Health psychology in the 21st century: acquired immunodeficiency syndrome as a harbinger of things to come.

An increasing focus on the human immunodeficiency virus (HIV) is important given the role of health psychology in preventing further spread of the epidemic and in maintaining quality of life in the estimated 1,500,000 Americans who are now infected. HIV presents health psychology with challenges reflecting 5 trends in medicine that have broad implications for the future, which extend beyond HIV: (a) the early identification of people who are at risk for disease, (b) the rising expectations for successful behavior change programs, (c) the growing populations of those who are coping with chronic disease, (d) the increasing shift to include community and public health perspectives, and (e) the emerging need to address health problems on a global scale.