As to the origin of the unconscious need for punishment, there can be, I think, no doubt. It behaves like a part of the conscience, like the prolongation of conscience into the unconscious; and it must have the same origin as conscience, that is to say it will correspond to a piece of aggressiveness which has been internalized and taken over by the super-ego. If only the words were less incongruous, we should be justified, for all practical purposes, in calling it "an unconscious sense of guilt." ... People in whom this unconscious sense of guilt is dominant, distinguish themselves under analytic treatment by exhibiting what is so unwelcome from the point of view of prognosis-a negative therapeutic reaction.
The need for punishment is an instinctual manifestation on the part of the ego, which has become masochistic under the influence of the sadistic super-ego, i.e. which has brought a part of the instinct of destruction at work within itself into the service of an erotic attachment to the super-ego.