Ethics

On Chronic Stress & the Brain (Goldberg)

By Daniel Goldberg

On Medical Humanities Blog, I've discussed the burgeoning evidence that chronic stress causes all sorts of long-term health problems, including deleterious effects on the brain.  The neuroendocrine pathway is particularly important as a causal explanation for the notion that social and economic conditions are primary determinants of health.  Those lower on the social gradient experience more chronic stress, and, over years and years, the excessive stress hormones (most notably cortisol) is linked with all of the most serious chronic conditions (stroke, CV disease, diabetes, etc.).

The wonderful documentary Unnatural Causes, about which I had the opportunity to participate as a panelist in a private screening last week at the ICC Symposium, discussed the effect of chronic stress on developing brains, citing evidence that persistently high levels of cortisol is actually toxic to developing brains.

Today comes news of a study published in the Archives of General Psychiatry finding that depression is actually a risk factor for Alzheimer's Disease.  From the news report, quoting the lead author:

"Our thinking is that depression somehow causes damage to part of the brain called the limbic system, and this is the part of the brain that Alzheimer's disease preferentially attacks," Wilson said.

The limbic system includes the hippocampus and amygdala, which play key roles in emotions and memory.

The subjects in the study, which appeared in the Archives of General Psychiatry, were asked about depressive symptoms and not about specific episodes.

"In terms of depressive symptoms, those are fairly consistent from year to year as people have a chronic tendency to be depressed or not be depressed -- it's not just something that randomly varied from year to year," Wilson said.

Damaged Connections

Wilson cited one theory that chronic stress from depression releases excessive amounts of the brain hormone cortisol that ultimately damages the filigreed connections between brain cells called dendrites.

This study simply adds to the mounting evidence that the neuroendocrine pathway is crucial both for understanding how chronic stress actually causes disease, and as a promising causal grounding for the robust evidence that social and economic conditions are primary determinants of health.

Full post as published by Neuroethics and Law on April 08, 2008 (boomark / email).