The Psychodynamic Model
Sigmund Freud was wrong about most things, but that does not stop him from being the most important psychiatrist of all time. His study of the subconscious helped debunk the quasi-rationalistic idea that what we are consciously aware of is all there is to the psyche.
These days practically all psychologists and psychiatrists accept the notion that there are parts of our psyche we are not consciously aware of, and that what is hidden there does influence our "ego" (the conscious side of our mind.)
Indeed, the concept of the unconscious is necessary if you want to make sense of the life journeys of many trans people, as social and cultural oppression makes they hide their transgender side deep down in their own minds, to the point where they can no longer recognize it for what it is. Crossdreaming and gender dysphoria are ways for the mind to bring that side up in the light of day again.
Unfortunately, Freud's thinking did not really help queer and trans people in the long run. His psychoanalysis (which is part of the broader psychodynamic tradition) became instead a tool for oppression.