Health TrialsbyHealthPanel

Rewards for Cannabis Abstinence-study

ConditionCannabis Use Disorder
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age16-22
SponsorParnassia Addiction Research Centre

About this trial

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).

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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

Disqualifiers

Health contra-indications (e.g., acute psychosis/suicidality)

Insufficient Dutch language.

Trial design

Design model

Parallel

Treatments tested in this trial

  • Abstinence-focused Contingency Management (CM) - stand alone

    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.

  • Standard Outpatient Cognitive Behavioural Therapy (CBT)

    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.

Treatment groups

154 Participants
are divided into 2 treatment groups
Group A: Abstinence-focused Contingency Management (CM)Experimental treatment 1 intervention
Group B: Cognitive Behavioural Therapy (CBT)Active comparator 1 intervention

Trial outcomes

Primary outcomes

1

Cannabis-abstinent days (biochemically verified)

Number of biochemically verified cannabis-abstinent days during the 12-week intervention period

Time frame
12 weeks

Secondary outcomes

1

long-term 'treatment response'

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.

Time frame
52 weeks
2

Incremental costs per treatment responder

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.

Time frame
52 weeks
3

Incremental costs per QALY

Incremental costs per quality-adjusted life years (QALY) gains based on the The 5-level EQ-5D version (EQ-5D-5L)

Time frame
52 weeks

Other outcomes

Sponsors and contacts

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Parnassia Addiction Research Centre

Lead sponsor

Leiden University Medical Center

Collaborator

Brijder Verslavingszorg

Collaborator

Antes

Collaborator

Novadic-Kentron

Collaborator

Amsterdam University of Applied Sciences

Collaborator

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

Collaborator

Trimbos

Collaborator

Het Zwarte Gat

Collaborator

Source ClinicalTrials.gov
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