The Nocebo Effect

EARLY IN MY TRAINING I realized that I must be very careful about what I say to patients as patients will listen more often than not to whatever advice and information their doctor provides. What I say matters. The power of suggestion is strong enough to induce positive or negative feelings in patients. A growing body of evidence has emerged for a phenomenon known as The Nocebo Effect. This is when a person is conditioned to expect a negative response, or to anticipate negative effects from an experience. It is the opposite of a placebo. 

The Placebo Effect demonstrates how positive thinking can improve treatment outcomes. The Nocebo Effect suggests that negative thinking may have the opposite effect. About 20 percent of patients taking a sugar pill in controlled linical trials of a drug spontaneously report uncomfortable side effects — an even higher percentage if they are asked. These effects are one kind of nocebo — a word that means in Latin “I will harm.” (Placebo means “I will please.”)

Katherine Lang’s recent article in Medical News Today noted that a recent study of COVID-19 vaccination trials analyzed data from twelve trials

and found that 35 percent of people given placebo injections experienced systemic effects — effects experienced in areas of the body other than the treatment site, such as headache and fatigue — following the first dose. This was compared with 46 percent of those given the real vaccine. As a result of this data, the study’s authors suggest that some 76 percent of adverse effects reported by those given the real vaccine were nocebo effects. In other words, they were not caused by the vaccine but by participants’ expectations.

An article in the Psychomed Journal for physicians gives clinical insights into the subject. If a doctor tells a patient “the great majority of patients tolerate this treatment very well” before giving a flu shot, patients experience fewer “adverse events.” As Gareth Cook notes in The New Yorker the larger problem lies outside the clinic, “The internet has become a powerful—and, to some, irresistible—nocebo-dosing machine. Pre-internet, it took weeks or even months for a person to gather enough reading to become very, very afraid. Now one can achieve a state of dread in a few short hours, surrounded by the comforts of home.” The most common reasons patients don’t comply to medications are intentional and include: high drug costs, fear of adverse events, being prescribed multiple medications, and experiencing either instant relief or medication ineffectiveness leading to self-discontinuation of medications. Additionally, television commercials are attempting to distract us as they sell a particular medication, with soothing visuals, while the adverse effects are quietly narrated in the background. In the U.S., many pharmaceutical companies market new prescription drugs through direct-to-consumer drug ads. These ads lead consumers to ask their doctors for prescriptions of often expensive new drugs despite the presence of existing options that are just as effective or affordable.  

So how do we not worry ourselves sick?

Ask your healthcare provider “How will the treatment improve my condition?”

Focus on how the medication will make you better – not on its minor side effects.

Be selective about searching the internet.

Monitor the effects of the medicine without prejudice.