The End of Sad

Power point: DBS patients have a cellphone-sized, 3.5‑volt battery pack sewn under the skin of their chest (Image: Courtesy of Medtronic Inc.)

Researchers at Toronto Western are at the forefront of experiments using deep brain stimulation. A team led by neurosurgeon Andres Lozano was the first in North America to test DBS on human Parkinson’s patients in 1993. Since that time, more than 60,000 people have received DBS to control movement disorders. DBS has also been used as an experimental treatment for eating disorders and Alzheimer’s.

Data collected during the DBS trials has allowed the researchers at Toronto Western to map different parts of the brain. They’ve realized it’s busier than previously thought. “People used to say you’re only using 10 per cent of your brain,” Lozano says. “That’s not true. You use 100 per cent of your brain.” Until surgeons went in and recorded activity in that other 90 per cent, many people assumed nothing was happening. “People would say that if you take out this part, you look the same. You still walk, you still talk. But guess what? If you take out this part, you might not feel sadness anymore.”

Early experiments with deep brain stimulation were performed on rats. They got so much satisfaction from zapping themselves by stepping on levers that they stopped doing anything else and died of starvation

Advances in imaging techniques have given researchers a better view of what goes on in the brain. With PET scans and functional MRIs, we’re able to examine in real time which areas become active when people think or feel certain things. Helen Mayberg, a neurologist at the University of Texas at San Antonio, was using imaging to study depression when she zeroed in on two parts of the brain, called Brodmann area 25, or the subcallosal cingulate. These zones are deep in the brain, just behind the eyes—one in the right hemisphere and the other in the left. When area 25 is engaged, the cognitive areas in the frontal lobe—identified with executive functions, like planning and decision making—become unusually quiet. When patients are given antidepressants or are treated successfully with cognitive therapy or electroconvulsive therapy, area 25 calms down and other areas in the frontal lobe become more active, as they are in non-depressed patients. Mayberg wondered what would happen if, for severely depressed patients not responding to other treatments, you went in and quieted down area 25 directly.

In 2001, Mayberg heard about Lozano’s research at Toronto Western and contacted him to talk about using DBS for severe depression. Lozano was intrigued. They began researching the possibilities and applied for funding from public and private donors on both sides of the border.

Two years later, Mayberg and Lozano launched a clinical trial. To be accepted into their study, the patients had to have tried at least four recognized treatments. They had to score a minimum of 20 on the Hamilton depression scale, in which a patient scoring above seven is considered depressed. In 2006, another group of patients joined the study. Out of the first 20 patients to get DBS for depression, Debra Prupas, who scored 23 on the Hamilton scale, was patient number 14.

In the years leading up to her surgery, Prupas had struggled to keep the appearance of being happy, as though she could will her illness away. She’d bought a house in Scarborough, adopted a baby girl from China, and met Bern Grush, a high-spirited tech entrepreneur, whom she married in 2000. When she told him about her condition, he was surprised. Depressed people were lethargic and uncommunicative and suicidal, he thought. That wasn’t the Debra he knew. She had been adept at hiding her sadness. In 2003, during one of her happy periods, they’d even adopted another daughter. But as her condition worsened, she became that stereotype of a depressed person her husband had first imagined.

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