The biopsychosocial model is a broad view that attributes disease outcome to the intricate, variable interaction of biological factors (genetic, biochemical, etc), psychological factors (mood, personality, behavior, etc.), and social factors (cultural, familial, socioeconomic, medical, etc.). The biopsychosocial model counters the biomedical model, which attributes disease to roughly only biological factors, such as viruses, genes, or somatic abnormalities. The biopsychosocial model applies to disciplines ranging from medicine to psychology to sociology; its novelty, acceptance, and prevalence vary across disciplines and across cultures.
In a 1977 article in Science, psychiatrist George L. Engel called for "the need for a new medical model." Engel later discussed a hypothetical patient, a 55-year-old man sustaining a second heart attack six months after his first. The patient's personality frames his own interpretation of his chest pain and explains his denial of it until his employer grants him permission to seek help. Although his heart attack can be attributed to an arterial blood clot, the wider personal perspective helps to understand that different outcomes may be possible depending on how the person responds to his condition. Subsequently, the patient in the emergency room develops a cardiac arrest as a result of an incompetent arterial puncture. We can analyse this event in wider terms than just a cardiac arrhythmia. It sees the event as due to inadequate training and supervision of junior staff in an emergency room. Thus while "no single definitive, irreducible model has been published," Engel's example offers a starting point for broader understanding of clinical practice.
Some thinkers see the model in terms of causation. Its biological component seeks to understand how the cause of the illness stems from the functioning of the individual's body. Its psychological component looks for potential psychological causes for a health problem such as lack of self-control, emotional turmoil, and negative thinking. Its social part investigates how different social factors such as socioeconomic status, culture, technology, and religion can influence health. However, a closer reading of Engel's seminal paper in the American Journal of Psychiatry (1980) embeds the model far more closely into patient care. It is not just about causation but also about how any clinical condition (medical, surgical, or psychiatric) can be seen narrowly as just biological or more widely as a condition with psychological and social components, which will impinge on a patient's understanding of her condition and will affect the clinical course of that condition.