[paulerdos]

You wrote "This kinda reminds me of how peptic ulcers were once thought to be caused by stress until they were found to caused by a virus [3].". First of all, if you read the article you reference, you'll note that Heliobacter Pylori is a bacterium, not a virus. Second, the presence of h. pylori in the gut is not conclusively proven to be a causal relationship for ulcers. That is, in some people h. pylori is just part of the normal gut flora. Further, it HAS been shown that stress is a strong cofactor in peptic ulcers.