Although there are many sources of stress, including nutritional and chemical from wrong foods and what they put in foods, emotional crisis is the beginning of most diseases, I'm convinced. My old naturopath--the late father of my current one--used to say a healthy body could endure a great load of emotional/mental stress, but that we should go "hang it on the cross" when things got bad in that way. My first major health crisis was spiritual and emotional in nature, clear back around 1972 (I'm a young 58, and getting younger). The healing that came was spiritual in nature, and involved a near death experience. You'd think after that a person would always remember how to deal with any kind of crisis, but I didn't. Sometimes it just takes some reminding...like on forum boards such as this.
Also, someone emailed me and reminded me that after I mentioned taking something gross out of my leg (don't know if it's cancer or just abnormal tissue from a 30-year-old unheal injury) and that it was on my website, I didn't provide a link. Don't look unless you have a strong stomach http://www.truthquest2.com
Also, there's a website about a German doctor who documented on over 40,000 patients that when emotional trauma occurs, it creates a lesion in the brain that can be observed by brain scan, which is followed afterwards by physical disease, often cancer. He created something called German New Medicine which went to healing the mind and spirit instead of jumping to more invasive conventional medical treatments. He went to prison for his efforts. Http://www.germannewmedicine.com