10:43 PM, Feb. 21, 2011 (DelawareOnline.com)
Special to The News Journal
People mired in the depths of chronic severe depression have another treatment option that is generating interest among clinicians and researchers.
Transcranial magnetic stimulation, or TMS, is a noninvasive, drug-free procedure designed to rejigger the brain’s circuitry in a beneficial way. It is currently approved for patients suffering from treatment-resistant depression, meaning those who have failed to respond to first-line approaches such as psychotherapy and medication.
How transcranial magnetic stimulation works to relieve depression is not fully understood, but there are clues. Imaging studies of the brains of depressed people show low levels of activity in the left prefrontal cortex, the area responsible for mood regulation. Indeed, depression is a common side effect in patients where stroke has affected the left side of the brain.
“About 50 percent of those patients get major depression as a complication of the stroke,” said Dr. John O’Reardon, associate professor of psychiatry at the Hospital of the University of Pennsylvania and director of the Treatment Resistant Depression Clinic.
During transcranial stimulation, the clinician places an electromagnetic coil against the patient’s scalp near the forehead. The magnetic pulses reach about an inch deep inside the skull, creating painless electrical currents in the brain and leading to improved mood.
“The three neurotransmitters which are closely associated with depression are serotonin, dopamine and norepinephrine,” said Dr. Sandeep K. Gupta, director of psychiatric emergency services at Christiana Care Health System, which began offering the procedure a year ago. “What TMS does is increase the level of these neurotransmitters.”
And unlike vagus nerve stimulation or deep brain stimulation, TMS does not require surgery or the implantation of electrodes to accomplish this.
It is also a gentler alternative to electroconvulsive therapy, which treats depression by inducing seizure to reorganize the brain’s circuitry. This requires sedation and hospitalization. While medical advances have refined the delivery of ECT, its checkered past and the risk of memory loss make patients fearful. “They’re scared of it,” said O’Reardon. “There’s a stigma around ECT.”
By contrast, transcranial magnetic stimulation requires no sedation and carries few side effects, which can include headache, mild discomfort at the treatment site and discomfort from noise during the procedure. TMS is performed in an outpatient setting, and patients remain awake and alert.
“You do not need anesthesia,” said Gupta. “You come driving and you go home driving back.”
Researchers also are investigating other applications for TMS. More than 200 clinical trials are under way to test its efficacy with a variety of neurological and psychological disorders, including Alzheimer’s, Parkinson’s, epilepsy, tinnitus and stroke rehabilitation.
“A lot of people think the next promising areas for TMS might be chronic pain, anxiety and post-traumatic stress disorder,” said Dr. Mehmet E. Dokucu, assistant professor of psychiatry and director of the Cancer Psychiatry Service at the Feinberg School of Medicine at Northwestern University. “It is already being used for brain mapping before extensive surgery as well as for determining the prognosis of some neurological diseases.”
Moreover, because the procedure targets the brain and does not pass through the bloodstream like medication, it can prove useful in treating pregnant and breastfeeding women, experts say.