Summary: The placebo effect is a positive effect on an illness or medical condition, or on a health-related outcome, that results from suggestion and expectation. This subtle psychological effect occurs whether or not the underlying treatment actually works and it is strong enough to continually distort medical studies into the effectiveness of health products and can make products seem effective when they're not. The placebo effect is particularly significant in areas such as pain relief and stress, and is therefore best at overcoming aches and pains, headaches, stress-related conditions including recovery from stomach ulcers and skin rashes. Most complementary and alternative medicines (CAM) and alternative therapies work through indirect psychological effects, and the placebo effect is the reason why these remedies appear to work for so many people, when in reality they don't have any medical effect and its effects can often support erroneous ideas as to how disease works, and how healing works.
How does it work? (1) There is a link between mood and mental states of mind, and between mood and our immune system, meaning, that our overall impressions of a treatment can affect our outlook, which can boost our immune system. (2) When it comes to pain, the prefrontal cortex of the brain can suppress pain messages from the insula and other places, meaning that if we prime ourselves to feel less pain (such as when expecting a pill to work) then it really does dull pain. Many experiments have confirmed the ability of people to mentally control pain. (3) Classical conditioning means that many elements of merely receiving a treatment cause our brain to release neurotransmitters and other learned responses in anticipation of feeling better, which improves how we feel. (4) The Hawthorne Effect - people tend to live healthier and perform better simply because they are being studied. (5) Receiving treatment can boost confidence and reduce stress, both of which can improve healing and feelings of wellbeing.