Étienne Eugène Azam (1822–1899) was a French surgeon from Bordeaux who is chiefly remembered for his work in psychology, particularly a case involving a female patient he named "Félida X" who seemed to have "alternating personalities", or what Azam referred to as doublement de la vie.
Over a number of years Azam studied Félida's psychological profile and from his research published three reports. He described Félida as a hysterical patient who had a serious and sad (normal) state, along with a merry and generous state. He analyzed these two states as two distinct, separate personalities that seemed to be unaware of the other.
The case of Félida X is one of the earliest documented descriptions of what would later be called a multiple personality disorder. At the time, this situation garnered interest in the medical community, and created several puzzling questions in regards to the concept of Self, as well as to the definition of personal ego. Additionally from a quasi-religious context, the concept of multiple personalities was contrary to the paranormal belief system of Spiritualism (religious movement), which had a large following in the 19th century.