How Scientists Finally Learned to Measure the Placebo Effect

"Suppose I launch a new pharmaceutical company and announce a revolutionary antidepressant called "Placebin." It's powerful, safe, and nearly free of side effects. To prove it, we will give Placebin to one million depressed Americans-free of charge. Weeks later, 350,000 people report dramatic improvement from the amazing new drug. They flood the talk shows with testimonials. There are dramatic mood improvements and no side effects at all. Friends and family join the chorus. The headlines write themselves."

"For decades, researchers assumed the only way to study placebo effects was through randomized controlled trials, dividing patients into drug and placebo groups. While valuable, this approach has serious limitations: The samples are artificial and highly selected. Real-world treatment rarely resembles these carefully engineered trials. "Sham" treatments are often transparent. In fact, for some treatments, such as psychedelic drugs to treat depression or anxiety, the development of a credible placebo group is virtually impossible."

Placebo effects can produce authentic symptom relief that may be indistinguishable from treatment effects in depression. A thought experiment with an inert pill ('Placebin') shows large, credible recovery reports despite no active ingredient. Traditional randomized controlled trials try to separate drug and placebo effects but face limits: trial samples are artificial and nonrepresentative; sham controls can be transparent or impossible (for example with psychedelics); many patients correctly guess assignment; and controlled trials are costly and administratively burdensome. These methodological challenges make it difficult to determine whether observed improvements arise from specific biomedical mechanisms or from expectations, context, and belief.

Read at Psychology Today