When it comes to such conditions as migraine, schizophrenia, back pain, depression, asthma, post-traumatic stress and neurological disorders, which are often defined by their symptoms, Moerman said patients' feelings about what helps them feel better "trump the judgment of the physician." In those cases, he wrote, dummy pills "can be as useful as 'real' ones."
Much of what convinces patients that a treatment is working stems from the meaning they invest in medical procedures and technology, as well as the "power and authority" they associate with white coats or uniforms, Moerman said. All of these have "power, regardless of what may be in the capsule or syringe."
A study published Monday in the Annals of Family Medicine found that the placebo effect reduced the duration of common colds. University of Wisconsin researchers compared the effects of four treatments on 700 newly diagnosed cold sufferers. Some received dummy pills; others, pills containing the herbal remedy echinacea. Some got echinacea pills without their knowledge, and some got nothing at all.
On average, colds were slightly shorter and symptoms milder among patients taking any pill compared to those getting nothing. Among study participants who were the strongest believers in echinacea's power to ease colds, any pill made their colds last 2.5 fewer days, again reflecting the power of mind over body.