Dementia risk linked to some medicines

In England, 1.5 to two million people are likely to be taking anticholinergics for depression, Parkinson's and bladder problems, according to BBC.

University of East Anglia researchers found more cases of dementia in patients prescribed larger quantities of particular anticholinergics.

But experts said patients should not stop taking them, as their benefits may outweigh any risk.

The study found no risk with other anticholinergic medicines used to treat common conditions such as hay fever, travel sickness and stomach cramps.

The research, funded by Alzheimer's Society and published in the British Medical Journal, looked at the medical records of 40,770 patients aged from 65 to 99 with a diagnosis of dementia between April 2006 and July 2015 and compared them with those of 283,933 people without dementia.

It also analysed more than 27 million prescriptions - making it the biggest study of its kind into the long-term impact of anticholinergic drugs in relation to dementia.

What are anticholinergic drugs?

They block acetylcholine, a chemical messenger that carries signals across the nervous system.

Some are available on prescription only.

What should patients do if they take any of these drugs?

The most important thing is "not to panic", according to Dr Ian Maidment, from Aston University.

"Don't do anything suddenly. Don't stop taking your medication," he told the BBC.

"As a patient, if you are concerned about it, go and speak to your doctor or your pharmacist. You don't have to see them urgently."

Not taking prescribed drugs could have serious consequences, Dr Maidment said.

"Having untreated depression is also a risk as people can die from that, so it is a question of balancing risks," he added.