Causes of mild cognitive impairment

There are many potential causes of MCI. Some of them are treatable and get better, while others may not.

For many people it’s not possible to know what’s causing their MCI, although it may become clearer over time.

A person can develop MCI at any age. However, the risk increases greatly with older age. About 1 in 4 people in their early 80s has MCI.

MCI caused by a treatable health condition

Sometimes MCI is caused by a health condition that can get better with time and treatment. These include:

• sleep disorders – for example, not being able to sleep (insomnia) or not breathing easily while asleep (sleep apnoea)
• side effects of medicines that cause confusion or drowsiness
• having low blood pressure
• mental health problems, such as depression, anxiety or long-term stress
• functional cognitive disorder 
• sight or hearing loss
• infections, including the after-effects of COVID or other viruses 
• severe constipation
• regularly drinking too much alcohol
• high or low levels of vitamins, minerals, hormones, or sugars in the body.

The effects of these may be worse if the person is also frail, tired, or in pain.

About 4 in 10 people with MCI will get better. However, there’s no guarantee that their recovery will be permanent. Many people who get better from MCI have similar problems again later. 

Some people with MCI get better over time even without medical treatment. This may be the case if they are recovering from a very stressful period, such as a bereavement or a viral infection.

Recovery can often be made easier with help from counselling, peer support groups or rehabilitation services.
 

MCI caused by a stable or progressive condition

MCI may sometimes be caused by a health condition affecting the brain. When this happens, the condition could be: 

• stable – memory and thinking don’t improve, but also don’t get worse.
• progressive – the condition gets worse over time and eventually leads to a diagnosis of dementia.

Stable MCI can happen with long-term health conditions that cause minor problems with thinking, but rarely lead to dementia. Conditions that can do this include heart failure, epilepsy, lung or kidney disease, and some types of stroke.

MCI caused by a stroke can be unpredictable. A person may remain stable for many years or they could decline more quickly and develop dementia. It’s very difficult to predict what will happen to any individual person.  

When MCI is being caused by a progressive brain disease like Alzheimer’s or Lewy body disease, it will get worse over time. Eventually MCI turns into dementia, although the time it takes to get to this stage varies a great deal from person to person.

Reducing the risk of mild cognitive impairment 

Although getting older is the biggest risk factor for MCI, evidence shows there may be things a person can do to reduce their long-term risk, with the right support.

These changes mainly involve keeping the body healthy and preventing damage to the brain. They include:

• being physically active
• eating healthily
• not smoking
• drinking less alcohol
• staying mentally and socially active
• looking after other health conditions, such as high blood pressure or diabetes.

It’s best to start from at least midlife, during your 40s and 50s. However, it’s never too late for the brain to get at least some benefit from living more healthily.