Expectation and belief can be powerful forces in sickness and health. This is the basis of the placebo effect, which occurs when people experience an improvement in symptoms after they take a placebo (a dummy pill or sham treatment). But what if your expectations are negative? That’s when the placebo’s dark twin—the nocebo effect—can come into play. Negative expectations, fears and anxiety can actually make people feel ill.
The nocebo effect explains why media reports about health risks, however unfounded, can themselves cause some people to experience adverse effects. This was seen in a recent German study in the Journal of Psychosomatic Research, which looked at “electromagnetic hypersensitivity,” a highly questionable condition in which people report experiencing vague symptoms when exposed to low-energy electromagnetic fields (EMFs) emitted by cell phones, power lines, Wi-Fi and appliances.
The study involved 147 participants, half of whom watched a documentary about the potential harms of EMFs; the other half, the control group, watched an unrelated film. Then they were all fitted with a headband with a mounted antenna that, they were told, was connected to a Wi-Fi router and would “bring the signal as close to your body as possible.” But, in fact, there was no Wi-Fi and no EMF exposure.
Still, people who watched the EMF documentary, especially those who rated high on an anxiety scale beforehand, were much more likely to report symptoms such as agitation, loss of concentration and tingling in their limbs and to attribute them to EMFs. Two participants left the study because their symptoms were so severe.
Over the years there have been concerns that EMFs may cause cancer, but research results have for the most part been reassuring. EMF hypersensitivity, on the other hand, is without merit. When studied, people who claim to have the condition react similarly to genuine and sham fields.
It’s hard to avoid the nocebo effect, because everyone is suggestible to some extent, and it occurs unconsciously. It’s important to know about potential health risks, of course, but try to watch out for your negative expectations, particularly if you’re prone to worrying. And beware of sensationalized media reports of new purported health hazards.