 The primary outcome measure will be cannabis craving assessed by the Marijuana Craving Questionnaire and visual analog scales before and after every rTMS session and at one- and two-week follow-up. Secondary outcome measures will be self-reported cannabis use and urine drug testing at each rTMS session and follow-up visit, and changes in regional brain responses to cannabis-associated visual cues assessed by fMRI done before and after the 5 rTMS sessions. 