title: Panic disorder and agoraphobia: A direct comparison of their multivariate comorbidity patterns.
abstract: BACKGROUND
  Scientific debate has long surrounded whether agoraphobia is a severe consequence of panic disorder or a frequently comorbid diagnosis. Multivariate comorbidity investigations typically treat these diagnoses as fungible in structural models, assuming both are manifestations of the fear-subfactor in the internalizing-externalizing model. No studies have directly compared these disorders' multivariate associations, which could clarify their conceptualization in classification and comorbidity research.
  
  
  METHODS
  In a nationally representative sample (N=43,093), we examined the multivariate comorbidity of panic disorder (1) without agoraphobia, (2) with agoraphobia, and (3) regardless of agoraphobia; and (4) agoraphobia without panic. We conducted exploratory and confirmatory factor analyses of these and 10 other lifetime DSM-IV diagnoses in a nationally representative sample (N=43,093).
  
  
  RESULTS
  Differing bivariate and multivariate relations were found. Panic disorder without agoraphobia was largely a distress disorder, related to emotional disorders. Agoraphobia without panic was largely a fear disorder, related to phobias. When considered jointly, concomitant agoraphobia and panic was a fear disorder, and when panic was assessed without regard to agoraphobia (some individuals had agoraphobia while others did not) it was a mixed distress and fear disorder.
  
  
  CONCLUSIONS
  Diagnoses were obtained from comprehensively trained lay interviewers, not clinicians and analyses used DSM-IV diagnoses (rather than DSM-5).
  
  
  CONCLUSIONS
  These findings support the conceptualization of agoraphobia as a distinct diagnostic entity and the independent classification of both disorders in DSM-5, suggesting future multivariate comorbidity studies should not assume various panic/agoraphobia diagnoses are invariably fear disorders.
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Greene
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA. Electronic address: nicholas.eaton@stonybrook.edu.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Eaton
mesh_terms: D000379:Agoraphobia / Q000175:diagnosis* / Q000453:epidemiology*; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D006801:Humans; D008960:Models, Psychological; D016584:Panic Disorder / Q000175:diagnosis* / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology
keywords: Agoraphobia; Classification; Comorbidity; Internalizing–externalizing; Panic disorder