Brain 'pacemaker' used to treat depression

Posted by Kate Taylor

A new way of stimulating the brains of people with depressive disorders  has been found to be effective in more than half of cases.

In the first blind test of deep brain stimulation (DBS) a team from Emory University has found it can safely and effectively be ued to treat unipolar major depressive disorder (MDD) and bipolar II disorder (BP).

Bipolar spectrum disorder - also known as manic depression - involves bouts of mania or hypomania alternating with episodes of depression. Attempts to treat it with antidepressant medications often simply switch patients into a hypomanic or manic episode.

"Depression is a serious and debilitating medical illness," says Emory's Professor Helen S Mayberg.

"When we found that the potential for effective and sustained antidepressant response with DBS for patients with otherwise treatment resistant major depressive disorder was high, the next step was to determine if patients with intractable bipolar depression could also be successfully treated."

DBS involves using high-frequency electrical stimulation to target a predefined area of the brain specific to the particular neuropsychiatric disorder.

Participants receive an implant of two thin, wire electrodes, one on each side of the brain, in the subcallosal white matter adjacent to a specific region of the cingulated gyrus.

The other end of each wire is connected under the skin of the neck to a pulse generator implanted in the chest, similar to a pacemaker, which directs the electrical current.

The participants received single-blind sham stimulation for four weeks - meaning they didn't know if the DBS system was on or off - followed by active stimulation for 24 weeks. They were then monitored for up to two years.

And, found the team, patients experienced significantly less depression with the continuing stimulation. After 24 weeks, 18 percent were now considered essentially well, with 41 percent showing an improvement in their symptoms of at least 50 percent.

After two years of active stimulation, the figures were 58 percent and 92 percent respectively.

"Most of these patients have been in a depressed state for many years and are disabled and isolated," says Paul E Holtzheimer, now at Dartmouth Medical School.

"As their depression improves, they need a process to help them achieve full recovery that includes integration back into society."