When we think of psychohistory, we usually think of using psychoanalysis to investigate the psychology of individual humans who are of historical importance, such as Hitler or Gandhi. And when we think of Freudian psychology, we usually think of the human psyche as fixed. Humans have drives, their minds are divided into conscious and unconscious as well as into ego, id, and superego.
Daniel Klenbort (Sat,) studied this question.