Reports from the 51. ACNP Congress — I. Botulinum Toxin A as an Antidepressant

At the 51st Congress of the American College of Neuropsychopharmacology (ACNP), 2nd – 6th December 2012 in Hollywood, Florida, Eric Finzi and Norman Rosenthal  from Chevy Chase Cosmetic Center in Chevy Chase, Maryland, reported today at the “Hot Topics” session on the results of their double-blind, placebo-controlled study of botulinum toxin A in patients with depression. Charles Darwin suggested that a person’s mood is not necessarily reflected in its facial expression, but that, conversely, the latter can have effects on mood and emotion. This hypothesis was later expanded by the American psychologist William James to the “facial feedback hypothesis”. It was again Darwin, who described that depressed people suffer from an over-activity of the corrugator (musculus corrugator supercilii, the “front-or brow corrugator”). Injection of botulinum toxin into the Glabella region (the region above the root of the nose) leads to effective paralysis of the muscle for about three months.

Finzi included patients with a depressive disorder into his study. More than 80% of patients in both groups suffered from recurrent depression. The mean duration of the current depressive episode was 27.9 months. Patients had to have a minimum score of 26 on the Montgomery-Asberg Depression Rating Scale (MADRS). They were then randomized to receive either Onabotulinum Toxin A (OBA) (29 U Women, 40 U Men) or placebo (0.9% NaCl). Response to treatment was defined as a reduction of the MADRS scores of at least 50%, remission as a reduction of MADRS scores on a value of 10 or below. The patients were re-evaluated after three and six weeks.

84 patients were randomized, 41 received placebo and 43 OBA. OBA was highly statistically significantly superior to placebo in reducing the MADRS scores. In the group treated with OBA, the score was reduced by 47.0% and  in the placebo group by 20.6% (p < 0.0004). The response rate in the OBA group was 51.5% and only 14.6% in the placebo group (p < 0.0009). Also, the remission rate was significantly higher in the OBA group  (27.3% versus 7.3%, p < 0.03).

This interesting study showed a very impressive superiority of botulinum toxin versus placebo in patients with a depressive disorder that requires further evaluation. The mechanism of action is unclear, but the author suspects that it is based on the concept of “emotional proprioception”, according to which the brain continuously monitors the relative importance of facial expressions, which thereby would have pronounced influence on mood.

On their website, the plastic surgeon Finzi and his colleague, the psychiatrist Norman Rosenthal, are still recruiting patients for their study.

This post is also available in: German

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