During the Middle Ages, victims of the imaginary illness "dancing manias" lost all inhibitions and whirled wildly through the streets. During the twentieth century, modern Americans fell prey to the misdeeds of a "phantom anesthetist" who entered homes and gassed the inhabitants. According to your text, how is mass psychogenic illness most different today from how it was in the Middle Ages

Today, mass psychogenic illness normally develops through the fear of a viral outbreak and other biological factors.

Explanation:

Unlike the past, today mass psychogenic illness does not develop through customs or ritualized behaviors. The "Dancing Manias" of the Middle Ages was believed to have caused due to religious beliefs like a curse sent by a godly entity or a punishment from the God.

However, modern mass psychogenic illness usually develops through the fear of a viral outbreak or other biological factors. Mass hysteria of being contracted with a certain disease or illness is mostly believed by the victims. They do not trace their illness to any supernatural elements but rather believes it as something man-made or a viral outbreak.