Many people take medicine every day without thinking much about possible long-term effects. Medicines for allergies, depression, high blood pressure, sleeping problems, motion sickness, and colds are commonly used around the world.
Some of these medicines belong to a group called anticholinergic drugs. They are available both with a prescription and over the counter, and millions of people rely on them to treat everyday health problems.
Anticholinergic drugs work by blocking a chemical messenger in the body called acetylcholine. This chemical helps control many important functions, including muscle movement, digestion, and the bladder.
It also plays a major role in learning, memory, and thinking. Because of this, scientists have wondered for many years whether regularly blocking acetylcholine could affect brain health, especially in older adults.
A new study from the University of California, San Diego, adds more evidence that these medicines may increase the risk of memory problems. The researchers followed 688 older adults for as long as 10 years to better understand how anticholinergic drugs might affect the brain over time.
At the beginning of the study, the participants were about 74 years old on average. None of them showed signs of memory loss or dementia. The researchers carefully recorded the medicines each person was taking, paying special attention to drugs with anticholinergic effects.
They then monitored the participants over many years to see who developed problems with memory and thinking.
The results were concerning. About one in every three participants was taking at least one anticholinergic medicine. Many people were taking several of these medicines at the same time, with an average of nearly five different drugs.
The researchers found that people using anticholinergic medicines were 47% more likely to develop mild cognitive impairment than those who were not taking these drugs.
Mild cognitive impairment is a condition in which people begin to have noticeable problems with memory, attention, or decision-making. These changes are greater than normal aging but are not yet severe enough to be called dementia. Some people remain stable for years, while others eventually develop Alzheimer’s disease or another form of dementia.
The study found that the danger was even greater for people who already had early signs linked to Alzheimer’s disease. Some participants had abnormal Alzheimer’s-related proteins in their spinal fluid, even though they had no memory problems when the study began.
Those who had these brain changes and also took anticholinergic medicines were about four times more likely to develop cognitive impairment than people without these risk factors.
Genes also made a difference. Some people carry genetic changes that increase their chance of developing Alzheimer’s disease.
The researchers found that participants with these higher-risk genes who also used anticholinergic drugs had about two and a half times the risk of developing memory problems compared with people who did not carry these genes and were not taking the medicines. This suggests that some people may be especially sensitive to the effects of these drugs.
These findings do not mean that everyone should immediately stop taking anticholinergic medicines. Many of these drugs are effective and necessary for treating certain medical conditions.
However, the study suggests that doctors and patients should regularly review medicines, especially in older adults. In some cases, there may be safer alternatives that do not have strong anticholinergic effects.
People should never stop prescription medicines without first speaking to their doctor or pharmacist. A healthcare professional can explain the benefits and risks of each medicine and decide whether another treatment might be more suitable.
The researchers believe their findings highlight the importance of protecting brain health before memory problems begin. As people live longer, preventing dementia has become a major public health goal.
Along with regular exercise, a healthy diet, good sleep, controlling blood pressure, staying mentally active, and managing diabetes, carefully choosing medicines may become another important way to help reduce the risk of memory decline.
The research was carried out by scientists at the University of California, San Diego and followed participants for up to 10 years. The findings provide another reminder that medicines can have both benefits and risks, and that regular medication reviews are an important part of healthy aging.
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