Transcranial magnetic stimulation (TMS) is a noninvasive treatment that stimulates nerves in the brain with magnetic pulses. If a person has treatment-resistant depression, a doctor may recommend TMS.

During TMS, a person receives short, quick, and repeated bursts of magnetic stimulation. Doctors focus the pulses on parts of the brain associated with emotional regulation.

Research has shown that TMS can be effective in relieving depression symptoms and improving mood. Although scientists do not fully understand how the treatment works, some suggest that it increases synaptic plasticity and enhances functional connectivity.

TMS is a safe, simple procedure that has few side effects. The Food and Drug Administration (FDA) has approved it for use in people with depression and obsessive-compulsive disorder (OCD).

Read on to learn about how TMS works, what to expect, and the possible side effects.

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Doctors usually treat depression with medication and therapy. However, if this approach does not relieve a person’s symptoms, a doctor may recommend other treatments, such as TMS.

During a TMS session, a healthcare professional places a magnetic coil against a person’s scalp or forehead. This coil delivers a magnetic pulse that passes through the skull, stimulating nerves in specific parts of the brain.

When someone has TMS, a doctor administers pulses one after the other in rapid succession. Using this technique produces longer lasting changes in the brain.

The magnetic pulses are the same type and strength as those that an MRI machine emits. A person will not feel them, and they should not cause any pain.

According to the FDA, people receiving TMS for depression should have treatment daily for 4–6 weeks.

During TMS for depression, doctors focus on the dorsolateral prefrontal cortex. This part of the brain is responsible for various cognitive processes, including memory, mood regulation, and conflict management.

However, it is often dysregulated in people with depression. This dysregulation can make it hard for people to manage their emotions, make decisions, and think clearly.

Researchers believe that stimulating this part of the brain with magnetic pulses changes how nerve cells fire. As a result, it may alleviate some of the symptoms associated with depression.

Moreover, stimulation of the left and right sides of the brain can have different effects. Some researchers believe that low frequency stimulation on the right side is more effective in alleviating depression than high frequency stimulation on the left side.

Although people generally respond well to TMS, its antidepressant effect can wear off over time.

A 2018 review reported that up to 50% of people continued to respond to TMS 12 months after their initial treatment, but more research is necessary to understand how effective it is as a long-term treatment method.

The treatment is an outpatient procedure, which means that it may take place in a hospital or a doctor’s office, and a person will be able to return home the same day.

Before a person begins TMS treatment, a doctor will ask them to remove any belongings containing metal. These items include coins, some jewelry, and credit cards.

Before treatment starts, a person will also need to put earplugs in to protect their ears from loud sounds.


In the first session, a doctor will measure a person’s head for TMS coil placement.

They will also measure motor threshold, which is the minimum amount of power necessary to make a person’s thumb twitch. This threshold varies from person to person.

Once a doctor knows a person’s threshold, they can deliver the correct amount of energy.

Treatment schedule and details

Usually, a person receives five daily treatments over 3–6 weeks. Doctors aim to deliver 20–30 sessions per treatment course.

During treatment, they administer high frequency TMS at about 10 Hertz. This treatment delivers more than 3,000 pulses within about 37 minutes, although the exact session duration may vary.

Due to the high number of pulses, people often refer to TMS as repetitive TMS, or rTMS.

Depression is a complicated condition, and it can be difficult to treat. Usually, the first-line treatment for depression is a combination of medication and therapy. If a medication does not work for an individual, a doctor may change the dosage, type, or both several times.

However, in some cases, this still does not relieve the symptoms, and doctors will determine that the person has treatment-resistant depression.

People who have treatment-resistant depression or cannot take medication for other reasons are good candidates for TMS.

It is not safe for a person to receive TMS if they have any of the following implants in their head:

  • facial tattoos with magnetic ink
  • metallic eye or ear implants
  • bullet or shrapnel fragments
  • aneurism clips or coils
  • deep brain stimulators
  • electrodes
  • stents

However, braces and fillings do not stop a person from being a candidate for TMS.

People with risk factors for seizures should also avoid TMS, as seizures are a possible side effect. These risk factors include:

  • epilepsy
  • a history of seizures
  • excessive alcohol consumption
  • history of severe head trauma
  • brain tumors
  • stroke
  • eating disorders
  • cocaine and ecstasy use

Although TMS is a safe and generally well-tolerated treatment, some people may experience side effects. These can include:

  • tension headaches
  • facial twitching during treatment
  • painful scalp during treatment
  • temporary hearing problems after treatment

A more serious side effect of TMS is seizures. However, the risk of having a seizure is low.

People with treatment-resistant depression and those who cannot tolerate depression medication are suitable candidates for TMS.

The treatment emits magnetic pulses into specific parts of a person’s brain. This can reset patterns of neuronal activity that are common in people with depression.

The FDA has approved TMS as a treatment for depression and OCD.