Elevation of plasma beta-endorphin levels of shy elderly in response to novel laboratory experiences

Heightened psychophysiological reactivity to the novel or unfamiliar is a leading characteristic of shy or behaviorally inhibited individuals. To assess one aspect of the physiological stress response in shyness, the authors compared the morning plasma beta-endorphin levels of 15 extremely shy, healthy elderly individuals with beta-endorphin levels of 15 extremely outgoing persons on three pairs of 2 successive days. The primary finding was that shy participants exhibited significantly higher levels of beta-endorphin on the 1st days of each pair of days, compared with the 2nd days in the laboratory. No main effect for shyness or interaction between shyness and diet on endorphin levels was found. The findings are consistent with a peripheral opioid hyperreactivity to novelty in shy elderly persons. Shyness may constitute a risk factor for panic disorder in younger adults and for nasal allergies and certain cancers in older adults. Experimental design and interpretation of future studies of shy individuals' stress responses may need to consider novelty versus familiarity of the procedures and setting.