Biopsychosocial models are a class of trans-disciplinary models which look at the interconnection between biology, psychology, and socio-environmental factors. These models specifically examine how these aspects play a role in topics ranging from human development, to health and disease, to information processing, and to conflict.
According to Derick T. Wade and Peter W. Halligan, as of 2017, it is generally accepted that "illness and health are the result of an interaction between biological, psychological, and social factors."
The term was first used to describe a model advocated by George L. Engel in 1977. It now also refers to any model which takes a similar approach, and has become an alternative to the biomedical and/or psychological dominance of many health care systems.
Gender can be thought of as biopsychosocial, as it is a complex matter formed from social, psychological, and biological aspects.
George L. Engel and Jon Romano of the University of Rochester in 1977, are widely credited with being the first to propose a biopsychosocial model. However, it had been proposed 100 years earlier and by others. Engel struggled with the then-prevailing biomedical approach to medicine as he strove for a more holistic approach by recognizing that each patient has their own thoughts, feelings, and history. In developing his model, Engel framed it for both illnesses and psychological problems.
Engel's biopsychosocial model reflects the development of illness through the complex interaction of biological factors (genetic, biochemical, etc.), psychological factors (mood, personality, behaviour, etc.) and social factors (cultural, familial, socioeconomic, medical, etc.). For example, a person may have a genetic predisposition for depression, but they must have social factors such as extreme stress at work and family life and psychological factors such as a perfectionistic tendencies which all trigger this genetic code for depression. A person may have a genetic predisposition for a disease, but social and cognitive factors must trigger the illness.