ohnson’s Behavioral System Model is a model of nursing care that advocates the fostering of efficient and effective behavioral functioning in the patient to prevent illness. The patient is identified as a behavioral system composed of seven behavioral subsystems: affiliative, dependency, ingestive, eliminative, sexual, aggressive, and achievement. The three functional requirements for each subsystem include protection from noxious influences, provision for a nurturing environment, and stimulation for growth. An imbalance in any of the behavioral subsystems results in disequilibrium. It is nursing’s role to assist the client to return to a state of equilibrium.