Cannabis Dependence, Cannabis Use, Cannabis Use Disorder, Cognitive Dysfunction, Memory Impairment, Neuroimaging, Psychotic Disorders, Schizophrenia; Psychosis
Conditions
Brief summary
Cognitive impairment is well established in people with psychosis and is associated with cannabis use. The current study will investigate the neurobiological basis of cognitive change associated with 28-days of cannabis abstinence in people with psychosis and non-psychiatric controls with cannabis use. Participants will be randomized to a cannabis abstinent group or a non-abstinent control group and will undergo magnetic resonance imaging at baseline and following 28-days of abstinence. This study will help characterize the neuropathophysiological processes underlying cognitive dysfunction associated with cannabis use and its recovery which may guide the development of novel interventions for problematic cannabis use.
Detailed description
Background/Importance: Cognitive impairment is well established in people with psychosis and is associated with cannabis use. Despite high rates of cannabis use among people with psychosis and the general population, cannabis' effects on cognition and the brain and their recovery remain unclear. Therefore, this study will investigate the neurobiological basis of changes in cognitive processes associated with cannabis abstinence in people with psychosis and non-psychiatric controls. Aims: To examine the effects of 28-days of cannabis abstinence in psychosis patients with cannabis use and non-psychiatric controls with cannabis use on (i) brain activity (paired with a memory task); (ii) brain morphology; (iii) to determine if changes in memory following 28-days of abstinence correlate with changes in brain activity and/or morphology and (iv) to determine if baseline brain function and morphology can predict successful abstinence. Methods: Seventy-four psychosis patients with cannabis use and 60 non-psychiatric controls with cannabis use will be randomized to: (1) contingency reinforcement where biochemically verified abstinence at day 28 will be rewarded; or (2) a non-abstinent control group. The investigators will also recruit a group of healthy non-psychiatric controls (n=40) to determine if neural outcomes in cannabis-using participants do indeed normalize ("recover") following abstinence. Participants will undergo structural and functional magnetic resonance imaging while completing a memory task at baseline (pre-abstinence) and following 28-days of abstinence. Urine samples will be collected twice weekly for abstinence verification. Relevance: This study will help to characterize the neuropathophysiological processes underlying cognitive dysfunction associated with cannabis use in people with psychosis and non-psychiatric controls which may help to guide the development of novel neurobiologically-informed interventions to treat problematic cannabis use.
Interventions
BEHAVIORALContingency management
Contingency management will be used to encourage abstinence
Sponsors
Douglas Mental Health University Institute
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Outcomes Assessor)
Masking description
Research Assistant
Eligibility
Sex/Gender
ALL
Age
16 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
* Able to provide informed consent in English or French * Heavy cannabis use (defined as weekly cannabis use for at six months) and/or DSM-5 diagnosis of CUD * Have a Full-Scale IQ ≥ 75 * Meet DSM-5 criteria for a psychotic disorder (psychosis patient arm only) * Be an outpatient receiving a stable dose of medication(s) for at least two months (psychosis patient arm only) * Clinically stable (as measured by the PANSS-6, total score \<30) (psychosis patient arm only)
Exclusion criteria
* current SUD (other than CUD) * MRI contraindications * Positive urine screen for psychoactive substances other than cannabis, nicotine, or caffeine * Current suicidal or homicidal ideation * Head injury requiring hospitalization or loss of consciousness \> 5 minutes * Current medical diseases that requires hospitalization or regular monitoring * Being pregnant * DSM-5 Axis 1 diagnosis (other than CUD) (non-psychiatric controls only) * Taking psychotropic medication
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in fMRI brain activity pattern | Baseline, Day 28 | fMRI will be used to measure differences between baseline (day 0) and day 28 in hemodynamic (BOLD) responses while participants complete a memory task |
| Change in behavior during fMRI task | Baseline, Day 28 | Behavioral responses (episodic memory performance) will be recorded by an external button box. These responses will be used to assess encoding accuracy during an episodic memory task. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in brain morphology: gray matter volume | Baseline, Day 28 | Using MRI, changes in gray matter volume will be analyzed from baseline (day 0) to day 28 |
| Change in brain morphology: cortical thickness | Baseline, Day 28 | Using MRI, changes in cortical thickness will be analyzed from baseline (day 0) to day 28 |
| Change in brain morphology: diffusion | Baseline, Day 28 | Using MRI, changes in diffusion based measures will be analyzed from baseline (day 0) to day 28 |
Countries
Canada
Contacts
CONTACTCharlene Osei-Afrifa
PRINCIPAL_INVESTIGATORRachel Rabin, Ph. D.
Douglas Mental Health University Institute
Outcome results
None listed