How Is Transcranial Magnetic Stimulation (TMS) Used to Treat Depression?

Depression is one of the most common mental health conditions. At least 17.3 million American adults have had at least one depressive episode. These episodes are usually marked by persistent feelings of sadness, hopelessness, apathy, irritability, fatigue, and even suicidal thoughts.

To manage these symptoms, therapy and medication are commonly recommended. However, there are cases where these treatments fail to provide relief or are not tolerated. In such instances, measures like Transcranial Magnetic Stimulation (TMS) may be used.

For those who find their depression to be treatment-resistant, TMS may help with managing their condition. This treatment can potentially provide relief from mental health disorder symptoms. 

What Is Transcranial Magnetic Stimulation?

TMS is a non-invasive procedure that applies strong magnetic fields to certain parts of the brain. For example, TMS can stimulate the prefrontal cortex (one area of the brain responsible for regulating mood) to help improve your overall mental state.

For this procedure to garner positive results, it requires magnetic pulses to be applied repetitively to the nerve cells in regions of the brain. This is why it is sometimes called repetitive transcranial magnetic stimulation (rTMS).

Recognizing its effects on depression, the Food and Drug Administration (FDA) has accepted TMS as a viable treatment option for the condition under certain circumstances.

In addition, this treatment has shown some promise in managing conditions like bipolar disorder, obsessive-compulsive disorder, Alzheimer’s disease, schizophrenia, and others.

What to Expect During Transcranial Magnetic Stimulation Therapy

As stated, TMS is non-invasive, which means no anesthesia or surgical incisions are required for this procedure. Instead, a coil is placed on the scalp, which produces the powerful electromagnetic fields delivered to the brain's specified region.

A physician or technician will determine the best location for maximum effect and then place the coil there.

Placement of the coil is important because it must align with the part of the brain involved with the patient’s condition. The coil is placed while the patient is seated (this position is maintained for the duration of the therapy). While seated, the patient must be free of any jewelry or magnet-sensitive objects.

People familiar with MRI machines may experience a similar ticking sound when they start TMS treatments. This sound is produced by the magnetic fields being projected to the brain. Because of this noise, patients may wear earplugs while receiving this therapy for noise-canceling and safety purposes. The patient may also feel some tapping while wearing the treatment coil.

TMS sessions usually last for about a four- to six-week period, and the patient may receive treatment five times a week. Depending on the coil used and the magnetic pulses delivered to the brain, sessions can last between 30 and 40 minutes. However, the number of sessions may change depending on the patient's response or the severity of the patient’s condition.

How Does Transcranial Magnetic Stimulation Treat Depression?

While the exact mechanism of action isn’t clear, it is believed that repetitive TMS produces effects similar to antidepressants and electroconvulsive therapy.

In addition to the prefrontal cortex, a depressed brain will also report decreased activity in areas like the frontal lobe, amygdala, and hippocampus—regions that affect emotions and mood.

By sending in targeted magnetic waves, these brain regions may have increased activation.

Repetitive TMS has also been shown to increase dopamine in certain brain regions. This is helpful because dopamine (the pleasure hormone) is an important neurotransmitter involved in the regulation of mood.

TMS has been found to benefit between 50%-60% of people who failed to observe improvements after using medication alone to manage their depression.

However, while improvements in symptoms may occur, these effects are not permanent. There is a chance that depression symptoms will return after a while, so additional rounds of treatment may be necessary.

Who Can Receive Transcranial Magnetic Stimulation?

Anyone with depression who finds medication, therapy, and their combination ineffective for treatment may consider TMS. Studies have consistently demonstrated that electroconvulsive therapy (ECT) is the most effective intervention for treatment resistant depression, however unlike TMS, it requires anesthesia and comes with greater potential side effects.

Patients with tooth fillings or braces are, however, able to receive this treatment.

Side Effects of rTMS

Transcranial magnetic stimulation is a relatively safe procedure. Its non-invasive approach, high tolerability, and minimal risk make it safe enough for use in children, although more research is needed in this area.

Likewise, these features make TMS safe, even for pregnant people. Older populations can also benefit from TMS therapy because of its safety and because TMS therapy has a low risk of interacting with medication.

However, minor side effects like pain in the scalp and headaches have been observed in patients that have received this treatment. You might experience fewer side effects as you continue to go through treatment or take any recommended medication.

Patients have also reported hearing issues immediately following the loud noise produced by the pulses. This is despite earplugs being administered during the procedure.

The most serious side effect of this process, however, is a chance of experiencing seizures. However, this risk is considerably low.

A Word From Verywell

Transcranial magnetic stimulation can be a game-changer for the management of treatment-resistant depression. Its non-invasive technique and low risk of side effects may make it a choice treatment for certain patients struggling with the symptoms of depression.

While there is evidence to support its positive effects in improving mood, more research is required to properly identify the mechanisms of action and likely effects of this treatment.