In this paper I describe some of my studies of monkeys in an effort to illuminate our understanding of anxiety and depression, with particular emphasis on two topics, the processes of adaptation and the functional transition from the biological to the psychological level of organization. From use of the experimental paradigm of mother loss, data are presented to document three main conclusions. First, the infant reacts to this stress adaptively, using both inborn and acquired coping mechanisms. Second, in the course of development the infant's reactions become psychobiological rather than purely biological as the inborn biological response systems of flight-fight and conservation-withdrawal are elaborated cognitively, motivationally, and affectively into the organismic states of anxiety and depression respectively. Third, depression is basically a state of helplessness.

Among the principal contributions of psychoanalysis to human understanding, in demonstrating that symptoms have meanings