Botox influences emotion control in the brain for people with borderline personality disorder

Summary: Botulinum toxin, or Botox, can help dampen negative emotions for those with borderline personality disorder.

Source: MHH

The bacterial toxin botulinum toxin (BTX), colloquially known as Botox, is probably known to most people as a wrinkle remedy. But botulinum toxin can do even more: if injected into the forehead, for example, it can relieve depression.

It also decreases negative emotions in people with borderline personality disorder, who suffer from extreme mood swings.

Professor Dr. Tillmann Krüger, senior physician and leader of the research group at the Clinic for Psychiatry, Social Psychiatry and Psychotherapy at the Hannover Medical School (MHH), demonstrated this years ago, together with his colleague Privatdozent (PD), the Dr. Marc Axel Wollmer of the Semmelweis University’s Asklepios Campus Hamburg.

Psychiatrists have now discovered where and how BTX influences the brain’s negative programming. With the help of magnetic resonance imaging (MRI), they have visualized the neural effects in borderline patients.

The result: botulinum toxin affects the so-called nucleus of the amygdala or almond in the temporal lobe of the brain, where fears arise and are processed.

The work was recently published in the journal Scientific reports.

Feedback between muscles and psyche

Negative moods are expressed on the face in the so-called glabellar region, the lower middle forehead area. When we are angry or tense, two different types of muscles contract and cause forehead or worry wrinkles to appear above the bridge of the nose.

When botulinum toxin is injected into the glabellar region, it paralyzes these muscles between the eyebrows. Since facial expressions and psychological state are closely related, this also reduces the intensity of emotions.

“A relaxed forehead conveys a more positive feeling, so to speak,” explains Professor Krüger.

In science, this feedback is discussed as facial feedback theory. In a previous meta-analysis, Professor Krüger and his team had already shown that an injection of BTX in the glaballar region has a positive influence on mood and mood arousal.

As a result, depressive symptoms improve significantly. “The treatment has several advantages at the same time: since the paralyzing effect lasts for three months or more, an injection should also be given only at these intervals. Infrequent injections are also less expensive than other therapy options and have very good tolerance and acceptance among patients,” explains Professor Krüger.

Botulinum toxin curbs the constant emotional fire in the nucleus of the amygdala

And this works for both depression and borderline personality disorder. Around three percent of Germans suffer from this disorder, and more than 62% of those affected are women. By disrupting the feedback loop between the forehead muscles and the brain, botulinum toxin also changes emotional feedback.

He has shown that botulinum toxin injections not only affect the muscles, but also the emotional control center of the brain: Professor Dr. Tillmann Krüger. Credit: Karin Kaiser / MHH

The researchers were able to demonstrate this in the brains of borderline patients who had been treated with an injection of botulinum toxin in the glabellar region. Just four weeks later, patients had significantly reduced symptoms, which also showed up on MRI images.

“We were able to see that botulinum toxin slows down the constant emotional fire in the nucleus of the amygdala, which accompanies the high-grade internal tension of affected people,” says the psychiatrist. A comparison group treated with acupuncture also showed improved clinical symptoms, but not the neural effects on MRI examination. However, the feedback between the muscles and the brain does not only work in the glabellar region.

This is the result of a database study in which Professor Krüger and his colleague Professor Wollmer participated and which was already published in the journal Scientific reports at the end of 2021.

In collaboration with the University of California, San Diego, they found that botulinum toxin can also relieve anxiety disorders when injected into the muscles of the head, muscles of the upper and lower limbs, and neck muscles.

Until now, however, BTX treatment for mental illness has not been covered by health insurance companies. The psychiatrist hopes that this will change when the mode of action has been better investigated.

Botulinum toxin, colloquially known as Botox, is the strongest known neurotoxin. It is produced by the bacterium Clostridium botulinum in the absence of air and causes the so-called botulism. Poisoning symptoms are usually caused by eating poorly preserved food in which the bacterial toxin has accumulated. This inhibits the transmission of excitation from nerve cells to other cells, especially at junctions with muscle and blood.

See also

This shows someone adding a lump of sugar to a black coffee

About this borderline personality disorder and emotional research news

Author: Stefan Zorn
Source: MHH
Contact: Stefan Zorn – MHH
Image: Image credited to Karin Kaiser / MHH

Original Research: Open access
“Neural effects of glabellar botulinum toxin injections using a valenced inhibition task in borderline personality disorder” by Tillmann HC Kruger et al. Scientific reports


Neural effects of glabellar botulinum toxin injections using a valenced inhibition task in borderline personality disorder.

Previous studies have indicated that glabellar botulinum toxin (BTX) injections can lead to sustained relief from depression. This can be achieved by interrupting a facial feedback loop, which potentially mitigates the experience of negative emotions.

Consequently, glabellar injection of BTX can attenuate amygdala activity in response to emotional stimuli. A prototypical condition with excess negative emotionality and impulsivity accompanied by heightened amygdala reactivity to emotional stimuli is borderline personality disorder (BPD).

In order to improve the understanding of how glabellar BTX may affect the processing of emotional stimuli and impulsivity, we performed a functional magnetic resonance imaging (fMRI) study.

Our hypotheses were (1) glabellar BTX leads to increased activation in prefrontal areas during inhibition performance and (2) BTX decreases amygdala activity during processing of emotional stimuli in general . Using an emotional go-/no-go paradigm during fMRI, we assessed the interference of emotion processing and impulsivity in a sample of n = 45 women with BPD.

Subjects were randomly assigned to treatment with BTX or serial acupuncture (ACU) of the head. After 4 weeks, both treatments resulted in a reduction in BPD symptoms.

However, BTX treatment was specifically associated with improved inhibition performance and increased activity in the motor cortex. Furthermore, the processing of negative emotional faces was accompanied by reduced right amygdala activity.

This study provides the first evidence that glabellar injections of BTX can modify central neurobiological and behavioral aspects of BPD. Because the control treatment produced similar clinical effects, these neurobiological findings may be specific to BTX and not a general correlate of symptomatic improvement.

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