Thomas W. McDade1
Life events research represents a major behavioral science paradigm for investigating the relationship between psychosocial stress and health, and has consistently reported significant - though relatively small - correlations with multiple physical and psychological health outcomes (Johnson 1986). Complementing the life events paradigm is a parallel emphasis on the role of social support in mitigating stress, where low social support has been associated with a two- to three-fold increased risk of death, an effect that is comparable to other health risk factors, including smoking, obesity, and physical activity (House et al. 1988).
Psychoneuroimmunology (PNI) has employed a number of enumerative and functional measures of immunity in an attempt to quantify the physiological effects of psychosocial stress and social relationships in humans (Schleifer et al. 1986, Glaser and Kiecolt-Glaser 1994, Uchino et al. 1996). Psychosocial stress has been significantly associated with decreased numbers of T, B, and NK cells, suppressed lymphocyte proliferation and cytotoxic activity, lower levels of secretory IgA and IgM, as well as elevated levels of herpesvirus antibodies (indicating suppressed cell-mediated immune function) (Herbert and Cohen 1993).
Some of the earliest PNI work investigated changes in immune function surrounding bereavement, and found consistent impairments in immune function following the loss of a loved one (Irwin et al. 1987). Immune suppression has also been associated with other negative life events, including divorce (Kiecolt-Glaser et al. 1994), caring for a loved one with Alzheimer’s disease (Kiecolt-Glaser et al. 1996), natural disasters (Ironson et al. 1997, Solomon et al. 1997), and medical school exams (Glaser et al. 1985, Glaser et al. 1994). A number of these studies also show stress-buffering effects of social support.
Psychoneuroimmunology has been critical in demonstrating the relevance of psychosocial experience to human immunity, but a shortcoming of current research is the fact that the vast majority of studies include only opportunistic,