Transcranial magnetic stimulation (TMS) is a brain-stimulation treatment sometimes used for people with treatment-resistant major depression, meaning other treatments haven’t been effective for them.
It’s also approved for obsessive-compulsive disorder (OCD), migraine, and smoking cessation when other treatments haven’t been successful, according to Mayo Clinic.
TMS is a noninvasive treatment that uses magnetic fields to stimulate nerve cells in the brain.
“As its name implies, it is actually working on the brain transcranially, meaning through the skull,” explains Cory R. Weissman, MD, the medical director of interventional psychiatry and an assistant clinical professor at UC San Diego Health in California. “It passes directly through the skin, the fat, and the bone with minimal impedance.”
During a TMS session, a magnetic coil is placed on the scalp. The coil delivers short, repeated magnetic pulses that target nerve cells in specific areas of the brain that are associated with emotional regulation, notes UNC School of Medicine.
Researchers believe that stimulation ultimately promotes neuroplasticity (new connections in the brain), which leads to positive changes in brain activity and function and symptom relief among people with treatment-resistant depression and related conditions, says Dr. Weissman.
There are different types of TMS, as well as various protocols for delivering the treatment, notes Weissman.
The type of TMS used for depression, OCD, and smoking cessation is called repetitive TMS (rTMS) because it delivers repeated magnetic pulses, according to Mayo Clinic.
Another type of TMS, called deep TMS (dTMS), involves a coil that stimulates deeper and wider areas of the brain than rTMS, per Mayo Clinic. It’s approved for OCD and smoking cessation.
“There are several companies that have developed different kinds of coils that produce different types of magnetic fields,” he says. “There are still questions about whether one coil is better than the other, but we think of them as roughly equivalent at this point.”
There are also differences in magnet strength, pulse frequency, and pulse patterns, depending on the type of TMS used, per Cleveland Clinic. The main TMS protocols for treating depression are:
Standard rTMS protocol Approved by the FDA in 2008, standard protocol takes about 37.5 minutes and delivers 10 Hz every 26 seconds, per research.
DASH protocol Approved by the FDA in 2016, DASH takes about 19 minutes and delivers 10 Hz every 11 seconds, says Subha Subramanian, MD, the director of TMS at Beth Israel Deaconess Medical Center in Boston.
iTBS protocol Approved by the FDA in 2018, iTBS takes about 3.5 minutes and delivers 50 Hz every 10 seconds, says Dr. Subramanian.
SAINT protocol Cleared by the FDA in 2022, SAINT follows iTBS protocol, but with a much shorter treatment period. Unlike other protocols, which are usually administered once daily for up to six weeks, SAINT is used to deliver 10 sessions per day over five days, with each daily session being 50 minutes apart, according to the Brain & Behavior Research Foundation.
Newer protocols, which aim to condense treatment time into fewer days with more treatment sessions per day, are being studied with promising preliminary results, Weissman adds.
The FDA has approved TMS to treat four specific conditions, according to Mayo Clinic:
Many research efforts have examined or are underway to assess TMS’s role in helping other brain-related conditions, adds Weissman. According to Cleveland Clinic, TMS is also being studied for:
Research shows that TMS can be an effective treatment for various conditions.
Treatment-Resistant Depression
Though not all patients respond to TMS therapy, research results for those with treatment-resistant depression are encouraging.
About 50 to 60 percent of people with depression who haven’t been helped by medication experience a meaningful difference in their symptoms with TMS, according to Harvard Medical School.
This response is defined as a greater than 50 percent improvement in symptoms, says Weissman. “This is a big deal, because these are many patients who don’t do well with standard treatments,” he says.
Additionally, about one-third of patients with treatment-resistant depression who undergo TMS experience a full remission, which means their symptoms completely go away, Harvard Medical School states.
Obsessive-Compulsive Disorder
When it comes to OCD, a study published in November 2019 in the American Journal of Psychiatry showed that about 45 percent of patients who underwent dTMS experienced reduced symptoms six weeks later. These results appeared to have lasted after another month of follow-up.
Smoking Cessation
Research on TMS for smoking cessation shows that just one rTMS treatment reduced nicotine cravings among people with nicotine dependence.
Another study showed that, among 262 people with tobacco use disorder, treatment with dTMS for three weeks daily, followed by once weekly for three weeks, reduced cigarette consumption and cravings significantly more than sham treatment.
Migraine
In a review published in 2021 in the Journal of Pain Research, researchers examined five studies testing TMS for migraine and found that the treatment reduced the intensity and duration of migraine headache.
What Does a Transcranial Magnetic Stimulation Session Feel Like?
TMS is usually performed in a doctor’s office or clinic setting, and no anesthesia is required. “An individual can come into the clinic on their own. You do not need to have a friend or family member bring you to or from treatments,” says Subramanian.
Before your first TMS treatment, your health provider will perform measurements of your head to determine the best location for the magnet as well as the optimal dosage of energy, according to Mayo Clinic.
You’ll wear earplugs to protect your hearing and sit in a reclining chair that’s located underneath or beside a magnetic coil. Then, a technician will position the magnet coil on your head. When the machine is turned on, you’ll hear a clicking noise and feel quick tapping sensations on your scalp, per Mayo Clinic.
“It feels like someone tapping on your head repeatedly for a few minutes, so it’s not necessarily pleasant, but overall, it’s pretty easy to tolerate,” explains Weissman.
A typical treatment session can last from 3.5 to 20 minutes. This varies by the type of stimulation pattern used, per Mayo Clinic. When your treatment is complete, you can drive yourself home and resume normal activities, states the University of North Carolina (UNC) School of Medicine in Chapel Hill.
A typical treatment course includes daily TMS sessions five days a week for four to six weeks, according to UC San Diego Health.
Although some patients may respond to treatments during the first half of the treatment course, others might not notice improvements in their symptoms right away, Subramanian adds.
“It is best to take treatment one week at a time,” she explains. “As of now, we have no way to predict who is going to respond or not. Sometimes, we do not see individuals respond until weeks five or six.”
While there are currently no guidelines on how often to undergo TMS after the initial series of treatments, Weissman says most providers do offer some form of maintenance therapy, but it’s typically quite limited by insurance coverage.
According to UC San Diego Health and Cleveland Clinic, possible side effects of TMS include:
Headache
Mild pain at the site of stimulation
Dizziness or light-headedness
Involuntary eye blinking or facial muscle contractions during treatment
Temporary ringing in the ears or sound sensitivity
These side effects usually go away within a day or so, according to UC San Diego Health.
Seizures are a rare but serious potential side effect of TMS. Research shows the risk of developing a seizure during the entire course of TMS therapy is about 0.1 percent.
How to Find a Transcranial Magnetic Stimulation Provider
If you’re considering TMS, Weissman says your starting point would ideally be a psychiatrist if you have one. If you don’t currently see a psychiatrist, contacting your primary care physician is a good start.
Weissman adds that while his center accepts referrals for TMS from both psychiatrists and primary care doctors, some facilities allow patients to self-refer.
If you’re having trouble finding a provider who performs TMS in your area, Weissman suggests searching for TMS programs at nearby academic centers. You could also locate a TMS provider in your area through online directories like the one offered by the Clinical TMS Society.
How to Prepare for a Transcranial Magnetic Stimulation Session
Prior to trying TMS, Weissman recommends contacting your health insurance company to see if the treatment is covered under your plan. “It’s not cheap. Each treatment can be hundreds of dollars, and the cost varies depending on the clinic and type of device,” he says.
After you confirm whether your health insurance will cover your TMS treatment, you’ll meet with a psychiatrist who’s trained in TMS, Subramanian says. During this visit, you’ll discuss your medical history and any medications you’re taking. If you currently take medication, your psychiatrist will let you know if any of your medication dosages need to be adjusted before you begin the therapy, she adds.
Before your first treatment, there’s very little prep needed. But because TMS creates a magnetic field, you will be asked to remove potentially magnetic-sensitive items, such as jewelry or credit cards, states Stanford Medicine.
Who Shouldn’t Try Transcranial Magnetic Stimulation?
Some people are not candidates for TMS, such as individuals who have a history of epilepsy or seizures or those with certain metal or implanted devices, such as cochlear implants, per Cleveland Clinic. But people with braces or dental fillings can receive TMS, Stanford Medicine notes.
TMS is a potential treatment option that may be effective for people with major depression, OCD, or migraine, or smoking addiction who’ve had little to no success with standard treatments. It’s currently being studied for many other conditions, too, like bipolar disorder, PTSD, borderline personality disorder, and schizophrenia, among others.
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