In brief
- A team from the University of Toronto compared 238 people using ketamine in clinical settings with 222 using it outside of them, based on the 2023 Global Psychedelic Survey.
- Both groups rated efficacy almost identically: an average of 83.3 in the clinical group and 81.2 in the non-clinical group, out of 100.
- The unsupervised group reported more long-lasting hallucinations after use (OR 2.58; 95% CI: 1.08–6.31), with a wide interval.
More and more people are turning to ketamine to manage their mood, but not everyone does so in a clinic. A study published in September 2026 in the Journal of Psychoactive Drugs quantifies that difference: who uses the substance with a doctor, who uses it without one, and what each group reports regarding its effects.
Two ways to use the same molecule
The authors, from the University of Toronto, drew from the 2023 Global Psychedelic Survey. From that data, they separated those who took ketamine under medical supervision (238 people) from those who did so on their own in informal contexts (222).
The profiles were not identical. Those who used ketamine outside of a clinical setting had more experience with other psychedelics and non-psychedelic recreational substances, as well as higher lifetime ketamine use.
What they reported
At the time of the survey, both groups showed mild symptoms of depression and anxiety, with no significant differences between them (p = 0.22 and p = 0.46). They were also asked to rate the efficacy of ketamine from 0 to 100. The clinical group gave an average of 83.3 (standard deviation of 15.0) and the non-clinical group 81.2 (standard deviation of 16.6). The difference was not statistically significant (p = 0.45).
Where a difference did appear was in hallucinatory side effects. People who used ketamine without supervision were more likely to report long-lasting hallucinations after consumption: an OR of 2.58, with a 95% confidence interval of 1.08 to 6.31. That interval approaches 1, so the estimate is imprecise and should be read as a signal rather than an exact measurement.
What it implies
The most striking result is the tie in perceived efficacy. Those who self-medicate do not believe it works any worse than those who go to a clinic, and the study finds no reason to suggest otherwise.
The other half of the finding points to where there is room for improvement. The authors interpret the higher frequency of prolonged hallucinations as a risk associated with unsupervised use. This must be read with caution: it is a cross-sectional survey, meaning it is a snapshot at a single point in time. It does not allow us to know what doses, frequencies, or product origins were behind each response, nor whether the non-clinical group started with higher baseline vulnerability. Furthermore, everything is based on what each person remembers and chooses to disclose.
What it does make clear is that there are two distinct populations of users with different profiles, and according to the authors, these differences have barely been characterized. Understanding the non-clinical group better, without judgment, is the first step toward ensuring that information about dosage, context, and support reaches those who need it. Those who want to review what is known about the substance can start with our ketamine and dissociatives guide and our guide on harm reduction and responsible use.
We also have a recent report on another risk of ketamine that appears with prolonged use: a British clinic is treating 60 minors for bladder damage caused by ketamine.
Source
- Syed OA, Petranker R, Nestor SM, Husain MI, Lipsman N, Alam F, Giacobbe P, Lake S, Lucas P. Real-World Therapeutic Use of Ketamine in Clinical and Non-Clinical Settings: A Cross-Sectional Survey. Journal of Psychoactive Drugs, September 2026 (PMID 42776060; DOI 10.1080/02791072.2026.2730550).
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.
