At least two major psilocybin studies will update their trial rules to require fluoxetine washout and publish this change publicly by July 30, 2026. This is a tighter deadline than the previous prediction and matters because protocol changes usually take months to approve through review boards.
This is largely a duplicate of the Q4 2026 washout prediction above but with a more aggressive resolve date of 2026-07-30, only three months away. Formal protocol amendments take time to negotiate with IRBs and FDA. The July 2026 deadline is very tight; base rate for two independent trial protocol amendments on a specific washout standard within 90 days from today is low. Confidence reduced significantly. The prediction is kept because it is falsifiable via ClinicalTrials.gov registry updates.