The goal of this study is to test a causal neural mechanism of cannabis use-related problem recognition in individuals with severe cannabis use disorder using a non-invasive form of neuromodulation called transcranial magnetic stimulation (TMS). The main question it aims to answer is:

-Does manipulating neural activity in the medial orbitofrontal cortex of the brain affect cannabis use-related problem recognition?

Researchers will compare three forms of theta burst stimulation (TBS; sham, intermittent, and continuous) in each participant to see if manipulations in neural activity lead to changes in cannabis use-related problem recognition.

Participants will complete a screening interview about their mental health and substance use history and complete four in-person laboratory sessions, which involve questionnaires, four brief magnetic resonance imaging (MRI) scans, three TBS sessions, and three electroencephalogram (EEG) sessions. Participants will also be asked to provide urine samples and take saliva and/or breathalyzer tests at some of the lab visits.

Inclusion Criteria:

• Meets criteria for current, severe Cannabis Use Disorder (CUD), as assessed by the Structured Clinical Interview (SCID) for the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) during the screening interview
• Reports engagement in cannabis use at least four days per week, on average, over the past year
• Provide a urine sample positive for tetrahydrocannabinol (THC)
• Able to read and write in English
• Has used cannabis at least 20 days in the past month
• Endorses at least 10 distinct (of 40 possible) cannabis use-related problems across the screening interview and Lab Visit 1 questionnaires

Exclusion Criteria:

• Other non-cannabis illicit substance use more than once per month, on average, over the past year
• Current DSM-5 moderate or severe Alcohol Use Disorder, as assessed by the Structured Clinical Interview (SCID) for the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) during the screening interview
• History of bipolar I or psychosis spectrum disorders, as assessed by the SCID for DSM-5 during the screening interview
• Acute suicidality requiring treatment escalation, as assessed during the screening interview
• Currently taking any daily psychotropic medication
• Failure to meet standard MRI inclusion criteria (i.e., no presence of claustrophobia; cardiac pacemakers; neural pacemakers; surgical clips in the brain or blood vessels; surgically implanted metal plates, screws, or pins; cochlear implants; implanted uterine devices; metal braces; other metal objects in the body; history of significant injury to the brain or spinal cord; or pregnancy)
• Medical contraindications for transcranial magnetic stimulation (TMS; i.e., presence of a neurological disorder known to alter risk for seizures [e.g., stroke, aneurysm, brain surgery, structural brain lesion, brain injury, frequent/severe headaches], current medication therapy known to alter seizure threshold [e.g., clomipramine, Monoamine Oxidase inhibitors, imipramine, clozapine], recurrent seizures or epilepsy or family history of hereditary epilepsy, pregnancy, metallic implants in the body or other devices that may be affected by magnetic fields, or significant heart disease or cerebrovascular disease)
• History of allergies to cosmetics/lotions or EEG gel
• History of migraines
• Currently engaged in treatment for Cannabis Use Disorder