>Many years ago, adequately
blinded trials of tricyclic antidepressants were done,
in which the placebo contained atropine, which
causes dryness in the mouth like the active drugs do.
These trials reported very small, clinically insignificant
effects of tricyclic antidepressants compared with
placebo (standardised mean difference 0·17, 95% CI
0·00–0·34).
https://pubmed.ncbi.nlm.nih.gov/7037102/
https://sci-hub.se/https://www.thelancet.com/journals/lanpsy...
>Many years ago, adequately blinded trials of tricyclic antidepressants were done, in which the placebo contained atropine, which causes dryness in the mouth like the active drugs do. These trials reported very small, clinically insignificant effects of tricyclic antidepressants compared with placebo (standardised mean difference 0·17, 95% CI 0·00–0·34).