A Preliminary Investigation of Pre-Frontal Repetitive Transcranial Magnetic Stimulation (rTMS) for the Treatment of Cannabis Use Disorder

Phase 2

Completed

Brief Summary: This investigation will preliminarily determine if a course of high-frequency rTMS applied to the left dorsolateral prefrontal cortex, will reduce behavioral craving, and fMRI cue-reactivity in treatment-seeking cannabis use disordered participants.

Detailed Description: The overarching goal of this proposal is to investigate if a course of excitatory DLPFC rTMS results in reduced cannabis behavioral craving in treatment-seeking individuals with CUD (Aim1). Additionally, the investigators seek to explore the mechanistic underpinnings of any observed effect, by collecting functional magnetic resonance imaging data during cannabis cue administration before and after the treatment course (Aim 2). These aims will be addressed through a nine-week, double-blind, randomized, sham-controlled study in which 72 treatment-seeking cannabis use disordered participants (36/group) will be given 20 sessions of either Active or Sham excitatory rTMS applied to the DLPFC. rTMS will be delivered over five weeks (2 sessions each day, two days each week). rTMS will be applied in conjunction with a validated three-session Motivational Enhancement Therapy (MET) behavioral intervention.

Recruitment & Eligibility

Inclusion Criteria

Participants must be able to provide informed consent and function at an intellectual level sufficient to allow accurate completion of all assessment instruments.
Participants must be between the ages of 18 and 60.
Participants must meet DSM-5 criteria for at least moderate Cannabis Use Disorder, with use of at least 20 out of the last 28 days.
Participants must express a desire to quit cannabis.
Participants must have a Positive UDS for cannabis during their baseline visit (confirming they are regular users).

Exclusion Criteria

Participants must not be pregnant or breastfeeding.
Participants must not meet moderate or severe use disorder of any other substance with the exception of Nicotine Use Disorder.
Participants must not be on any medications that have central nervous system effects.
Participants must not have a history of/or current psychotic disorder or bipolar disorder.
Participants must not have any other Axis I condition requiring current treatment and must have a HRSD24 ≤10 indicating no clinically relevant depressive symptoms.
Participants must not have a history of Dementia or other cognitive impairment.
Participants must not have active suicidal ideation, or a suicide attempt within the past 90 days.
Participants must not have any contraindications to receiving rTMS (e.g. metal implanted above the head, history of seizure, any known brain lesion).
Participants must not have any unstable general medical conditions.

Arm && Interventions

Group	Intervention	Description
Sham rTMS	Sham rTMS	Sham rTMS applied to the left DLPFC
Active rTMS	Active rTMS	10 Hz rTMS applied to the left DLPFC

Primary Outcome Measures

Name	Time	Method
Marijuana Craving Questionnaire-Short Form Score as a Measure of Behavioral Craving	Baseline (pre) and Week-5 (post)	The investigators hypothesize that as compared to those participants receiving sham rTMS, those participants receiving active rTMS will have a reduced level of behavioral cannabis craving prior to their final rTMS session as compared to prior to their first rTMS session. The investigators will measure behavioral cannabis craving using the marijuana craving questionnaire. Score range: 12 to 84, higher scores represent more craving.
Cue Reactivity	Baseline (pre) and Week-5 (post)	The investigators hypothesize that as compared to those participants receiving sham rTMS, those participants receiving active rTMS will have a reduced BOLD response in reward structures (dorsal striatum, ventral striatum, and anterior consulate cortex) during a validated cue-reactivity fMRI paradigm prior to their final rTMS session as compared to prior to their first rTMS session (change score). The following beta scores represent the change score (post-pre) in scans in the drug stimuli minus neutral stimuli subtraction map. Generally, more activation (a positive score) represents more cannabis image cue-reactivity, and the reported range represents standard units as output in the fMRI.

Secondary Outcome Measures

Name	Time	Method
Abstinence	4-weeks	Number of weeks (out of a total of 4 possible), in the follow-up period, where participants were abstinent from cannabis. Missing data was conservatively assumed to be non-abstinant. More weeks of abstinence is more favourable