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.
Theodor Ziehen
Ziehen published nearly 450 works on psychology, neurology, anatomy, et al. He was author of a textbook titled "Die Geisteskrankheiten des Kindesalters" (Mental Diseases of Childhood), a book that reportedly was the first systematic work on child psychiatry in Germany. He also penned "Psychiatrie für Ärzte und Studirende", a textbook that was published in four editions between 1894 and 1911. In his writings, Ziehen is credited with introducing the terms "affective psychosis" and "psychopathic constitution".