The relationship between anxiety sensitivity and fear-potentiated startle

Includes bibliographical references (pages [88]-102)The present study evaluated the effects of fear/anticipatory anxiety on the acoustic startle reflex of participants with differing levels of anxiety sensitivity. The eyeblink component of the startle reflex, elicited by an abrupt auditory stimulus (i.e., noise burst), was measured using a paradigm involving the anticipation of electric shocks (i.e., fear-potentiated startle). Fifty-three males and forty-seven females were divided into one of three groups based on their scores on the Anxiety Sensitivity Index (ASI). The experiment consisted of four conditions: adaptation, threat (i.e., threat of electric shock), safe (i.e., absence of threat), and recovery. Participants were administered the state scale of the State-Trait Anxiety Inventory (STAI-S) at the end of each condition to measure their level of state anxiety. Males generally manifested lower startle amplitudes than females during all four conditions. There were no significant differences between the three AS groups in the amplitude of the startle response during any condition; however, there was a significant difference in the pattern of eyeblink amplitude between the AS groups for females. Low AS females demonstrated higher startle amplitudes during the Threat condition than during the Adaptation and Recovery conditions. Middle AS females demonstrated higher startle amplitudes during the Adaptation condition compared to the Recovery condition. There was no difference in startle responding across conditions for females in the High AS group. The results revealed a significant interaction effect for gender, AS group, and conditions on a subjective measure of anxiety, the STAI-S. High AS females across conditions reported higher state anxiety than Low and Middle AS females, while High AS males reported higher state anxiety than Low and Middle AS males during the Adaptation and Threat conditions relative to the Safe and Recovery conditions. The results of the experiment provide a contribution to the study of the AS construct using the fear-potentiated startle paradigm. Possible explanations for lack of group differences in startle responding and suggestions for future research are discussed.Ph.D. (Doctor of Philosophy