Botulinum toxin injections demonstrate anti-depressive effects

New research suggests botulinum toxin type A has anti-depressive qualities along with its well-known cosmetic effects.

Researchers from the University of Texas Southwestern, Austin, found that botulinum treatments injected between the eyebrows had an anti-depressive effect even after the treatment wore off and wrinkles returned. This suggests that the improvement in mood isn’t related solely to the treatments’ cosmetic benefits.

The study was conducted by the husband-wife team of Michelle Magid, M.D., clinical associate professor of psychiatry at the University of Texas Southwestern in Austin, and Jason Reichenberg, M.D., associate professor of dermatology at the same institution.

“The most significant finding in our study is that the anti-depressant effects of the treatment lasted beyond the cosmetic effects,” Dr. Magid tells Dermatology Times. “In other words, even when patients’ frown lines went back to baseline, their depression symptoms continued to get better.”

Dr. Magid presented the findings at the recent American Academy of Dermatology 72nd Annual Meeting held in Denver.

Thirty participants with symptoms of depression took part in the 24-week, randomized, double-blinded, placebo-controlled study. The group that first received placebo began receiving botulinum treatments after week 12, while the group receiving the botulinum treatments first were later switched to placebo after week 12. Researchers noted both groups’ improved scores on the Hamilton Depression Rating Scale. Significantly, however, though the treatments’ cosmetic effects wore off between weeks 12 and 16 in the group that received botulinum followed by placebo, improvement in depressive symptoms was maintained for the full 24 weeks.

“There are two theories as to why botulinum toxin injections in the forehead may be improving mood,” Dr. Reichenberg tells Dermatology Times. “The first involves behavior. If we look less sad and anguished, people will engage with us more. When social interaction improves, self-esteem and mood will most likely improve as well.”

The second involves biology, he says, explaining that the trigeminal nerve in the face sends sensory information to the amygdale, the area in the brain often associated with heightened fear response, depression and anxiety. Subsequently, reducing trigeminal nerve signals with botulinum injections can also reduce hyperactivity in the amygdala, which can lead to improved anxiety and depression states.

“Other biologists hypothesize that the effect may be due to relaxed facial muscles cooling the blood flowing to the brain, in a manner similar to relaxation disciplines like yoga and tai chi,” Dr. Reichenberg says.

According to Dr. Magid, three small, double-blinded, placebo-controlled trials have examined the treatment of depression using botulinum toxin type A.

“We are not advocating that this intervention is ready for prime time yet,” she says. “However, there is enough positive pilot data to suggest that a larger trial is warranted. And if larger trials can replicate the findings of the three smaller trials, botulinum toxin may become another tool in the toolbox when treating depression.”

Dr. Magid says the study will be published in an upcoming issue of the Journal of Clinical Psychiatry.