title: The relationship between worry, rumination, and comorbidity: evidence for repetitive negative thinking as a transdiagnostic construct.
abstract: BACKGROUND
  Repetitive negative thinking (RNT) increases vulnerability to multiple anxiety and depressive disorders and, as a common risk factor, elevated RNT may account for the high levels of comorbidity observed between emotional disorders. The aims of this study were to (a) compare two common forms of RNT (worry and rumination) across individuals with non-comorbid anxiety or depressive disorders, and (b) to examine the relationship between RNT and comorbidity.
  
  
  METHODS
  A structured diagnostic interview and measures of rumination, worry, anxiety, and depression were completed by a large clinical sample with an anxiety disorder or depression (N=513) presenting at a community mental health clinic.
  
  
  RESULTS
  Patients without (n=212) and with (n=301) comorbid diagnoses did not generally differ across the principal diagnosis groups (depression, generalised anxiety disorder, social anxiety disorder, panic disorder) on worry or rumination. As predicted, comorbidity was associated with a higher level of RNT.
  
  
  CONCLUSIONS
  Cross-sectional design precluded causal conclusions and findings may not generalize to excluded anxiety disorders.
  
  
  CONCLUSIONS
  Consistent with the transdiagnostic hypothesis, RNT was associated with a range of anxiety disorders and depression and with comorbidity for those with a principal depressive disorder, supporting recent evidence that RNT is a transdiagnostic process. The presence of RNT, specifically worry and rumination, should be assessed and treated regardless of diagnostic profile. Future research may show that both pure and comorbid depressed or anxious patients receive incremental benefit from transdiagnostic protocols developed to treat core pathological processes of RNT traditionally associated with separate disorders.
authors.affiliation: Centre for Clinical Interventions, Perth, Australia; School of Psychology, University of Western Australia, Perth, Australia. peter.mcevoy@health.wa.gov.au
authors.forename: Peter M
authors.initials: PM
authors.lastname: McEvoy
authors.forename: Hunna
authors.initials: H
authors.lastname: Watson
authors.forename: Edward R
authors.initials: ER
authors.lastname: Watkins
authors.forename: Paula
authors.initials: P
authors.lastname: Nathan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001007:Anxiety / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D015897:Comorbidity; D003863:Depression / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011581:Psychological Tests; D011795:Surveys and Questionnaires; D013850:Thinking; D055815:Young Adult
keywords: Comorbidity; Repetitive thinking; Rumination; Transdiagnostic; Worry