If you do not have the disire to fight illness, you surely will not be able too. I do think that the mind definitely plays a large role in the healing process. There are many reasons for that. If you have a positive outlook, you are more likely to be somewhat active, and less depressed. You are more likely to seek treatment, and more likely you won't be laying around in a miserable ball.
I am sure more goes into it, but, never forget the role of the doctors who are out there to help you. Have faith in them.