How Does Vagus Nerve Stimulation Work? Could This Be the Secret Weapon in Fighting Stress?

A stimulation technique called vagus nerve stimulation is considered a promising therapy in fighting chronic stress.

What Is a Vagus Nerve?

The human body contains 12 cranial nerves, which come in pairs and help connect the brain with other areas, such as the head, torso, and neck. Some nerves send sensory information to the brain, like details about sight, sound, smell, and taste. Cranial nerves also control the movement of different muscles and actions of particular glands, also known as motor functions.

While some cranial nerves either have motor or sensory functions, others have both. One such nerve is the vagus nerve which is known as the longest cranial nerve in the human body. Also known as cranial nerve X, it is present on each side of the body, both starting at the brainstem and passing through the neck to the chest and abdomen.

The vagus nerve is responsible for different internal organ functions, like heart rate and reflex actions such as vomiting, swallowing, sneezing, and coughing. It also plays a crucial role in the autonomic nervous system, which controls involuntary actions like digestion and breathing. Experts also believe that the vagus nerve can form a link between the brain and the gut in what they call the gut-brain axis.

One of the vagus nerve's sensory functions is providing somatic sensation information to certain parts of the throat, the external part of the ear canal, and the skin behind the ear. It also supplies information on visceral sensations for the lungs, heart, and digestive tract.

Meanwhile, the vagus nerve's motor functions include stimulating the heart muscle, larynx, and pharynx. It also stimulates involuntary contractions in the stomach and most of the intestines.

Vagus Nerve Stimulation as Medical Therapy

Vagus nerve stimulation is a form of treatment that involves placing a device in a person's body to stimulate the nerve using electrical impulses. It is used to treat cases of epilepsy and depression which do not respond to conventional treatments.

In carrying out this method, health experts usually place a device under the skin of the chest and connect it to the left vagus nerve with a wire. Upon device activation, electrical signals are sent through the vagus nerve to a person's brainstem, delivering information to the brain.

Experts are still studying how the vagus nerve is involved in mental health. They believe that the connection between mental health and a healthy gut biome explains how vagus nerve stimulation can help treat depression and anxiety. In 1997, the US Food and Drug Administration (FDA) approved vagus nerve stimulation as a cure for patients with treatment-resistant epilepsy, and in 1999, as an accessory treatment for patients with major depressive disorder.

According to the American Psychological Association, more than 76% of adults report symptoms of stress, like tiredness, headache, or sleeping problems. Unfortunately, there are no specific treatments for anxiety, although there are treatments to alleviate some of its signs and symptoms. As of now, the three major approaches to chronic stress treatment include medicinal intervention, psychotherapy, and lifestyle changes.