Frontier: Deep brain stimulation helps lift severe depression

by Sandra A. Swanson

September, 2008

Standard treatments fail to help 10 to 20 percent of depression patients, prompting exploration of new options. These include deep brain stimulation (DBS), already an effective Parkinson’s disease treatment. A study to be published in the Sept. 15 issue of the journal Biological Psychiatry underscores DBS’s depression-lifting potential.

Helen Mayberg of the Emory University School of Medicine collaborated with University of Toronto researchers to assess DBS in the subcallosal cingulate gyrus (SCG), a brain region involved with negative mood. The study builds on the researchers’ work from 2005, in which six patients had electrodes implanted in the SCG and received constant electric pulses of about 4 to 4.5 volts. The new research tracks the year-long progress of 20 patients who received DBS in this brain target.

All patients started with a score above 20 on the Hamilton scale (a quantitative measurement for depression), indicating severe cases. After one month, seven patients responded—their Hamilton scores improved by at least 50 percent—including two who entered remission. At six months, 12 of the 20 patients were responders, including seven in remission. Those effects remained fairly constant at 12 months.

But do patients’ high expectations trigger a placebo effect? To address that possibility, Mayberg and her Emory colleagues have begun a single-blind, one month placebo trial. All participants will have implants, but some won’t be activated.

Ultimately, Mayberg wants to pinpoint ideal DBS candidates and electrode placement based on patients’ anatomy or physiology: “Perhaps we can have a 95 percent or greater response rate if we can determine who is an optimal candidate for this intervention.”