The dark power of the placebo effect

The idea that mental expectations can shape physical outcomes is considered laughable, but it has been scientifically demonstrated in many experiments. Commonly known as the placebo, this effect has a dark side too - the nocebo.

Placebo effect is when people get a sugar pill they think is a new drug, and then they actually experience the beneficial effects of the drug. The nocebo effect is placebo in reverse. People are given a new "drug," told about its bad side-effects, which they then experience.

These two effects are so pervasive and powerful that to learn the actual efficacy of a new drug, companies give placebo tablets to a control unit. This is necessary to separate a drug's actual therapeutic power from the brain expecting positive effects, and somehow inducing them.

A paper in Neuron Review argue that the "expectation-induced activation of the brain-reward circuitry, Pavlovian conditioning, and anxiety mechanisms" might explain these two effects, but the exact reason isn't properly understood.

Irving Kirsch, a lecturer at Harvard Medical School, argues in a 2008 paper that more than 80% of the effective response induced by antidepressants is explained by the placebo effect. People expect the drug to make them feel better, and so it does.

When people are given a sugar pill and told that they're receiving a drug that raises the heartbeat, it does increase their heartbeat. When the same people are later given the same sugar pill but told it lowers the heartbeat, their heartbeat goes down.

These effects raise interesting conundrums for everyone. Because of the nocebo effect, sometimes a patient might experience negative side effects from a drug just because he was told they might occur. But the doctor can't withhold this information either.

What is in the patient's interest? To know about the potential negative side effects of a drug and risk experiencing them due to the nocebo effect? Or to stay ignorant? Treatment transparency vs the power of placebo - where's the balance?

Books like The Secret and The Power of Your Subconscious Mind apply the placebo idea to other areas of life. You get what you expect; you attract what you're thinking about. The body follows the mind, and the mind follows your vision of the future - a vision you control.

Bottom line. Mind over matter, yes, but only sometimes. You can't climb out of every hole with your thoughts alone. But thoughts, though they are weightless and invisible, are more important than you think. Use positive expectations to get the most out of medical drugs and life.