New 'brain pacemaker' shocks depression away

Jeanne Harris had felt so depressed for so long that she was willing to let doctors drill two holes in her head and implant electrodes in her brain, in one of the most radical mood-altering experiments on the medical books.

Depression first seized Harris 10 years ago. Since then, the former Toronto psychiatric nurse had sobbed through an entire summer on her condo balcony, spent six months in bed, shunned food and friends and fought off steady thoughts of suicide.

Nothing had worked, neither medication nor psychotherapy.

But today, two years after she agreed to take part in the landmark Canadian experiment, Harris could hardly be happier for the electrodes buried in her brain: two wires, nearly as thick as spaghetti and a foot long, pulsing 130 times a second to silence the negativity of her mind.

"It is an unbelievable, dramatic change for me," said the 50-year-old Harris. "For the first time in 10 years, I feel alive. I have energy, it's like a light bulb being turned on."

Four of the six patients who participated in the unprecedented investigation, led by scientists at the Baycrest Center's Rotman Research Institute and the University of Toronto, report experiences similar to Harris'.

The results, albeit from a small sample, offer the world's first new possibility of an effective therapy for treatment-resistant depression.

"Some people will say this is pretty extreme, but this condition is pretty extreme," neurologist Helen Mayberg said, describing the therapy known as deep brain stimulation, or DBS. "I never could have dreamed that we'd have the kind of clinical effect that we've seen."

Mayberg, the lead author of the study to be published this week in the journal Neuron, emphasized the research is preliminary and that she remains optimistic, but cautious.

Unlike electroconvulsive therapy (ECT), which shocks the entire brain with electricity to induce brain seizures as a treatment for severe depression, DBS is designed to electrically stimulate only the brain region known to be overactive in people with the condition.

It is part of an expanding field known as "brain pacemakers," in which doctors implant devices that electrically alter neural circuits to treat disorders such as Parkinson's disease, epilepsy and even obsessive-compulsive behavior.

DBS is also less painful than ECT, with patients unable to feel the presence of the electrodes, or even whether they are turned on. In addition, in stark contrast to other external, electrical therapies, the beneficial effects of DBS appear, so far, to be long lasting.

"The stimulation is on constantly," said Andres Lozano, co-author of the study. Although each patient requires a slightly different level of stimulation, in each case signs of their depression returned within two weeks after the electrodes were turned off, he said.

Harris had an adjustment several months ago. She's had occasional bouts of depression, but they've been brief and mild.

Lozano, also a neurosurgeon at Toronto Western Hospital, explained that the two electrodes were threaded through the top of the skull and down, with one on each side of the brain, using a rod and strawlike device.

The electrodes are connected to wires that run from the top of the head beneath the scalp, down behind the ears, beneath the skin of the neck and then connect to a small battery pack (with an estimated five years of life) that's embedded beneath the collar bone.

The pack also contains a program chip, powered by remote control, that sets the frequency and voltage of the electrodes.