Neuroimaging Biomarkers for Predicting rTMS Response in OCD

Inclusion Criteria:

   1. meets Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)
   criteria for OCD with a moderate level of severity as defined by a Yale-Brown
   Obsessive Compulsive Scale (YBOCS) score of at least 18.

   2. stable on Serotonin Re-uptake Inhibitor (SRI) medication for at least 8 weeks prior to
   (with plans to continue throughout) the study Note: Medications that are known to
   increase cortical excitability (e.g., buprorion, maprotiline, tricyclic
   antidepressants, classical antipsychotics) or to have an inhibitory effect on brain
   excitability (e.g., anti-convulsants, benzodiazepines, and atypical antipsychotics),
   or any other medications with relative hazard for use in TMS will be allowed upon
   review of medications and/or motor threshold determination by TMS specialist.

   3. failed at least 1 prior trial of standard first-line OCD treatment per American
   Psychological Association (APA) Practice Guidelines (serotonin reuptake inhibitor
   [SRI] or cognitive behavioral therapy with exposure and response prevention)OR had
   refused these treatments for individual reasons.

   4. capacity to provide informed consent.

   5. ability to tolerate clinical study procedures.

   6. successfully complete the screening forms at the Stanford Center for Cognitive and
   Neurobiological Imaging (CNI) without any contraindications.

Exclusion Criteria:

   1. Current psychosis (re-assessed only if screening appointment was more than 30 days ago
   - Structured Clinical Interview for DSM-IV (SCID) - 5 Module B)

   2. Current bipolar disorder (assessed during baseline if screening appointment was more
   than 30 days ago - SCID-5 Module D)

   3. Severe depression [Note: 17-item Hamilton Depression Rating Scale (HDRS-17) must be
   less or equal to 20 to enter study, assessed during baseline if last assessment was
   more than 1 week ago]

   4. Current active suicidality (as determined by C-SSRS at baseline of 3 or above)

   5. Current moderate or severe Alcohol Usage Disorder or Substance Usage Disorder (except
   nicotine and caffeine) according to the DSM-5 criteria (assessed only if screening
   appointment was more than 12 months ago - SCID-5 Module E)

   6. Current eating disorder (assessed during baseline if screening appointment was more
   than 3 months ago - SCID-5 Module I)

   7. History of seizure, having an EEG, stroke, head injury (including neurosurgery),
   implanted devices, frequent or severe headaches, brain related conditions (e.g.,
   intracranial mass lesions globe injuries, hydrocephalus), illness that caused brain
   injury or first degree relative with seizure disorder (assessed during screening via
   medical history assessment and TMS Safety Screen by study MD)

   8. Individuals with primary hoarding disorder without a DSM-5 OCD diagnosis (as
   determined by SCID-5 and YBOCS checklist assessed only if screening appointment was
   more than 30 days ago)

   9. Planning to commence Cognitive Behavioral Therapy (that includes exposure and response
   prevention) during the period of the study or have begun Cognitive Behavioral Therapy
   within 8 weeks prior to enrollment (assessed during baseline by study MD)

10. Pregnant or nursing females (assessed via urine dipstick if screening appointment was
   more than 30 days ago)

11. Positive urine screen for illicit drugs (assessed via urine dipstick if screening
   appointment was more than 30 days ago) [Exceptions: (1) any prescribed medication that
   participant is currently taking and (2) positive cocaine metabolite after consumption
   of coca tea]

12. History of any implanted device or psychosurgery (assessed during baseline by study
   MD)

13. History of receiving Electroconvulsive Therapy (ECT) (assessed during baseline by
   study MD)

14. Age of OCD symptom onset >30