['It has been suggested that botulinum toxin A (BTX-A) treatment for frown lines can also be used as a treatment for depression. A psychological mechanism for this effect is reviewed in which paralysis of the corrugator (frown) muscles leads to less facial feedback for negative emotions. Consequently, a negative affect is harder to maintain and so the person has a more positive mood.', 'In order to test this mechanism, the mood of patients who had received BTX-A treatment for glabelar frown lines was measured and compared with patients who had received other cosmetic treatments.', 'The BTX-A-treated patients showed significantly less negative mood.'] Does botulinum toxin cosmetic therapy correlate with a more positive mood?