What is mild cognitive impairment?

Mild cognitive impairment. also referred to as MCI, describes memory and thinking problems that are mild but still noticeable.

Mild- not severe.

Cognitive- to do with the way our brains think, plan and understand.

Impairment- not working as well as it should.

As we get older, we may notice a natural decline in our memory and thinking. For a person with MCI, these problems are worse than expected for their age. But unlike dementia, they may not get in the way of day-to-day life.

Research suggests that two out of 10 people over the age of 65 have MCI. But because the condition isn’t always diagnosed, it is difficult to know exactly how common it is.

What causes mild cognitive impairment?

MCI can be caused by a range of conditions or existing health problems. These include:

  • depression, stress, and anxiety
  • vitamin deficiencies
  • thyroid disorders
  • autoimmune conditions
  • infections
  • side effects from medication
  • sleep disorders like sleep apnoea
  • early stages of Alzheimer’s disease or another type of dementia.

Depending on the cause, some people with MCI may find their memory and thinking problems stay the same, and for others they may get worse over time. MCI does not necessarily lead to dementia because it can be caused by other conditions.

It is important to know what is causing a person’s MCI. If it is a symptom of a condition like those mentioned above, or the early stages of a disease like Alzheimer’s which leads to dementia, then this will affect the treatment or support their doctor may offer.

What is the difference between MCI and dementia?

The word dementia describes a group of symptoms that affect a person’s ability to carry out daily activities more and more overtime. It is caused by a range of diseases, with Alzheimer’s being the most common cause. Dementia symptoms include memory problems, confusion, communication difficulties and mood changes. A person with dementia will usually have at least two of these symptoms, which are noticeable and get worse over time.

In comparison to dementia, someone with MCI has mild symptoms and may not be affected in so many ways. This means someone with MCI is usually able to work, drive and manage day-to-day responsibilities safely and without support from other people. This is different from dementia, which gets in the way of everyday life.

Does MCI lead to dementia?

Research has found that having MCI can raise the risk of developing dementia in future, but this depends on the underlying cause.

Every year, about one in 10 people who have been diagnosed with MCI develop dementia. For half of people with MCI their symptoms do not get worse or get better. For those who do go on to develop dementia, the time this takes can vary from one person to another.

When MCI is caused by the early stages of Alzheimer’s disease, vascular dementia or another type of dementia symptoms will get worse over time and start to affect a person’s ability to carry out daily activities. This worsening can be very gradual and not noticeable to begin with. It is important to speak with your doctor if you notice your MCI symptoms getting worse.

Have you or a loved one been diagnosed with MCI?

If you have been diagnosed with mild cognitive impairment in the last two years and would like to share your experience to help shape our work please get in touch via stories@alzheimersresearchuk.org 

What is mild cognitive impairment?

This introductory leaflet aims to help you understand mild cognitive impairment. It’s for anyone who might be worried about their own or someone else’s memory.

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Alzheimer’s Research UK has a wide range of information about dementia. Order booklets or download them from our online form.

This information was updated in November 2023 and is due to be reviewed in November 2025. It was written by Alzheimer’s Research UK’s Information Services team with input from lay and expert reviewers.

Our information does not replace advice that doctors, pharmacists, or nurses may give you.


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