Rewards for Cannabis Abstinence-study

Recruiting now · Not applicable

Conditions studied: Cannabis Use Disorder

In brief

The goal of this clinical trial is to investigate the (cost-)effectiveness of contingency management (CM) compared with Cognitive Behavioural Therapy (CBT) for the treatment of cannabis use disorder (CUD) in youth (16-22 years). The main questions it aims to answer are: * What is the efficacy of 12 weeks outpatient CM versus CBT in youths with a CUD, in terms of cannabis abstinence during the intervention period? * What is the long-term efficacy of CM versus CBT at 6- and 12-months follow-up (FU)? * What is the cost-effectiveness of CM versus CBT at 12-months FU from a societal perspective? Study hypotheses are: 1\. CM will result in more cannabis-abstinent days than CBT during the intervention; 2. CM is more effective and cost-effective than CBT at 12 months follow-up. Eligible patients (n=154) will be randomly assigned to either 12 weeks of outpatient CM or CBT. Assessments are conducted by trained research-assistants at baseline, after 6, 12, 26 and 52 weeks, and twice-weekly during treatment and consist of questionnaires, a computer task and collection of urine samples. Primary endpoint is the number of biochemically verified cannabis abstinent days in the 12-week treatment period. Key secondary endpoint: Treatment response: 50% or more reduction in cannabis use days in the past 4 weeks, compared with baseline. The primary outcome will be modelled in the intention-to-treat population in a (negative binomial) regression analysis with treatment group as independent variable and stratification variables as covariates. Cost-effectiveness and cost-utility analysis (CEA; CUA) will be performed from a societal perspective. CEA: Treatment response is the central clinical endpoint for calculations of incremental costs per responder. CUA: Incremental costs per QALY (based on EuroQoL).

Key facts

Study ID

NCT05836207

Run by

Parnassia Addiction Research Centre

People needed

154

Starts

2023-11-21

Expected to finish

2027-09-01

Last updated by the study team

2025-07-31

Who can join

Age: 16 and older, up to 22. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Youths (16-22 years) seeking treatment for a primary CUD
• Regular cannabis use (≥14 days) in past 4 weeks
• Intention to cease cannabis use during intervention
• Able and willing to attend the treatment center and submit urine samples under supervision twice-weekly
• Informed consent.

You may not qualify if…

• Health contra-indications (e.g., acute psychosis/suicidality)
• Insufficient Dutch language.

Where it is running

• Jellinek, Stichting Arkin B.V. — Amsterdam, Netherlands (enrolling)
• IrisZorg — Arnhem, Netherlands (enrolling)
• Antes Youz — Rotterdam, Netherlands (enrolling)
• Brijder — The Hague, Netherlands (enrolling)
• Novadic-Kentron — Vught, Netherlands (enrolling)

Full record on ClinicalTrials.gov

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