Psychosis is when a person’s thoughts or how they perceive the world are abnormal in so much as the person may have difficulty understanding what is real and what is not. Psychosis is extremely rare, experienced usually by people with schizophrenia. Most people don’t experience psychosis (or anything like it) in their lifetime.

Putting these two together and we get what is more commonly referred to as mass psychogenic illness (MPI) or, in pop psychology terms, mass hysteria or mass delusion. These are the terms that have some research basis.