Response and remission are thresholds applied to a rating scale such as the MADRS. Response usually means the score has fallen by at least 50% from the start; the 2026 EPISODE trial used exactly that definition (Mertens et al., 2026). Remission is stricter: the score has fallen below a low cut-off set in the protocol, meaning only mild symptoms or none remain.
The two can move differently. In a 2021 trial, 71% of participants responded and 54% were in remission at week 4 after psilocybin (Davis et al., 2021). In a 2023 trial, more psilocybin participants had sustained response than with niacin, but not more remission (Raison et al., 2023). In the 2006 ketamine study, 71% met response criteria and 29% remission the day after an infusion (Zarate et al., 2006).
Percentages from small trials swing widely, and a response at one week says little about the months after. Readers should check when the threshold was measured, against what comparison, and whether it was the trial’s primary endpoint.
Sources
- Mertens et al., JAMA Psychiatry, 2026
- Davis et al., JAMA Psychiatry, 2021
- Raison et al., JAMA, 2023
- Zarate et al., Archives of General Psychiatry, 2006
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