In brief
- A systematic review aggregates fifteen studies involving 118 people with moderate to severe obsessive-compulsive disorder (OCD) treated with ketamine.
- A single 0.5 mg/kg intravenous infusion achieves a response in 50–60% of cases, but the relief dissipates within about a week when ketamine is used alone.
- Protocols that combine the substance with exposure therapy maintain remission for weeks or months. The authors also report dysphoria and suicidal ideation occurring between 24 and 48 hours in a subset of patients.
Between 40% and 60% of people with OCD do not improve with serotonergic antidepressants or standard behavioral therapy. A review published on August 27 in Psychopharmacology examines the available evidence on ketamine for this group and reaches a two-sided conclusion: it provides rapid relief, but on its own, the effects are short-lived.
Fifteen studies, 118 people
The research team, hailing from several Iranian universities, followed the PRISMA methodology and searched databases through January 2026. They selected fifteen studies: three randomized trials, four open-label studies, and eight clinical cases, totaling 118 participants. In the controlled trials, a single intravenous infusion of 0.5 milligrams per kilogram produced a rapid response regarding obsessions in 50–60% of participants. The problem arises afterward: when used as a standalone treatment, the improvement generally faded within a week.
Therapy changes the equation
The most interesting data lies in protocols that administer ketamine while the individual undergoes exposure and response prevention therapy, the gold-standard psychological treatment for OCD. In these cases, remission was maintained for weeks or months. The authors interpret this as a synergistic effect: ketamine may open a window in which exposure exercises become more tolerable. Both intravenous and oral routes were effective; the intranasal route faced a high rejection rate due to fear of spray contamination—a significant detail in a disorder that often revolves around that specific preoccupation.
A safety signal specific to this condition
The review identifies a pattern not seen in the same way in trials of ketamine and dissociatives for depression: in a subgroup of patients, late-onset dysphoria and suicidal ideation emerged between 24 and 48 hours after the infusion. For this reason, the authors call for prolonged clinical monitoring, rather than just the hour following the session.
What this implies
It is important to read this work for what it is: fifteen studies, 118 people, and only three randomized trials. Based on this, no definitive claims about efficacy can be made, and the authors themselves call for longitudinal studies to clarify dosage, timing, and integration with the rest of the treatment. What is clearly outlined is a concrete and testable hypothesis, in line with what we have previously reported on ketamine and psychotherapy for chronic pain: the value of the substance may not lie in its direct effect, but in the time it opens up to work on other therapeutic goals.
Source
- Eghdami S, Boroon M, Keshavarz-Akhlaghi AA, Shalbafan M. Efficacy and tolerability of ketamine in moderate to severe obsessive-compulsive disorder: a systematic review. Psychopharmacology, August 27, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
