhabilitation, Bâtiment des Cèdres, Prilly, Switzerland. charles.bonsack@chuv.ch
authors.forename: Charles
authors.initials: C
authors.lastname: Bonsack
authors.forename: Silvia
authors.initials: S
authors.lastname: Gibellini Manetti
authors.forename: Jérôme
authors.initials: J
authors.lastname: Favrod
authors.forename: Yves
authors.initials: Y
authors.lastname: Montagrin
authors.forename: Jacques
authors.initials: J
authors.lastname: Besson
authors.forename: Pierre
authors.initials: P
authors.lastname: Bovet
authors.forename: Philippe
authors.initials: P
authors.lastname: Conus
mesh_terms: D000293:Adolescent; D000328:Adult; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D002189:Marijuana Abuse / Q000517:prevention & control*; D009042:Motivation; D011614:Psychotherapy, Brief / Q000379:methods*; D011618:Psychotic Disorders / Q000534:rehabilitation*; D012559:Schizophrenia / Q000534:rehabilitation; D013557:Switzerland