If you view what happened to the diplomats in Havana as an “attack,” you must look for something capable of producing such an assault. It would have to emit a sound that varied widely from listener to listener. It would have to strike only people who worked at the embassy. It would have to assail them wherever they happened to be, whether in their homes or staying at a hotel. It would have to produce a wide range of symptoms that seemed to bear no relation to one another. And it would have to start off small, with one or two victims, before spreading rapidly to everyone in the group.
As it happens, there is and always has been one mechanism that produces precisely this effect in humans. Today it’s referred to in the medical literature as conversion disorder—that is, the conversion of stress and fear into actual physical illness. But most people know it by an older, creakier term: mass hysteria. […]