Sigmund Freud, the founder of the psychodynamic approach, is one of the most famous psychologists in history. The psychodynamic approach includes "all the theories in psychology that see human functioning based upon the interaction of drives and forces within the person, particular unconscious between the different structures of the personality" (McLeod, 2007)
For example, "according to interpersonal theory a depressed person's negative interpersonal behaviors cause other people to reject them. In an escalating cycle, depressed people, who desperately want reassurance from others, start to make an increasing number of requests for reassurance, and the other people (to whom those requests are made) start to negatively evaluate, avoid, and reject the depressed people (or become depressed themselves)" (Nemade, Reiss, & Dombeck, 2007)