 Following a baseline phase to evaluate subject characteristics, subjects will be randomly assigned to receive 5 days of active or sham rTMS. rTMS at 1 Hz and strength 120 of the motor threshold will be applied to the dorsolateral prefrontal cortex DLPFC using a figure 8 coil , beginning 1 second after presentation of a cannabis-associated visual cue and lasting for 30 seconds. Brain site localization will use a computerized navigation system based on structural MRI scans obtained before the first session. Each rTMS session lasting around 31 minutes will consist of 54 trials cue presentations: 36 with cannabis-associated cues and 9 each with non-drug-associated positive or neutral cues. No rTMS will be administered with the non-cannabis-associated cues. Subjects return for follow-up assessments one and two weeks after the final rTMS session. 