For instance, he might notice the slight rapping at his apartment door in the late hours of the night. Or that every morning there seems to be a new scratch across the iron keyhole that rests just below the door handle. A more precarious fellow might assume that others of malignant intent are reducing a way in.
To the same degree, he may also take note of each window and egress when entering any room here forth. His eyes catching glimpses of familiar pupils as they peer through smudged panes. Something has gone arwy, the very walls collude against me, he may think with a profound dread.
In his mind he may structure all of these happenings into a portent of terror. He may lash out at himself or others, should he feel cornered and caged as an animal. It is all a slight of the mind, his circle assures him, now have you taken your medicine today?