Masking of treatment assignment at the time of primary outcome assessment
BANG
Participant and rater guesses of treatment allocation, made at the time of primary outcome assessment, are judged as most relevant to interpretation of the primary outcome. Bang Blinding Index scores (Supplementary material) in cohort 1 were statistically significantly positive (i.e. a tendency for guesses to be correct) for both participants and raters, for midazolam but not ketamine. In cohort 2, masking was not achieved for raters or participants in the midazolam group, and was achieved for raters but not participants in the ketamine group. Across treatment groups in both cohorts, most rater guesses (90–100%) were based on treatment efficacy, whereas most participant guesses were based on treatment efficacy or a combination of efficacy and treatment experience (Supplementary material). See Supplementary material for further details.