Most of us have heard of “the placebo effect,” the heal-inducing effect patients in clinical trials experience when they believe they’re getting a fancy new drug or surgery but are actually getting fake treatment. The placebo effect is real, it works about 18-80% of the time, and it’s not just in your head - it actually dilates bronchi, heals ulcers, makes warts disappear, drops your blood pressure, and even makes bald men who think they’re getting Rogaine grow hair!
Unwanted Side Effects
But the placebo effect has a shadow side. The same mind-body power that can heal you can also harm you. When patients in double-blinded clinical trials are warned about the side effects they may experience if they’re given the real drug, approximately 25% experience sometimes severe side effects, even when they’re only taking sugar pills.
Those treated with nothing more than placebos often report fatigue, vomiting, muscle weakness, colds, ringing in the ears, taste disturbances, memory disturbances, and other symptoms that shouldn’t result from a sugar pill.
Interestingly, these nocebo complaints aren't random; they tend to arise in response to the side effect warnings on the actual drug or treatment. The mere suggestion that a patient may experience negative symptoms in response to a medication (or a sugar pill) may be a self-fulfilling prophecy. For example, if you tell a patient treated with a placebo he might experience nausea, he’s likely to feel nauseous. If you suggest that he might get a headache, he may. Patients given nothing but saline who thought it was chemotherapy actually threw up and lost their hair!