The KARMA-Dep2 trial delivered a shocking headline: up to eight serial ketamine infusions were no better than the midazolam placebo for hospitalized adults with moderate to severe depression. In an era of intense hope for ketamine’s rapid antidepressant effects, this result demands a closer look.

This episode critically dissects why this large, pragmatic trial may have failed to show a significant difference, focusing on a central challenge in ketamine research: blinding.

* The Active Placebo Problem: The trial used midazolam as an active placebo to mimic the transient side effects (like sedation and disorientation) of ketamine. However, previous meta-analyses (Wilkinson et al., 2019) show that midazolam itself produces a subs ...