LIFE EVENTS, CARDIOVASCULAR REACTIVITY, AND RISK BEHAVIOR IN ADOLESCENT BOYS

Background. Risk behavior contributes to injuries, one of the most imp ortant sources of morbidity and mortality in adolescents. Although res earch has shown that environmental stress makes adolescents more likel y to engage in risk behavior and to sustain injuries, the magnitude of these associations has been small. Little is known about the role of individual differences in psychobiologic reactivity to stress in moder ating the impact of stressful events. In this study, we examined assoc iations among environmental stressors, cardiovascular reactivity to st ress, and the level of risk behavior in adolescent boys. Methods. Twen ty-four 14- to 16-year-old boys underwent a laboratory protocol design ed to measure responses to psychologically and physically stressful ta sks. Changes in heart rate and mean arterial blood pressure were measu red serially at standard points in the protocol, and levels of positiv e and negative life events and recent risk behavior were measured usin g self-report questionnaires. Results. Neither life events nor cardiov ascular reactivity were independently associated with risk behavior. P ositive life events and mean arterial blood pressure reactivity signif icantly interacted, however, in predicting risk behavior (R(2) increme nt = .25). Boys with high reactivity who reported numerous positive li fe events engaged in markedly less risk behavior than their peers. Con clusion. We conclude that adolescents with exaggerated cardiovascular responses to laboratory stressors are associated with less risk behavi or in a setting of positive life circumstances. This result suggests t hat reactivity may exert protective, rather than harmful, influences i n some environments.