Psychophysiological correlates of anxiety: a single-case study.

We examined the relationship between self-reported anxiety and physiological measures (blood pressure and heart rate) in a series of exposures to a feared situation of a single participant with panic disorder with agoraphobia. During each exposure, readings of heart rate, systolic blood pressure and diastolic blood pressure were taken every 20 s. Over 30 exposures, we found a near-linear relationship between anxiety and the three physiological measures. Implications of this result for usefulness of physiological measures in anxiety research and in the clinical treatment of anxiety disorders are discussed.