Please notice that Webster 1913's definition of hysteria was written in...1913. Today, we would call it a manifestation of post-traumatic stress disorder.

In 1914, World War I broke out, and all of a sudden thousands of cases of Hysteria suddenly appeared among men (although it was usually called shell-shock).

Through the pioneering work of Sigmund Freud and his new technique of psychoanalysis, it was discovered that Hysteria was almost always caused by repressed trauma -- the subject had experienced something too horrible for the mind to cope with (such as physical or sexual abuse, or a soldier's best buddy's guts suddenly splattered all over), and the mind repressed it, causing mental feedback loops that resulted in the symptoms of bizarre behavior.

Hysteria patients made up the largest contingent of mental hospital residents during the Victorian Era. Whenever you look back at that era and are tempted to long for its seemingly genteel lifestyle, remember the minds that this repressive society destroyed.