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

BackgroundLithium inhibits glycogen synthase kinase-3, an enzyme implicated in the pathogenesis of dementia.AimsTo examine the association of lithium and dementia risk in a large claims-based US cohort of publicly insured older adults with bipolar disorder.MethodThe 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.ResultsCompared 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.ConclusionsContinuous lithium treatment may reduce dementia risk in older adults with bipolar disorder.