Female hysteria was once a common diagnosis for women. It is actually one of the oldest medical conditions mentioned in historical medical literature, although it is no longer recognized as a medical disorder. So-called cases of female hysteria have been documented as far back as 1900 B.C. in ancient Egypt. The ancient Greeks believed that the uterus was a living creature that wanders throughout a woman's body, blocking passages, obstructing breathing, and causing disease. The concept of a wandering womb was later viewed as the source of the term hysteria, which was derived from the Greek word for uterus "hystera." Another cause was thought to be the retention of a supposed female semen, thought to have mingled with male semen during intercourse. The female semen was believed to have been stored in the womb. Hysteria was referred to as "the widow's disease", because the female semen was believed to turn venomous if not released through regular sexual climax or intercourse. During the 18th and 19th centuries, female hysteria was a catch-all diagnosis used whenever a woman suffered from symptoms that a doctor couldn't explain. It was reportedly fairly common for doctors that diagnosed female patients with hysteria to "treat" them by either manually or mechanically stimulating them to orgasm (termed "hysterical paroxysm") well into the 20th century. Some historians theorize that the vibrator was invented to more quickly expedite hysterical paroxysm treatments. By the mid-20th century, diagnosis of female hysteria had largely declined, and in 1956, it was removed from the American Psychiatric Association's list of recognized psychiatric conditions. By that time, the field of psychiatry had grown significantly, and many of the symptoms that were formally attributed to female hysteria were recognized as symptoms of mental illnesses that had previously been undiscovered such as schizophrenia, borderline personality disorder, conversion disorder, and anxiety attacks.