The mind is truly all powerful. This is jsut another instance that proves it, and I agree. My mom used to kiss my knee after I fell down and it instantly felt better.
Placebos are only used in experimental situations to control for the effects (or non-effects) that a certain experimental drug has. Like beefeater, I am also a psychologist (well, working on it- I'm an undergrad).
The mind is very powerful. If you can convince yourself that something is not true (eg. that you're abusive significant other "loves you") why should a sugar pill be any different? You are what you believe.
Pretty much it's all do with your mind, and the way you think about something. If you REALLY believe something is going to help you- it will, if you truly believe something wont- that’s exactly what will happen.
It's like the "story" or stress- your brain gets stressed, your body suffers.
I'm not saying EVERYTHING can be healed with positive thinking- that would be stupid, but if you think better, you'll feel better.
You just gotta be careful about when you "play" with the Placebo effect or not- it's not safe to assume your pain will always go away because you want it too.
Sugar pills should usually only be given when professionals are experimenting or like TayRawwr said i guess when the doctor thinks it's needed for someone- but really if you're seeking pills for and illness that does not exist i think that's an underlying problems in itself.
If you think a pill is going to work then you're in that mind set and you're mind has the poweron it's on to release the certain neurotransmitters in order to activate the pain receptors therefore it works.
The mind is a powerfuk thing, trust me I'm a psychologist.
I just want to add, or rather correct something. Sugar pills are given to persons who only think they are sick. The person thinks they are getting a pill to help with their "illness" so they get better because they think its going to work. The mind doesn't heal the body because you think a pill is working.