New 'deep brain stimulation’ technique to cure depression?

Severely depressed patients who do not respond to conventional therapy may be helped by deep brain stimulation (DBS), according to the most-extensive study to date of the experimental procedure, Nature reports today.

In a clinical trial in Toronto, Canada, 12 out of 20 patients who had stimulating electrodes placed in a brain area called the subcallosal cingulated gyrus showed significant improvement in their depression, with seven of them going into full remission.

The benefits lasted at least a year, according to the results published this week in the journal Biological Psychiatry1. Patients in the study had failed to respond to cognitive therapy, antidepressant drugs and electroconvulsant therapy.

Neurologists think that the therapy works by activating or damping down particular brain circuits. At the moment, no-one knows which of the targets within these circuits will eventually prove to be the most optimal.

Advanced Neuromodulation Systems, a company based in Piano, Texas, that makes DBS electrodes, is now sponsoring a double-blind, controlled phase III trial on up to 200 patients at three centres in the United States.

Participants in the study, called BROADEN (Brodmann Area 25 Deep Brain Neuromodulation), will have DBS devices implanted, targeting the same part of the brain as the Canadian study. Half of the devices will be switched on immediately after surgery, while the other half will wait for six months before being stimulated. Neither the patients nor the scientists and clinicians will know who is switched on at any particular time. The study is expected to take several years to complete.

“In the meantime we need to know why some of the patients don’t respond at all,” says Mayberg. “Are we missing the target, or are there different subtypes of the disease?” Her team is now trying to find out how to identify those who will respond to DBS, and those who won’t. “Brain surgery is not like getting your nails done, so it is important to try to find out who will benefit.”

The centres are also investigating the value of DBS in other psychiatric disturbances, such as obsessive compulsive disorder and addiction.

Will this new technique revolutionise how depression is treated? Would you have such drastic treatment if you were experiencing depression? And does this mean that depression is simply a neurological illness, and not a product of situation or experience?