Dementia or something else?

Expert reviewer Rahul Bhattacharya, Consultant Psychiatrist
Next review due August 2022

Dementia can be difficult to spot, especially in the early stages. It’s easy for people – including doctors and nurses – to mistake dementia signs for another problem or health condition, or vice versa. This page gives an overview of problems that may cause similar symptoms to dementia.

Hands of an elderly woman

Why dementia can be difficult to spot

There are a number of reasons why dementia can be difficult to spot.

The main reason is that there are many possible dementia signs and symptoms. Lots of these aren’t only found in dementia, so a doctor can’t diagnose dementia based on one specific symptom. Symptoms also appear slowly and progress gradually, making them difficult to spot.

In most cases, there are also no reliable laboratory tests such as blood tests that can confirm a dementia diagnosis. Instead, to start with, the doctor generally has to rely on their observations and the history of someone’s symptoms.

It is generally older people who get dementia, which presents another challenge. As we get older, we are at a higher risk of other conditions that can easily be mistaken for dementia, for example, Parkinson’s disease and delirium. At the same time, it’s important to note that dementia isn’t a ‘normal’ part of ageing. Many people live into their 90s and beyond without signs of dementia, and dementia is different from normal age-related memory loss.

Dementia can also exist alongside conditions with similar symptoms. In fact, more than nine out of 10 people with dementia have another health condition. For example, just because someone has dementia, it doesn’t mean they can’t also have a thyroid gland problem. If someone does have dementia and another condition, the other condition might be missed if any symptoms are just attributed to dementia.

It’s important for a doctor to accurately and confidently diagnose dementia – or rule it out. This page outlines some conditions and problems that may be mistaken for dementia and may produce ‘dementia-like symptoms’. There are also rarer causes of dementia that you may find it helpful to learn more about.

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Conditions that may be mistaken for dementia

Depression and delirium

These are two conditions that can overlap with dementia in quite complicated ways. Depression, delirium and dementia are sometimes referred to as ‘the three Ds’.

Mild cognitive impairment

‘Mild cognitive impairment’ is really a set of symptoms rather than a particular illness. People affected by it may have problems with:

  • thinking and focusing; for example, following conversations
  • language; for example, finding words
  • memory loss

These symptoms can also be associated with dementia, but they’re less severe when someone has mild cognitive impairment (MCI). If only one aspect of someone’s mental ability is affected, or they’re generally coping well with daily activities, they may be diagnosed with MCI rather than dementia. It can be seen as somewhere in between normal ageing and dementia.

People with MCI have an increased risk of dementia, but it doesn’t mean they will definitely go on to develop it. But in around one in two people with MCI, dementia will develop. MCI symptoms will get worse and start to interfere with daily life. If the doctor diagnoses MCI, they’ll monitor it closely, and suggest activities and lifestyle changes that may have a chance of slowing or preventing the progression to dementia.


Everyone feels anxious from time to time, but generalised anxiety disorder is a more extreme and long-lasting form of anxiety. At any one time, it is thought to affect around one in a hundred people. There are some anxiety symptoms that also occur in dementia, including restlessness, poor concentration, irritability and disturbed sleep. Poor concentration makes it difficult for people to take in information, which can be mistaken for poor memory. People with dementia also often have anxiety, making the situation more unclear.

If you are diagnosed with anxiety, there are a number of treatments that can help. Your doctor may suggest medicines, including antidepressants. They may also suggest a form of counselling called cognitive behavioural therapy. There are also many ways you can help yourself, including learning relaxation or meditation techniques, taking steps to improve sleep and exercising more.

Gland problems

There are some gland problems that can cause dementia-like symptoms. An underactive thyroid can affect memory, concentration and mood. An overactive thyroid can cause restlessness and anxiety. A range of other conditions, including Cushing’s syndrome, underactive pituitary gland and porphyria may also be confused with dementia.

Other problems that may be mistaken for dementia

Age-related memory changes

As we get older, our memory naturally starts to get a little worse. But it’s important to distinguish these expected memory problems and dementia symptoms, which are something completely different.

Reactions to medication

There are a wide range of medicines with adverse reactions that are similar to dementia symptoms. These medicines don't cause dementia, but reactions to them may be mistaken for dementia. Groups of medicines that can do this include:

  • benzodiazepines (eg diazepam) – often prescribed for anxiety
  • analgesics (eg codeine) – often prescribed to relieve pain
  • antidepressants (eg citalopram)
  • anticholinergics (also called antimuscarinics) – generally used for bowel conditions, but also heart, respiratory and other conditions
  • antipsychotics – used to calm intense agitation or disturbance
  • anticonvulsants – used to treat seizures
  • corticosteroids– often prescribed for respiratory conditions

Older people may be at particular risk of adverse reactions to medicines. This is because they’re more likely to be taking more than one at the same time, meaning the medicines may interact with each other. But changes in metabolism as we get older can also increase the chances of medicines causing problems. These interactions may be mistaken for dementia, as confusion is often the first sign of a reaction to a medicine. When doing dementia tests and trying to reach a dementia diagnosis, a doctor will usually look into the medicines that a person is taking.

Doctors should also carefully monitor the medicines they prescribe to older people, so that they’re aware of when they’re producing adverse reactions.

Vitamin deficiency

Vitamin B12 is found in meat, eggs, cheese, and yogurt. Thiamine is also a B vitamin and is found in whole-grain foods, meat, fish, poultry, eggs, milk products, vegetables, nuts and seeds.

Both play an important role in the functioning of the nervous system. If someone does not get enough of either of these vitamins, they may have some symptoms that could be mistaken for dementia. These include confusion, memory loss, irritability, difficulties with problem-solving, depression and irrational thoughts.

Head injury

Injury caused by a major blow to the head, or even from repeated smaller blows over a period of time, can cause dementia-like symptoms. These include memory problems, mental slowness, difficulty problem solving, poor concentration and lethargy. Usually, these problems do not get worse over time (unlike dementia). But someone with a long history of blows to the head (eg boxers or other sportspeople) may develop a condition called chronic traumatic encephalopathy (CTE), which does get worse over time.

Hearing or eyesight problems

Problems with hearing or eyesight reduce someone’s ability to take in information, which can make it look like their mental ability is affected.


Drinking too much alcohol can affect people’s judgement and memory in the short term. In the long term, regularly drinking too much alters the chemistry in your brain and may cause brain damage that can lead to dementia. Following sensible drinking advice before this becomes a problem may help.

Going for an assessment

The lists of conditions and problems above are not exhaustive. There’s a whole range of things that can occasionally cause dementia-like symptoms for some people, and it’s not possible to go into them all here.

There is not always a quick answer to the question 'Is it dementia or something else?' But the most important thing is that if someone has dementia-like symptoms, they should see their GP for a full assessment, to work out what the problem is.

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  • Reviewed by Graham Pembrey, Lead Editor, Bupa Health Content Team, August 2019
    Expert reviewer Dr Rahul Bhattacharya, Consultant Psychiatrist
    Next review due August 2022