All the patients in this article are composites and do not represent individuals.

Before Long Covid, before TikTok Tourette’s, there was Havana Syndrome. Diplomats in Cuba heard strange noises, felt strange vibrations, and developed nonspecific symptoms. Nonspecific is a term of art: it means symptoms that could arise from any number of causes. Symptom is also a term of art: it’s not the same as a sign. A symptom is something you feel, something internal that you tell people about. A sign is what somebody else can see when they examine you.