Medical comorbidity in bipolar disorder: implications for functional outcomes and health service utilization.

OBJECTIVE: This is the first cross-national population-based investigation exploring the prevalence and functional implications of comorbid general medical disorders in bipolar disorder.
METHODS: Data were extracted from the Canadian Community Health Survey (N = 36,984). Analyses were conducted to ascertain the prevalence and prognostic implications of predetermined comorbid general medical disorders among persons who screened positive for a lifetime manic episode (indicative of a diagnosis of bipolar disorder). Within the subpopulation of people who screened positive for a manic episode, the effect of medical comorbidity on employment, functional role, psychiatric care, and medication use was examined.
RESULTS: When the data were weighted to be representative of the household population of the ten provinces in 2002, an estimated 2.4 percent of respondents screened positive for a lifetime manic episode. Rates of chronic fatigue syndrome, migraine, asthma, chronic bronchitis, multiple chemical sensitivities, hypertension, and gastric ulcer were significantly higher in the bipolar disorder group (all p < .05). Chronic medical disorders were associated with a more severe course of bipolar disorder, increased household and work maladjustment, receipt of disability payments, reduced employment, and more frequent medical service utilization.
CONCLUSIONS: Comorbid medical disorders in bipolar disorder are associated with several indices of harmful dysfunction, decrements in functional outcomes, and increased utilization of medical services.