Exploring the association between therapeutic use of Lithium and the risk of dementia

PI Title: Dr Barbara Iyen

Lead member: Nottingham

Dementia is a very common cause of disability, dependency, and death among older people worldwide. It is one of the greatest healthcare challenges faced because of an ageing population, affecting an average of 55 million people in the world, and 1 in 11 people over the age of 65 in the UK. There are currently no treatments for dementia, so an understanding of interventions to reduce dementia risk and the overall burden of dementia is essential. Mental health conditions like depression and bipolar disease have been found to increase the risk of dementia. Evidence from previous research studies which had methodological limitations, suggest that Lithium - a medication commonly used to treat mood disorders - may be beneficial and reduce the risk of dementia by helping to protect brain cells. Treatment with lithium is usually initiated by hospital specialists but patients must ensure strict dose adherence and regular blood monitoring in primary care to minimise toxic effects of this medicine. Although lithium is the gold standard treatment for bipolar disease, prescribing of this medicine has declined in countries such as the United States, Canada, Germany, and Austria, and this is thought to be due to its’ unfavourable side effects, and greater use of other alternatives including anticonvulsants and newer second-generation antipsychotics. In England, over 800,000 lithium prescriptions were dispensed in 2008, however 2022 figures from NHS England show that lithium prescriptions issued in the last financial year were 3% lower than the average over the previous five years.

There is a need for a large-scale population-based study to find out if Lithium does indeed have any benefit in preventing or reducing the risk of dementia. The proposed research aims to assess the link between lithium use and the risk of dementia. We will use a large database of computerised primary care records to identify people with dementia. Each person with dementia will be matched with up to five people of a similar age, sex and registered in the same general practice, who do not have dementia. Individuals with dementia and their matched non-dementia individuals, will be compared and assessed in terms of their differences in prior use of Lithium. As lithium is primarily used to treat mood disorders or other mental health conditions, we will adjust for these conditions in our analysis. In doing this, we will be able to assess the risk of dementia associated with lithium prescribed for individuals up to 20 years before the diagnosis of dementia.

Findings from this research will address the gap in evidence about whether lithium affects the risk of developing dementia. The results may influence the way doctors prescribe lithium to individuals with mental health conditions, especially if it is found to reduce dementia risk.

Amount awarded: £50,149