Proposed Specific Factors for Generalized Anxiety Disorder Within the Integrative Hierarchical Model of Anxiety and Depression

Open Access
Author:
Fisher, Aaron Jason
Graduate Program:
Psychology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
May 30, 2008
Committee Members:
  • Michelle Gayle Newman, Thesis Advisor
  • Michelle Gayle Newman, Dissertation Advisor
Keywords:
  • Comorbidity
  • Depression
  • Anxiety
  • Tripartite
  • Integrative
  • SEM
Abstract:
Since its first appearance in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III, 1980), generalized anxiety disorder (GAD) has provided challenges to the discriminative validity of the mood and anxiety disorders. Although the removal of autonomic symptoms from the diagnostic criteria for GAD in DSM-IV helped to increase the diagnostic reliability from a range of .27 (Mannuzza et al., 1989) to .56 (Williams et al., 1992) based on DSM-III-R criteria and .67 based on DSM-IV criteria (Brown, Di Nardo, Lehman, & Campbell, 2001), some researchers have expressed concern that this distinction further confuses the boundary between GAD and mood disorders (Clark & Watson, 1991; Brown et al., 1995). It has been argued that though the removal of these symptoms from the diagnostic criteria improved the overall reliability of GAD, as well as the discriminative validity of GAD in relation to the other anxiety disorders, the overlap with depressive disorders and the discriminative difficulties therein still remain. Research based on DSM-IV criteria has shown that GAD shares a closer relationship to the mood disorders than it does to other anxiety disorders (Mineka, Watson, & Clark, 1998; Brown, Chorpita, & Barlow, 1998; Watson, 2005). Clark and Watson (1991) developed the tripartite model, in which depression and anxiety share a common factor of negative affectivity, depression is indicated by low positive affectivity (PA) and anxiety by high autonomic arousal (AA). Mineka, Watson, and Clark expanded on this model with the integrative hierarchical model, within which each anxiety disorder is indicated by an idiosyncratic predictor. Watson (2005) has made the argument that this model can and should be extended to new taxonomic systems, including the approaching DSM-V. However, a specific factor remains to be determined for GAD within this model. The present study sought to determine possible specific factors for GAD within the integrative hierarchical model. Research participants (n = 423) completed a packet of questionnaires related to the constructs of interest. Participants were mostly female (69%) and Caucasian (85%), with an average age of 20 years. Latent path relationships were examined using structural equation modeling (SEM) in LISREL (Joreskog & Sorbom, 2006). The initial model replicating the tripartite structure of NA, GAD, and depression fit the data extremely well. Three competing models with possible specific latent factors for GAD were then examined: worry, perfectionism, as represented by a dimensional measurement of obsessive-compulsive personality disorder (OCPD), and positive beliefs about worry. The latter latent factor consisted of scales related to perceptions of worry as preparatory and motivating. All models fit the data exceptionally well. Both perfectionism and positive beliefs about worry strongly related to GAD and failed to demonstrate a statistically significant relationship with depression. Worry, despite demonstrating a large and significant relationship with GAD (β = .88), also significantly, albeit negatively, related to depression as well (β = -.09). Due to concerns regarding the instrumental relationship of worry to current GAD diagnostic criteria and possible resultant tautological statistical findings, models were tested to determine if positive beliefs about worry and perfectionism remained significant predictors of GAD while controlling for the latent factor for worry. These models fit the data exceptionally well. Perfectionism and positive beliefs about worry were retained as specific factors for GAD.