Defensive reactivity in patients with panic disorder and agoraphobia : from basic research to clinical application Paniksyndrom Angst Panikstörung Agoraphobie defensive Reaktivität Verhaltenstest Furcht panic disorder agoraphobia defensive reactivity behavioral avoidance test fear The learning theory of panic disorder differs between panic attacks and anxious apprehension as distinct emotional states. Acute panic is accompanied by extreme fear experience of strong body symptoms reflecting autonomic surge and flight tendencies. In contrast anxious apprehension is associated with hypervigilance towards bodily sensations and increased distress when subtle somatic symptoms are identified. Following animal models these clinical entities reflect different stages of defensive reactivity depending upon the imminence of interoceptive or exteroceptive threat cues with lowest distance to threat during panic attacks. We tested this model by investigating the dynamics of defensive reactivity in a large group of patients suffering from panic disorder and agoraphobia (PD AG) prior to a multicenter controlled clinical trial. Three hundred forty five patients participated in a standardized behavioral avoidance test (being entrapped in a small dark chamber for 10 minutes). Defensive reactivity was assessed measuring avoidance and escape behavior self reports of anxiety and panic symptoms autonomic arousal (heart rate and skin conductance) and potentiation of the startle reflex before and during the exposure period of the behavioral avoidance test. While 125 patients showed strong anxious apprehension during the task (as indexed by increased reports of anxiety elevated physiological arousal and startle potentiation) 72 patients escaped from the test chamber ...