I actually believe that all illness is self-created (at some level). Here's a quote from my favorite book in regards to this:
"Now let's understand what you probably already know: all illness is self-created. Even conventional medical doctors are now seeing how people make themselves sick.
Most people do so quite unconsciously. (They don't even know what they're doing.) So when they get sick, they don't know what hit them. It feels as though something has befallen them, rather than that they did something to themselves.
This occurs because most people move through life—not simply health issues and consequences—unconsciously.
People smoke and wonder why they get cancer.
People ingest animals and fat and wonder why they get blocked arteries.
People stay angry all their lives and wonder why they get heart attacks.
People compete with other people—mercilessly and under incredible stress—and wonder why they have strokes.
The not-so-obvious truth is that most people worry themselves to death.
Worry is just about the worst form of mental activity there is—next to hate, which is deeply self destructive.
Worry is pointless. It is wasted mental energy. It also creates bio-chemical reactions which harm the body, producing everything from indigestion to coronary arrest, and multitude of things in between.
Health will improve almost at once when worrying ends."