title: Dynamics of defensive reactivity in patients with panic disorder and agoraphobia: implications for the etiology of panic disorder.
abstract: BACKGROUND
  The learning perspective of panic disorder distinguishes between acute panic and anxious apprehension as distinct emotional states. Following animal models, these clinical entities reflect different stages of defensive reactivity depending upon the imminence of interoceptive or exteroceptive threat cues. The current study tested this model by investigating the dynamics of defensive reactivity in a large group of patients with panic disorder and agoraphobia (PD/AG).
  
  
  METHODS
  Three hundred forty-five PD/AG patients participated in a standardized behavioral avoidance test (being entrapped in a small, dark chamber for 10 minutes). Defense 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 exposure of the behavioral avoidance test.
  
  
  RESULTS
  Panic disorder and agoraphobia patients differed substantially in their defensive reactivity. While 31.6% of the patients showed strong anxious apprehension during this task (as indexed by increased reports of anxiety, elevated physiological arousal, and startle potentiation), 20.9% of the patients escaped from the test chamber. Active escape was initiated at the peak of the autonomic surge accompanied by an inhibition of the startle response as predicted by the animal model. These physiological responses resembled the pattern observed during the 34 reported panic attacks.
  
  
  CONCLUSIONS
  We found evidence that defensive reactivity in PD/AG patients is dynamically organized ranging from anxious apprehension to panic with increasing proximity of interoceptive threat. These data support the learning perspective of panic disorder.
authors.affiliation: Department of Biological and Clinical Psychology, University of Greifswald, Greifswald, Germany. jan.richter@uni-greifswald.de
authors.forename: Jan
authors.initials: J
authors.lastname: Richter
authors.forename: Alfons O
authors.initials: AO
authors.lastname: Hamm
authors.forename: Christiane A
authors.initials: CA
authors.lastname: Pané-Farré
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Gerlach
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Gloster
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Wittchen
authors.forename: Thomas
authors.initials: T
authors.lastname: Lang
authors.forename: Georg W
authors.initials: GW
authors.lastname: Alpers
authors.forename: Sylvia
authors.initials: S
authors.lastname: Helbig-Lang
authors.forename: Jürgen
authors.initials: J
authors.lastname: Deckert
authors.forename: Thomas
authors.initials: T
authors.lastname: Fydrich
authors.forename: Lydia
authors.initials: L
authors.lastname: Fehm
authors.forename: Andreas
authors.initials: A
authors.lastname: Ströhle
authors.forename: Tilo
authors.initials: T
authors.lastname: Kircher
authors.forename: Volker
authors.initials: V
authors.lastname: Arolt
mesh_terms: D000328:Adult; D000379:Agoraphobia / Q000503:physiopathology* / Q000523:psychology; D000704:Analysis of Variance; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology; D001143:Arousal / Q000502:physiology; D001362:Avoidance Learning / Q000502:physiology*; D003674:Defense Mechanisms; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D016584:Panic Disorder / Q000503:physiopathology* / Q000523:psychology; D010698:Phobic Disorders / Q000503:physiopathology*; D011581:Psychological Tests; D013216:Reflex, Startle / Q000502:physiology