About ABCD - Anticholinergics, Benzodiazepines, Cognition and Dementia Study
Exploring the cognitive effects of long term medication use
The ABCD (Anticholinergics, Benzodiazepines, Cognition and Dementia) study aims to understand the effect of anticholinergic medication, benzodiazepine and Z-drug use on cognitive decline and dementia incidence in older people.
This three-year study is advancing our knowledge of the effects of specific classes of commonly used medicines on cognitive decline and dementia incidence in the older population. We are using routine data collected through the Clinical Practice Research Datalink (CPRD) and data from two cohort studies, the MRC Cognitive Function and Ageing Study (MRC CFAS) and The Irish Longitudinal Study on Ageing (TILDA).
Background to the study
Recent studies suggest that there is a higher rate of dementia among people who use certain commonly used medicines for long periods of time. Benzodiazepines (used for sleeping disorders and anxiety) and medications with ‘anticholinergic’ activity have been particularly implicated.
Data routinely collected in general practice provides an opportunity to examine these effects in the UK population. We are using data from the Clinical Practice Research Datalink to estimate the effect of regularly taking these medications on dementia diagnosis rates, taking into account known individual risk factors.
A major methodological challenge is to account for the possibility of confounding by indication. We are carefully exploring the possibility that the disease or symptom for which a medicine is prescribed is the cause of excess dementia risk or is a prodromal symptom of dementia, rather than the medicine itself conferring the excess risk.
This study is funded by the Alzheimer's Society.