There are cancer researchers who die of cancer and yet some believe that we have the cure but drug comapnies are paying someone not to market it. You really think that researcher is going to die to protect the secret cure for cancer that we have and are not allowed to use?
This, this, thissity this.
Yknow what, it's true that positive thinking is incredibly powerful for all sorts of reasons. Your general health, your
perception of your general health, and your
tolerance to minor ill health will go through the roof.
There are also many psychosomatic conditions that are well known. It is also well known that you can make yourself ill with worry for instance, and that a strong mental attitude (just as with placebo) can help immensely
alongside your body's natural healing processes.
The placebo effect is incredibly powerful and worth reading up on. It forms the basis of pretty much all "alternative" medicine. I recommend a book called Bad Science by Ben Goldacre on this very subject. There's a fascinating study he refers to where the people were given ipecac for a bad gut under the false impression that it was a fantastic new cure... and it settled their stomachs! I'm not on pubmed or anything so I can't link to the study without some digging, but I'll try to find it. Placebo. It's fascinating.
(edited to add reference: Dr Stewart Wolf. effects of suggestion and conditioning on the action of chemical agents in human subjects: the pharmacology of placebos. J Clin Invest (January 1950); 29 (1): 100-9)
PDF here
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC439730/pdf/jcinvest00402-0111.pdf
Sure there are always edge cases where the medics don't know what happened. People recover from cancer, at least one guy has recovered from HIV/AIDS, but if there was a reproducible cure here, it would change the world. There would be more than a handful of recipients, and these guys wouldn't need to market books and expensive seminars, because the entire medical community would be showering them with riches.
At the end of the day, I refer you to a quote from Tim Minchin, an Aussie comedian who's exceptionally and eloquently vocal on this subject.
You know what they call Alternative Medicine that's been proven to work? Medicine.