Acute Physiological Arousal in Panic Disorder

Although an abrupt onset of physiological symptoms is one of the hallmarks of panic attacks, it is clearly not a defining feature of the disorder. Individuals with panic disorder are not more autonomically hyperactive to standard laboratory stressors than nonpanickers (Taylor, 2000). Furthermore, even though 24-hour ambulatory heart rate monitoring of panic patients indicates that most panic attacks involve a distinct eleva- tion in heart rate, a significant minority of self-reported attacks (i.e., 40%) are not associated with actual increase in heart rate or other physiological responses and most episodes of physiological hyperarousal (i.e., tachycardia) occur without self-reported panic episodes (e.g., Barsky, Cleary, Sarnie, & Rushkin, 1994; Lint, Taylor, Fried-Behar, & Kenardy, 1995; Taylor et al., 1986). Moreover, individuals with panic disorder do not have more cardiac arrhythmias in a 24-hour period than nonpanic patients investigated for heart palpitations (Barsky et al., 1994). As discussed below, it is not the presence of physiological symptoms that is critical in the pathogenesis of panic but rather how these symptoms are interpreted.