Does Blocking Facial Feedback Via Botulinum Toxin Injections Decrease Depression? A Critical Review and Meta-Analysis

Researchers have proposed that blocking facial feedback via glabellar-region botulinum toxin injections (GBTX) can reduce depression. Random-effects meta-analyses of studies that administered GBTX to individuals with depression indicate that, 6 weeks postintervention, GBTX groups were significantly less depressed compared to placebo groups ( d = 0.83) and pretreatment levels ( d = 1.57). However, we noted the following concerns: (a) effect sizes...