The placebo effect has an evil twin: the nocebo effect, in which dummy pills and negative expectations can produce harmful effects. The term ‘nocebo’ was coined in 60’s and means ‘I will harm’ in Latin. Nocebo effect has been studied far less than the placebo effect but the results are as far-reaching.

Robert Hahn of the US Centers for Disease Control and Prevention, who has studied the nocebo effect extensively, says: “Beliefs and expectations are not only conscious, logical phenomena, they also have physical consequences.” In clinical trials, about a quarter of patients in control groups experience negative side effects, often matching in severity to those associated with real drugs. Patients undergoing chemotherapy often start feeling sick days before the treatment.

According to Hahn, surgeons are often wary of operating on people who think they will die – because such patients often do. The mere belief that one is susceptible to a heart attack is itself a risk factor. One study found that women who believed they are particularly prone to heart attack are nearly four times as likely to die from coronary conditions than other women with the same risk factors. The ultimate cause of the nocebo effect, however, is not neuro-chemistry but belief!

Sam Shoeman was diagnosed with end stage liver cancer in 1970s and given just months to live. Continue reading →