Transcranial magnetic stimulation: An experimental depression treatment

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Transcranial magnetic stimulation: An experimental depression treatment

Transcranial magnetic stimulation — Learn about this experimental depression treatment.

Depression is usually a very treatable condition. Often, standard treatment with antidepressant medications, psychotherapy or electroconvulsive therapy can help improve even severe cases of depression.

But if standard depression treatment doesn't work, you might wonder if experimental treatment can help. One potential option is transcranial magnetic stimulation. This procedure remains experimental because it hasn't been approved by the Food and Drug Administration to treat depression, but it may be available to you through a clinical trial.

Understand the transcranial magnetic stimulation procedure

Transcranial magnetic stimulation (TMS) is an experimental procedure that uses magnetic fields to alter brain activity.

There are different ways to perform the procedure. But in general, a large electromagnetic coil is held against your scalp near your forehead, often on the left side. An electric current creates a magnetic pulse, or field, that travels through your skull. The magnetic pulse causes small electrical currents in your brain. Those currents stimulate nerve cells in the region of your brain involved in mood regulation and depression.

Transcranial magnetic stimulation doesn't involve surgery, and you require no anesthesia. You also don't need to be hospitalized. Transcranial magnetic stimulation can be done on an outpatient basis in a doctor's office or clinic that's running a clinical trial for the procedure.

During transcranial magnetic stimulation, the magnetic coil is held against your head while electric current is switched on and off. You may feel a slight tapping or knocking sensation on your head. Although transcranial magnetic stimulation is generally painless, it may cause the muscles of your scalp or jaw to contract. The procedure lasts about a half-hour.

How transcranial magnetic stimulation works remains unclear

It's not clear precisely how transcranial magnetic stimulation may help relieve symptoms of depression. Networks of brain regions are thought to play a role in mood regulation. Stimulating the brain can change how it functions.

In some types of transcranial magnetic stimulation, brain activity is suppressed. In other types, brain activity is increased. In either case, the changes may be associated with improved mood. These improvements in symptoms may last for days or weeks.

Researchers are still trying to determine the best dosage of stimulation and the best area of the brain to stimulate.

Transcranial magnetic stimulation

Illustration of transcranial magnetic stimulation

In transcranial magnetic stimulation, a magnetic coil is held against your scalp, creating magnetic fields that alter brain chemistry and possibly boost mood.

Who may benefit from transcranial magnetic stimulation

Because it's experimental, transcranial magnetic stimulation isn't recommended as a first treatment for depression. It's used only as a research tool and is available in the United States only through clinical trials. In countries where transcranial magnetic stimulation has been formally approved to treat depression, it's typically used only for people with depression that hasn't improved with standard treatments or for those who may be considering electroconvulsive therapy but want an alternative.

People who have long-standing depression or depression that hasn't improved with standard treatments may be candidates for this experimental procedure. Talk to your doctor to see if it may be a good option for you.

Who should avoid transcranial magnetic stimulation

Certain people shouldn't have transcranial magnetic stimulation because of increased or unknown risks to their health. These include people:

  • With metal implants in the head
  • Who are pregnant
  • With cardiac pacemakers
  • Who have poorly controlled migraines
  • Who have had a stroke
  • With a family history of seizures
  • Who have had neurosurgery

Side effects of transcranial magnetic stimulation

Although transcranial magnetic stimulation is noninvasive, it still poses a risk of adverse side effects.

Of major concern is the possibility that transcranial magnetic stimulation can cause a seizure. Because of that risk, the International Society for Transcranial Stimulation advises that the procedure be performed only when medical help is quickly available and that those who administer it be trained as first responders who can provide emergency medical help.

Common side effects and adverse health problems associated with transcranial magnetic stimulation include:

  • Headache
  • Lightheadedness
  • Discomfort from noise during treatment
  • Pain at the site of stimulation
  • Tingling of facial muscles
  • Mild spasms or contractions of facial muscles

Because transcranial magnetic stimulation involves changes in brain function, unknown long-term adverse health effects are possible. However, research studies so far haven't uncovered any serious problems, such as unwanted behavioral changes or disturbances in memory or thinking. It remains to be seen what types of long-term consequences, if any, that transcranial magnetic stimulation poses.

Balancing the pros and cons of transcranial magnetic stimulation

For people with depression that doesn't get better with standard treatments, life can be miserable. Transcranial magnetic stimulation may provide hope that symptoms can improve. And for some people, it offers advantages over electroconvulsive therapy (ECT). Unlike ECT, transcranial magnetic stimulation doesn't typically induce convulsions, doesn't require anesthesia and may have fewer troubling side effects, such as memory loss.

However, research data about the effectiveness of transcranial magnetic stimulation are mixed. Some studies have shown that some people who undergo transcranial magnetic stimulation see a significant improvement in their symptoms that lasts for two weeks or more. Other research, though, has suggested that transcranial magnetic stimulation is no more effective than a placebo.

Researchers will learn more and perhaps hone the technique as more studies are done. Stronger stimulation done over a minimum of several weeks may be found more effective, for instance.

Last Updated: 07/24/2006
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