title: Differences in the burden of psychiatric comorbidity in MS vs the general population.
abstract: OBJECTIVE
  We aimed to compare the incidence and prevalence of psychiatric comorbidity in the multiple sclerosis (MS) population and in controls matched for age, sex, and geographic area.
  
  
  METHODS
  Using population-based administrative health data from 4 Canadian provinces, we identified 2 cohorts: 44,452 persons with MS and 220,849 controls matched for age, sex, and geographic area. We applied validated case definitions to estimate the incidence and prevalence of depression, anxiety, bipolar disorder, and schizophrenia from 1995 to 2005. We pooled the results across provinces using meta-analyses.
  
  
  RESULTS
  Of the MS cases, 31,757 (71.3%) were women with a mean (SD) age at the index date of 43.8 (13.7) years. In 2005, the annual incidence of depression per 100,000 persons with MS was 979 while the incidence of anxiety was 638, of bipolar disorder was 328, and of schizophrenia was 60. The incidence and prevalence estimates of all conditions were higher in the MS population than in the matched population. Although the incidence of depression was higher among women than men in both populations, the disparity in the incidence rates between the sexes was lower in the MS population (incidence rate ratio 1.26; 95% confidence interval: 1.07-1.49) than in the matched population (incidence rate ratio 1.50; 95% confidence interval: 1.21-1.86). Incidence rates were stable over time while prevalence increased slightly.
  
  
  CONCLUSIONS
  Psychiatric comorbidity is common in MS, and more frequently affected the MS population than a matched population, although the incidence was stable over time. Men with MS face a disproportionately greater relative burden of depression when they develop MS than women.
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada. rmarrie@hsc.mb.ca.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: John D
authors.initials: JD
authors.lastname: Fisk
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: Helen
authors.initials: H
authors.lastname: Tremlett
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Wolfson
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: Sharon
authors.initials: S
authors.lastname: Warren
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: Aruni
authors.initials: A
authors.lastname: Tennakoon
authors.affiliation: From the Departments of Internal Medicine (R.A.M.) and Community Health Sciences (R.A.M., S.L.), University of Manitoba, Winnipeg; Departments of Psychiatry and Medicine (J.D.F.), Dalhousie University, Halifax; Department of Medicine (Neurology) (H.T.), University of British Columbia, Vancouver; Department of Epidemiology and Biostatistics and Occupational Health (C.W.), McGill University, Montreal; Faculty of Rehabilitation Medicine (S.W.), University of Alberta, Edmonton; and Department of Community Health Sciences (S.B.P.), University of Calgary, Canada.
authors.forename: Stella
authors.initials: S
authors.lastname: Leung
authors.forename: Scott B
authors.initials: SB
authors.lastname: Patten
mesh_terms: D000328:Adult; D000368:Aged; D001008:Anxiety Disorders / Q000453:epidemiology*; D001714:Bipolar Disorder / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology*; D015995:Prevalence; D012559:Schizophrenia / Q000453:epidemiology*