Depression, distress, and immunity: Risk factors for infectious disease

Immunological findings from studies of depressed populations are reviewed, and selected methodological issues are addressed related to the area of human behavioral immunology. Of particular interest here is the role of natural killer (NK) cell activity in health risk, and the possible effects of negative mood or distress as a modifier of natural immunity in normal populations. Results from a longitudinal study of community volunteers suggested that individuals who were currently healthy, but who exhibited a persistently low pattern of basal natural immunity and who perceived their environment as more stressful, were at risk for development of infectious disease over follow‐up. The results also suggested that plasma beta endorphin might be playing some moderating role in affecting the observed pattern of NK activity in the sample.