What to Know About Repetitive Transcranial Magnetic Stimulation (rTMS)

Medically Reviewed by Smitha Bhandari, MD on July 17, 2023
4 min read

Repetitive transcranial magnetic stimulation (rTMS) uses painless, magnetic pulses to help lessen the symptoms of depression. You do not have to be hospitalized for rTMS, and you don’t need sedation or anesthesia. Typically, you go five times a week to a clinic or doctor’s office for the treatments. A course of rTMS usually lasts four to six weeks.

‌The strength of the magnetic field used in rTMS is about the same as that of a magnetic resonance imaging (MRI) scan. The magnetic pulses stimulate (wake up) nerve cells in the parts of your brain that control your mood.

‌Before the treatment starts, you will need to remove anything that would be sensitive to a magnet, such as metal jewelry and credit cards. You must wear earplugs to protect your hearing, as rTMS makes a loud clicking noise. For each session of rTMS, you will sit in a comfortable reclining chair.

The first session takes about an hour. The doctor or tech will take measurements to find the best place to put the electromagnetic coil that will deliver the magnetic pulses. They will position the electromagnetic coil so that it is resting against your head.

To find the right dose (magnetic strength) for your treatment, the doctor will first target the motor cortex. This is the part of the brain that controls muscle movement. They will administer a few brief magnetic pulses until they find the strength that makes your hand or fingers twitch. This is known as your motor threshold.

The doctor will then move the electromagnetic coil forward to target a different part of the brain called the dorsolateral prefrontal cortex. This area of the brain is known to be involved in depression. The measurements and the test to find your motor threshold don’t have to be repeated at every appointment.

‌The treatment itself lasts about 30 to 40 minutes. During the treatment, you will probably feel a tapping on your scalp under the coil and hear a loud, clicking noise. This is from the electromagnetic coil turning off and on to deliver the magnetic pulses. It’s about as loud as an MRI scan.

‌Most people don’t have a lot of side effects from rTMS. During rTMS treatment, some people do experience mild and temporary side effects, such as:

Headaches. About 50% of people have headaches during or after their first rTMS sessions. These headaches are generally mild and can be treated with over-the-counter pain relief medicine. Over the course of rTMS treatment, the headaches typically become less and less bothersome.‌‌

Discomfort. Less commonly, people feel a tingling or twitching in the muscles of their face during their first rTMS treatment. Others say they feel pain on their scalp under the electromagnetic coil. The doctor can adjust the position of the coil and the strength of the magnetic pulses right away to make the treatment less painful. Any remaining discomfort usually fades with additional treatments.

Lightheadedness. Some people feel dizzy during or right after rTMS treatments. The dizziness typically goes away quickly after the session and is less noticeable with each treatment.

‌Repetitive transcranial magnetic stimulation is considered a safe and effective treatment, with little risk of serious side effects. Risks include:

Hearing Problems. Even with earplugs, a small percentage of people say they have trouble hearing right after an rTMS session. This side effect is temporary. On the other hand, long-term hearing loss is a risk of rTMS if you don’t wear earplugs.‌‌

Worsening of bipolar disorder symptoms. There have been reports of rTMS triggering a manic episode in people who already have bipolar disorder. Symptoms of a manic episode include risky and impulsive behavior, racing thoughts, and feeling like you don’t need to sleep or eat much.

Seizures. This side effect happens very rarely with rTMS. However, it is important to tell your doctor if you have a seizure disorder or have experienced seizures in the past. Your doctor may not recommend rTMS if you have a medical condition that puts you at an especially high risk for seizures.

If you have depression, antidepressants and talk therapy are the first treatments your doctor will try. Antidepressants are medications that help your brain control your mood. In talk therapy, you work with a counselor to learn new ways of thinking and behaving that can help relieve the symptoms of depression.

‌Most people find that medication and talk therapy reduce their symptoms. For some people, however, antidepressants and counseling don’t make a difference. This is called treatment-resistant depression. Repetitive transcranial magnetic stimulation is used to help people who have treatment-resistant depression.

Some people cannot have rTMS because they have metal in their head that can’t be removed. Braces and dental fillings are okay. If you have any of the following, you should not have rTMS:

  • Aneurysm clips or coils
  • Stents in your neck or brain
  • Deep brain stimulators
  • Electrodes
  • Bullet fragments in your head or neck
  • Scalp or face tattoos with metallic ink

‌In studies of people who had treatment-resistant depression, 50% to 60% found rTMS helpful. Around 30% of those people had a full remission (their symptoms were completely gone). Like most treatments for depression, the effects of rTMS are not permanent. On average, symptoms return after about a year. Some people choose to have another set of rTMS treatments when their depression returns.