Deep brain stimulation of the subcallosal cingulate gyrus: further evidence in treatment-resistant major depression

Deep brain stimulation (DBS) is currently tested as an experimental therapy for patients with treatment-resistant depression (TRD). Here we report on the short- and long-term (1 yr) clinical outcomes and tolerance of DBS in eight TRID patients. Electrodes were implanted bilaterally in the subgenual cingulate gyrus (SCG; Broadman areas 24-25), and stimulated at 135 Hz (90-mu s pulsewidth). Voltage and active electrode contacts were adjusted to maximize short-term responses. Clinical assessments included the 17-item Hamilton Depression Rating Scale (HAMD(17); primary measure), the Montgomery-Asberg Depression Rating Scale (MADRS) and the Clinical Global Impression (CGI) Scale. In the first week after surgery, response and remission (HAMD <= 7) rates were, respectively 87.5% and 50%. These early responses were followed by an overall worsening, with a response and remission rates of 37.5% (3/8) at 1 month. From then onwards, patients showed a progressive improvement, with response and remission rates of 87.5% and 37.5%, respectively, at 6 months. The corresponding figures at 1 yr were 62.5% and 50%, respectively. Clinical effects were seen in all HAMD subscales without a significant incidence of side-effects. Surgical procedure and post-operative period were well-tolerated for all patients. This is the second independent study on the use of DBS of the SCG to treat chronic depression resistant to current therapeutic strategies. DBS fully remitted 50% of the patients at 1 yr, supporting its validity as a new therapeutic strategy for TRD.