EXPERIMENTAL STRESS AND IMMUNOLOGICAL REACTIVITY - A CLOSER LOOK AT PERCEIVED UNCONTROLLABILITY

Objective: Although stressor uncontrollability has been shown to suppr ess immune responses in animals and for human subjects, the results ha ve been inconsistent. We reanalyzed results of our previous study rega rding stress-related immune deviation in man, to establish whether per ceived uncontrollability of an acute stressor acts as a co-determinant in the observed changes in immunological parameters. Method: Three ty pes of cognitive reactions to an acute interpersonal stressor were ass essed: ''motivation,'' ''uncontrollability,'' and ''guiltiness.'' Stre ss-induced changes in the number of several types of immune cells in p eripheral blood and proliferative responses of lymphocytes to antigens and mitogens were assessed. Results: In comparison with control subje cts and with subjects perceiving high control over the experimental st ress situation, the subject perceiving low control showed a stressor-i nduced decrease in the number of T helper cells. Reversely, subjects p erceiving high control showed an increase in the number of B cells as opposed to the other two groups. The effects of perceived uncontrollab ility could not be accounted for by mood changes, but they were relate d to previously experienced life stress. Conclusions: Perceived uncont rollability of an acute stressor can have immuno-modulating effects ov er and above those of the stressor per se.