The biopsychosocial model states that the workings of the body, mind, and environment all affect each other. According to this model, none of these factors in isolation is sufficient to lead definitively to health or illness—it is the deep interrelation of all three components that leads to a given outcome.
Health promotion must address all three factors, as a growing body of empirical literature suggests that it is the combination of health status, perceptions of health, and sociocultural barriers to accessing health care that influence the likelihood of a patient engaging in health-promoting behaviors, like taking medication, proper diet or nutrition, and engaging in physical activity.
Source: Boundless. “The Biopsychosocial Model of Health and Illness.” Boundless Psychology. Boundless, 10 Sep. 2016. Retrieved 12 Sep. 2016 from https://www.boundless.com/psychology/textbooks/boundless-psychology-textbook/stress-and-health-psychology-17/introduction-to-health-psychology-85/the-biopsychosocial-model-of-health-and-illness-326-12861/