How much do cholinesterase inhibitors really help in slowing cognitive decline in Alzheimer's disease?
In mild to moderate Alzheimer's disease, these medications measurably slow cognitive decline. The benefit is modest: side effects such as nausea cause nearly one in three people to discontinue treatment early.
These medications, which include donepezil, galantamine and rivastigmine, slow cognitive decline in mild to moderate Alzheimer's disease. The average benefit on the most widely used cognition test is approximately 2.7 points on a scale of 70. That is measurable, but barely noticeable in daily life. On another commonly used test, people taking donepezil scored on average just over 1 point higher on a scale of 30 after six months. That difference is also small.
In the area of daily activities, such as dressing or washing oneself, small improvements are visible. For behavioural symptoms such as restlessness or agitation, no clear difference compared with placebo was generally found. And for quality of life, no difference attributable to these medications has been demonstrated.
In severe Alzheimer's disease, there is limited evidence that donepezil offers some cognitive benefit, but far less research has been conducted in this group than in people with mild to moderate dementia.
Side effects are a serious factor. Approximately 29% of people discontinue treatment early, compared with 18% in the placebo group. Nausea, vomiting and diarrhoea occur considerably more often. Rivastigmine causes the most complaints; a slow dose titration can reduce that risk. Of the three, donepezil has the most favourable side-effect profile, although direct head-to-head comparisons regarding efficacy are contradictory.
Whether one medication works better than another cannot be stated with confidence: two studies find no difference, one finds donepezil superior to galantamine, and one finds rivastigmine superior to donepezil. If you or someone close to you is using these medications, it is worthwhile discussing with your doctor which medication is appropriate and how the dose should be titrated.
This answer is based on multiple large-scale review studies that summarise dozens of randomised, double-blind, placebo-controlled trials. The evidence base for the cognitive effect is solid, but the clinical significance of the improvements found is widely debated in the literature: the researchers themselves consistently describe the effects as "statistically significant but modest" and emphasise that the individual patient is unlikely to notice much difference. For quality of life and behavioural symptoms, the evidence is thin. Studies contradict one another when it comes to comparing the three medications directly.
Is there a clinical strategy in development that can actually prevent Alzheimer's disease?
There are promising indications that an active lifestyle and treatment of risk factors such as high blood pressure and diabetes can reduce risk. Proven prevention does not yet exist, but starting on those modifiable factors now will in any case yield real health benefits.
Does a low dose of lithium help protect the ageing brain?
There are preliminary indications that low doses of lithium may offer brain protection, but the evidence is still too thin and the risks are real enough that lithium should only be used under medical supervision.
Do your brains really shrink as you get older?
Your brain does indeed shrink with age, particularly in areas involved in memory and planning. High blood pressure accelerates that process, while exercise and cognitive effort strengthen your brain's compensatory activity.
Does creatine supplementation reduce brain fog?
Creatine may ease cognitive complaints, but the effect depends heavily on your situation: people with chronic fatigue, sleep deprivation or a plant-based diet are most likely to benefit, while for healthy, well-rested individuals it appears to do little.
What can I concretely do to prevent dementia?
Various lifestyle choices demonstrably lower your risk, but no single approach guarantees that you will prevent dementia. Regulating blood pressure, exercising, not smoking and staying mentally active are the best-supported steps you can take.
Is there a link between oral bacteria and the development of Alzheimer's disease?
There is a consistent association between oral bacteria and Alzheimer's disease, but a proven cause-and-effect relationship in humans has not yet been established. Good oral care is sensible, but do not expect it to offer proven protection against Alzheimer's disease.