title: Association between generalized anxiety disorder and asthma morbidity.
abstract: BACKGROUND
  Generalized anxiety disorder (GAD) is common among people with asthma, but its association with asthma morbidity remains unexplored. This study examined cross-sectional associations between GAD and asthma control, quality of life, and self-efficacy.
  
  
  METHODS
  Seven hundred ninety-four adults with confirmed asthma were recruited from the outpatient clinic of a university hospital. Patients underwent a sociodemographic and medical history interview (to assess health service use and medications), followed by a brief psychiatric interview (Primary Care Evaluation of Mental Disorders) to assess GAD. Patients completed questionnaires assessing asthma control, quality of life, and asthma self-efficacy and underwent spirometry. General linear models and logistic regression were used to assess associations between GAD and asthma morbidity measures, adjusting for covariates.
  
  
  RESULTS
  GAD affected 4% of the sample. The analyses revealed significant associations between GAD and worse overall asthma control (β = 0.62, standard error [SE] = 0.18, p < .001), increased bronchodilator use (β = 10.60, SE = 2.64, p < .001), worse asthma quality of life (β = -0.91, SE = 0.23, p < .001), and worse asthma self-efficacy (β = -59.56, SE = 13.59, p < .001) after the adjustment for covariates. Separate sensitivity analyses including major depressive disorder and asthma self-efficacy as additional covariates rendered many of these associations nonsignificant. There were no associations between GAD and emergency visits or hospitalizations.
  
  
  CONCLUSIONS
  GAD is associated with worse asthma morbidity independent of age, sex, smoking, and asthma severity; however, comorbid major depressive disorder and low asthma self-efficacy may account for many of these associations. Only breathlessness and the frequency of bronchodilator use were uniquely associated with GAD. Future research should examine whether treatment of GAD can affect asthma outcomes.
authors.affiliation: Montreal Behavioural Medicine Centre, Research Centre, Hôpital du Sacré-Coeur de Montréal, affiliated with the University of Montreal, Canada. k-lavoie@crhsc.rtss.qc.ca
authors.forename: Kim L
authors.initials: KL
authors.lastname: Lavoie
authors.forename: Maxine
authors.initials: M
authors.lastname: Boudreau
authors.forename: Annik
authors.initials: A
authors.lastname: Plourde
authors.forename: Tavis S
authors.initials: TS
authors.lastname: Campbell
authors.forename: Simon L
authors.initials: SL
authors.lastname: Bacon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000453:epidemiology*; D001249:Asthma / Q000453:epidemiology* / Q000503:physiopathology / Q000523:psychology; D002648:Child; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D020377:Self Efficacy; D011795:Surveys and Questionnaires; D055815:Young Adult