The ABCD Study The ABCD Study

Key Research Questions

Are people who use anticholinergic medications, benzodiazepines or Z-drugs at greater risk of neuropathological changes, cognitive impairment or dementia compared to those who do not?

Is this increase explained by the disease for which the medicine was prescribed, or by the medicine itself?

Research Design and Outputs

The ABCD Study is an observational study using epidemiological data from the UK and Ireland and data routinely collected in UK general practice to estimate how long-term anticholinergic or sedative medication use affects cognitive decline and dementia. The study will contribute to academic and policy debates about the use and overuse of medicines, as well as providing a possible approach to dementia prevention should an excess risk be identified. 

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).

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 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. 

The Research Team

Prinicipal Investigator 


UEA Team

External Collaborators

  • Prof Rose Anne Kenny

  • Dr Kathleen Bennett

  • Prof Malaz Boustani

  • Dr Noll Campbell

  • Prof Phyo Myint

  • Prof Paul Ince

  • Prof Carol Brayne

  • Prof Fiona Matthews


The main funding for this project comes from The Alzheimer's Society.

Key Partners and Collaborators

University of Cambridge

University of Sheffield

Trinity College Dublin

Aston University

Indiana University

MRC Biostatistics Unit