Drugs that affect acetylcholine often begin with “ant” or “anti”: antihistamine, anti-anxiety, antidepressant, antacid, antimuscarinic (used to manage an overactive bladder) and more.

These drugs do not need to be taken for long before an effect manifests: one study found that drugs with strong anticholinergic effects – which are thought to be cumulative – had the potential to cause cognitive impairment when taken continuously for as short a period as 60 days.

Anticholinergic drugs – some of which are sold as OTC (over-the-counter) medicines – work by blocking the action of acetylcholine.

Acetylcholine has been called the “memory molecule” for the crucial role it plays in recall, learning and focus. It was one of the first neurotransmitters identified – about a century ago – and is one of the most abundant in our nervous system.

A typical early sign of insufficient amounts of acetylcholine might manifest as “senior moments”.

Another early symptom is loss of spatial awareness. (I remember feeling puzzled when my mother asked, ‘Now, where’s the bathroom again?’ How did she not know?)

Acetylcholine is imperative in the conversion of short-term memories to long-term ones, like a program to transfer data to an archive. It’s not just important because it helps us to learn, concentrate and stay mentally engaged; it also helps modulate REM sleep, emotion and even thirst.

Acetylcholine also enhances brain plasticity.

There is substantial research that points to the dementia risk of taking ACB drugs.

A study published in early 2015 found the most common ACB drugs included tricyclic antidepressants (an older generation antidepressant), first-generation antihistamines, and antimuscarinics.

A follow-up seven years later revealed that almost a quarter of the cohort that had been taking ACB drugs had developed dementia. The study pressed for an increase in awareness among health professionals about these risks. That same year, a medication to control her “irritable” bladder was added to my mother’s script. She was 75.

A 2018 study published in the BMJ suggests “a robust association between some classes of anticholinergic drugs and future dementia incidence”, a result observed from exposure 15 to 20 years before a diagnosis.

More recently, a 2019 study found such drugs carried “significant” dementia risk in an at-risk older population.

Did my mother’s doctor not know this when he added a drug to manage urinary incontinence to her antidepressant, anti-anxiety script? She certainly didn’t.

Acetylcholine levels decline as we age. And it’s in these advanced years that our physicians may see fit to prescribe drugs to boost mood or aid sleep or alleviate incontinence – Oxybutynin, say, which scores a maximum three on the ACB scale (the medication my mother was prescribed a decade ago).

Or something for a sluggish digestion, Ranitidine (with a burden of two), perhaps.

Of course these drugs have a place. But perhaps they don’t all have a place at the same time. Perhaps there are safer alternatives? Doctors need to be mindful of the risks they pose, especially to an already at-risk population: the over 65s.

According to the anticholinergic burden calculator – which uses two different scoring systems, the German Anticholinergic Burden score and the Anticholinergic Cognitive Burden Scale – a score of three+ is associated with increased cognitive impairment and mortality.

A study cited by the UK’s NHS found that 20 per cent of patients over 65 who scored four or more had died by the end of the two-year study period compared with 7 per cent of patients with a score of zero.

My mother’s ACB, based on current and past prescriptions, stands at seven. She has carried this burden for 45 years.