Transcranial magnetic stimulation (TMS) is a procedure that uses strong magnetic fields to stimulate the brain cells. Doctors mostly recommend it to treat severe depression or PTSD when medications have been ineffective.

TMS is a type of noninvasive brain stimulation therapy. This means that healthcare professionals perform the procedure outside the patient’s body by placing magnets on the head. The technique is painless but may cause muscle twitching during the procedure.

TMS has received approval from the Food and Drug Administration (FDA) for use in people with depression and obsessive-compulsive disorder (OCD).

This article explores TMS and explains its related risks. It also discusses how a person can prepare for this procedure.

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TMS is a form of brain stimulation treatment that applies strong magnetic fields to the brain areas responsible for depression and regulating how a person feels.

The body responds well to TMS — the most common side effect a person may experience is a headache. That said, other medications may be more likely to cause adverse effects.

There are two types of TMS therapy: repetitive transcranial magnetic stimulation and deep transcranial magnetic stimulation.

Repetitive transcranial magnetic stimulation

Repetitive transcranial magnetic stimulation (rTMS) is a procedure where a doctor places a small, sealed device on the scalp over the brain area that controls mood. This device contains a coil that carries an electric current and produces a magnetic field.

The session lasts for 40 minutes and takes place without a person requiring sedation or anesthesia.

Doctors may recommend rTMS on its own or with antidepressant drugs.

Deep transcranial magnetic stimulation

During a deep transcranial magnetic stimulation (dTMS) session, doctors use coils that can reach regions about 4 centimeters beneath the skull’s surface.

If a person has depression or OCD, they may use the H1 coil. This coil has approval from the Food and Drug Administration (FDA) for treating these mental health conditions.

dTMS is an outpatient procedure that doctors can perform without administering anesthesia. It requires individuals to wear a cushioned helmet that produces brief magnetic fields similar to what MRI machines generate.

Sessions last 4–6 weeks, and every appointment is about 20 minutes long.

During a TMS procedure, the coil that the doctor places on the patient’s scalp generates short pulses that travel through the skull to stimulate the brain’s nerve cells.

TMS can target specific areas of the brain. This helps reduce the risk of side effects relating to other brain stimulation procedures, such as electroconvulsive therapy.

Doctors may recommend TMS procedures for people with certain conditions, such as the ones below.

Depression

Doctors mainly perform TMS for individuals who have depression and have not experienced any improvements after taking medications. The technique can target the brain’s dorsolateral prefrontal cortex, which controls mood, social behavior, and decision making.

According to a 2019 article, 30% of people with depression do not find relief from medication and psychotherapy.

Between 50% and 60% of individuals have found TMS to be beneficial in improving their symptoms. While the procedure may not be a permanent solution, follow-up sessions may be available if symptoms reappear.

Anxiety and PTSD

TMS may also be a suitable option for those with anxiety. It may help reduce the nerve cell activity of the brain’s prefrontal cortex, which increases when a person is anxious.

One meta-analysis found that people with post-traumatic stress disorder (PTSD) may also benefit from TMS. It also reported that the side effects among participants were inconsistent.

Stroke recovery

Doctors may perform TMS on people who have had a stroke.

The procedure can help promote motor recovery, as the magnetic impulses can alter the activity of the motor cortex. This area of the brain is responsible for voluntary movement.

Parkinson’s disease

Authors of a 2019 clinical trial found that high frequency rTMS may improve symptoms of dysphagia in those with Parkinson’s disease.

A person may notice improvements for up to 3 months after the procedure if they opt for monthly top-up sessions during that period.

TMS therapy may be unsuitable for individuals who have nonremovable metal in their head, such as:

The National Institute of Mental Health (NIMH) mentions some of the side effects that a person may experience when undergoing a TMS procedure:

  • headaches
  • discomfort
  • tingling
  • brief lightheadedness

There is also a small risk of developing seizures, but the incidence rate is about 0.1% across an entire course of treatments.

Additionally, researchers do not yet know the long-term effects of TMS.

Before starting TMS sessions, the doctor or technician should discuss what the person will experience during treatment.

They may also discuss any side effects that may appear.

The individual may consider asking someone to drive them to their TMS sessions. It is possible to develop headaches after the first few sessions, and it may be uncomfortable to drive back home.

Before the procedure, individuals may have to remove any magnetic-sensitive objects, such as jewelry and credit cards. The healthcare professional administering the treatment may provide them with earplugs to protect their hearing, as there may be a loud clicking sound during the procedure.

A healthcare professional may also determine the location where they will place the coil. It should be in line with the area responsible for the person’s symptoms.

Additionally, they may have to measure a person’s motor threshold, which is the minimum amount of power they use to twitch their thumb. This may be important to determine the energy they need to stimulate brain cells.

Afterward, the individual has to remain seated while the TMS is taking place.

Depending on the coil the healthcare professional uses, sessions may last around 30–40 minutes. Individuals can often resume their everyday activities after treatment, though they may experience slight discomfort and headaches.

Authors of a 2019 review noted that TMS is a safe and effective treatment for depression. It can be beneficial for people who find that medications are ineffective.

According to Harvard Medical School, TMS may not provide permanent results, and individuals may have to attend sessions again if symptoms reappear. However, this approach offers a positive outcome without using medications.

It may also be a suitable idea to consult a therapist, as they can help people manage stressful situations.

Depression is a treatable mental health condition that causes persistent feelings of sadness, guilt, and trouble sleeping, among other symptoms.

Medications for the condition may not work for everyone, so TMS may be an option.

The American Psychiatric Association estimates that most individuals respond well to depression treatment. It also suggests discussing issues with a therapist and joining community groups to learn from the experiences of others.

TMS is a brain stimulation therapy that targets the areas of the brain that control a person’s mood. It may be beneficial for those with depression who have not experienced the desired benefits from antidepressant drugs.

TMS may also help those who have anxiety, dysphagia, or PTSD. While the technique is painless and noninvasive, it may cause headaches, discomfort, or tingling. Additionally, doctors may not recommend it for those with brain stents or aneurysm clips.

However, TMS may not provide permanent relief. Individuals may have to consult their doctor for follow-up sessions, especially if they develop symptoms again.