How Placebos Work

A placebo can be a sugar pill, a saline injection or a glass of coloured water: inert treatments that shouldn’t produce a physiological response. But they often do; Wharrad’s case is not unusual. In fact, placebos are increasingly proving to be more powerful than active drugs in trials—and they may just be the key to reducing our dependence on medications. 

The so-called placebo effect happens when the brain convinces the body that a fake treatment is authentic, which stimulates relief. The medical community has long been aware of this phenomenon, but in the last 50 years, neurologists began examining the molecular mechanisms and pathways at play when a mock treatment creates real healing. To a large extent, it’s still a mystery, but scientists have confirmed that simply perceiving that you’re being treated affects the part of our brain that processes symptoms. 

Since the body-brain response that controls the placebo effect is neurological, they work best for conditions controlled by the neurological system, such as pain, irritable bowel syndrome, depression and Parkinson’s disease. Placebos can’t change things like a viral infection; they won’t lower your cholesterol, shrink a tumour or reduce a cold’s duration. 

When they do work, expectations play a significant role: if you think a pill can cure you, it is more likely to do so. In a Lancet review of placebo studies, researchers described a case where post-surgery patients were given morphine for pain. For some, the medication was delivered secretly with a hidden pump, while others received it from a physician who explained that it would make them feel better. The patients expecting the drug and its positive effects experienced far greater pain reduction than those who were unaware they had received it.