A review of the principle of constancy, as it appeared in Freud's writings, shows that it was inspired by his clinical observations,

first with Breuer in the field of cathartic therapy and then through experiences in the early usage of psychoanalysis. The recognition that memories repressed in the unconscious created increasing tension, and that this was relieved with dischargelike phenomena when the unconscious was made conscious, was the basis for his claim to originality in this area.