Around 4 million people in the U.S. have depression that doesn't respond to medication. Some studies have suggested that deep-brain stimulation might be useful for these people and researchers at Harvard Medical School in Boston studied the effectiveness of the technique on 12 people who had been depressed for a long time and who had not responded to nine or ten different drugs. A small hole was cut in the participants' skulls and electrodes used to stimulate a part of the brain called the left dorsolateral prefrontal cortex, which is thought to play an important role in the development of depression. Half of the participants were given an active treatment while the other half were given a sham one. After 8 weeks the depression 'scores' of those who had been given the active treatment improved by 22%, compared to only 3% in those who had been given the sham treatment. After eight weeks all the participants were given the active treatment and the improvements made were maintained at further assessments after six months and a year.
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