Inclusion Criteria: OCD group
- current primary diagnosis of obsessive-compulsive disorder and Yale-Brown Obsessive Compulsive Scale total score ≥ 16;
- 18-55 years of age;
- ability to speak, read, write, and understand English sufficiently well to complete study procedures and provide informed consent;
- either no use of psychiatric medication or stable psychiatric medication use for 6 weeks prior to study entry, limited to use of serotonin reuptake inhibitors and PRN use of benzodiazepines (other psychiatric medication use excluded), and
- right-handed.
Inclusion Criteria: Healthy Control group
- 18-55 years of age;
- ability to speak, read, write, and understand English sufficiently well to complete study procedures and provide informed consent;
- right-handed.
Exclusion Criteria: OCD group
- active problematic substance use;
- lifetime psychosis or bipolar mood disorder or OCD beliefs of delusional nature;
- clinically significant hoarding symptoms;
- active suicidal or homicidal ideation;
- significant neurological disease or intracranial pathology;
- use of medications which increase risk for seizures during TMS;
- significant or unstable medical disorders or contraindication to TMS or MRI scan.
Exclusion Criteria: Healthy Control group
- current psychiatric diagnosis;
- lifetime psychosis, bipolar mood disorder, or OCD;
- active suicidal or homicidal ideation;
- significant neurological disease or intracranial pathology;
- use of psychiatric medications;
- use of medications which increase risk for seizures during TMS;
- significant or unstable medical disorders or contraindication to TMS or MRI scan.