More than 14 million adults in the United States are affected by major depressive disorder, according to the Depression and Bipolar Support Alliance. For most of those individuals, management of symptoms means a variety of medications and therapy sessions. A select few, however, also receive a treatment known as transcranial magnetic stimulation, or the use of magnetic fields to stimulate nerve cells within the brain.
Also known as TMS, transcranial magnetic stimulation is the first and only nonsystemic and noninvasive treatment for depression according to the Rush University Medical Center. This form of therapy is considered the next step for patients who do not respond to traditional medications or psychotherapy sessions. Approved by the Food and Drug Administration (FDA) in 2008, TMS is considered a relatively new therapy, and because of this not much in the way of long-term research supports its use.
How does transcranial magnetic stimulation work?
For the majority of patients, TMS is painless. It involves placement of an electromagnetic coil on the scalp near the forehead. Electric currents are then sent through the coil into the areas of the brain associated with mood control and depression. Treatment sessions last approximately 40 minutes depending on the clinical setting, and patients require no sedation or admittance to a hospital for the procedure.
“TMS uses an electromagnetic coil on the scalp to create an extremely potent (near 1.5 T) but brief magnetic field,” states a study published in the journal Psychiatry. “This magnetic field enters the surface of the brain without interference from the skin, muscle, and bone. In the brain, the magnetic pulse encounters nerve cells and induces electrical current to flow. Thus, the magnetic field created from electrical energy in the coil passes through the skull and is converted back into electrical energy in the brain. It is for this reason that TMS is sometimes called ‘electrodeless electrical stimulation.'”
Occasionally, muscle cramps, headaches and mild discomfort can occur at the site where the coil is placed, and in rare situations TMS can cause seizures, but for as many as 50 percent of patients, a significant improvement in major depression symptoms is reported. What’s more, only 20 percent experience minimal to no improvement of symptoms.
The future of transcranial magnetic stimulation
While thus far seen as an effective treatment for depression, transcranial magnetic stimulation may have applications for other conditions, particularly in the field of pain management.
“Mood-regulating centers in the brain overlap significantly with the neural pathways involved in pain regulation, especially the regions involved in determining whether a pain is really bothersome. Thus, researchers are exploring whether TMS might have a therapeutic role in treating acute, chronic or perioperative pain,” wrote the experts in the Psychiatry study. “There are exciting reports that TMS over prefrontal cortex or motor cortex acutely decreases pain in healthy adults or patients with chronic pain.”
Current studies focusing on TMS are also looking into the application process as well as the seizure risk, attempting to develop a safe, smaller device patients could use in the comfort of their own homes.
Overall, the studies existing on TMS suggest it is a durable form of depression treatment, has promise as a treatment for several other mental disorders, and should eventually be a reliable means of pain management.