title: Defensive mobilization in specific phobia: fear specificity, negative affectivity, and diagnostic prominence.
abstract: BACKGROUND
  Understanding of exaggerated responsivity in specific phobia-its physiology and neural mediators-has advanced considerably. However, despite strong phenotypic evidence that prominence of specific phobia relative to co-occurring conditions (i.e., principal versus nonprincipal disorder) is associated with dramatic differences in subjective distress, there is yet no consideration of such comorbidity issues on objective defensive reactivity.
  
  
  METHODS
  A community sample of specific phobia (n = 74 principal; n = 86 nonprincipal) and control (n = 76) participants imagined threatening and neutral events while acoustic startle probes were presented and eyeblinks (orbicularis occuli) recorded. Changes in heart rate, skin conductance level, and facial expressivity were also measured.
  
  
  RESULTS
  Principal specific phobia patients far exceeded control participants in startle reflex and autonomic reactivity during idiographic fear imagery. Distinguishing between single and multiple phobias within principal phobia and comparing these with nonprincipal phobia revealed a continuum of decreasing defensive mobilization: single patients were strongly reactive, multiple patients were intermediate, and nonprincipal patients were attenuated-the inverse of measures of pervasive anxiety and dysphoria (i.e., negative affectivity). Further, as more disorders supplanted specific phobia from principal disorder, overall defensive mobilization was systematically more impaired.
  
  
  CONCLUSIONS
  The exaggerated responsivity characteristic of specific phobia is limited to those patients for whom circumscribed fear is the most impairing condition and coincident with little additional affective psychopathology. As specific phobia is superseded in severity by broad and chronic negative affectivity, defensive reactivity progressively diminishes. Focal fears may still be clinically significant but not reflected in objective defensive mobilization.
authors.affiliation: Center for the Study or Emotion & Attention, University of Florida, Gainesville, 32611, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: McTeague
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lang
authors.forename: Bethany C
authors.initials: BC
authors.lastname: Wangelin
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Laplante
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Bradley
mesh_terms: D000328:Adult; D000339:Affect; D001008:Anxiety Disorders / Q000150:complications / Q000523:psychology; D003674:Defense Mechanisms; D003866:Depressive Disorder / Q000150:complications / Q000523:psychology; D004576:Electromyography / Q000379:methods; D004644:Emotions; D005149:Facial Expression; D005239:Fear / Q000523:psychology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D007092:Imagination; D008297:Male; D010698:Phobic Disorders / Q000150:complications / Q000175:diagnosis* / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D013216:Reflex, Startle