Acetylcholine (ACh) is a neurotransmitter (chemical messenger) occurring widely in the brains and bodies of humans and many animals. Anticholinergics are chemical substances (drugs) which block the action of acetylcholine at synapses in the central and the peripheral nervous system. For some years, many scientists have suspected that long-term use of various anticholinergics might tend to increase the risk of dementia. A succession of studies have shown a strong association between long-term use of various anticholinergics and the later development of dementia. We set out three of them here. In total, the three studies involved 637,843 participants.

The most recent study was published June 24, 2019. It showed that the strongest associations between anticholinergics and dementia was for these classes of drugs: antidepressants, bladder antimuscarinics (treating overactive bladder), antipsychotics and antiepileptic drugs.

Here are four media articles about the most recent work:

Anticholinergic Drugs Associated With Dementia Risk

Commonly prescribed drugs are tied to nearly 50% higher dementia risk in older adults, study says

Widely used class of drugs linked to dementia

Anticholinergic Drugs Could Account for 10% of Dementia Cases

Here is the original research article, together with a page of commentary by related experts:

Anticholinergic Drug Exposure and the Risk of Dementia, A Nested Case-Control Study

expert reaction to anticholinergic drug exposure and risk of dementia

Here are summaries concerning anticholinergic drugs:

Anticholinergic Drugs to Avoid in the Elderly

List of Anticholinergic Drugs and Why Some of Them are Dangerous for Seniors

Here is a table merging the information from the two pages above:

Table of Anticholinergic Drugs

The next study was published April 25, 2018 and showed that anticholinergics for depression, Parkinson’s and urinary incontinence carry a higher risk of dementia than others.

Here are three media articles about this research:

Some antidepressants linked to dementia risk

Certain common medications tied to 30% higher dementia risk, study finds

Some antidepressants and incontinence drugs linked to dementia

CAN ALLERGY MEDICATIONS HARM YOUR BRAIN?

Here is a summary concerning anticholinergic drugs:

Anticholinergics

Here is an NIH abstract of the research, together with the original research article:

Anticholinergic drugs and risk of dementia: case-control study. (NIH Abstract)

Anticholinergic drugs and risk of dementia: case-control study (Full Publication)

The research reports above both build on earlier work, in particular research reported on March 1, 2015. Here are two articles about that work:

Common anticholinergic drugs like Benadryl linked to increased dementia risk

Benadryl and Other Common Medications are Linked to Dementia in Men and Women

And here is the original research article:

Cumulative use of strong anticholinergics and incident dementia: A prospective cohort study

All links have been added to Alzheimers > Risk Factors.