Neurocircuitry of Obsessive-Compulsive Disorder: Modulation by Transcranial Magnetic Stimulation

Inclusion Criteria:

- Current primary OCD diagnosis and current Y-BOCS total score of ≥16

- 18-70 years of age

- Ability to speak, read, write, and understand English sufficiently well to complete
study procedures and provide informed consent

- No use of psychiatric medications or stable psychiatric medication use for a minimum
of 6 week prior to study entry

- Ongoing psychotherapy allowed if already established for three months or more before
study entry

Exclusion Criteria:

- History of primary psychotic disorder or bipolar disorder

- Present acute suicidality

- History of head injury, epilepsy, or other clinically significant neurological illness
except tic disorders

- Active systemic medical (metabolic, endocrine, chronic inflammatory, vascular,
autoimmune) disease

- Premorbid intelligence quotient (IQ) estimate < 80

- Visual disturbance (<20/40 Snellen visual acuity, corrected)

- Current, or alcohol or illicit substance abuse/dependence in the last 3 months

- Contraindications to TMS or MRI: metallic foreign objects, e.g., aneurysm
clips/pacemakers, or questionable history of metal fragments, claustrophobia

- Women who are pregnant or breastfeeding. All women participants of reproductive age
are required to have a negative pregnancy test prior to enrollment and use medically
acceptable birth control throughout the study (barrier and/or oral contraceptives)

- Current psychotic symptoms

- An increased risk of seizure, determined by history

- Medications judged to notably affect cortical excitability e.g., anticonvulsants or
high-dose benzodiazepines (> 4 mg/day of clonazepam or equivalent)

- Predominant hoarding symptoms