APA: Deep Brain Stimulation Lifts Depression in Multicenter Trial

By Michael Smith
WASHINGTON, 06 may 2008-- Deep brain stimulation relieved depression in 56% of patients treated in a multicenter Canadian trial.
Six months after the treatment, nine of 16 patients had at least a 40% improvement on the Hamilton Rating Scale for Depression, according to Sidney Kennedy, M.D., of the University Health Network in Toronto.
The "findings are robust," Dr. Kennedy said at the annual meeting of the American Psychiatric Association, adding that they should be followed up with a double-blind randomized trial.
The study follows the technique used in a pilot study three years ago, led by Helen Mayberg, M.D., of Emory University, but uses a different device, Dr. Kennedy said.
That earlier study sparked an outburst of interest in the idea of stimulating brain areas as a possible therapy for major depression. Dr. Mayberg discussed the technique with MedPage Today in an exclusive interview. Dr. Mayberg and colleagues have since expanded their initial study to 20 patients and a paper detailing their results is in press, she said, but she was reluctant to give details until the paper is published.
The 20-patient study reported by Dr. Kennedy was intended to show that the results obtained by the Toronto group could be reproduced by doctors elsewhere. (Dr. Mayberg was consulted on its design but was not otherwise involved, she said.)
"We wanted to show it wasn't just a Toronto effect," Dr. Kennedy said.
The method involves inserting electrodes into the subgenual cingulate cortex Brodmann Area 25, which is part of a brain circuit thought to be disregulated in depressed patients.
Because the treatment has only been used a few dozen times -- one estimate says about 50 cases worldwide -- the patients selected are usually highly refractory to treatment, Dr. Kennedy said.
In his study, volunteers had to have documented resistance to at least four types of treatment, including cognitive behavioral therapy. They also had to be in a depressive episode at least two years long and have a score on the Hamilton scale of 20 or higher.
The researchers treated five cases in Vancouver, six in Montreal, and nine in Toronto, but several patients had not yet reached the six-month landmark when the poster was prepared, Dr. Kennedy said.
When the researchers considered the latest follow-up, rather than the six-month mark, 15 of 19 (or 79%) had at least a 40% improvement on the Hamilton scale, he said. (The 20th patient was not included because the implant was too recent.)
The results are "exciting," said Thomas Insel, M.D., director of the National Institute of Mental Health, and the whole approach "could be tremendously informative" about which brain circuits are involved in depression.
"What you really want to know," Dr. Insel said, "is how these interventions affect the circuitry."
"I think we're going to get closer to that with (deep brain stimulation) than with pharmacotherapy," he added.
One of the next steps is to combine the intervention with neuroimaging to pin down exactly which brain regions are involved in depression and how they interact to cause the disease.
"I think that's where this will have to go," Dr. Insel said.