A team from the University of Mainz, in Rhineland-Palatinate examined the phenomenon in which people report sensitivity to electromagnetic fields, complete with symptoms such as headaches, dizziness, and sensations on their skin.
"Despite this, there is a considerable body of evidence that electromagnetic hypersensitivity might actually be the result of a so-called nocebo effect," said Dr Michael Witthöft, from the university.
"The mere anticipation of possible injury may actually trigger pain or disorders. This is the opposite of the analgesic effects we know can be associated with exposure to placebos."
He and his team showed their 147 volunteers documentaries - one group saw a film about the health hazards associated with electromagnetic fields while the other watched one about the security of internet data.
Then all were exposed to fake Wifi signals which they were told were real. Even though they had been exposed to nothing, 54 percent of the volunteers reported anxiety, agitation, activity impairment, and twitching of the fingers, arms, legs and feet.
Two even left early because their reaction was so severe, the university said in a release marking the publication of the study in the Journal of Psychosomatic Research.
The study demonstrates that sensationalized media reports on potential risks, which often lack scientific evidence, can have a significant effect on the health of large sections of the population, the statement said.
"Science and the media need to work together more closely and make sure that reports of possible health hazards from new technologies are as accurate as possible and are presented to the public using the best available scientific data," said Witthöft.