Moderate-to-severe Cannabis Use Disorder (CUD), as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Mental and Behavioural Disorders Mental and behavioural disorders due to use of cannabinoids
Conditions
Interventions
Blinding details:
The study includes “blinded” and “unblinded” testers, with distinct roles described below.
1. Selected researchers will administer face-to-face clinical and cognitive assessment, and
Sponsors
Australian Catholic University
Eligibility
Sex/Gender
All
Age
18 Years to 55 Years
Inclusion criteria
Inclusion criteria: Inclusion criteria for all participants: 1. Aged 18 to 55 years 2. Normal-to-corrected vision 3. Fluent in English 4. Meeting safety criteria for MRI scan Inclusion criteria for cannabis users: 1. Daily/almost daily (>3 days per week) cannabis use for >12 months 2. CUD 4+ DSM-5 symptoms 3. Tried to quit/reduce cannabis use at least once within the past 24 months
Exclusion criteria
Exclusion criteria: Exclusion criteria for all participants: 1. Any illicit substance and alcohol use for 12 hours before assessment (confirmed by self- report) 2. Currently using prescription medication that affect the central nervous system 3. Current or past diagnosed psychiatric disorders 4. Any current severe psychiatric diagnosis, excepting diagnoses of depression or anxiety 5. History of any neurological disorders 6. History of acquired or traumatic brain injury 7. Currently pregnant 8. Suicidality Exclusion criteria for cannabis users: 1. Significant use or dependence on alcohol and any illicit substances other than cannabis 2. Illicit drug use past 4 weeks (other than cannabis) Exclusion criteria for non-cannabis using controls: 1. Significant use or dependence on alcohol and any illicit substances 2. Illicit drug use past 4 weeks
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Structural and functional brain outcomes will be measured using Magnetic Resonance Imaging (MRI) at baseline and follow up. 1.1. Brain structure will be measured by assessing the volumes and thickness of the hypothesised brain regions of interest (see above for details) 1.2. Brain function will be measured while performing a number of fMRI tasks outlined below: 1.2.1. A cue reactivity fMRI task (10 minutes) will be run to examine brain function when the participant views cannabis-related pictures versus matched neutral pictures. There are two versions of this task, which are identical in procedure but contain different pictures (matched for picture complexity, object size, colours, and brightness) in order to minimise the confounding impact of memory and recognition on cue reactivity. The two task versions are delivered in counterbalanced order at baseline and follow up assessment, via a pseudorandomised procedure. 1.2.2. A Monetary Incentive Delay fMRI task (15 minutes) will be run to investigate brain function while: 1.2.2.1. Anticipation (vs receipt) of monetary outcomes 1.2.2.2. Anticipation of monetary outcomes (vs neutral outcomes) 1.2.2.3. Receipt (vs anticipation) of monetary outcomes 1.2.2.4. Receipt of neutral outcomes (vs monetary outcomes) 1.2.3. An Avoidance Learning fMRI task (15 minutes) will be run to measure brain function while: 1.2.3.1. Anticipating rewards and losses 1.2.3.2. Learning to avoid losses and obtain rewards 1.2.4. A resting-state fMRI task (10 minutes) will be run to investigate functional connectivity during rest (eyes open, while looking at a fixation cross) | — |
Secondary
| Measure | Time frame |
|---|---|
| 1.1. Repeated measures of craving, anxiety and other psychological states throughout the face-to-face baseline and follow up assessments. These measures are delivered online via Qualtrics: 1.1.1. Changes to cannabis craving, relaxation, tension, and mindful attention level: 1.1.1.1. The Visual Analogue Scale (VAS) will be used to measure on a 1-to-10 point scale current levels of cannabis craving, relaxation, tension, and mindful attention. The number of VAS administrations will vary according to which group the participant is allocated to. Cannabis users allocated to the mindfulness or relaxation intervention group will complete five administrations of the VAS (I-V outlined below), cannabis users allocated to the no-intervention group will complete four administrations of the VAS (I-IV outlined below), and non-using controls will complete three administrations of the VAS (I-III outlined below). (I) immediately pre-MRI scan (II) during the MRI scan, immediately before the cue reactivity fMRI task (see 1.2.1 above) (III) during the MRI scan, immediately after the cue post cue reactivity fMRI task (IV) immediately before the delivery of the audio intervention (V) immediately after the delivery of the audio intervention 1.1.1.2. A single item from the VAS will be used to measure on a 1-to-10 point scale the participant’s current level of cannabis craving. This will be administered twice: (I) immediately pre-attentional bias dot probe task (see 2.4.1.1 below) (II) immediately post-attentional bias dot probe task 1.1.2. Changes to state anxiety and cannabis craving symptom scores pre-to-post the MRI scan: 1.1.2.1. The Marijuana Craving Questionnaire (MCQ). It has 45-items rated on a seven-point Likert-type scale ranging from "strongly disagree" to "strongly agree." The items relate to four distinct constructs: (1) compulsivity e.g. inability to control marijuana use; (2) emotionality, e.g. use of marijuana in anticipation of relief from withdrawal or negative mood; (3 | — |
Countries
Australia
Contacts
Public ContactValentina Lorenzetti
Outcome results
None listed