Rewards for Cannabis Abstinence-study

Not Applicable

Recruiting

• Conditions: Cannabis Use Disorder

• Registration Number: NCT05836207
• Lead Sponsor: Parnassia Addiction Research Centre

Brief Summary

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).

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-04-18
• Study First Submitted QC: 2023-04-18
• Study First Posted: 2023-05-01
• Study Start: 2023-11-21
• Status Verified: 2025-07
• Last Update Submitted: 2025-07-29
• Last Update Posted: 2025-07-31
• Primary Completion: 2026-12
• Study Completion: 2027-09-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 154

Inclusion Criteria

• 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.

Exclusion Criteria

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Cannabis-abstinent days (biochemically verified)	12 weeks	Number of biochemically verified cannabis-abstinent days during the 12-week intervention period

Secondary Outcome Measures

Name	Time	Method
Incremental costs per QALY	52 weeks	Incremental costs per quality-adjusted life years (QALY) gains based on the The 5-level EQ-5D version (EQ-5D-5L)
long-term 'treatment response'	52 weeks	defined as 50% or more reduction in cannabis use days in the 4 weeks preceding week 12 (end-of-treatment), and week 26 and 52, compared with baseline.
Incremental costs per treatment responder	52 weeks	Incremental cost-effectiveness ratio (ICER) per treatment responder (see above) will be determined based on the incremental costs and effects of CM compared with CBT.

Trial Locations

Locations (5)

Jellinek, Stichting Arkin B.V.; 🇳🇱 Amsterdam, Netherlands

IrisZorg; 🇳🇱 Arnhem, Netherlands

Antes Youz; 🇳🇱 Rotterdam, Netherlands

Brijder; 🇳🇱 the Hague, Netherlands

Novadic-Kentron; 🇳🇱 Vught, Netherlands