A preliminary randomized controlled trial of repetitive transcranial magnetic stimulation applied to the left dorsolateral prefrontal cortex in treatment seeking participants with cannabis use disorder

Cannabis use disorder (CUD) is a common and consequential disorder. When applied to the dorsolateral prefrontal cortex (DLPFC), repetitive transcranial magnetic stimulation (rTMS) reduces craving across substance use disorders and may have therapeutic clinical effects when applied in serial-sessions. The present study sought to preliminarily determine whether serial-sessions of rTMS applied to the DLPFC had a therapeutic effect in CUD. This study was a two-site, phase-2, double-blind, randomized-controlled-trial. Seventy-two treatment-seeking participants (37.5% Women, mean age 30.2±9.9 SD) with ≥moderate-CUD were randomized to active or sham rTMS (Beam-F3, 10 Hz, 20-total-sessions, two-sessions-per-visit, two-visits-per-week, with cannabis cues) while undergoing a three-session motivational enhancement therapy intervention. The primary outcome was the change in craving between pre- and post- treatment (Marijuana Craving Questionnaire Short-Form—MCQ-SF). Secondary outcomes included the number of weeks of abstinence and the number of days-per-week of cannabis use during 4-weeks of follow-up. There were no significant differences in craving between conditions. Participants who received active-rTMS reported numerically, but not significantly, more weeks of abstinence in the follow-up period than those who received sham-rTMS (15.5%-Active; 9.3%-Sham; rate ratio = 1.66 [95% CI: 0.84, 3.28]; p=0.14). Participants who received active-rTMS reported fewer days-per-week of cannabis use over the final two-weeks of the follow-up period than those receiving sham-rTMS (Active vs. Sham: −0.72; Z=−2.33, p=0.02). This trial suggests rTMS is safe and feasible in individuals with CUD and may have a therapeutic effect on frequency of cannabis use, though further study is needed with additional rTMS-sessions and a longer follow-up period.