Rewards for Cannabis Abstinence-study

NCT ID: NCT05836207

Last Updated: 2025-07-31

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

154 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-11-21

Study Completion Date

2027-09-30

Brief Summary

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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

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Conditions

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Cannabis Use Disorder

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Abstinence-focused Contingency Management (CM)

Youths receive 12 weeks of outpatient abstinence-focused CM consisting of providing incentives for cannabis abstinence, based on twice-weekly rapid test urinalysis.

Group Type EXPERIMENTAL

Abstinence-focused Contingency Management (CM) - stand alone

Intervention Type BEHAVIORAL

Outpatient abstinence-focused contingency management (CM) as stand-alone treatment (12 weeks). Monetary incentives (vouchers) are provided for cannabis abstinence, based on twice-weekly rapid test urinalysis and an escalating reward scheme with bonuses. Urine samples are collected at the treatment centre during 15-minute sessions by a trained CM-practitioner. For each cannabis-negative urine, patients receive a monetary voucher starting at €5 and escalating to max. €35 after eight consecutive weeks of cannabis abstinence, with an additional €10 bonus after two consecutive cannabis-negative urines. The voucher-value is reset to €5 after a cannabis-positive urine test. Total earnings can be max. €675 for 12 weeks of consecutive cannabis abstinence (average: €8 p/day). Youths sign an agreement stating that vouchers must be spent on recovery-oriented goals.

Cognitive Behavioural Therapy (CBT)

Youths receive 12 weeks of outpatient usual care CBT consisting of once-weekly 60-minute sessions according to the standard CBT youth protocol by a trained psychologist.

Group Type ACTIVE_COMPARATOR

Standard Outpatient Cognitive Behavioural Therapy (CBT)

Intervention Type BEHAVIORAL

CBT is the usual care first line treatment for CUD in youth, in the Netherlands. CBT for CUD is focused on learning cognitive, emotional, motivational and behavioral skills to reduce or cease cannabis use, and generally consists of 12 once-weekly 60-minute sessions and 'homework' exercise assignments, provided by a psychologist.

Youths receive 12 weeks of outpatient usual care CBT consisting of once-weekly 60-minute sessions according to the standard CBT youth protocol by a trained psychologist. CBT-youths receive the same cannabis urine-testing procedures as CM-youths, but test results will not be disclosed to treatment staff or patient, and no rewards will be given for cannabis abstinence.

Interventions

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Abstinence-focused Contingency Management (CM) - stand alone

Outpatient abstinence-focused contingency management (CM) as stand-alone treatment (12 weeks). Monetary incentives (vouchers) are provided for cannabis abstinence, based on twice-weekly rapid test urinalysis and an escalating reward scheme with bonuses. Urine samples are collected at the treatment centre during 15-minute sessions by a trained CM-practitioner. For each cannabis-negative urine, patients receive a monetary voucher starting at €5 and escalating to max. €35 after eight consecutive weeks of cannabis abstinence, with an additional €10 bonus after two consecutive cannabis-negative urines. The voucher-value is reset to €5 after a cannabis-positive urine test. Total earnings can be max. €675 for 12 weeks of consecutive cannabis abstinence (average: €8 p/day). Youths sign an agreement stating that vouchers must be spent on recovery-oriented goals.

Intervention Type BEHAVIORAL

Standard Outpatient Cognitive Behavioural Therapy (CBT)

CBT is the usual care first line treatment for CUD in youth, in the Netherlands. CBT for CUD is focused on learning cognitive, emotional, motivational and behavioral skills to reduce or cease cannabis use, and generally consists of 12 once-weekly 60-minute sessions and 'homework' exercise assignments, provided by a psychologist.

Youths receive 12 weeks of outpatient usual care CBT consisting of once-weekly 60-minute sessions according to the standard CBT youth protocol by a trained psychologist. CBT-youths receive the same cannabis urine-testing procedures as CM-youths, but test results will not be disclosed to treatment staff or patient, and no rewards will be given for cannabis abstinence.

Intervention Type BEHAVIORAL

Eligibility Criteria

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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.
Minimum Eligible Age

16 Years

Maximum Eligible Age

22 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Leiden University Medical Center

OTHER

Sponsor Role collaborator

Brijder Verslavingszorg

UNKNOWN

Sponsor Role collaborator

Antes

UNKNOWN

Sponsor Role collaborator

Novadic-Kentron

UNKNOWN

Sponsor Role collaborator

Amsterdam University of Applied Sciences

OTHER

Sponsor Role collaborator

Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

OTHER

Sponsor Role collaborator

Trimbos

UNKNOWN

Sponsor Role collaborator

Het Zwarte Gat

UNKNOWN

Sponsor Role collaborator

Parnassia Addiction Research Centre

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Renske Spijkerman, PhD

Role: PRINCIPAL_INVESTIGATOR

PARC

Vincent Hendriks, Prof. dr.

Role: STUDY_DIRECTOR

PARC

Locations

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Jellinek, Stichting Arkin B.V.

Amsterdam, , Netherlands

Site Status RECRUITING

IrisZorg

Arnhem, , Netherlands

Site Status RECRUITING

Antes Youz

Rotterdam, , Netherlands

Site Status RECRUITING

Brijder

The Hague, , Netherlands

Site Status RECRUITING

Novadic-Kentron

Vught, , Netherlands

Site Status RECRUITING

Countries

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Netherlands

Central Contacts

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Eva Garssen, MsC

Role: CONTACT

+3188 358 20 34

Renske Spijkerman, PhD

Role: CONTACT

+31630661532

Facility Contacts

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Anneke Prof. dr., PhD

Role: primary

+31-88-5051220

Wiebren Markus, PhD

Role: primary

+31-88-6061396

Jasmijn Kruithof

Role: primary

Fleur Noach

Role: primary

Renske Spijkerman, PhD

Role: backup

0031630 66 15 32

Laura DeFuentes-Merillas, PhD

Role: primary

Other Identifiers

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10390012110082

Identifier Type: -

Identifier Source: org_study_id

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