Effect of antidepressant use on admissions to hospital among elderly bipolar patients

The goal of this study was to examine the association between antidepressant use and hospitalization rate for mania or bipolar depression in a large, community-based sample of elderly bipolar patients.

Population-based retrospective cohort design. Administrative healthcare databases were linked for all individuals aged 66 years or older in the Province of Ontario, Canada. Bipolar subjects who received a prescription for an antidepressant medication (n = 1,072) between 1 April 1997 and 31 March 2001 comprised the antidepressant cohort. The control group (n = 3,000) consisted of randomly selected subjects from the eligible bipolar population who did not receive a prescription for an antidepressant medication during the same surveillance period. Primary outcomes were admission to hospital for a manic/mixed or depressive episode.

During a total of 5135 person-years of follow up, 113 admissions for a manic/mixed episode and 28 admissions for a depressive episode were identified. Model based estimates adjusted for a number of covariates revealed that, as compared with the control group, the antidepressant cohort had significantly lower likelihood of admissions for manic/mixed (adjusted rate ratio [aRR] = 0.5, 95% CI = 0.3-0.8) but not depressive episodes (aRR = 0.7, 95% CI = 0.2-2.2).

Antidepressant use among elderly bipolar patients was associated with decreased rates of hospitalization for manic/mixed episodes. This finding requires confirmation with further data of antidepressant use among elderly bipolars.