Evidence category
Placebo effects, unblinding, and what trial design reveals about belief.
Recognizable side effects unblind psychiatric trials: appetite suppression, sleep disturbance on stimulants; SSRI sexual dysfunction. Active-placebo trials mimicking side effects show SMD 0.17 versus 0.39 with inert placebo. Kirsch's severity interaction is real—placebo response drops in severe depression, drug response stays flat. Publication bias inflated efficacy by 32%. Neither 'it's all placebo' nor 'double-blind means the estimate is clean' survives.