placebo effect
Placebo Effect: Harnessing Your Mind's Power To Heal
From Science Daily - original

Itís true that some people who participate in research studies and take inactive medications called placebos do see health improvements. People taking placebos have experienced reduced pain, healed ulcers, eased nausea and even warts isappeared.

The January issue of Mayo Clinic Womenís HealthSource details several theories on how the placebo effect might work:

Benefit from attention: In a placebo-controlled research study, patients often have frequent and intensive medical attention. Some people respond favorably.

Stimulus response: People may have a trained positive response to taking a pill or receiving treatment, whether itís real or not.

Beliefs or expectations, including the meaning you attach to a treatment: A person with positive expectations of the treatment may experience the placebo effect more than someone with lower expectations.

Relationship with your doctor: A person whose doctor is supportive and positive may experience more benefit from a placebo -- or the standard treatment -- than someone who doesnít have that relationship.

Pleasing your doctor: You feel better because -- consciously or unconsciously -- you want to show your doctor that youíre a good patient and you appreciate the care.

Probably a combination of many psychological and physiological mechanisms are at work. Research studies and theories hold important clues to solve the mystery behind the placebo effect, but more research is needed to examine how these factors interplay to produce this healing force.

Placebo effect in Scientific American

The placebo effect - discussion

Placebo effect - neuroimaging

The Placebo Prescription - NYT archives

Evidence based medicine