June 22, 2005 – Chronic stress would not only cause physical harm: it is now also associated with impaired learning and memorization abilities.
This is what reveals a synthesis of studies1 carried out at the Douglas Hospital in Montreal, aimed at taking stock of the long-term impact of stress on intellectual capacities, among others in the elderly and children.
In the elderly, we measured, over a period of three to six years, the levels of cortisol – a hormone whose concentration increases with the level of stress. It was found that in people with high cortisol levels, the hippocampus volume was 14% smaller than in those with moderate stress. An integral part of the brain, the hippocampus plays an important role in learning and declarative memory (the memory of what can be described verbally, rather than that of skills). In addition, the most stressed seniors performed poorly on memory tests.
The researchers also compared cortisol levels in young children aged six to ten, depending on their socioeconomic background. They observed that those from disadvantaged backgrounds had a higher level of baseline cortisol, and therefore stress, than those from well-off backgrounds. In addition, they found in these children a link between high cortisol levels and symptoms of depression in their mothers.
According to Sonia J. Lupien, director of the Center for Studies on Human Stress at the Douglas Hospital, the conclusions of the 15 studies analyzed all point in the same direction. “Regardless of age, too much stress affects memory, which impairs the ability to learn and adapt. “
Stress is relative
According to Ms. Lupien, the human body was not designed to have to respond to the level of stress imposed by today’s lifestyle. The clearly circumscribed “absolute stress” to which man was once subjected (at the sight of a predator, for example) has given way to “relative stress” which must constantly be reassessed.
“Today’s” stressors “are all relative, that is to say they require an interpretation of the situation by the person who is experiencing it”, explains the researcher. However, for some people, the ability to sort through relevant information is blurred. “People come to overestimate the risks associated with certain situations, and chronic stress sets in. “
Sonia J. Lupien therefore intends to “return to the field”, with young people and workers, and promote greater dissemination of information on the nature of stress, which is above all psychological. “By knowing its origin, we will be better equipped to face the problem,” she concludes.
Martin LaSalle – PasseportSanté.net
1. Lupien SJ, Fiocco A, Wan N, et al. Stress hormones and human memory function across the lifespan, Psychoneuroendocrinology, April 2005, Vol. 30, No 3, 225-42.
