Depth Psychology is a collective term for all psychological and psychotherapeutic approaches to observation and healing that attach great importance to unconscious mental processes.
One of the most important concepts of depth psychology schools is the assumption of unconscious motivational processes for the purpose of conflict and self-regulation, such as the mechanism of repression and other so-called defense mechanisms. The concept of transference also usually plays a role: A transference would be when someone unconsciously directs expectations, desires, fears, or ideas that have formed in earlier important relationships to the behaviour or characteristics of other people. These earlier experiences now form a kind of template that is revived when the relationship pattern has a structure similar to that of the original reference person. For example, the partner activates unconscious memories of how one experienced one's mother or the boss triggers a reaction that one showed to the father.
The terms persona and shadow play an important role especially in C.G. Jung: While the persona means the self-image that one likes to project outward as a self-ideal, the shadow is, so to speak, the antithesis to it. It is those motivations, feelings and behaviours that do not correspond to one's own values and positive self-image. Since the ego-consciousness mostly reluctantly deals with these own dark sides, they are pushed into the unconscious and the person becomes unaware of their existence. Therefore the shadow is unconsciously acted out / projected in relationships and mirrored by the social environment.