Distinct psychophysiological reactivity to predictable and unpredictable threat of shock in anxiety pathologies

Authors

• G Alvarez
• M Ernst
• C Grillon

Abstract

Understanding variation in reactivity to threat is crucial to discerning the mechanisms underlying differential patterns of anxious thoughts and behavior. Characterizing phenotypes of these different behaviors is essential to improving the understanding and classification of distinct anxiety disorders. This study sought to distinguish aversive reactivity to predictable and unpredictable threat in control and anxious patients. 72 control and 71 non-medicated anxiety patients participated in the study. Patients were diagnosed with generalized anxiety disorder (GAD) and/or social anxiety disorder (SAD) and 24 patients had a history of panic attacks (PA). Startle magnitude was used to assess aversive reactivity during three different experimental conditions. Participants experienced a predictable condition where shocks were signaled by a cue, an unpredictable condition where shocks were not paired with a cue, and a no shock neutral condition. Broadly, patients with PA history displayed hypersensitivity to the unpredictable threat. SAD patients showed greater sensitivity to predictable threat while GAD patients displayed exaggerated baseline startle reactivity, probably reflecting contextual anxiety to the threatening environment. The results identified three distinct psychophysiological correlates of clinical anxiety. First, PAs were associated with hypersensitivity to unpredictable threat which supports previous results in panic and posttraumatic stress disorder. This overlap suggests that this hypersensitivity may be a transdiagnostic phenotype. Second, hypersensitivity to predictable threat is specific to patients with SAD. Finally, exaggerated reactivity during baseline may reflect a hypersensitivity to distal threat in patients with GAD. These results have clinical implications for enhancing the understanding of pathophysiology in anxiety disorders.

Scientific Focus Area: Social and Behavioral Sciences

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