"Most of the patients respond to the therapy. The remarkable thing is that the effect is also lasting. Other forms of therapy often lose their effectiveness in the course of time. This makes deep brain stimulation a highly promising approach for people with previously non-treatable depression," says principal investigator Prof. Dr. Thomas Schläpfer, head of the Interventional Biological Psychiatry Unit at the Department of Psychiatry and Psychotherapy of the Medical Center - University of Freiburg. Deep brain stimulation is a method based on mild electric impulses that can be used to influence selected brain regions with great precision.
The eight test subjects had suffered continuously for three to eleven years from a severe depression that responded neither to drugs nor to psychotherapy or treatments like electroconvulsive therapy. The doctors implanted razor-thin electrodes and stimulated a brain region that is involved in the perception of pleasure and is thus also important for motivation and quality of life. The doctors evaluated the effect of the therapy each month with the help of the established Montgomery-Asberg Rating Scale (MARDS). The patients' average MARDS score fell from 30 points to 12 points already in the first month and even dropped slightly further by the end of the study. Four patients achieved a MARDS score of less then 10 points, the threshold for diagnosis of depression.
Some of the patients suffered briefly from blurred or double vision. "We managed to alleviate the side effects by reducing the intensity of the stimulation, without diminishing the antidepressant effect of the therapy," says Prof. Dr. Volker A. Coenen, head of the Stereotactic and Functional Neurosurgery Unit at the Department of Neurosurgery of the Medical Center - University of Freiburg. The doctors did not observe personality changes, thought disorders, or other side effects in any of the patients.