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: 2024-05
• Last Update Submitted: 2024-05-20
• Last Update Posted: 2024-05-22
• Primary Completion: 2026-03
• Study Completion: 2027-01

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 (3)

Antes Youz; 🇳🇱 Rotterdam, Netherlands

Brijder; 🇳🇱 the Hague, Netherlands

Novadic-Kentron; 🇳🇱 Vught, Netherlands