“Who’s Afraid of Virginia Woolf?” by Edward Albee (post 4): Why was the play’s original title “The Exorcism” (which became the title of its third act)?

I haven’t begun to read it yet, but I understand that the play’s climax is the revelation that George and Martha’s adult son, whom they have mentioned throughout the play, turns out to have been imaginary. And since the play is secular, with no religious rites, I wonder why their finally giving up belief in their imaginary son is called an “exorcism.”

The title of the play or even the title of the third act is too prominent a use of the word “exorcism” if the author really felt it was nothing more than a metaphor for dispelling illusions. After all, there are two traditional uses for exorcism: 1. expelling demons, and 2. expelling alternate personalities whom you mistake for demons, as illustrated in the following abstract of a journal article:

Exorcism rituals: effects on multiple personality disorder patients

Author: Fraser, George A.

Journal: Dissociation, Vol. 6, No. 4, p. 239-244, December 1993

Abstract: The persistent belief that spiritual entities can "possess" mere mortals has resulted in various rituals and ceremonies to expel these unwanted intruders. This act has been known as exorcism and is sanctioned even today by many traditional religions. This is pertinent to the field of multiple personality disorder because often the presentation or influence of dissociated ego states fulfills the conceptualized criteria of those who believe in the reality of spirit possession. 

        This paper addresses the issues of a group of multiple personality patients, treated by the author, who previously had been exposed to exorcism rites. Seven patients were interviewed about the effects of these ceremonies on their ego functioning. The results varied from mildly negative to severely disruptive; they included numbing of religious fervor, struggling physically with the exorcist, attempting suicide, creating demon alters, and believing that an alter had been banished and was perpetually suffering in hell.