Is Deep Brain Stimulation Useful In Treating Depression?

Considering the long controversy over the use of electroconvulsive therapy (ECT) in treating mental illness, it hardly seems surprising that new approaches involving deep brain stimulation to treat depression are being viewed with suspicion by mental health critics.  While use of electrodes surgically placed in the brain to modify brain functioning in humans and animals has a relatively long history, deep brain stimulation (DBS) involving the implantation of a brain pacemaker sending electrical currents to specific parts of the brain first became an established procedure in the 1990s. Since that time, DBS has been formally approved by the Food and Drug Administration in the United States for a range of neurological disorders such as Parkinson's Disease, essential tremor, chronic pain, and dystonia,

Although the use of DBS in the treatment of treatment-resistant depression has faced resistance from anti-ECT groups, a recent study by a team of researchers has indicated that the procedure is safe and effective.  Led by Dr. Helen Mayberg, professor of psychiatry and neurology at Atlanta's Emory University, the researchers tested DBS on seventeen patients, including one from Canada, and found that half of the patients were still in remission after two years of continuous stimulation.    The study follows up on similar research in Canada by Dr. Mayberg and Toronto neurosurgeon, Dr. Andres Lozano as well as psychiatrist Dr. Sidney H.  Kennedy which had previously shown that DBS could be useful in treating depression.

The Emory study, which included patients with depression and bipolar disorder, selected patients who had previously failed to benefit from at least four treatment regimens, including ECT and who had been diagnosed as depressed for at least four years.   The DBS procedure involved placing the patient's head in a special frame while attaching them to an operating table.  A quarter-sized incision then inserted two electrodes on either side of the brain focusing on a specific region of the brain known as Brodmann area 25 (also known as the subgenual area cingulate) which is extremely rich in serotonin transporters and has been linked by Dr. Mayberg and other researchers to treatment-resistant depression.  The area is known to be a central control mechanism to a vast neural network extending to the hypothalamus, amygdala, brain stem and insula and has been implicated in mood, anxiety, appetite, sleep, as well as self-esteem. 

Once the electrodes are in place, the surgeon tunnels under the skin to connect the electrodes to an implantable battery placed under the collarbone.  The current to the electrodes are adjusted using a handheld computer and seventy per cent of patients undergoing the procedure report a response as soon as the electrodes are switched on in the operating room.  The patient remains awake during the procedure except for a general anesthetic.   For the purposes of the study, patients were told that they would receive a real or "sham" stimulation for four weeks post-surgery when, in fact, none of them received actual stimulation during the trial period.  There was little meaningful clinical benefit suggesting no placebo effect during the no-stimulation period.  Afterward, patients received a six-month period of actual stimulation with 41 per cent of patients reporting an improvement in depressive symptoms.   After one year, 36 per cent of the study patients experienced a remission in depression while another 36 per cent reported significant benefit (meaning at least a fifty percent improvement on clinical measures of depression).  After two years of active stimulation, most patients reported significant benefit although at least 58 percent reported remission of symptoms. 

While Dr. Mayberg acknowledged that DBS was not a "happiness" treatment, she summarized her results by saying that "we seem to be removing that deep, dark negative empty sadness — that interference that is so profound that it totally hijacks your brain from doing anything else".    Patients undergoing DBS treatment seem to go through two phases, the first phase during which they realize that the severe mental pain which makes life not worth living is no longer there and the second phase when they ask themselves, "what do I do now?"    While DBS helps control deep depression, extensive rehabilitation is still needed, especially for patients who have been dealing with severe depression for a long time. 

Although the Emory study is preliminary in nature, DBS treatment is not likely to be available for most patients with depression.  There are significant medical risks associated with the necessary surgery which can include risk of hemorrhage, stroke, seizures, infection, or even death from the general anesthesia.   DBS treatment for depression has been licensed by St. Jude Medical Neuromodulation which will conduct further clinical trials in the United States and Canada.

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Comments

[Zoloft and alcohol]

Electroconvulsive therapy is one of the oldest form of treatment still used today. Electric shocks are delivered but are regulated in varying degrees. There is a downside to it though, patients suffer from short term memory loss after receiving the electric shocks.