Botox affects emotional control in the brain for people with borderline personality disorder

Overview: Botulinum toxin, or Botox, can help temper negative emotions for people who suffer from borderline personality disorder.

Source: MHH

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

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

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

Now the psychiatrists have discovered where and how BTX affects the negative program in the brain. Using magnetic resonance imaging (MRI), they have mapped the neuronal effects in borderline patients.

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

The work was recently published in the magazine Scientific Reports.

Feedback between muscles and psyche

Negative moods are expressed on the face in the so-called glabellar area, the area of ​​​​the lower middle forehead. When we are angry or tense, two different types of muscles contract and cause frown lines or worry lines above the root of the nose.

When botulinum toxin is injected into the glabellar area, 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 gives a more positive feeling, as it were,” 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 a BTX injection in the glaballar region has a positive influence on mood and mood arousal.

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

Botulinum toxin emotionally inhibits constant fire in the tonsil core

And this works for depression as well as borderline personality disorder. About three percent of Germans suffer from this condition, and more than 62% of those affected are women. By interrupting the feedback loop between the forehead muscles and the brain, botulinum toxin also alters emotional feedback.

Has shown that botulinum toxin injections affect not only muscles but also the emotional control center in the brain: Professor Dr. Tillmann Kruger. Credit: Karin Kaiser/MHH

The researchers were able to prove this in the brains of borderline patients who had been treated with a botulinum toxin injection in the glabellar area. Just four weeks later, the patients had significantly reduced symptoms, which was reflected in the MRI images.

“We have been able to see that botulinum toxin slows down the emotional constant fire in the tonsil nucleus, which accompanies the high inner tension of the affected individuals,” says the psychiatrist. A comparison group treated with acupuncture also showed improved clinical symptoms, but not the neuronal effects in the MRI study. However, the feedback between muscles and brain does not only work in the glabellar region.

This is the result of a database study involving Professor Krüger and his colleague Professor Wollmer, already published in the journal Scientific Reports 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 main muscles, the muscles of the upper and lower extremities, and the neck muscles.

However, until now, BTX treatment for mental illness has not been included in the services of health insurers. The psychiatrist hopes that this will change once the mode of action has been better investigated.

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

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Author: Stefan Zorn
Source: MHH
Contact: Stefan Zorn – MHH
Image: The image is attributed to Karin Kaiser / MHH

Original research: Open access.
“Neuronal effects of glabellar botulinum toxin injections using a valence inhibition task in borderline personality disorder” by Tillmann HC Kruger et al. Scientific Reports


Abstract

Neuronal Effects of Glabellar Botulinum Toxin Injections Using a Valence Inhibition Task in Borderline Personality Disorder

Previous studies have shown that glabellar botulinum toxin (BTX) injections can lead to sustained relief from depression. This can be achieved through the disruption of a facial feedback loop, which may reduce the experience of negative emotions.

Accordingly, glabellar BTX injection can attenuate amygdala activity in response to emotional stimuli. A prototypical disorder with an excess of negative emotionality and impulsivity associated with increased amygdala reactivity to emotional stimuli is borderline personality disorder (BPD).

To better understand how glabellar BTX can affect emotional stimulus processing and impulsivity, we conducted a functional magnetic resonance imaging (fMRI) study.

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

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

However, BTX treatment was specifically associated with improved inhibitory performance and increased activity in the motor cortex. In addition, the processing of negative emotional faces was associated with a reduction in the activity of the right amygdala.

This study provides the first evidence that glabellar BTX injections can alter the central neurobiological and behavioral aspects of BPD. Since the control treatment produced similar clinical effects, these neurobiological findings may be specific for BTX and not generally related to symptomatic improvement.

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