Anticholinergic drugs and non-degenerative mild cognitive impairment in elderly people

Monday 13 February 2006 12:00AM (view full episode)

Anticholinergics are drugs which block the actions of an important nerve transmitter called acetyl choline. A study in France assessed the potential of these drugs as a cause of non-degenerative mild cognitive impairment in elderly people.


Norman Swan: Welcome to the program. This morning on the Health Report a growing belief that we've been deluded about the heart benefits of alcohol (sorry about that); a disturbing study of cannabis use in Aboriginal communities; new statistics on dementia which have some surprises and dementia which isn't.

Could some people who've been told, or indeed assume for themselves that they're heading for dementia not be and the reason for their thinking and memory problems be the medications they're on? Well if a study in the south of France has echoes in Australia, the answer is yes, because the medications in question are called anticholinergics and are very commonly used. These are drugs which block the actions of an important nerve transmitter called acetyl choline. The study was led by expatriate Australia Dr Karen Ritchie, who's based in Montpellier.

Karen Ritchie: It's been known for a long time that certain drugs with anticholinergic properties do affect cognitive functioning in elderly people. I think this is the first really systematic study where we've looked at a very wide range of cognitive tests and that a high amount of these drugs give rise to cognitive disorders which mimic early Alzheimer's disease.

Norman Swan: So tell me what you actually did.

Karen Ritchie: Well it was a population study that was based on a network of general practitioners in our region and through them we saw 833 people without dementia who were more or less representative of general practice in the region. And they had a neurological examination, we took blood, but particularly the neuropsychological testing was very complete, we had information on response time, a lot of qualitative work. So these people were followed up for another two years and then there was an eight year follow up. What we were interested in is looking at the drugs they were consuming. There was a very high drug consumption. The elderly people in this area are taking around six to eight drugs each and we wondered to what extent they were taking anticholinergic drugs.

Norman Swan: And what are we talking about here when we talk about anticholinergic drugs, what sorts of medications?

Karen Ritchie: Really quite a broad range of medication. It includes antihistamines, drugs that are used in psychiatry, some of the older forms of anti depressant, anti-anxiolytics, benzodiazepine for example is a very high anticholinergic load. We find drugs used for urinary incontinence, bronchodilators and even some herbal teas have high anticholinergic properties.

Norman Swan: And what relationship then did you find to their thinking ability, what was the link?

Karen Ritchie: We took people who were on a very high level of these drugs at the first examination and people who were still taking them a year later and we compared them with people who had never taken them. And what we found is that they had quite significant impairment on psychomotor speed, on immediate and short term memory, recall of stories for example, construction tasks. We tried to explain this in every other way, which might have been other explanations for this type of cognitive impairment, we controlled for this in our analysis.

Norman Swan: And how severe was the impairment?

Karen Ritchie: It was sufficient for 80% of them to be classified as what we call mild cognitive impairment, which is considered to be a pre-clinical form of Alzheimer's disease.

Norman Swan: And yet in your paper you say they didn't have dementia, how do you know that?

Karen Ritchie: We followed them up for the next eight years, so eight years later we found that there were a small number of people who had dementia but no greater than the general population.

Norman Swan: And when they stopped the anticholinergics what happened?

Karen Ritchie: Well unfortunately we didn't do that sort of wash out trial.

Norman Swan: So in other words they had this thinking ability problem sufficient that if a doctor or a neuropsychologist such as yourself were to see them you think oh gosh, they're heading towards Alzheimer's disease but when you followed them up eight years later they actually had not progressed to Alzheimer's disease, it was kind of in the same state as it was when you first saw them?

Karen Ritchie: That's right, the most alarming thought for us is that these people might have been given drugs for Alzheimer's disease which are usually pro-cholinergic drugs so that you're in the rather stupid position of taking pro-cholinergic drugs to combat the anticholinergic drugs that you're already taking. And many of these drugs with high anticholinergic properties have alternatives. So I think very much the take home message from us is that before we conclude that people may have an early stage of Alzheimer's disease one really needs to look very closely at other possible causes, which might be reversible.

Norman Swan: And the theory behind that, why would the anticholinergic drugs cause mental impairment?

Karen Ritchie: Because we know that the cholinergic system is what is first affected in Alzheimer's disease. It's the neurotransmitter system and it affects neurones, which are in that part of the brain which particularly effect memory and attention.

Norman Swan: Do we know whether it happens to younger people?

Karen Ritchie: It's an interesting thought. We do know that if we give scopolamine to younger people which is an anticholinergic agent, we find that they have a profile which is almost identical to the profile we saw in the elderly people. However, one would imagine with younger people that the effects would be perhaps less dramatic. I remember we talked together you know a few years ago about Jeanne Calment and the fact that this very elderly lady had quite good cognitive function.

Norman Swan: We should just explain that Jeanne Calment was a woman who remembered Van Gogh coming into her father's shop and remembers the Eiffel Tower going up and in her day, which was about ten or twelve years ago, she was the oldest woman in the world.

Karen Ritchie: That's right. Well in fact when I first saw her she was being given a fairly popular heart medicine, not because she had a problem but you know at the time it was fashionable to do it preventively. And when we asked that it be withdrawn because there was really no reason for her to take it we suddenly saw a huge upturn in her cognitive functioning and that particular medicine also had high anticholinergic properties. So she was quite a good example of that. Just having this chronic memory problem must be making life a little bit miserable for people and certainly making them feel a little bit older than they really are. But one of the problems we have now is that when elderly people present in general practice complaining of quite handicapping memory problems, then immediately we focus on the possibility of dementia and perhaps we're not sufficiently rigorous in looking at other factors that might be reversible.

Norman Swan: Dr Karen Ritchie is Research Director of a group studying neurological disorders at the French National Institute of Medical Research based in Montpellier.


Ancelin ML et al. Non-degenerative mild cognitive impairment in elderly people and use of anticholinergic drugs: longitudinal cohort study. British Medical Journal Online First, 1 February, 2006:


Dr Karen Ritchie
Research Director,
French National Institute of Medical Research
Montpellier, France


Dr Norman Swan
Brigitte Seega