As difficult as living under the cloud of depression can be, most cases significantly improve with standard treatments over time. 20% of depressed individuals, unfortunately, do not respond to therapy or medication, but a developing treatment that initially seems drawn from the pages of science fiction may prove more effective for these most severe cases than traditional anti-depressants. Deep brain stimulation is a form of treatment in which a small mechanical device implanted in the body sends mild electrical currents into electrodes in the brain to calm overactivity in the neurological regions responsible for controlling mood and facilitating the symptoms of clinical depression. Developing research implies that it could be very helpful to at least some of the millions whose depression resists all other treatments.
The approach is not technically new as it has been approved for the treatment of unrelated conditions like essential tremor, multiple sclerosis and Parkinson's disease since 1997. But it does amount to a somewhat radical departure from standard depression therapies. Those reminded of horror stories regarding brain damage and electroconvulsive therapy gone wrong can rest easy as the device resembles a pacemaker in form and function: a self-contained power-generating device or "pulse stimulator" is implanted in the chest area and sends mild electronic pulses through extended wires attached, via permanently implanted electrodes, to problem areas of the brain (in the case of depressed individuals, affected areas include those known to be responsible for mood regulation). The current may be turned on and off by the patient. Its levels can be adjusted as well, and the device's functions are gentle enough to ensure that no brain tissue is damaged or destroyed. Each machine lasts from 3 to 5 years until additional surgeries must be performed to replace its batteries.
Because of its highly experimental nature, very little research has been devoted to deep brain stimulation for depression, but the results of recent small-scale studies are encouraging. In one such study, sponsored by manufacturer Medtronic Inc., 50% of the 16 subjects who received the deep brain stimulation therapy reported a notable reduction in symptom severity after a 12-month treatment period. This success rate is higher than that of many anti-depressants, and it is particularly notable considering the fact that every other attempt at treatment had failed each of these individuals, who joined the study due to the desperation of years without any form of sympomatic relief. This study was not randomized in the manner of most reliable research, but the possibility that the its results were strictly products of a placebo effect was countered by the fact that patients whose devices accidentally turned off also reported more intense depressive symptoms and suicidal thoughts.
The subject pool in this study was small and it was not extensive or lengthy enough to determine how long the benefits of this treatment will last. Experts are still unclear as to exactly how deep brain stimulation works, but it has proven effective enough to warrant further long-term study. One such study, sponsored by patent holder St. Jude Medical Inc., is already underway. The fact that the study is sponsored by the device's manufacturer may present conflict of interest issues, but it will be larger, more formal and properly randomized for accuracy and its results should still be of great interest to anyone in the mental health field. A significant minority of individuals suffering from depression find no relief in available treatments, and any developing technology designed to attend to their needs should be viewed with both scrutiny and hopeful optimism. Medtronic's deep brain stimulation device is already marketed for the treatment of Parkinson's disease and, if continuing research yields the same positive results as this study, we hope that it will soon be available for the severely depressed as well. The St. Jude study's results are eagerly anticipated.
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