During the past several decades many investigators have devoted their efforts to determining whether psychosocial factors, such as stress or depression, are associated with the onset, course, or outcome of physical illness. Considerable evidence suggests that both stressful life events and depressive disorders are associated with increased morbidity and mortality.1 A large body of research in the last few years has considered the possibility that immunologic alterations may be associated with depressive disorders and depressive symptoms accompanying stressful life events. The related immunologic alterations have been viewed as a link between depression and stress and increased risk for immune-related disease states, such as cancer, autoimmune disorders, and infections, including human immunodeficiency virus (HIV).
However, there has been a lack of substantial evidence supporting the association between depression or stress and increased morbidity or mortality due to disorders involving the immune system. In a series of articles recently published in