Lithium treatment and risk for dementia in adults with bipolar disorder: Population-based cohort study

Abstract

Background: Lithium inhibits glycogen synthase kinase-3, an enzyme implicated in the pathogenesis of dementia. Aims: To examine the association of lithium and dementia risk in a large claims-based US cohort of publicly insured older adults with bipolar disorder. Method: The cohort included individuals ⩾50 years diagnosed with bipolar disorder who did not receive dementia-related services during the prior year. Each follow-up day was classified by past-year cumulative duration of lithium use (0, 1–60, 61–300 and 301–365 days). Dementia diagnosis was the study outcome. Anticonvulsants commonly used as mood stabilisers served as a negative control. Results: Compared with non-use, 301–365 days of lithium exposure was associated with significantly reduced dementia risk (hazard ratio (HR) = 0.77, 95% CI 0.60–0.99). No corresponding association was observed for shorter lithium exposures (HR = 1.04, 95% CI 0.83–1.31 for 61–300 days; HR = 1.07, 95% CI 0.67–1.71 for 1–60 days) or for any exposure to anticonvulsants. Conclusions: Continuous lithium treatment may reduce dementia risk in older adults with bipolar disorder.