Clinical study with pitfalls
A major trial of deep brain stimulation to treat depression is being discontinued, despite the fact that many patients are doing better. What happened?

Neurologist Helen Mayberg had been honing her model of depression for more than 15 years when she tested the first treatment based on it. To do this, she first drilled two holes in the top of a patient's skull. Then she slowly pushed electrodes deep into his brain until they reached Brodmann's area 25. Once in place, she connected the electrodes to a battery pack implanted in the patient's chest and turned it on.
Between 2003 and 2006, Mayberg performed her experimental surgery, called deep brain stimulation (DBS), initially on 20 patients. These people had suffered from nagging depression for years, and no approved treatment could help them. The researcher published the results of the first six patients in 2005, and those of the remaining 14 in 2008. Overall, the brain stimulation had worked surprisingly well: most of the study participants felt noticeably better, and more than a third got over their depression completely. Achieving such success with such sick patients was spectacular. Tom Insel, then director of the US National Institute of Mental He alth, spoke of "a new way of understanding depression"…