A retrospective study to investigate whether the use of some of the commonly prescribed medications (including statins, antidepressants, and antipsychotics) very late in life quickens or slows the rate of cognitive decline compared to use of these medications earlier in life in three diagnostic cohorts (people with dementia, mild cognitive impairment, and no cognitive diagnosis), and to investigate the relationship between rate of cognitive decline and cholesterol levels in different age categories.

Dementias are thought to be caused at a molecular level by the build-up of misfolded proteins (such as beta-amyloid) in the brain. Preliminary work from Professor Rajendran’s laboratory has suggested that, in dementia, cholesterol may be detrimental earlier in life and beneficial later in life. It has been proposed that decreased cholesterol leads to the body being in “starvation” mode, resulting in increased clearance of toxic products such as these misfolded proteins; however, in later life, decreased cholesterol resulted in synaptic loss. Synapses are important for cognitive function. Some studies also suggest that antidepressants and antipsychotics may influence dementia risk. We aim to investigate whether cognition in patients with dementia, mild cognitive impairment, and no cognitive diagnosis is affected by the age at which cholesterol-lowering therapy, antidepressants, and antipsychotics are taken, and to investigate the relationship between cognition, cholesterol, and age.