All mental illnesses are defenses. More precisely, they are ways of withdrawing from perceived threats. In psychosis, the threat is external in nature. The subject withdraws from that threat denying it. And he denies it by scrambling the information that he has at his disposal about the external world. Hence his hallucinations (scrambling of sensory information) and his delusions (scrambling of post-sensory information).

 

In neurosis, the threat in question is internal in nature. It is an impulse that, if acted upon, would jeopardize the subject’s well-being. The subject withdraws from that threat by denying. And he denies it by repressing it -- by keeping it outside of consciousness.

 

This act of repression leaves a blind-spot in the subject’s awareness of internal reality; that blind-spot is filled in with tendentious ...https://www.freudinstitute.com/single-post/2018/09/06/Mental-Illness-as-Withdrawal-What-do-You-Perceive-as-a-Threat