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Comment by dekhn | Hacker News Reader

Note that the "ulcer story" is more complicated that the mainstream story. In particular: ulcers are exacerbated by stress, so it's not completely surprising people thought they were "caused by" stress. Also, in many people, the bacteria that causes ulcers also have other protective effects (more commonly in third world countries with poor sanitation).

In the case of CFS, there are probably multiple underlying etiologies, only some of which are induced by microbes.

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But how does stress causes ulcers?

I'd guess it's because stress weakens the immune system, thus bacteria/viruses have greater effect. AFAIK stress also increases the production of stomach acid.

Stress (and especially sleep deprivation) has a noticeable effect on my immune system. Dunno about people in general.

I was diagnosed with ulcerative colitis 18 years ago and can confidently say when my sleeping pattern is off for prolonged periods of time the impact is definitely visible. I do not think it is a cause but coupled with other habits , bad eating , higher stress , weaker immune system etc I find lack of sleep to be a leading indicator that I need to prioritize getting sleep quickly...or else

Chronic stress also causes consistently elevated cortisol levels, which is not good long term (https://en.wikipedia.org/wiki/Cortisol -- wound healing, other areas, pretty good overview of some of the negative effects of stress)

it doesn't cause ulcers. that's the part of the theory that changed, rightly. But stress can increase the intensity of symptoms of the ulcer , changing it from non-symptomatic to a major pain in the stomach lining. So it's not surprising people once thought it was causative, since it was observed so frequently in ulcer cases. This area is still not well understood, although stress can decrease stomach pH as well as have immunomodulation effects.

That's pretty interesting. I thought ulcers were more of an erosive scenario induce by functional issues in the rest of the GI tract.

Stress/anxiety and other strong negative mental states can impact the functions of the GI tract's such as peristalsis and digestive efficiency of food.

This in turn sets up a negative feedback loop as things like nutrient absorption declines and toxin levels rise worsening the functionality of the tract. By toxins I also imply bacteria and viruses besides just 'regular' chemicals.

Erosion of various parts of the GI tract happens slowly and you get an ulcer. Ulcers in the stomach aren't the only place to see bleeding in the GI tract.

And I wonder if stress isn't caused/exacerbate by ulcer. I mean, cortisol levels increasing because you have an ulcer, then suffering a sudden burst when something else triggers it.

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