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Transcranial magnetic stimulation (TMS): Uses and risks

Reviewed by Diane Warns, PT

An image of a brain lit up.

Transcranial magnetic stimulation (TMS) is a noninvasive treatment that uses magnetic fields to stimulate nerve cells in the brain to decrease symptoms of depression. TMS is most often used when other forms of treatment, like medication or talk therapy, have not been effective.

What Is TMS Therapy?

TMS therapy is a noninvasive mental health treatment that uses magnetic fields for brain stimulation. It has shown to be an effective therapy for those who are experiencing medication-resistant depression. Some studies1 indicate that 50–60% of individuals for whom medications didn’t work were able to experience a “meaningful” response to TMS therapy. It is increasingly2 being used to treat depression and other mental health disorders.

History of TMS

Magnetic fields were first demonstrated by Michael Faraday in the 1880s. It took another hundred years before magnetic fields were used for mental health treatment in the 1980s. TMS was developed and studied for effectiveness in the 1990s. Over time, the technique has been introduced to more clinics and treatment centers.

How Does TMS Work?

TMS therapy works by placing an electric coil toward the front of the patient’s head. Magnetic pulses will travel from the coil to the brain as the coil is activated. This stimulates nerves in the brain, particularly in the parts of the brain that control mood and emotions.

TMS therapy is painless, and the therapy is typically completed in the doctor’s office or clinic. An initial session will measure the placement of the coil on the forehead and personalize the settings that will be used. 

During TMS therapy, it is common for patients to hear clicking noises and feel a steady tapping coming from the coil. The doctor will control the intensity of the magnetic pulses, and it may be increased until the fingers or hand twitch.

TMS therapy sessions typically last about 30 to 60 minutes. They take place five times a week for a period of four to six weeks. The TMS therapist will determine the length and duration of treatment based on the patient’s individual symptoms.

What Does TMS Therapy Treat?

TMS therapy is most commonly used to treat depression, but it is also approved by the FDA to treat obsessive compulsive disorder (OCD) and may be effective for other issues.

TMS Therapy for Depression

Most of the research surrounding TMS therapy is in regards to its effectiveness in treating depression. It has proven useful in treating depression that is not responding to standard treatments, such as talk therapy or medication. TMS may help individuals experiencing depression by stimulating cells in the brain and increasing brain activity.

TMS for Anxiety

TMS may also reduce anxiety by reducing activity in the brain’s prefrontal cortex. It can also reduce anxiety by treating other mental health disorders, like OCD, that can include anxiety as a symptom.


As of 2018, TMS has been approved for treating OCD when symptoms don’t respond to medication or other therapies. People with OCD may experience an increase in nerve cell activity in the prefrontal cortex; TMS appears to reduce this nerve cell activity, reducing the symptoms of OCD.


TMS appears to be a promising treatment for posttraumatic stress disorder (PTSD). As with other mental health disorders, this effectiveness seems to be related to reducing nerve cell activity in the prefrontal cortex.

Pros and Cons of TMS Therapy

Before deciding on TMS therapy, it may be helpful to consider the pros and cons of TMS. 

The pros of using TMS therapy include:

  • Success rates: TMS can have high success rates in treating mental health disorders, particularly when medications and other therapies haven’t worked.
  • Safety: TMS is noninvasive, and it is targeted on particular parts of the brain. While there may be some side effects, they tend to subside shortly after the end of the session.
  • Long-term results: While medications may need to be taken daily to maintain effectiveness, four to six weeks of TMS therapy can produce results for a year or longer.

While there are many positives to TMS therapy, there are some disadvantages to the treatment. These include:

  • Daily treatments: During the course of TMS therapy, patients need to have sessions five days a week for up to six weeks, and there may be additional sessions that taper off for a few more weeks. While missing a day or two here and there may not impact treatment, consistency is important with TMS therapy.
  • Cost: While insurance may cover TMS therapy, it often requires that individuals try medication and other forms of therapy first. If those are not successful, then TMS therapy may be approved. Without insurance, a course of TMS therapy can cost more than $10,000 out of pocket. 

Discomfort: While TMS therapy isn’t painful, it can cause discomfort. The tapping of the coil against the scalp can be a strange sensation. Some individuals may also experience jaw or facial movement during the treatment. While these effects typically dissipate after the treatment is finished, TMS can create some discomfort during the therapy.

TMS Side Effects

While TMS therapy is relatively safe, individuals may experience some side effects. Typically, they are short-lived. These can include:

  • Tingling or muscle contractions in the jaw or face
  • Headache
  • Lightheadedness

In rare cases, TMS can trigger seizures, or it can cause mania for people who have bipolar disorder.

Other Brain Stimulation Therapies

TMS shares some characteristics with other brain stimulation therapies. Other therapies that use brain stimulation include:

  • Electroconvulsive therapy (ECT): ECT is a procedure that sends electrical pulses through the brain. It is most often used to treat severe depression that has not responded to medication or other therapies. 
  • Vagus nerve stimulation (VNS): This rare procedure is informed by polyvagal theory and involves placing a pulse generator on the chest and stimulating the vagus nerve. The vagus nerve carries messages to the brain about sleep and mood. 

Deep brain stimulation (DBS): DBS involves surgically placing electrodes in the brain and a pulse generator in the chest. This therapy is experimental, but it has been approved by the FDA to treat OCD.

Is TMS Therapy Right for You?

TMS may be right for you if you’ve tried medication or other therapies for treating a mental health issue without success. It can also be a good option if you cannot tolerate certain medications or cannot take them for other reasons. People at a high risk of epilepsy or who have metallic devices or objects in or around their head should not use TMS therapy.

If you are interested in learning more about whether TMS therapy is right for you, contact a TMS therapist today.

About the author

The editorial team at works with the world’s leading clinical experts to bring you accessible, insightful information about mental health topics and trends.