Skepticism about Recent Evidence That Psilocybin Liberates Depressed Minds

A recent paper in Nature Medicine found that psilocybin therapy in patients with depression decreased brain network modularity (measured with task-free functional magnetic resonance imaging), an effect supposedly not found with the selective serotonin reuptake inhibitor S-citalopram. This decrease in network modularity also correlated with depression. Here, we raise several issues with this paper, including inconsistencies in reports of the primary clinical outcome, statistical flaws including a one tailed test, nonsignificant interaction, and regression to the mean, the ambiguity and overinterpretation of resting state data, and a missing reference for a conceptually similar study that exemplifies why a one-tailed test cannot be justified. Together, these issues make us question the uniqueness and impact of these findings, as well as the unwarranted media hype that they generated.

Automated summary

A recent paper suggests that psilocybin therapy can decrease brain network modularity in patients with depression, which is not found with the selective serotonin reuptake inhibitor S-citalopram. However, there are several issues raised regarding the inconsistencies in clinical outcomes, statistical flaws, and overinterpretation of resting state data.