The placebo effect ! Subject sleeping better.
In one common placebo procedure, however, a patient is given an inert pill,or cream, told that it may improve his/her condition, but not told that it is in fact inert. Such an intervention may cause the patient to believe the treatment will change his/her condition; and this belief may produce a subjective perception of a therapeutic effect, causing the patient to feel their condition has improved — or an actual improvement in their condition. This phenomenon is known as the placebo effect.