Stress, Immunity, and Health in HIV Infection

HIV-infected people encounter a large number of major stressors, which, based on the way they perceive them, may result in different emotional responses. These affective responses may relate to altered levels of certain neuroendocrine substances (e.g., cortisol and catecholamines) that have been shown to have depressive effects on lymphocytes.

These stress responses may also be accompanied by behaviors (e.g., substance use, unprotected sex, and poor medication adherence) that could have negative implications for the health of HIV-infected people. We now summarize the evidence relating depression and health behaviors to immune function and the evidence relating immune alterations to stress-intervening variables (stressor appraisals, coping responses, and social supports) that may influence physical health status.

Depression and Immunity in HIV Infection. Depression and depressed affect are associated with immunosuppression in healthy individuals. Among HIV-infected people, some studies have found that a depressive state was unrelated to changes in CD4 counts or HIV-related symptoms over 6- and 12- month periods, respectively. Other studies examining immunological and health changes over longer periods found interesting but conflicting results.

One found that gay men scoring above the criterion for depression showed a faster rate of decline in CD4 cell counts over a 66-month follow-up period than those scoring below this value. This association was strongest in men who were at the earliest stages of disease. In a separate cohort showing more progressed disease at the time of the depression evaluation, these findings were not evident.

Another study showed that chronically depressed affect (sustained severe depressed mood over a 2-year period) predicted declines in CD4 counts among HIV+ gay men without AIDS as compared to a group of nonchronically depressed men matched on age and CD4 levels. Subsequent work, incorporating more sophisticated statistical procedures and time- dependent covariates (including medication regimen), showed that depression, in combination with elevated stressful life events, does in fact predict a faster rate of disease progression in HIV+ men for up to 9 years.

Depressive symptoms among women with HIV have also been shown to predict accelerated rates of CD4 cell decline and HIV-related mortality over a 7-year period. Resolution of major depression is paralleled by increases in NK cell cytotoxicity among HIV+ women. Depressed affect may be associated with an accelerated decline in CD4 counts and a faster rate of clinical disease progression among HIV-infected men and women.

This association appears stronger when the potential confounding somatic effects of the disease are controlled by either sampling (excluding progressed subjects), questionnaire refinement (excluding somatically based depression items from the test battery), or statistical controls. Beyond studying the influence of depressive symptoms, it is also important to consider the role of anxiety-related symptoms (e.g., tension and rumination) in the quality of life, immune status, and physical health of HIV-infected individuals.