PHILADELPHIA, July 28 (UPI) -- The results of the first large-scale clinical trial using deep brain stimulation, or DBS, to treat depression failed to show a significant improvement in symptoms.
DBS has previously been shown in smaller studies to be effective for depression and obsessive-compulsive disorder, and has been shown to be highly effective in treating Parkinson's disease, essential tremor, and other neurologic conditions.
DBS therapy requires doctors to drill a small hole in the skull and insert an electrode into the brain. The electrode delivers electrical impulses designed to block neural impulses from the specific part of the brain that is thought to be the source of the symptoms.
Researchers enrolled 30 patients with treatment-resistant depression in the sham-controlled study, with some receiving impulses and some receiving "sham" placebo treatment for 16 weeks. Improvement in symptoms was measured by the Montgomery–Åsberg Depression Rating Scale, a series of 10 questions used to numerically measure responders' symptom levels.
The group that received actual treatment had a 20 percent response rate to treatment on the scale, while the sham group had a 14 percent response rate.
"While initial open-label trials of DBS at the ventral capsule/ventral striatum target were promising, the results of this first controlled trial were negative," said Dr. Darin Dougherty, director of neurotherapeutics at Massachusetts General Hospital, in a press release. "Alternative study designs will have to be considered as we conduct future clinical trials in this critical area."
Despite a 20 to 26 percent response rate from patients who received actual treatment over the course of 12, 18 and 24 month followups, the researchers said DBS treatment for depression needs at least to be rethought based on the negligible difference between patients who received electrical impulses and those who did not.
"This study raises serious questions about the advisability of continuing to stimulate these reward regions in the manner employed in this study," said Dr. John Krystal, Editor of Biological Psychiatry. "It is critical to understand that this study is not a universal indictment of DBS as a strategy for depression. It may turn out that stimulating other brain regions or stimulating these regions in different ways could provide important benefit."
The study is published in Biological Psychology.