General information on the INCANT Main Study*

Summary of the research proposal

This website features a research study based on the Five-Countries Action Plan for Cannabis Research. This plan was adopted in April 2003 by representatives of, or on behalf, of the Ministries of Health of Belgium, France, Germany, the Netherlands, and Switzerland.

Said Action Plan stresses the need of a trial to test an outpatient treatment of cannabis use disorders in troubled youth. The treatment selected is Multidimensional Family Therapy (MDFT), developed by researchers from the University of Miami. This choice was based on a systematic review of the treatment literature.

Applying the rules of evidence based practice, MDFT emerged as best supported treatment in the adolescent cannabis treatment literature, with strong evidence of efficacy and effectiveness in U.S. treatment settings.

The five countries mentioned have carried out a successful Pilot Study to assess the feasibility of a trial of MDFT in Western Europe, and have now started the so-called INCANT Main Study. ‘INCANT’ stands for INternational CAnnabis Need of Treatment. The INCANT Main Study is a multi-site, trans-national randomized controlled trial (RCT). In technical terms, it is a Phase III(b) RCT with open-label, parallel group design.

Cannabis is the most often used illegal drug in the general population in the Western world. Adolescents are quite sensitive to the development of cannabis disorders. In youth, these disorders are not easily overcome without treatment. Cannabis abusing and dependent youth show high rates of concurrent psychiatric co-morbidity (e.g., anxiety, depression, conduct disorder), alcohol disorders and psychosocial problems. MDFT acknowledges that treatment should focus on this multiplicity of problems rather than on cannabis alone.

The INCANT Main Study will compare MDFT to treatment as usual (TAU, minimally standardized) in Belgium, France, Germany, the Netherlands, and Switzerland both at the local (national) level and across these five countries, with a cost-effectiveness component to be included in one or two of these countries. The trial will be implementation oriented, i.e., will focus on transportability of MDFT to (varying) European context.

Multidimensional Family Therapy (MDFT) is a family based and developmentally oriented outpatient treatment for adolescent substance use disorders and associated or related problems. It has been the focus of empirical development and refinement since 1985. MDFT is an integrative set of interventions, having been tested with success in different doses and treatment delivery settings.

A full course of MDFT is delivered in two to three sessions each week over four to six months or slightly more. Sessions may be held in a variety of places including the home, treatment office, community settings (e.g., school, court), or by phone. The format of MDFT can be modified to suit the treatment needs of different clinical populations.

MDFT sees substance use disorders as part of a potentially deleterious lifestyle often including other problem behaviours. Therefore, in MDFT the therapist targets as many life domains and problem behaviours as possible. An exclusive focus on substance use would not achieve lasting benefit.

Because of these multiple facets, MDFT involves a broad array of interventions. Many of these are not unique to MDFT, but the particular combination, sequence and focus of interventions make MDFT special among contemporary family based treatments for adolescent substance use disorders.

In the INCANT Pilot Study, therapists from the five Western-European countries appeared to be trainable in MDFT. Moreover, the data from this investigation suggest that MDFT can be implemented in European practice, though not without effort or change of routine.

Current European treatment practice often boils down to a therapist conducting sessions with an adolescent or sometimes family that are limited in setting (the therapist's office) and focus, and widely spaced in time. In contrast, MDFT is outreaching, with the therapist paying home visits and conducting sessions in the community whenever needed, and contacting and visiting school and sometimes juvenile court, speaking to peers, and bringing material from one source into other sessions and vice versa in frequently scheduled sessions.

MDFT has been shown in U.S. based trials among adolescents to engage and retain clients and their families in treatment, to reduce cannabis and other substance use, to diminish hanging out with drug using peers, to improve family and school functioning, and to reduce delinquency and symptoms of internalizing (anxiety, depression) and externalizing (disruptive conduct) behaviours more than comparison treatments. Adolescents, families and therapists alike are generally quite appreciative of MDFT. Effect sizes are usually moderate to big.

MDFT is not necessarily or overly long in duration for the kind of clients considered, but is quite intense and focused. The effort may pay off in favourable cost-effectiveness ratios according to U.S. based MDFT research, to be confirmed in Europe.