Investigating Two rTMS Strategies to Treat Cannabis Use Disorder

In this trial we will work with a group of participants who are having problems related to marijuana use (they have Cannabis Use Disorder) and who want to reduce the amount of marijuana they use or quit using marijuana completely. We are testing to see if a treatment called repetitive transcranial magnetic stimulation (rTMS) can help them achieve that goal when combined with a brief three-session counseling therapy. Participants will receive rTMS to one of two different parts of the brain (the dorsolateral prefrontal cortex--the DLPFC or the ventromedial prefrontal cortex--the vmPFC) to see if applying rTMS to one brain area is more helpful than the other brain area.

In this preliminary trial, we will test whether applying repetitive transcranial magnetic stimulation (rTMS) to one of two brain areas will help participants with Cannabis Use Disorder reduce the amount of cannabis they use or quit using cannabis completely. To do so, we will recruit participants from the community (or addictions medicine treatment centers) who meet the criteria for Cannabis Use Disorder (heavy use of cannabis causing social, occupational, or health problems) and want to either substantially reduce the amount of cannabis they use or quit using cannabis entirely. Participants will be randomized (in a 1:1 allocation) to receive rTMS to either the left dorsolateral prefrontal cortex (DLPFC) or the ventromedial prefrontal cortex (vmPFC). All participants will also receive evidence-based counseling to help them reduce the amount of cannabis they use. We will deliver study treatment with rTMS to participants over 18-study-visits occurring either two or three times each week and then will see whether the study treatment has helped by meeting with participants four times over six weeks. We will also see how the rTMS effected brain function by having participants undergo two scans using magnetic resonance imaging (MRI).

Eligibility Criteria:
Inclusion Criteria:

1. Participants must be able to provide informed consent and function at an intellectual level sufficient to allow accurate completion of all assessment instruments.
2. Participants must be between the ages of 18 and 60.
3. 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.
4. Participants must express a desire to reduce cannabis use or quit.
5. Participants must have a positive UDS for cannabis during their enrollment visit (confirming they are regular users).
6. The investigative team must believe each participant is a good study-candidate.

Exclusion Criteria:

1. Participants must not be pregnant or breastfeeding.
2. Participants must not meet moderate or severe use disorder of any other substance with the exception of tobacco/nicotine.
3. Participants must not be on any medications that have central nervous system effects that have changed in the past 4-weeks.
4. Participants must not have a history of/or current psychotic disorder or bipolar disorder.
5. Participants must not have any other Axis I condition requiring current treatment.
6. Participants must not have a history of Dementia or other cognitive impairment.
7. Participants must not have active suicidal ideation, or a suicide attempt within the past 180 days.
8. Participants must not have any contraindications to receiving rTMS or MRI (e.g. metal implanted above the head, history of seizure, any known brain lesion).
9. Participants must not have any unstable general medical conditions.