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What Is TMS Treatment for Depression?

US News & World Report - Health logo US News & World Report - Health 2/7/2022 Lisa Esposito
Scientist conducting transcranial magnetic stimulation (TMS) experiment on patient © (Getty Images) Scientist conducting transcranial magnetic stimulation (TMS) experiment on patient

You sit in a comfortable chair, wearing earplugs. A clinician puts a magnetic coil on your scalp, toward the front of your head. You feel a tapping on your forehead and hear clicking sounds as the machine turns on and the transcranial magnetic stimulation, or TMS, begins.

By this point, the TMS expert physician has already determined the minimum amount of power needed to stimulate your brain cells, this will meet your individual threshold and can cause your thumb muscles to twitch. Now, the TMS technician administers the actual treatment. Your scalp may tingle as the magnetic pulses pass through to your brain.

You’re awake and alert for the half-hour or so that the procedure takes. Once treatment is done and the coil comes off your head, you leave and go about your normal daily routine.

You repeat the TMS treatment five days a week, Monday through Friday, for the next six weeks or so. The goal: That persistent depression symptoms will improve or disappear entirely. Some may experience early improvements in symptoms after a week or two, but a typical course takes over a month to bring remission.

Not everyone with depression is a candidate for TMS. To qualify for insurance coverage in the U.S., you must have a diagnosis of major depressive disorder and already tried one or more antidepressant medications but experienced inadequate or no symptom relief.

Not everyone responds to TMS, either. But for those who do, the noninvasive treatment helps them feel better and once again be able to enjoy things and function like they did before their depression began.

What TMS Is

TMS is a noninvasive procedure using magnetic fields to stimulate nerve cells, or neurons, in the brain. Treatment is given through repetitive magnetic pulses, known as repetitive TMS, rTMS, or TMS therapy.

In a standard TMS session, clinicians place an electromagnetic coil on your scalp near your forehead. This coil delivers a series of magnetic pulses to stimulate neurons in the cortex brain areas involved in regulating emotions. TMS is believed to work by activating brain regions and networks that are malfunctioning when a person has persistent depression.

While it’s difficult to give a precise number of individual patients who receive TMS yearly, it is estimated that more than 20 million treatments have been given in the U.S. since it was approved by the Food and Drug Administration in 2008, says Dr. Linda Carpenter, a psychiatrist at Butler Hospital and a research professor in the department of psychiatry and human behavior at Brown University. Carpenter directs the Butler Hospital TMS Clinic and Neuromodulation Research Facility in Providence, Rhode Island.

“Patients that qualify for TMS are those who have failed to get better with standard antidepressant medication,” Carpenter says. “That’s probably a third of all patients that get treated for depression.”

It’s important not to confuse TMS with the electricity-based treatment called electroconvulsive therapy, or ECT, although both are used for treatment-resistant depression. ECT uses electrical currents, rather than the magnetic fields that TMS uses. ECT causes a brief, controlled seizure that affects neurons and brain chemicals as its treatment goal. By contrast, TMS therapy activates targeted brain areas, and patients are awake and aware throughout.

Unlike some other forms of brain stimulation, TMS does not require implanted electrodes or surgery. Nor does TMS require anesthesia, unlike ECT.

Who It Treats

Devices capable of delivering transcranial magnetic stimulation to the human brain were first developed in 1985.

In 2008, the FDA approved TMS for adults with depression that’s resistant to standard treatments. Specifically, it’s currently approved for what’s called "primary" major depressive disorder without psychotic symptoms, Carpenter says. Psychotic symptoms relate to being out of touch with reality, such as hallucinations or delusions. The depressive syndrome for which TMS is approved “is characterized by a certain number of symptoms that persist for weeks: depressed or low mood, loss of ability to experience pleasure and problems with sleeping, appetite, interests, concentration and motivation. Sometimes anxiety is also a symptom.”

TMS represents a significant therapeutic option for people in need. “It plays a really important role in what we refer to as ‘treatment-resistant depression,’” says Dr. Alexander McGirr, principal investigator for the McGirr Lab, part of the Hotchkiss Brain Institute of the University of Calgary in Alberta, Canada.

“In Canada, our guidelines advocate that after a single failed antidepressant, you should be considering TMS,” McGirr says. “Because it has a different mechanism of action, you’re more likely to benefit from it than you would be from switching to a different medication.”

In 2018, the FDA approved TMS to treat obsessive-compulsive disorder, or OCD. In 2020, TMS was approved as a smoking cessation therapy.

Researchers have investigated rTMS for a variety of brain-based disorders, such as relapsing multiple sclerosis and Parkinson’s disease. However, most of these are not FDA-approved indications.

Patient Experience

The Butler Hospital Clinic treats about 100 new patients a year, along with many returning patients, Carpenter says. “Sometimes the patients will get better and then come back again a couple years later, or at some point in the future, to get a repeat course of treatment if their depression comes back,” she says.

Carpenter describes how TMS works: “Magnetic energy passes through your scalp and your skull tissues,” she says. “It’s pulsed from a little device called a 'coil' that sits on your head. When magnetic pulses reach the brain tissue called the cortex, the outer layer of the brain, it induces current activation. Your neurons conduct electricity and this induces electrical current in the neurons located under the coil. These neurons produce electricity and use it to send signals to neurons in other areas of the brain, so there is communication through brain networks.”

According to patient feedback, Carpenter says, “The first day of TMS might feel like there’s a woodpecker pecking on your head. There's a percussion or tapping sensation when the pulses are delivered to the patient's head. Sometimes there’s a little bit of twitching in the muscles around the forehead, and scalp around the coil, because TMS can activate nerves to some of those muscles we use to raise our eyebrows or make facial expressions."

Most patients become accustomed to TMS after a couple sessions. “The sensation is diminished and they don’t feel that much,” Carpenter says. “Sometimes it feels sort of soothing and people get drowsy during the stimulation; they get used to it. Your brain's awareness of the sensation tunes down and accommodates it, so it doesn’t really feel like much after you've had a few sessions.”

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TMS Effects

TMS effects can be measured both in the area of the brain directly beneath the coil, called the prefrontal cortex, as well as through connections or relationships with other areas of the brain that are deeper and further back, Carpenter explains.

It doesn’t take long for patients to start seeing results. During the first week, they might have a little more energy than before, Carpenter says. "After a week or two of daily TMS, patients start to notice: 'Gee, I'm more interested in things, I have more energy and I'm concentrating better.'" For the Butler clinic, Carpenter notes, "We usually see gradually accumulating symptom improvement over the weeks.”

Of his TMS patients, McGirr says, “When it works, it’s really quite remarkable.” About 25% experience an extremely rapid response. “Sometimes they’ll use metaphors: It’s like a light went on and they see the light again,” he says. “And they feel much better.”

About half of patients have a gradual, progressive improvement, McGirr says. “They describe it as a slow improvement and they didn’t really notice it much, at first,” he says. “Then they started to notice things at the two-to-four week mark.” Changes continue, with other people in patients’ lives commenting on the difference.

However, some patients don’t have improvement even after daily TMS treatment for up to six weeks. “Unfortunately, there are those people who do not benefit from this treatment and that can be a little bit frustrating, because it is a fairly demanding treatment,” McGirr says.

Types of TMS

Various TMS devices deliver magnetic brain stimulation using different treatment protocols. These include:

  • Repetitive transcranial magnetic stimulation. As described above, rTMS is the established version. Typically, it involves high-frequency stimulation to the brain’s prefrontal cortex.
  • Intermittent theta burst stimulation. Also called iTBS, this newer form of rTMS is also FDA-approved for stimulating the cortex in once-daily sessions. A course of therapy requires the same number of weeks, but each session is shorter because magnetic pulses are delivered very quickly.

Side Effects

During TMS treatment, while attached to the coil, patients may experience side effects including:

  • Headache.
  • Facial muscle tingling or twitching.
  • Scalp discomfort or irritation.
  • Lightheadedness or dizziness.
  • Hearing loss (preventable by proper earplug use).

Rare but serious side effects may include:

  • Seizures.
  • Mania in people with bipolar disorder.

Although the risk of seizures with TMS treatment is less than 1% overall, it does exist, according to an evidence review published in December 2020. Proper screening to rule out TMS treatment for individuals at increased seizure risk is an important step in prevention, according to an April 2020 National Institute of Mental Health expert lecture on TMS risks and safety.

Adding TMS to the Treatment Arsenal

Medication and psychotherapy, or talk therapy, are first-line treatments for depression. However, access to talk therapy can be difficult with only a limited number of sessions covered by insurance. Antidepressant medications work for many people, but they may cause burdensome side effects in others.

For example, the most frequently prescribed class of antidepressants is the selective serotonin reuptake inhibitors. Agitation and anxiety, sexual problems like low libido, dizziness, headaches, nausea, diarrhea, insomnia and tremor can all be SSRI side effects.

Even among those who originally respond to antidepressant medications, the effectiveness can wane over time. Alternatives or adjuncts may be needed to fill treatment gaps.

The advantage of TMS “is that it’s a fundamentally different way of treating the depression, whereas a lot of our medications have common mechanisms of action,” McGirr says. “So, we know that when switching (from one depression medication) to the next, you get vanishingly smaller return for your investment with each step you go.”

By contrast, moving to TMS may make a notable impact. “Switching to something that works entirely differently – so actually trying to drive plasticity in the parts of the brain related to depression – we can try to get at the neurocircuitry that’s changed with depression and try to restore it,” McGirr says. In other words: “We’re trying to make the brain work the way it did before depression.”

Oftentimes, patients treated with TMS continue to take their antidepressant medications. “We usually recommend that people stay on their medications because they have gotten some effect, and the medications themselves have a variety of effects on the brain that could potentially be healing of the brain,” McGirr says.

Evaluation for Treatment

Patients considering TMS typically undergo a physical and psychiatric evaluation to determine if the treatment is safe and appropriate for them. Clinicians will also ask patients other medical conditions, pregnancy, medications or supplements they take, and alcohol and substance use among other information.

Reasons that patients may not be recommended to receive TMS include:

  • Having implanted devices such as heart stents, aneurysm clips or coils, implanted stimulators or electrical medical devices like a pacemaker or a cardioverter-defibrillator, cochlear hearing implants, bullet fragments or other nonremovable metal implants inside the body within a few feet of the head. Dental metal is not a problem.
  • Seizure history or epilepsy.
  • Brain illness or significant history of brain injury, such as a stroke, brain tumor or traumatic brain injury.

Data: Does TMS Help?

A growing body of evidence finds TMS effective for patients with major depressive disorder that hasn’t responded well to standard treatments.

  • A randomized clinical trial with data supporting TMS treatment was published in 2007, showing about 24% of depressed patients responded to the treatment. A subsequent trial, funded by the NIMH, was published in May 2010. During the first study phase, about 15% of participants achieved remission – a symptom-free period in their depression. During the second study phase, nearly 30% experienced remission.
  • A meta-analysis of 81 studies encompassing nearly 4,250 patients treated with various types of TMS, published in February 2017 in JAMA Psychiatry, found all types more effective, and at least as tolerable, as sham (placebo) TMS treatment for major depressive episodes.
  • The Three-D study, published in April 2018 in The Lancet, which compared rTMS and iTBS, found them equally safe, tolerable and effective in treating patients with major depressive disorders.
  • A meta-analysis of 10 studies encompassing nearly 700 patients, published in May 2021 in the journal Translational Psychiatry, found a similar, positive effect rates for both rTMS and theta burst stimulation compared to sham TMS treatment for major depressive disorder.
  • A small study of a new, intensive form of TMS called Stanford neuromodulation therapy, published in October 2021 in the American Journal of Psychiatry, found rapid improvement in nearly 80% of the 29 participants, all with severe, treatment-resistant depression. This form of TMS, which involves 10 TMS sessions per day, will be evaluated in large clinical trials to determine if it is suitable for standard TMS practice.
  • A study of 700 U.S. military veterans, appearing in the January 2022 issue of the Journal of Affective Disorders, found TMS was effective in treating veterans with major depressive disorder, including participants with symptoms of posttraumatic stress disorder.

It’s unclear whether TMS works for different forms of depression. For instance, a randomized clinical trial of 37 patients with bipolar depression, led by McGirr and published in March 2021 in JAMA Network Open, did not find theta burst stimulation more effective than sham TMS. Bipolar depression is characterized by periods of mania as well as depression, unlike the unipolar depression for which TMS treatment is approved.

Seeking TMS

If you’re looking into TMS for depression, choose the treatment facility carefully and ask questions. “The main thing that patients want to look for is a practice with doctors and clinic staff that are providing evidence-based care,” Carpenter says.

“There are a lot of different brain regions and a lot of different stimulation protocols that could be used in TMS care," Carpenter says. "But you want to find a doctor and a clinic that will deliver a published, scientifically sound stimulation protocol. And it’s important that patients look for a clinic where TMS physicians are prescribing the stimulation and day-to-day monitoring is done by TMS clinicians who are skilled and trained."

Check your insurance coverage. “For a regular course of TMS therapy to treat depression, all insurance companies now and federal payers – Medicare/Medicaid – all cover a course of TMS to treat depression,” Carpenter says. “Many policies have different criteria and they require that you have failed a certain number of antidepressant medication trials. Policies describing coverage criteria for TMS practice have changed over time as the evidence base has evolved. At this point, TMS coverage is fairly good for appropriate candidates, but not every person who could benefit lives near a TMS clinical practice."

It’s not too soon to consider TMS if you’re suffering from depression without relief, McGirr says. “This is something that should be on the table as soon as any first-line intervention – any medication trials have failed or any psychotherapy has failed – and somebody is having continuing depression and they have not responded to some of our best treatments,” he says. “(TMS) is something that should be in the discussion early.”

Copyright 2022 U.S. News & World Report


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