A systematic review of controlled clinical trials presented at the American Academy of Dermatology's annual meeting indicates that botulinum toxin A injections, commonly used for dermatologic purposes, may also alleviate symptoms of major depressive disorder (MDD). (A full article examining this review will be published in the upcoming issue of The Chronicle of Cosmetic Medicine + Surgery.)
Dr. Leah Johnston led the review, which analyzed 11 studies from an initial pool of 5,619 articles involving botulinum toxin. Seven of the studies focused on MDD treatment, and one study each looked at its use for wrinkles, chronic migraine, tension headache, and temporomandibular disorders (TMDs). She is a graduate of the University of Calgary’s Cumming School of Medicine and a Clinical Research Fellow in Dermatology at the University of Massachusetts T.H. Chan School of Medicine.
Dr. Johnston noted nine of the studies utilized placebo comparator groups, while three included standard treatment comparators such as sertraline for MDD, topiramate for chronic migraine, and oral appliances for TMDs.
According to the study results, five out of six studies showed significant improvements in depression severity compared to placebo at six weeks; two studies demonstrated significant improvement in depression severity at nine to 12 weeks; and one study reported improvement in depression severity at six months.
Dr. Johnston proposed several theories explaining the mood-enhancing effects of botulinum toxin. “There is a thought that this [toxin] can actually alter perception of negative stimuli, and that it therefore reduces negative emotional states,” she said. “There is also the thought that by preventing the ability to frown, people appear happier.” In patients with conditions such as chronic migraine, the alleviation of pain with effective treatment may be at least partially responsible for the improvement in mood, she added.
One study found that botulinum toxin A provided comparable improvement in depression to daily sertraline treatment after 12 weeks. Notably, botulinum toxin demonstrated a quicker onset of mood improvement compared to sertraline, which typically requires four to six weeks for adequate antidepressant effects.
Compared to daily oral medications to treat depression or mood disorders, botulinum toxin may have a more favourable side effect profile and it could potentially involve treatment only every three to four months, Dr. Johnston said.
“Botulinum toxin A is not currently approved by the U.S. FDA and Health Canada for the treatment of depression based on the available data,” said Dr. Johnston. “I think that there is definitely more research that is needed in phase II and phase III randomized, controlled trials. But in the meantime, dermatologists might be able to mention to their patients who are undergoing botulinum toxin A for other indications that it can improve mood. It is a very interesting finding, and something that I hope will be explored more in future clinical trials.”
—with files from Chronicle Correspondent Louise Gagnon
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