New Legitimacy For 'Fake' Treatments

It doesn't seem to matter whether people know they are getting a placebo and not a "real" treatment.

• A 2001 study published in Science found that placebo was effective at improving Parkinson's disease symptoms at a magnitude similar to real medication. The placebo actually induced the brain to produce greater amounts of dopamine, the neurotransmitter known to be useful in treating the disease.
• With depression, an estimated 30% to 45% of patients—or even more, in some studies—will respond to a placebo, according to a review published in December in Clinical Therapeutics. An additional 5% of patients were helped by an antidepressant in cases of mild depression, and an additional 16% in cases of severe depression. 
• Fertility rates have been found to improve in women getting a placebo, perhaps because they experience a decrease in stress. A recent randomized trial of women with polycystic ovarian syndrome found that 15%, or 5 of 33, got pregnant while taking placebo over a six-month period, compared with 22%, or 7 of 32, who got the drug—a statistically insignificant difference. Other studies have demonstrated pregnancy rates as high as 40% in placebo groups.
• Eighty patients with irritable bowel syndrome, a chronic gastrointestinal disorder, were assigned either a placebo or no treatment. Patients in the placebo group got pills described to them as being made with an inert substance and showing in studies to improve symptoms via "mind-body self-healing processes." Participants were told they didn't have to believe in the placebo effect but should take the pills anyway. After three weeks, placebo-group patients reported feelings of relief, significant reduction in some symptoms and some improvement in quality of life.

WSJ: Why Placebos Work Wonders