Deep Brain Stimulation (DBS) is a neuromodulation technique that involves the implantation of electrodes into specific parts of the brain. DBS is reversible, nondestructive, and can be modified by adjustment of the stimulator settings after implantation. Since 1998 we investigate DBS as a therapeutic option for severe, treatment-refractory obsessive-compulsive disorder (OCD). DBS in the anterior limbs of the internal capsules induced clinically significant therapeutic benefit in this patient group, not only in severity of OCD symptoms, but also on the patient's mood scores.

Despite advances in biological treatment and psychotherapy for major depression (MD), a substantial number of patients fail to improve.

Based on the results of DBS in OCD, this study investigates the effectiveness, safety, and tolerability of DBS in the same target for treatment-refractory MD.

Three patients with a longstanding history of MD, who failed to improve even after years of pharmacotherapy, psychotherapy, electroconvulsive therapy and even experimental interventions were selected. Bilateral DBS leads were implanted in the ventral part of anterior limb of the internal capsule. Participants underwent standardized and detailed psychiatric assessments on a regularly scheduled basis, both pre- and postsurgically.

After six months of chronic DBS, all three patients showed a clinically significant reduction in depression severity of 50 percent or greater on the Montgomery-Asberg Depression Rating Scale. Two of the three patients were in remission. Quality-of-life measures improved as well.

Further research is warranted, but patients with severe, longstanding, treatment-refractory MD may benefit from DBS.