http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11466595&dopt=AbstractPeople appear to behave paradoxically, by persisting in repeated self-change attempts despite previous failures. It is argued, though, that self-change attempts provide some initial rewards even when unsuccessful. Feelings of control and optimism often accompany the early stages of self-modification efforts. In addition, unrealistic expectations concerning the ease, speed, likely degree of change, and presumed benefits of changing may overwhelm the knowledge of one's prior failures. It is thus important to learn to distinguish between potentially feasible and impossible self-change goals in order to avoid overconfidence and false hopes leading to eventual failure and distress.
Quite applicable to each of us and all of the current research, dont you think? In reply to my email to her Prof Polivy agrees that her theory is equally applicable to medical "promises":
You are correct in what you say about the promises of miracle cures (not just for MS, but for cancer and almost any other disorder you can think of) being different from diets in that they are promising something that may well be utterly impossible to achieve. The similarity, of course, is that, once again, the promise is what the person wants to hear, that the goal (or cure) is indeed attainable. This seems to me to be a crueler "false hope" than offering weight loss or to cure one's gambling addiction.
An interesting interview with Prof Polivy in the Sydney Morning Herald: http://www.smh.com.au/articles/2003/02/26/1046064099948.html?oneclick=true