American officials have reported experiencing symptoms in Vietnam, Austria, Britain, Cuba and China, as well as the Washington DC area. At least 200 cases are under investigation, half of them involving spies, diplomats, soldiers and other US officials.
New guidelines are part of the federal government's plan to respond faster to potential cases, after it was discovered that a quicker response benefits the health of the victim and the investigation.
It is a shift in the US response after years of skepticism in some corners of government about whether the strange and unexplained health issues are real and connected.
"We need to believe our personnel who are coming forward," a senior administration official told US political website McClatchy DC.
"People are facing real symptoms," they said. "We are very conscious that people are experiencing something very real, and it is having a real negative effect on their health. And we're seeing better health outcomes the sooner we can respond to that."
The unnamed official firmly denied the idea that the syndrome is a "mass hysteria", saying "the physical effects we've seen in several cases are very, very real".