The study focuses on evaluating the safety and feasibility of an investigational intervention on OCD symptoms. We will assess changes in symptoms, functioning, and related cognitive and physiological measures using interviews, questionnaires, and other research assessments.

By collecting this information, we hope to improve understanding of OCD and contribute to future research efforts aimed at developing more effective treatment approaches for individuals living with OCD.

You may be eligible for this study if you meet the following criteria.

Inclusion Criteria:

• Age 18–65 years
• Meet diagnostic criteria for obsessive-compulsive disorder (OCD) (may be determined during screening)
• Have not experienced adequate improvement with at least one standard OCD treatment (e.g., medication or CBT) or have declined these treatments for personal reasons
• Able to provide informed consent
• Able to travel to the study site for in-person visits
  
  

Exclusion Criteria:

• Pregnant or breastfeeding, or able to become pregnant and not using an effective form of birth control
• Use of psychotropic medications within one month prior to study enrollment (assessed during screening)
• Known allergy or hypersensitivity to ketamine
• Any current or past medical or psychiatric condition that, in the opinion of the study physician, would make participation unsafe
• Recent transcranial magnetic stimulation (TMS) within 2 weeks prior to study start
• Lifetime history of deep-brain stimulation

The study lasts approximately 4–6 weeks. Once enrolled, participation includes a minimum of three in-person visits at Stanford University, as well as some activities you can complete from home.

In person:

• A screening period that includes psychiatric interviews, medical assessments (such as ECG and laboratory testing), and questionnaires. Informed consent will be completed remotely prior to in-person visits.
• One on-site infusion visit, where you will receive a single intravenous infusion of either the investigational study medication (RR-HNK) or placebo, followed by close safety monitoring for several hours.
• Follow-up visits after the infusion, including symptom assessments, EEG recordings, and computer-based cognitive tasks.
  
  

From home:

• Informed consent and psychiatric interviews will be completed remotely.
• Some screening and follow-up questionnaires can be completed remotely.
• Neurocognitive computer tasks can also be completed from home.
• Remote check-ins and assessments continue through approximately Week 4.

There is no payment for participating in this study. You will have the option to enroll in another clinical study of Exposure and Response Prevention at no cost to you if you are interested after completion of this study.

There is no cost for you to participate in our research study.