Physical comorbidities increase the risk of psychiatric comorbidity in multiple sclerosis.
Risk factors for psychiatric comorbidity in multiple sclerosis (MS) are poorly understood.



We evaluated the association between physical comorbidity and incident depression, anxiety disorder, and bipolar disorder in a MS population relative to a matched general population cohort.



Using population-based administrative data from Alberta, Canada we identified 9624 persons with MS, and 41,194 matches. Using validated case definitions, we estimated the incidence of depression, anxiety disorder, and bipolar disorder, and their association with physical comorbidities using Cox regression, adjusting for age, sex, socioeconomic status, and index year.



In both populations, men had a lower risk of depression and anxiety disorders than women, as did individuals who were ≥45 years versus <45 years at the index date. The risk of bipolar disorder declined with increasing age. The risks of incident depression (HR 1.92; 1.82-2.04), anxiety disorders (HR 1.52; 1.42-1.63), and bipolar disorder (HR 2.67; 2.29-3.11) were higher in the MS population than the matched population. These associations persisted essentially unchanged after adjustment for covariates including physical comorbidities. Multiple physical comorbidities were associated with psychiatric disorders in both populations.



Persons with MS are at increased risk of psychiatric comorbidity generally, and some physical comorbidities are associated with additional risk.
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada; Department of Community Health Sciences University of Manitoba Winnipeg Manitoba Canada.
Ruth Ann
RA
Marrie
Department of Community Health Sciences University of Calgary Calgary Alberta Canada.
Scott B
SB
Patten
Department of Clinical Neurosciences and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada.
Jamie
J
Greenfield
Department of Community Health Sciences University of Calgary Calgary Alberta Canada; School of Public Health University of Alberta Edmonton Alberta Canada; Surveillance and Assessment Alberta Health Edmonton Alberta Canada.
Lawrence W
LW
Svenson
Department of Community Health Sciences University of Calgary Calgary Alberta Canada; Department of Clinical Neurosciences and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada; O'Brien Institute for Public Health University of Calgary Calgary Alberta Canada.
Nathalie
N
Jette
Department of Medicine (Neurology) University of British Columbia Vancouver British Columbia Canada.
Helen
H
Tremlett
Department of Epidemiology and Biostatistics and Occupational Health McGill University Montreal Quebec Canada.
Christina
C
Wolfson
Faculty of Rehabilitation Medicine University of Alberta Edmonton Alberta Canada.
Sharon
S
Warren
Faculty of Nursing University of Alberta Edmonton Alberta Canada.
Joanne
J
Profetto-McGrath
Departments of Psychiatry and Medicine Dalhousie University Halifax Nova Scotia Canada.
John D
JD
Fisk
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
James
J
Blanchard
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
Patricia
P
Caetano
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
Lawrence
L
Elliott
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
Bo Nancy
BN
Yu
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
Virender
V
Bhan
Department of Internal Medicine University of Manitoba Winnipeg Manitoba Canada.
Larry
L
Svenson
administrative data; anxiety; comorbidity; depression; multiple sclerosis
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