The Nocebo Effect is Serious Medicine

December 4, 2011

A decade ago I read an intriguing article entitled “The Nocebo Effect: Placebo’s Evil Twin” which argued a patient’s pessimistic attitude could have negative consequences on their health.  Research showed that patients who were warned of gastrointestinal side effects from repeated use of aspirin were almost three times as likely to exhibit the side effects as those who were not warned.   In the intervening years, I’ve seen other scattered reports that a patient’s anxiety around a disease can lead to a hastened death, even when medicine suggests the patient should recover.

The term nocebo, which is Latin for “I will harm”, was allegedly chosen by Walter Kennedy in 1961 as a reaction to the then recently-coined term placebo.  According to Irving Kirsch, a psychologist at the University of Connecticut, “nocebos often cause a physical effect, but it’s not a physically produced effect.  In many cases [the cause] is an unanswered question.”  For obvious reasons, the nocebo effect has not been well-studied: it’s unethical to encourage illness in patients who are not sick. 

Science might now be closer to an answer of how to treat the nocebo effect.  A recent Oxford University study demonstrates that nocebo pain is detectable in an MRI scanner. This suggests patients are responding to actual pain at a neurological level.  A University of Turin study goes one step further by identifying a neurochemical called cholecystokinin which appears to be responsible for this effect.  When scientists use drugs to block cholecystokinin, patients do not feel the nocebo pain. 

The realness of the nocebo effect makes me to wonder about its impact on doctor-patient relationships.  To avoid being sued, doctors might be tempted to emphasize drug side effects to their patients but the mere act of highlighting these side effects might make them more likely to happen.  On the other hand, patients who do not completely trust their doctor’s prescriptions might reduce the efficacy of their own treatments.  This is the ultimate Catch-22.

While it might seem easy to laugh off, the nocebo effect is clearly real and important to consider in treating patient health.  The nocebo effect could even explain how anxiety can cause patients to become worried sick or literally scared to death.