The buzz surrounding psychedelics often positions them as a miracle cure, but the “magic” might actually be a matter of patient expectation.
Researchers from the University of California San Francisco (UCSF), the University of California Los Angeles (UCLA), and Imperial College London found that when patients know exactly what drug they are taking, psychedelics perform no better than standard antidepressants in tackling depression.
The challenge of functional unblinding in trials for psychedelics
The scientific community has seen a surge of enthusiasm for psychedelic-assisted therapy.
Recent clinical trials have suggested that psychedelics are significantly more effective than traditional antidepressants. However, these findings often carry a significant methodological caveat.
In standard drug trials, researchers use a double-blind design in which neither the patient nor the doctor knows who received the active drug and who received a placebo; this helps isolate the specific treatment effect of a medication. Traditional antidepressants often show only a small margin of benefit over placebos in double-blinded trials, leading some to question their clinical value.
Double-blinding in psychedelic trials is more difficult—it is nearly impossible to hide the fact that a patient has received a potent hallucinogen. Data suggests that between 90% and 95% of participants in these trials correctly guess their treatment group. In contrast, only ~63% of participants in traditional antidepressant trials guess correctly.
This disparity creates a massive gap in patient expectations. If participants know that they received an active drug compared to a placebo, they are more likely to report feeling better.
To level the playing field, a new study compared results from psychedelic trials directly to open-label antidepressant trials, where every patient knew they were taking an active drug.
Comparing the clinical effectiveness of antidepressants and psychedelics
The team performed a systematic review and meta-analysis of 24 trials, which included 8 studies on psychedelics involving 249 patients and 16 open-label trials of traditional antidepressants with over 7,900 participants. The researchers used statistical tools to track changes in depression scores.
When both groups knew they were receiving an active treatment, the difference between the two therapies wasn’t statistically significant.
While neither treatment proved superior, patients in both groups saw their depression scores drop by an average of 12 points on standard clinical scales.
The analysis confirmed that while blinding significantly changes the perceived effectiveness of traditional antidepressants, it has almost no impact on psychedelic trials. This is largely because patients can feel the effects of psychedelics so clearly, and so these trials are effectively always open-label.
Future implications and limitations for medical psychedelics
These findings suggest that the clinical advantage of psychedelics might be a product of trial design rather than a superior pharmacological effect.
“Unblinding is the defining methodological problem of psychedelic trials. What I wanted to show is that even if you compare psychedelics to open-label antidepressants, psychedelics are still much better,” said corresponding author Dr. Balázs Szigeti, a clinical data scientist at UCSF. “Unfortunately, what we got is the opposite result—that they are the same, which is very surprising given the enthusiasm around psychedelics and mental health.”
Szigeti and the team concluded that the perceived superiority of psychedelics often stems from disappointed placebo groups who realize they have not received the active treatment.
The sample size for psychedelics was much smaller than the massive datasets available for standard antidepressants, and the timelines were inconsistent; antidepressant trials lasted around eight weeks, while the psychedelic trials averaged just over three weeks. There is also a lack of diversity in current research, which makes it difficult to know if these results apply to the broader population.
Ultimately, the study calls for more rigorous, head-to-head comparisons.
“Psychedelics may still be a valuable treatment option,” said Szigeti. “But if we want to understand their true benefits, we have to compare them fairly—and when we do that, the advantage over standard antidepressants is much smaller than many people, including myself, expected.”
Future research must move beyond the hype to determine where these substances truly fit in modern medicine.
Reference: Williams ZJ, Barnett H, Sziget B. Psychedelic therapy vs antidepressants for the treatment of depression under equal unblinding conditions. JAMA Psychiatry. 2026. doi: 10.1001/jamapsychiatry.2025.4809
This article is a rework of a press release issued by the University of California San Francisco. Material has been edited for length and content.