Judging by any standards of pathology, hysteria must be the most extraordinary disease ever encountered by medicine. Countless generations have found in it a source of inspiration for investigation, research and discussion for the furtherance of medical science. The story of their results does not tell altogether of success or even satisfaction. On the contrary, hysteria has proved to be a source not only of inspiration, but of frustration, baffling uncertainty and downright exasperation. Furthermore, it has maintained a state of dissatisfaction and discord more persistently and for a greater length of time than any other feature of medical pathology. It cannot be surprising therefore, that amongst the foremost characteristics of hysteria is a readiness to cause suspicion in the minds of those who meet it. On many occasions throughout its history the question has arisen whether in fact hysteria should be recognised as a unit of illness. In the second half of the twentieth century the doubts and uncertainties reached a peak that motivated some medical authorities to heed the extent of their misgivings and take official action. Thereafter, in many classifications the name ‘hysteria’ ceased to appear as that of an illness in its own right.