A Trial of Intranasal Ketamine for the Treatment of Obsessive-Compulsive Disorder

Inclusion Criteria: 1. Male or female age ≥ 18 and ≤ 55 2. Meets DSM-IV50 criteria for OCD as the primary presenting diagnosis as determined by the investigator (participants with secondary comorbid dysthymia, major depression, anxiety disorders, eating disorders, and other obsessive-compulsive spectrum disorders will still be eligible for enrollment). 3. Score of ≥ 18 on the Y-BOCS at screening Exclusion Criteria: 1. Unwillingness or inability to provide written informed consent. 2. Active suicidal ideation at screening 3. Lifetime history of psychotic disorder or autism spectrum disorder 4. DSM-IV diagnosis of alcohol or substance dependence, with the exception of nicotine dependence, within three months prior to screening 5. Any history of intolerance or hypersensitivity to ketamine 6. Any history of nasal/sinus anomalies or dysfunction (e.g., nasal obstruction or history of nasal surgery) 7. Clinically significant medical disease including, but not limited to, cardiac (including uncontrolled hypertension or uncontrolled hypotension, arrhythmias, congestive heart failure, angina), pulmonary, hepatic, renal, or endocrine disorders, which would increase the risk to the participant or interfere with interpretation of results as judged by the principal investigator. 8. Clinically significant neurologic disease including, but not limited to, seizure disorder, neurodegenerative diseases, transient ischemic attacks, neural vascular disease, stroke, cerebral aneurysms, and history of traumatic brain injury. 9. Female participants with a positive serum or urine pregnancy test at screening 10. Pregnancy. Females of childbearing potential must be using an effective contraceptive method (e.g., abstinence, prescription oral contraceptives, contraceptive injections, double-barrier method, male partner sterilization). Women that are not of childbearing potential are defined as: postmenopausal (\>45 years of age with amenorrhea for at least 12 months, or any age with menorrhea for at least 6 months and a serum follicle stimulating hormone (FSH) level \>40 IU/ml); permanently sterilized (e.g., tubal occlusion, hysterectomy, bilateral salpingectomy); or otherwise be incapable of pregnancy. 11. Female participants who are lactating. 12. Any screening laboratory abnormality deemed clinically significant by the investigator 13. Currently taking opiate pain medications, dextromethorphan, St. John's Wort, theophylline, or tramadol. 14. Any participation in an investigational drug trial within 30 days of enrollment in study. 15. Contraindication to having an MRI.