A new commentary published in npj Mental Health Research raises questions about a widely cited meta-analysis comparing ketamine and psilocybin therapy. Author Ramūnas Janavičius points out that the ketamine studies included in the original analysis did not involve psychotherapy, while all the psilocybin studies did, making the two groups hard to compare fairly. He also flags that different measurement tools were used for each drug, which may explain why psilocybin appeared more strongly linked to therapeutic outcomes. The piece argues that when similar mystical experience scales were used in ketamine studies, the results were comparable to psilocybin, suggesting ketamine’s therapeutic potential may be underestimated in the original research.
Source: npj Mental Health Research, “Matters arising: Methodological concerns and interpretative limitations of assessing subjective effects of ketamine”, published September 22, 2026.