At least in a controlled study. Where their doctors give them lots of attention. Where they, as participants in a study, may be hoping that the 'treatment' works. When they've been told that science says placebos can work. Et cetera....
No need for me to recapitulate the debates. Instead, links!
The original paper, Placebos Without Deception
Steve Silberman, author of the awesome Wired magazine article on placebos, has a nice rundown here.
I suppose you can guess Respectful Insolence's Orac's take from his introduction of the topic
The investigators, led by Dr. Ted J. Kaptchuk of Harvard's Osher Research Center. The Osher Center, for those of you not familiar with it, is Harvard's center of quackademic medicine; only this time they seem to be trying to do some real research into placebo effects.
Skepticism aplenty there.
Ed Young likes the study a bit better.