The ... problem with placebo religion is this: imagine a patient with a serious illness is given a placebo pill as treatment. Since there is no substantive therapeutic medication in it, the patient will continue to suffer from the illness and perhaps even die. The same danger exists in placebo religion: it has no real substance other than the placebo effect. The believer will continue to be vulnerable to the ill effects of everyday life while he is convinced his belief in the placebo religion is having a positive effect on a negative reality.
http://philosophos.sdf.org/feature_articles/philosophy_article_161.html
[See the LeM of Rav Nahman of Breslov. This problem is discussed in a somewhat different kind of way in his discussions of Torah scholars that are demons in LeM vol I chaps 12 and 28. Even the very first lesson in the LeM discusses the fact that the evil inclination [Satan] disguises himself in mitzvot.]
