Anxiety
The philosopher Søren Kierkegaard, in "The Concept of Anxiety" (1844), described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the self-conscious exercise of responsibility and choosing. In "Art and Artist" (1932), the psychologist Otto Rank wrote that the psychological trauma of birth was the pre-eminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of – and desire for – separation, individuation, and differentiation.
Hervey M. Cleckley
Hervey Milton Cleckley (1903 – January 28, 1984) was an American psychiatrist and pioneer in the field of psychopathy. His book, "The Mask of Sanity," originally published in 1941 and revised in new editions until the 1980s, provided the most influential clinical description of psychopathy in the twentieth century. The term "mask of sanity" derived from Cleckley's belief that a psychopath can appear normal and even engaging, but that the "mask" conceals a mental disorder.
By the time of his death, Cleckley was better remembered for a vivid case study of a female patient, published as a book in 1956 and turned into a movie, "The Three Faces of Eve", in 1957. His report of the case (re)popularized in America the controversial diagnosis of multiple personality disorder. The concept of psychopathy continues to be influential through forming parts of the diagnosis of antisocial personality disorder, the Psychopathy Checklist, and public perception.