Publication of Hildegard Peplau's book Interpersonal Relations in Nursing (1952) heralded the introduction of the first systematic theoretical framework for psychiatric nursing and focused on the nurse-client relationship. Her theory has been described as drawing from developmental (Blake, 1980) interpersonal (Peplau, 1952) and learning (Lego, 1980) theories. Peplau (1952) has defined nursing as, "a significant, therapeutic, interpersonal process that aims to promote a patient's health in the direction of creative, constructive, productive, personal, and community living" (page 16).
Peplau considered the relationship between nurse and client the key to the nursing process (Peplau, 1962; 1965). She conceptualized the nurse-client relationship as developing through phases: orientation, identification, exploitation, and resolution. The nurse and client have changing goals and roles as they pass through each phase. Peplau (1952) described the phases as "overlapping" and "interlocking" (page 17). For example, the nurse and client may return to an earlier phase. After initial issues have been resolved during exploitation they may return to problem identification to identify new issues to work on. Within this theory, awareness of the current stage of the-relationship is essential for the nurse to plan appropriate interventions.