[Botulinum toxin for the treatment of major depressive disorder]

Botulinum toxin (BTX) plays an important role in the treatment and prophylaxis of migraine and is also used for the treatment of focal dystonia, spasm, hypersalivation, and hyperhydrosis. Recent clinical trials suggest that BTX treatment of muscles involved in the development of negative emotions may also have an antidepressant effect. This article gives a systematic review of the literature regarding BTX in the treatment of major depression.

We screened the databases of Medline and Scopus using the search terms [("botulinum toxin" OR "botox") AND ("antidepressant" OR "depression" OR "depressed")]. The website www.clinicaltrials.gov was screened with the same search terms in order to detect current studies.

As of April 2013, we identified 3 studies that evaluated the antidepressant effects of BTX in the treatment of major depression. An improvement in mood after treatment with BTX was seen in a case series of 10 depressed patients. In a randomised, placebo-controlled study of thirty patients assigned to a verum (BTX, n = 15) or placebo (saline, n = 15) group, treatment with BTX has also shown a positive effect on mood. Another prospective, open-label study evaluated the antidepressive effect of BTX in 25 subjects with major depression. On www.clinicaltrials.gov we identified 2 ongoing studies, which are currently investigating the antidepressant effect of BTX.

Recently published studies have shown a reduction of depressive symptoms after treatment of the glabellar frown lines with BTX injections. Further clinical studies in larger patient samples are necessary to prove the efficacy and safety of BTX injections used for the treatment of depressive disorders.