Socially inhibited individuals show heightened DTH response during intensesocial engagement

To determine whether altered cellular immune response might mediate the inc reased health risks associated with social inhibition, we examined delayed type hypersensitivity (DTH) responses in 36 adults under conditions of low and high intensity social engagement. Participants come from a study of psy chological factors in functional bowel disease and fibromyalgia. Under high engagement conditions, socially inhibited individuals showed significantly increased induration in response to intradermal tetanus toroid. Under low engagement conditions, these individuals showed less pronounced DTH respons es that did not differ in magnitude from those of uninhibited individuals. This pattern of results was found using two different measures of social in hibition and was independent of social inhibition's definition as a continu ously distributed trait vs a discrete category. These data are consistent w ith the general hypothesis that social inhibition represents a predispositi on to physiologic hyperresponsiveness that requires an exogenous social tri gger for expression. (C) 1999 Academic Press.