Repetitive Transcranial Magnetic Stimulation for Cannabis Use Disorder

There has been a considerable rise in cannabis consumption in recent years, with estimates of 200 million individual users globally. Importantly, 3% of these individuals have cannabis use disorder (CUD), with this prevalence increasing to 33% amongst regular users, making it one of the most common substances use disorders (SUDs) worldwide. CUD is associated with substantial health, societal, and economic costs, and worsening of other psychiatric disorders. Despite this clinical burden, effective treatment options are limited. No pharmacological treatments have emerged as clearly efficacious, and psychotherapeutic interventions have shown tempered results. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain-based approach in which alternating magnetic fields are applied to the scalp to induce electrical currents in cortical tissue. As it can modulate neural circuits implicated in neuropsychiatric disorders, it is a promising brain-based approach in the treatment of addictions. Evidence has indicated its efficacy in reducing drug craving and consumption across numerous SUDs, although research into cannabis has been largely unexplored. Recently, a novel circular rTMS coil, the MagVenture MMC-140, has been developed with the capacity to modulate both the bilateral prefrontal cortex (PFC) and insula, both of which are implicated in the neurocircuitry of craving and executive function. As such, it shows potential for CUD treatment. This proof-of-concept clinical trial will evaluate the feasibility and tolerability of a 4-week course of rTMS to the PFC/insula using MMC-140 as a treatment for CUD. Feasibility of both high frequency (HF; excitatory) and low frequency (LF; inhibitory) stimulation parameters will be evaluated. In addition, pre/post rTMS changes in cannabis use outcomes (e.g., consumption, craving, and withdrawal), executive function, and PFC/insula functional connectivity will be explored. By comprehensively investigating clinical, cognitive, and neuroimaging effects of rTMS, this study could pave the way for the first brain-based intervention in CUD that could be widely adopted into clinical settings using a novel, cost-effective and accessible rTMS device.