This transnational trial tested the use of U.S.-developed multidimensional family therapy (MDFT) to treat adolescents heavily using cannabis in five European countries.
Cannabis use disorder was responsive to treatment in a transnational trial (the International Need for Cannabis Treatment [INCANT] study) implementing U.S.-developed multidimensional family therapy (MDFT) in Belgium, France, Germany, The Netherlands, and Switzerland. MDFT exceeded Individual Psychotherapy (IP) in decreasing the prevalence of cannabis dependence. MDFT is applicable in Western European outpatient settings and may show moderately greater benefits than IP in youth with more severe substance use. INCANT was a 2 (treatment condition) × 5 (time) repeated measures intent-to-treat randomized effectiveness trial comparing MDFT to IP. Data were gathered at baseline and 3, 6, 9 and 12 months thereafter. Study participants were recruited at outpatient secondary level addiction, youth, and forensic care clinics in Brussels, Berlin, Paris, The Hague, and Geneva. Participants were adolescents from 13 through 18 years of age with a recent cannabis use disorder. 85% were boys; 40% were of foreign descent. One-third had been arrested for a criminal offence in the past 3 months. Three primary outcomes were assessed: (1) treatment retention, (2) prevalence of cannabis use disorder and (3) 90-day frequency of cannabis consumption. Positive outcomes were found in both the MDFT and IP conditions. MDFT outperformed IP on the measures of treatment retention (p < 0.001) and prevalence of cannabis dependence (p = 0.015). MDFT reduced the number of cannabis consumption days more than IP in a subgroup of adolescents reporting more frequent cannabis use (p = 0.002). (Published Abstract Provided)