The purpose of this study is to understand how ketamine brings about rapid improvement in Obsessive-Compulsive Disorder (OCD) symptoms.

Obsessive-Compulsive Disorder (OCD) is a chronic and disabling disorder that costs the economy over $2 billion annually and represents a significant public health problem. This study aims to build on our discovery that a potent NMDA receptor antagonist, ketamine, has rapid (in hours) and robust therapeutic effects in OCD. The proposed projects test the acute mechanism of action of ketamine at the level of molecules, circuits, and network synchrony to determine how NMDA receptor antagonism modifies the underlying pathology of OCD to relieve repetitive thoughts and behaviors.

Inclusion Criteria for participants with OCD:

• age 18-65
• Primary diagnosis of OCD
• Sufficient severity of OCD symptoms
• ability to tolerate a treatment-free period
• capacity to provide informed consent

Inclusion criteria for healthy controls:

• ages 18-65
• capacity to provide informed consent

Exclusion criteria for participants with OCD:

• Psychiatric or medical conditions that make participation unsafe
• pregnant or nursing females
• concurrent use of any medications that might increase the risk of participation (e.g. drug interactions)
• presence of metallic device or dental braces

Exclusion criteria for healthy controls:

• any current or lifetime psychiatric diagnosis
• pregnant or nursing females
• major medical or neurological problem
• presence of metallic device or dental braces