Inclusion Criteria:

   - SCID confirmed diagnosis of SUD, severe

   - Last use of stimulants >1 and <6 weeks

   - Stable medication regimen (no change in dose or agents between 2 weeks prior to the
   start of and throughout the treatment phase of the study)

   - Stable social environment and housing to enable regular attendance at clinic visits.

   - Ability to undergo cognitive testing, fMRI scans, and rTMS (no contraindications)

   - IQ > 80

   - Stable medical health

   - Veteran at Palo Alto VA's Addiction Treatment Services

Exclusion Criteria:

   - Pregnant or lactating female

   - History of prior adverse reaction to TMS

   - On medications thought to significantly lower seizure threshold, e.g.:

      - clozapine

      - chlorpromazine

      - clomipramine

      - bupropion > 400 mg/day

   - Use of direct dopaminergic antagonists or agonists

   - History of seizures or conditions known to substantially increase risk for seizures

   - Implants or medical devices incompatible with TMS

   - Acute or unstable chronic medical illness that would affect participation or
   compliance with study procedures, e.g. unstable angina

   - Unstable psychiatric symptoms that precludes consistent participation in the study,
   e.g.:

      - active current suicidal intent or plan

      - severe psychosis

   - Inability to undergo fMRI scan, e.g. claustrophobia, presence of ferromagnetic objects
   in subject's body

   - Other substance use disorder not in sustained remission

   - Chronic or recurring Axis I psychiatric condition preceding SUD other than PTSD