The biopsychosocial model: its future for the internist

The need to broaden explicitly the biopsychosocial model to include the human environmental context is described. Lessons learned from past advocacy of a broad model of the human patient and his illnesses should guide us in a basic further extension of this fundamental frame of reference. Development of the biopsychosocial model of patient care as we now have it may well be the principal intellectual achievement of medicine in the last 30 years. The contributions of George Engel and his colleagues are gratefully acknowledge.