Neurosis and Human Growth: The Struggle Toward Self-Realization is the magnum opus of German-American psychoanalyst Karen Horney. In it she outlines her theory of neurosis. In Horney's view, the key difference between neurosis and healthy growth is the difference between compulsive actions fueled by anxiety and spontaneous actions fueled by one's full range of emotions. If a person grows up able to maintain his or her spontaneity, that person grows up by a process which Horney calls self-realization. Horney describes self-realization as the development of a person's given potentialities, and compares it with the process of an acorn growing, given fertile soil, into a tree.