Stress, adaptation, and immunity: studies in humans.

The notion that some combination of excessive "stress" and inadequate coping may increase susceptibility to illness has long been part of our conventional wisdom. Yet, until recently, there have been few data to support this contention. During the past decade, the relationship between stress, adaptation, and human immunity has come under closer scrutiny. There is now considerable evidence that certain types of experimental and naturally-occurring stress are associated with alterations of human cellular immune function. Furthermore, these observed changes generally are immunosuppressive. However, the mediating mechanisms underlying this relationship remain poorly understood. Critical factors in the stress-adaptation-immunity relationship are: the duration and proximity of the stressor, the adaptive capacity of the individual, and the differential effects of certain stressors on immunologic components.