Stressed? Remember this

Scientists believe that memory loss is more than just a natural condition of aging; it may be linked to prolonged exposure to stress.

Researchers led by Sonia Lupien, a psychiatry professor at McGill University in Montreal, were able to induce memory loss in elderly patients by manipulating levels of cortisol, a hormone secreted by the adrenal glands in times of stress. This research reinforces previous work by this team that suggested that long-term exposure to high levels of cortisol may lead to atrophy of the hippocampus, the region of the brain responsible for memory, and to memory impairment.

For the current study, scientists used agents to suppress cortisol production in 17 patients between the ages of 60 and 80, some with mild cognitive impairment, and then restored it to its original levels. Patients underwent memory tests at each stage of the study.

The results were fascinating. For patients with normal cortisol levels, inhibiting its secretion caused them to perform poorly on memory tests. Memory was restored when cortisol levels were returned to normal.

Patients with naturally high cortisol levels also had memory impairment, and suppressing the hormone had no effect. When cortisol was restored to its elevated levels in these patients, performance on memory tests declined further.

“You need [cortisol],” explains Lupien. “If you don't have it, your memory is just as impaired as if you have too much. Everything in the hormonal system is about equilibrium.”

Why some people produce more cortisol than others remains a mystery. But discovering the cause-and-effect relationship between stress and memory loss may lead to treatment. Lupien is optimistic: she looks forward to a time when a blood test detects overabundant cortisol early on, as well as medication that prevents further memory decline by regulating cortisol. Best of all, she predicts these developments are a mere five to 10 years away.

From Canadian Living, October 2003