Greta Thunberg's critics say the climate activist is unstable, hysterical and mentally ill. That's because she challenges the view that the world is theirs to conquer.
Multiple sclerosis and endometriosis in women both used to be diagnosed as hysteria. The same could be happening with 'Havana syndrome.'
Sociologists know what conditions make it more likely a mass delusion will take hold and spread through a group – whether adherence to a fashion fad or belief in a doomsday cult.
Random clown sightings don't make everyone laugh. A psychologist who has studied creepiness explains why clowns are especially adept at making us squirm.