Oct 27 2009
Stress: Not so Almighty
Many medical professionals treat stress as if it were a supernatural force. Back problem – Probably stress-related. Headaches — Probably stress-related. Fatigue — Probably stress-related. Depressed — Probably stress-related.
Although stress might play a role in physical and mental health, too often there is an assumption that it definitely does. For those lacking better answers, it provides a handy gap-filler. Rather than “God done it” — filling a gap in our knowledge or providing a more comprehensible answer to minds averse to complexity — there is instead, “stress done it.”
For generations it was assumed that stress causes ulcers. Guess what? A type of stomach bacteria is the cause. Now new research is strongly suggesting that stress may play no significant role in depression.
In the oddly titled news release, Why antidepressants don’t work for so many (odd because the news was primarily about research into the link between stress and depression) I learned of this somewhat surprising development:
[Eva] Redei, the David Lawrence Stein Professor of Psychiatry at Northwestern’s Feinberg School, found powerful molecular evidence that quashes the long-held dogma that stress is generally a major cause of depression. Her new research reveals that there is almost no overlap between stress-related genes and depression-related genes.
For those interested, below the fold I have provided material from the article that clearly spells out how the study was conducted and what the actual results were. Important stuff. Because the news release included this information, I’ve got to give it kudos, despite the misleading title.
Mind you, where you find back pain you may find stress, and where you find depression you may also find concomitant stress. Being ill is stressful. And perhaps asking any person, ill or healthy, if they are experiencing stress in their lives might yield a positive response.
In a sense, it would be nice if stress were a major cause of all that ails us. If so, medical professionals could simply prescribe things like vacations, spa visits and meditation. Some do. It would also legitimize the shifting of responsibility for illness and health onto the patient’s shoulders. For good. And for bad.
Redei used microarray technology to isolate and identify the specific genes related to depression in these animals. She examined the genes in the brain regions — the hippocampus and amygdala — commonly associated with depression in rats and humans.
[She] took four genetically different strains of rats and exposed them to chronic stress for two weeks. Afterwards, she identified the genes that had consistently increased or decreased in response to the stress in all four strains in the same brain regions.
Redei now had one set of depression-related genes that came out of an animal model of depression and one set of stress-related genes that came our of her chronic stress study.
Next she compared the two sets of genes to see if there were any similarities. “If the ‘stress causes depression theory’ was correct, there should have been a significant overlap between these two sets of genes,” she said. “There weren’t.”
Out of a total of over 30,000 genes on the microarray, she discovered approximately 254 genes related to stress and 1275 genes related to depression, with an overlap of only five genes between the two.
“This overlap is insignificant, a very small percentage,” Redei said. “This finding is clear evidence that at least in an animal model, chronic stress does not cause the same molecular changes as depression does.”
