Continuing on the Dr. Mabuse riff from yesterday, I searched the internet for a specific phobia that dealt with the fear of being possessed, of losing self-control or of insanity, but was unable to find one. That seems very strange to me. Of all fears, I think fear of losing one's mind ought to be in the list! But apparently, that fear is so generalized that it doesn't. Rather, it falls under the umbrella term "depersonalization." Depersonalization is the state of being divorced from your own self--that your body and sensations seem to be apart from your mind, and everything seems dreamy.
Still, what I'm after is not this--which is yet another example of loss of free will--but of the fear of it, the anxiety that it may happen to me, whether or not it already has.
Lear's line, "O, let me not be mad, not mad, sweet heaven/
Keep me in temper: I would not be mad!" (1:5) seems to get right at what I am trying to describe. A fear of mental dissolution, of loss of will, of being possessed by a demonic force that subverts the will.
This also could be an anxiety response to a conflict between conscious and unconscious motives. Perhaps when the conscious mind becomes aware of the intrusion of an unconscious desire or motive, consciousness regards this as a foreign assault and reacts with fear: the emotion of self-preservation.