Psychological stress and susceptibility to upper respiratory infections.

The biologic plausibility of a link between psychological states and host resistance is discussed. Although there is substantial evidence for the association between psychological stress and both cellular and humoral immune response, these data do not necessarily suggest increased susceptibility to infectious agents among stressed persons. Epidemiologic and viral-challenge studies suggest that psychological stress is a risk factor for upper respiratory infections with the strongest evidence provided by recent well-controlled, prospective viral-challenge trials. However, there is still little direct evidence for the nature of neuroendocrine, immune, or behavioral pathways through which stress might alter susceptibility.