Why the FBI Labeled Havana Syndrome 'Mass Hysteria'

A decade ago, U.S. personnel in Havana, Cuba, began suffering mysterious symptoms—piercing head pressure, dizziness, nausea, loss of balance, and even cognitive decline. These cases, dubbed Havana Syndrome, soon spread to China, across the world, and even inside the United States. Victims include some of the U.S.'s most talented spies and other American officials, some of whose lives have never been the same. In this video, "The Havana Syndrome" co-authors Oriana Zill de Granados and Michael Rey discuss the phenomenon and the FBI's controversial classification of it as mass hysteria. They delve into the evidence and the ongoing debate over whether the syndrome is a real attack or a case of mass psychogenic illness. For more context and news coverage of the most important stories of our day, click here: https://www.nbcnews.com