Lithium as a Protective Factor against Dementia in Bipolar Patients—A Retrospective Cohort Study

Abstract

Background: Controversial research has indicated potential neuroprotective qualities of lithium in the prevention of dementia, but it did not lead to a definite conclusion. Aim: We seek to examine whether lithium has a protective effect in an elderly population suffering from bipolar disorder. Patients and Methods: Of a retrospective cohort including 433 patient files that met inclusion criteria (age over 65 years and bipolar disease coded by ICD), 147 files contained enough relevant data. The patients' files were divided into lithium users (LU) for those who used lithium for at least a minimum of 3 months and non-users (LNU) for those who did not use lithium at all or used it for a period of less than 3 months. We searched for dementia incidence in these two groups. Results: 433 files were collected initially through a computerized search using ICD10 code for bipolar affective disorder. One hundred twenty three files were excluded due to age (younger than 65 years), 7 were excluded due to neurological background, and 49 were excluded due to either a secondary or a not strictly bipolar psychiatric diagnosis. One hundred and seven were excluded due to insufficient/uncertain data. The remainders of 147 files were included in the final analysis. Twenty five of the 147 bipolar patients were diagnosed with dementia (17%). Amongst the 92 LNU patients, 16 developed dementia (17.4%) and of the 55 LU patients, 9 developed dementia (16.4%); Pearson's χ 2 (1) = 0.026, p < 0.05. Our analysis showed no significant difference between the two groups. Conclusions: No cognitive protective qualities of lithium treatment in elderly bipolar patients were demonstrated by our study.