Media health warnings trigger symptoms from sham exposure

(HealthDay)—Individuals who watched a news report about the adverse health effects of exposure to electromagnetic fields (EMF) were more likely to experience symptoms after a 15-minute sham exposure to a WiFi signal than those who watched a control film, according to a study published in the Journal of Psychosomatic Research.

Michael Witthöft, Ph.D., and G. James Rubin, Ph.D., of King's College London, randomly assigned participants to watch either a television report about the health hazards of exposure to EMF (76 participants) or a control film (71 participants). After watching the film, all participants received a 15-minute sham exposure to a WiFi signal. Participants filled out questionnaires to evaluate anxiety and symptom scores at baseline, after watching the film, and after receiving the sham exposure.

The researchers found that about half (54 percent) of the participants reported symptoms that they believed were caused by the sham exposure to a WiFi signal. Those who watched the health warning film had significant increases in worries related to EMF. Other significant increases that occurred among those who watched the warning film included post sham exposure symptoms, in those with pre-existing high anxiety; the chances of symptoms being attributed to the sham exposure, in those with high anxiety; and the chances of those who believed their symptoms were related to the sham exposure thinking that they were sensitive to EMF.

"Media reports about the adverse effects of supposedly hazardous substances can increase the likelihood of experiencing symptoms following sham exposure and developing an apparent sensitivity to it," the authors write. "Greater engagement between journalists and scientists is required to counter these negative effects."