How to Monitor Relapse After Psilocybin in Treatment-Resistant Depression
How should clinicians monitor for depressive relapse or recurrence after a single dose of psilocybin in treatment-resistant depression?
Patients with treatment-resistant depression may show early benefit after psilocybin yet still relapse or require additional treatment over the following months. This study provides a practical framework for long-term follow-up by defining what counted as a depression-related event and when participants were reassessed through 52 weeks.
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Define the follow-up window from psilocybin baseline
Anchor monitoring to the same baseline used in the study: 1 day prior to psilocybin administration. Continue follow-up out to 52 weeks, because the study tracked long-term efficacy and safety across that period and observed clinical benefits out to approximately 6 months.
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Schedule repeated depression severity assessments
Reassess depressive symptoms at recurring follow-up visits rather than relying on a single post-treatment check. In the observational follow-up, MADRS assessments were performed at weeks 16, 20, 24, 28, 40, and 52, with blinded independent rating; earlier weeks 6, 9, and 12 assessments were also available for the adjunctive COMP 003 cohort.
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Track whether any new antidepressant treatment is started
Count initiation of any new antidepressant treatment as a depression-related event. The study defined this broadly to include pharmacologic, psychological, or somatic treatments, and this was the most frequently reported event category across groups.
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Monitor suicidality using MADRS item 10 thresholds
Treat increased suicidality as a depression-related event if MADRS item 10 reaches 5 or 6, or if it reaches 3 or higher with an increase of at least 2 points from baseline. This threshold was prespecified in the study's event definition and should prompt recognition of clinically important worsening.
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Identify MADRS worsening that meets event criteria
Count worsening as a depression-related event if the MADRS total score increases by 5 or more points from baseline at any postbaseline time point. Also count an event if the MADRS total score is 15 or higher and the increase of 5 or more points persists across 2 or more consecutive visits; in that case, the first date of the 5-point increase is the event date, and if this occurs at the final visit no further confirmation is required.
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Capture major clinical deterioration events
Also classify hospitalization due to depression or suicidality, suicide attempt, prevention of an imminent suicide attempt, completed suicide, or discontinuation for an MDD-related adverse event or lack of efficacy as depression-related events. These criteria were part of the study's comprehensive long-term relapse framework.
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Expect relapse monitoring to extend beyond the acute response period
Use long-term follow-up because the median time to first depression-related event in the primary descriptive analysis was 92 days with 25 mg, 83 days with 10 mg, and 62 days with 1 mg. These data indicate that clinically relevant worsening or treatment change often emerges months after administration rather than only in the immediate post-dose period.
Clinical Considerations
- The study was descriptive and unpowered, so no formal significance testing was performed between dose groups.
- Only 58 of 126 COMP 001 completers offered enrollment entered the long-term follow-up, which limits representativeness.
- Participants entering the follow-up were not fully representative of the original trial population at week 12, creating potential selection bias.
- No further pharmacologic treatment or psychological support was provided in the observational follow-up, so this monitoring framework reflects posttreatment observation rather than an ongoing intervention protocol.
Bottom Line
After psilocybin for treatment-resistant depression, monitor through 52 weeks for new antidepressant treatment, suicidality, and MADRS worsening using explicit event thresholds rather than assuming early improvement will persist.
