High Quality Content by WIKIPEDIA articles! Obsession, also known as spirit obsession, is a technical term within the Spiritist belief and practice defined by the author Allan Kardec as the interference of a subjugating spirit with a weaker spirit (cf. Latin obsidere, "besiege"). Although the term most commonly refers to the negative influence of the spirit of an evil deceased person on the mind or spirit of a living person, obsession can occur in either direction.