"Brain Pacemaker" Shows Promise for Treatment-Resistant Depression

A new study suggests that deep brain stimulation may be effective for patients with treatment-resistant depression. (©T. L. Furrer/stock.adobe.com)

Deep brain stimulation (DBS) of the subcallosal cingulate (SCC) area of the brain provided a strong and long-term antidepressant response in patients with treatment-resistant depression in a new study.

The study, published online October 4 in the American Journal of Psychiatry, examined whether DBS – when a neurostimulator (or “brain pacemaker”) is surgically implanted and continuously sends electrical signals to areas of the brain responsible for disease symptoms – is effective for the most severe form of depression.

Patients with treatment-resistant depression – the failure of depressive symptoms to respond to ≥2 antidepressant trials – are highly susceptible to recurrent depressive episodes.

Because of this, “the ability of DBS or any treatment to support long-term maintenance of antidepressant response and prevention of relapse in severe and intractable depression would be an important treatment advance,” wrote researchers led by Helen S. Mayberg, MD, professor of neurosurgery, neurology, neuroscience, and psychiatry at The Mount Sinai Hospital, New York, New York.

The study

In the long-term follow-up study, 28 participants received SCC DBS between 2007 and 2013. The first 17 patients underwent implantation between 2007 and 2009 in an open-label trial with a 1-month single-blind stimulation-off lead-in period.

The additional 11 patients underwent implantation between 2011 and 2013 using tractography-guided anatomical targeting. A total of 178 patient-years of data were collected and combined for analysis.

All patients:

• Met criteria for either major depressive disorder or bipolar II disorder
• Were in a current depressive episode of at least 1 year 
• Did not respond to at least 3 antidepressant treatments (at least 4 lifetime treatment failures)
• Completed at least 1 year of follow-up
• Had the same surgeon and same device implanted

The majority of participants were female (67.9%) and white (96.4%); mean age of 45 years; 20 patients had major depressive disorder, 7 had bipolar II disorder, and 1 reclassified from major depressive disorder to bipolar II disorder.

SCC DBS effective long-term

Antidepressant response rates were maintained at ≥50% and remissions rates were maintained at ≥30% through years 2-8 of follow-up.

Throughout the entire study, 20 patients (71%) showed consistent improvement of ≥25% from baseline and 18 (64%) showed ≥50% improvement from baseline. Among these long-term patients, 6 patients (21%) maintained ≥50% improvement continuously over all 8 years.

Among the 28 patients, 14 patients completed ≥8 years of follow-up, 11 patients finished ≥4 years, 3 patients dropped out before finishing the 8 years, and 23 patients are currently in long-term follow-up.

Mayberg also led the first study of DBS in SCC white matter, or Brodmann Area 25, back in 2005 for treatment-resistant depression which yielded similar results.

“What my colleagues and I were seeing as we continued to follow patients from our initial trials was that over time, they were getting better and not only that, they were staying better,” Mayberg stated in a Mount Sinai press release.

Implantation itself was safe and well tolerated. No side effects of acute or chronic stimulation were observed. Occurrence of medical or surgical complications was similar to rates observed in studies of DBS for other indications.

Researchers concluded that while these results are promising, “more qualitative studies of DBS patient characteristics and the quality of patients’ experience of depression before and after DBS are needed in order to optimize patient selection for DBS in the SCC and other brain targets.”

DBS treatment is currently FDA-approved for essential tremor, Parkinson disease, epilepsy, and obsessive-compulsive disorder.