Widdershins by Oliver Onions, Fiction, Horror, Fantasy, Classics

At first blush, Widdershins a conventional haunted house story involving an unsuccessful writer, who moves into an empty house in hope that isolation will help his failing creativity. His sensitivity and imagination are enhanced by his seclusion, but his art, his only friend and his sanity are all destroyed in the process. . . .
The story can be read as narrating the gradual possession of the protagonist by a mysterious and possessive feminine spirit, or as a realistic description of a psychotic outbreak culminating in catatonia and murder, told from the psychotic subject's point of view. The precise description of the slow disintegration of the protagonist's mind is terrifying in either case.