I'm a degree holding scientist, and I think in drug trials it's absolutely essential that you make the subjects feel faith that your control treatment will heal them. Faith, of course, defined as a belief held without evidence. If you fail to make the control group feel faith, then you're not actually controlling against faith and you cannot predict the effectiveness of your drug in comparison with a placebo. You need to control for faith just like you control for any other physical quality that can act as a variable.