Havana syndrome describes a series of bothersome and sometimes debilitating symptoms that first were described in the staff of the U.S. Embassy in Havana, Cuba, in 2016. The condition was initially dismissed as mass hysteria or a reaction caused by stress, but it has been suggested to be caused by ultrasonic or microwave energy used as a weapon. Symptoms are like those of a mild head injury such as headache, nausea, dizziness, confusion, and difficulty concentrating, among other symptoms. These symptoms have mostly been reported by diplomats, intelligence officers, military personnel, and others deployed on foreign soil.
Owens, Brian. "Havana Syndrome Attacks Leave Baffling Symptoms." WebMD.com. June 11, 2021. <https://www.webmd.com/a-to-z-guides/news/20210611/havana-syndrome-attacks-leave-baffling-symptoms>.