Washington, Jan 3 : Deep brain stimulation (DBS) is a safe and effective intervention for treatment-resistant depression in patients with either unipolar major depressive disorder (MDD) or bipolar ll disorder (BP), say researchers.

“Depression is a serious and debilitating medical illness,” said Helen S. Mayberg, MD, professor in the Departments of Psychiatry and Behavioral Sciences and Neurology at Emory University School of Medicine, who led the study.

“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,” he stated.

Bipolar spectrum disorder, sometimes referred to as manic-depression, is characterized by bouts of mania or hypomania alternating between episodes of depression.

Although people with bipolar ll disorder do not have full manic episodes, depressive episodes are frequent and intense, and there is a high risk of suicide.

A major challenge in treating bipolar depression is that many antidepressant medications may cause patients to “switch” into a hypomanic or manic episode.

DBS uses high-frequency electrical stimulation targeted to a predefined area of the brain specific to the particular neuropsychiatric disorder.

Here, each study participant was implanted with two thin wire electrodes, one on each side of the brain. The other end of each wire was connected under the skin of the patient’s neck to a pulse generator implanted in the chest – similar to a pacemaker – that directs the electrical current.

Study participants (17) received single-blind stimulation for four weeks (patients did not know if the DBS system was on or off), followed by active stimulation for 24 weeks. Patients were evaluated for up to two years following onset of active stimulation.

A significant decrease in depression and increase in function were associated with continuing stimulation.

Remission and response rates were 18 percent and 41 percent after 24 weeks; 36 percent and 36 percent after one year and 58 percent and 92 percent after two years of active stimulation.

Patients who achieved remission did not experience a spontaneous relapse. Efficacy was similar for Major Depressive Disorder and Bi-Polar patients, and no participant experienced a manic or hypomanic episode.

Why and how this treatment works is the primary focus of ongoing research.

The study was published Online First by Archives of General Psychiatry, one of the JAMA/Archives journals. (ANI)