Problematic cannabis use. Effect-evaluation of the 'Wiet-Check', the Dutch version of the Adolescent Cannabis Check-Up (ACCU).

Cannabis is the most used (illegal) drug among young people in the Western
world. Evidence is growing that frequent cannabis use, especially at a young
age, has adverse effects on both health and social functioning. Young people
using cannabis frequently are at risk for a number of problems including
dependency. Yet, they dont see their own use as problematic. Therefore
interventions reaching out to non-treatment seeking populations of young
frequent cannabis users are an important part of the addiction care for young
people. Indicated preventive interventions are rare in the Netherlands and
their effectiveness has not been examined. The Adolescent Cannabis Check-Up
(ACCU) is an intervention that has been found effective in reducing cannabis
use in non-treatment seeking Australian adolescents with frequent cannabis use.

The main objective is to translate and adapt the Adolescent Cannabis Check-Up
(ACCU) to the Dutch context and setting, and to evaluate its effects on the
cannabis use of adolescents in the Netherlands. The Dutch version of the ACCU
is called Wiet-Check

The main research question is:
Will the Wiet-Check generate superior effects over prevention as usual (an
informational session) in terms of:
a. reduction of cannabis use
b. reduction of symptoms of dependence
And will these effects be maintained up to three months and a year?

The effectiveness of the intervention will be tested in a randomized controlled
trial (RCT) with two conditions: the experimental condition (Wiet-Check) and
the control condition. Participants in the experimental condition receive the
Wiet-Check (two sessions) and participants in the control condition receive one
informative session. The baseline measurement (T0) takes place before the
Wiet-Check or the informative session. There are two follow up measurements at
three months (T1) and at twelve months (T2). A total of 280 adolescents is
needed to end up with 70 participants in each condition.

The Wiet-Check is a brief intervention based on the principles of motivational
interviewing and consists of two sessions of 60-90 minutes each. The
intervention will be delivered by trained professionals from organisations for
addiction care. The first session (the assessment session) consists of a
structured interview designed to assess the young person's cannabis and other
substance use history, symptoms of cannabis abuse and dependece and other
aspects of their cannabis use (pros and cons, expectations on
increased/decreased use) and his/her life expectations. This information
provides the content for a personal feedback report.

In the second session (the feedback session), about a week after the first, the
professional provides structured feedback and discussion of information on the
young person's cannabis use compared to age-specific normative data and other
topics discussed in the first session. The personal feedback report is used as
a basis for the structured feedback and information. During the feedback
session, the professional uses motivational interviewing strategies to elicit
the participant's active and candid involvement in the session. Expressions of
motivations for change are reinforced. When the participant clearly expresses a
desire to change his/her cannabis use, various change options will be
discussed, including self-managed change or referrals to drug treatment.

The burden will mainly be in the duration of the sessions (180 minutes
maximum), the evaluation form and the questionnaires (45 minutes for each
measurement). We estimate that the burden of the questions and the intervention
is acceptable. Experiences with the same intervention in Australia shows that
participants were enthusiastic about the sessions and did not experience these
as a burden or as judgemental. None of the participants agreed with the
statement that their participation was a 'waste of time'. A large majority of
the participants reported the intervention as helpful. Part of the sessions
will be recorded to be able to conduct a fidelity rating. In the Australian
study, this did not prove to be a hindrance to participate in the study and the
intervention. We expect the same experiences in this study.

The risk associated with this study is not exceeding the risks participants
take in their daily life. The extent of psychological burden as a result of the
intervention will be minimal. The intervention is based on motivational
interviewing. One of the main features of this counseling style is the
client-centered and non-confrontational approach. This makes the intervention
particularly attractive to young people and keeps the burden to a minimum.