SSRI washout protocols will be formally required (via FDA mandate or sponsor-initiated amendments across at least five active trials) for MDMA and psilocybin INDs by August 2026, causing measurable enrollment delays at multiple sites.

Within 18 months, the FDA (or major drug companies running trials) will require people to stop taking SSRIs for a set period before joining MDMA or psilocybin trials. This will slow down enrollment because fewer people will be eligible, and the waiting period will be longer.

Regulatory bodies move slowly; a formal mandate across all active trials within 3 months is historically unprecedented absent a clinical safety event. Sponsor-driven amendments are more likely but still require IRB and FDA concurrence. 'Measurable enrollment delays' adds an additional falsifiable bar that is hard to verify without site-level data.