Meta-analysis of efficacy of cholinesterase inhibitors on individual neuropsychiatric symptoms in Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies

Alzheimer's disease (AD) is the most prevalent type of dementia, affecting approximately 24 million people globally [1]. It is estimated that Parkinson's disease (PD) and dementia with Lewy bodies (DLB) together affect an additional 10 million people globally (~1.5% of the elderly population [1]).
Cognitive deficits, such as problems with memory, planning and reasoning, and neuropscyhiatric disturbances, such as depression and anxiety, are both important features of these diseases. Cholinesterase inhibitors (ChEIs), such as donepezil and rivastigmine, form a type of drug that has a well established effect on the cognitive deficits. However, the beneficial effect on neuropsychiatric disturbances is much less clear [2,3]. A possible explanation for the inconsistent results of ChEIs on neuropsychiatric disturbances is that the definition of 'neuropsychiatric' is too broad, as it includes symptoms such as hallucinations and delusions, but also depression, anxiety and irritability, among others.
Therefore, we want to conduct a meta-analysis on the efficacy of ChEIs on all individual items of neuropsychiatric outcome measures, to assess which subdomains benefit from treatment and which do not. Individual trials are usually not powered for this subanalysis, which is why we want to pool all the available data.
We believe that this meta-analysis will form the basis for a more targeted approach for treating neuropsychiatric symptoms in PD, AD and DLB.