title: Comorbidity patterns of anxiety and depressive disorders in a large cohort study: the Netherlands Study of Depression and Anxiety (NESDA).
abstract: BACKGROUND
  Comorbidity of depressive and anxiety disorders is common and has been shown to be a consistent predictor of chronicity. Comorbidity patterns among specific depressive and anxiety disorders have not been extensively reported. This study examines comorbidity patterns and temporal sequencing of separate depressive and anxiety disorders using data from a large psychiatric cohort.
  
  
  METHODS
  Baseline data (N = 1,783) of the Netherlands Study of Depression and Anxiety, collected between September 2004 and February 2007, were used. Current and lifetime comorbidity rates for depressive and anxiety disorders (DSM-IV-TR criteria) were calculated. Associations of comorbidity with sociodemographic, vulnerability, and clinical characteristics, and temporal sequencing of disorders were examined.
  
  
  RESULTS
  Of those with a depressive disorder, 67% had a current and 75% had a lifetime comorbid anxiety disorder. Of persons with a current anxiety disorder, 63% had a current and 81% had a lifetime depressive disorder. Comorbidity of depressive and anxiety disorders was associated with more childhood trauma (OR = 1.19; 95% CI, 1.06-1.33), higher neuroticism (OR = 1.05; 95% CI, 1.02-1.08), earlier age at onset of first disorder (OR = 1.59; 95% CI, 1.22-2.07), longer duration of depressive and/or anxiety symptoms (OR = 1.01; 95% CI, 1.01-1.01), and higher symptom severity (ORs ranging from 1.01 to 1.03; all P values < .05). In 57% of comorbid cases, anxiety preceded depression, and in 18%, depression preceded anxiety. Comorbidity with preceding depression compared to preceding anxiety was associated with a shorter duration of symptoms of depressive and/or anxiety symptoms (OR = 0.99; 95% CI, 0.98-0.99), earlier age at first onset (OR = 0.46; 95% CI, 0.31-0.68), and fewer fear symptoms (OR = 0.98; 95% CI, 0.97-0.99).
  
  
  CONCLUSIONS
  Comorbidity rates in anxiety and depressive disorders were very high, indicating that it is advisable to assess both disorders routinely regardless of the primary reason for consultation. This is especially important since comorbid patients showed a specific vulnerability pattern, with more childhood trauma, neuroticism, and higher severity and duration of symptoms.
authors.affiliation: Department of Psychiatry/EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands. f.lamers@vumc.nl
authors.forename: Femke
authors.initials: F
authors.lastname: Lamers
authors.forename: Patricia
authors.initials: P
authors.lastname: van Oppen
authors.forename: Hannie C
authors.initials: HC
authors.lastname: Comijs
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Smit
authors.forename: Philip
authors.initials: P
authors.lastname: Spinhoven
authors.forename: Anton J L M
authors.initials: AJ
authors.lastname: van Balkom
authors.forename: Willem A
authors.initials: WA
authors.lastname: Nolen
authors.forename: Frans G
authors.initials: FG
authors.lastname: Zitman
authors.forename: Aartjan T F
authors.initials: AT
authors.lastname: Beekman
authors.forename: Brenda W J H
authors.initials: BW
authors.lastname: Penninx
mesh_terms: D000328:Adult; D017668:Age of Onset; D001007:Anxiety / Q000453:epidemiology / Q000523:psychology; D001008:Anxiety Disorders / Q000453:epidemiology* / Q000523:psychology; D016009:Chi-Square Distribution; D015331:Cohort Studies; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010555:Personality Inventory; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors