What predicts who responds to psychedelic-assisted therapy? A review of 54 studies

The question

Can we predict which people will benefit from psychedelic-assisted therapy, and which factors matter most?

What they did

Researchers searched the published literature from its earliest records through March 2024 for studies that looked at predictors of response to therapy using classic psychedelics for mental disorders. They included 54 studies. Participants were adults diagnosed with substance-use disorders, major depressive disorder, anxiety disorders, obsessive-compulsive disorder, post-traumatic stress disorder, or distress linked to life-threatening illness, plus naturalistic samples of people reporting symptoms without a formal diagnosis.

What they found

The predictor reported most often was the intensity of the acute drug experience itself, especially so-called mystical-type experiences. However, this link was not consistent across every disorder or at every follow-up time point. Factors relating to the person’s mindset (“set”), the environment (“setting”) and the dose were frequently associated with how likely and how intense those mystical-type experiences were. The authors concluded that the evidence base is not yet strong enough to identify reliable predictors.

The fine print

This is a narrative synthesis, not a statistical pooling of results, so no overall effect size is given. The included studies varied widely in design, population and quality, and some involved naturalistic use without confirmed diagnoses, where self-selection and self-report can bias results. The abstract does not report the total number of participants across studies, and the authors note follow-up was often short and methods inconsistent. This summary is based on the abstract only.

What it means

Across the research so far, the intensity of the acute psychedelic experience is the factor most often linked to later improvement, but the evidence is inconsistent and not yet reliable enough to predict who will benefit.

Evidence grade: Low. A systematic review that summarizes 54 heterogeneous studies, including uncontrolled and naturalistic ones, without pooling results statistically.

This summary is based on the study’s published abstract.