TMS therapy: what is it, benefits, side effects

Transcranial magnetic stimulation (TMS) is an effective treatment for major depression. Unlike psychotherapy or medication, TMS works by deploying magnetic fields to stimulate the brain. Despite its sci-fi-sounding name, transcranial magnetic stimulation is not a scary or invasive procedure. It’s also not the first option prescribed for treating depression, but when medications and psychotherapy fail, TMS can offer benefits. 

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There are several types of psychotherapy, antidepressants, and other medications that lessen symptoms of depression for many people. But for some people, those approaches just don’t work. In such cases, transcranial magnetic stimulation provides a treatment option (Stern, 2018). 

TMS has also been tested as a possible treatment for schizophrenia, attention deficit-hyperactivity disorder (ADHD), and post-traumatic stress disorder (PTSD), but results on these three possibilities are as-yet not conclusive (Cole, 2015; Alyagon, 2020; Namgung, 2019; Cleveland Clinic, 2018).

Transcranial magnetic stimulation (TMS) uses magnetic fields, delivered from electromagnetic coils set near the forehead, to stimulate nerve cells in the brain. It targets areas of the brain thought to control our moods, specifically where activity decreases when we’re depressed (Mann, 2021). 

The procedure is non-invasive and typically painless, with mild side effects (Trevino, 2011). A newer variation is called deep transcranial magnetic stimulation (dTMS), in which the magnetic pulses are administered through a helmet (Levkovitz, 2015).

Exactly how TMS works, biologically, is not fully understood. Repeated magnetic pulses, similar in strength to an MRI (magnetic resonance imaging) machine, appear to increase blood flow in the targeted areas and increase synapses' plasticity (Rizvi, 2019). Synapses are the junction boxes between neurons, and their plasticity determines how effectively the neurons communicate, and thus the brain’s ability to adapt to new information (University of Queensland, n.d.).

Sometimes called rTMS, or repetitive transcranial magnetic stimulation, the procedure is prescribed by a physician and administered by a trained technician, typically under the physician's supervision (Johns Hopkins Medicine, n.d.).

A person can be diagnosed with serious depression—formally major depressive disorder or persistent depressive disorder—if they experience ongoing sadness or depressed mood accompanied by one or more several other common symptoms. These can include losing interest in normal activities, poor sleep, and fatigue (American Psychiatric Association, DSM-5, 2013).

There’s evidence that repetitive transcranial magnetic stimulation can be a productive alternative for many people with depression who didn’t respond to other therapies and medicines. 

One review found that at least 50% of people with severe depression saw some benefit from TMS, and around a third experienced remission. Other trials found that 30 to 40 percent of participants treated with TMS saw sustained improvement in depressive symptoms, similar to the success of antidepressants but without serious side effects (Rizvi, 2019). 

Another review concluded the popularity of TMS is increasing, and a growing body of evidence supports its use for treating depression, alone or in conjunction with medications. (Somani, 2019).

The third review, in the journal BMC Psychiatry, found support for using transcranial magnetic stimulation to treat depression even in people who have not had extensive attempts with pharmacological treatments (Voigt, 2019).

You’ll be awake during your TMS treatment, sitting in a chair. Here’s what happens (Mayo Clinic, 2018): 

• A technician or doctor will place the electromagnetic coil next to your head and begin and make adjustments called mapping.

• The machine will make clicking sounds, and you’ll feel something like tapping on your forehead. Here’s the weird part: The intensity will be adjusted until your hand or fingers start to twitch—that’s when they know the right intensity level has been achieved.

• The formal treatment then involves about 40 minutes of ongoing pulses.

The full TMS treatment runs several days a week for four to six weeks. You’ll walk out after each session—no need to recover before resuming normal activities (Johns Hopkins Medicine, n.d.).

Side effects are usually mild but can include seizures in people who have a history of them. You might experience light-headedness or even headaches, tingling in your face, and scalp pain that can be easily managed (Trevino, 2011; NAMI, n.d.). 

TMS can be riskier for some people. For example, it should not be used on people with metal or electronic implants. But when patients are properly assessed and monitored, the procedure is considered safe (Taylor, 2018). 

TMS should also not be used on someone whose depression is accompanied by psychosis or bipolar disorder, or if they’re at high risk of suicide (NAMI, n.d.).

Make sure your doctor knows if you have any history of seizures or brain injury, whether you are pregnant, and be detailed about any medical conditions you have or medications you take (Mayo Clinic, 2018).

Perhaps you’ve heard of electroshock therapy, the treatment with the negative image dating back to the 1940s. That procedure has evolved notably into a useful treatment now called electroconvulsive therapy (ECT).

It involves passing electric currents through the brain while a person is sedated. ECT is also used to treat people with severe depression who don’t respond to medication, but typically when they also have psychosis or bipolar disorder (NAMI, n.d.).

Transcranial magnetic stimulation (TMS) is nothing like ECT.

There are other brain stimulation therapies used for depression (NAMI, n.d.): 

Vagus nerve stimulation (VNS) can also treat depression, but it involves an invasive procedure. A stopwatch-sized device is inserted in the chest to stimulate the vagus nerve, which carries sensory and motor instructions and information to and from the brain (U.S. Centers for Medicare & Medicaid Services).

Any brain-stimulation therapy is considered only after a diagnosis. So if you think you might benefit from transcranial magnetic stimulation, seek advice from a healthcare professional on your condition and the many treatment options. Oh, and as with any mental health treatments, check with your health insurance provider before choosing a path—many companies do not cover TMS therapy (Johns Hopkins Medicine, n.d.).

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Current version

June 10, 2021

Written by

Robert Roy Britt

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.