Placebo effect is a very interesting subject. and side effects can be as severe as a real drug.
.Did you know that research showed that the mind can influence and enhance the success of the drug by interpreting the strength of pill (colour, red stronger than white), or capsule (better and stronger than pill) or injection (stronger still )or the person who recommends/dispenses it to them (ordinary clothes,versus white coat)? After all everyone knows expensive cosmetics are much better for your skin.....
And they did indeed find people successfully treated with a placebo even though the patient knew it contained only sugar.
I was under the impression, however, that there was one drawback, if you used a placebo over a longer period, the effect could become more uneven or more unreliable.