Complex sentence: Narcissism was discussed in the writings of Sigmund Freud, and psychopathy as a clinical diagnosis was addressed in the early writings of Hervey Cleckley in 1941 with the publication of The Mask of Sanity.
Split into simpler sentences: Narcissism was discussed in the writings of Sigmund Freud. Psychopathy as a clinical diagnosis was addressed in the early writings of Hervey Cleckley in 1941 with the publication of The Mask of Sanity.