Understanding Dementia and Personality Changes

Medically Reviewed by: Dr Jackie Gray, Public Health Expert and Retired GP
(Carents Trusted Reviewer Programme – Last reviewed February 2026)

Personality changes happen because dementia damages specific parts of the brain.

If areas linked to motivation are affected, someone may lose interest in things they once cared about. They may seem withdrawn, flat, passive or indifferent.

If areas that control impulses are damaged, a person may:

• speak bluntly or rudely

• act without thinking

• struggle to plan or concentrate

These behaviours are not deliberate. They are symptoms of brain damage.

Different types of dementia can be linked to specific patterns of change.

• Alzheimer’s disease is often linked to apathy, low mood, and depression.

• Vascular dementia commonly causes mood swings and sudden emotional changes.

• Frontotemporal dementia is more likely to cause loss of social filters, impulsive behaviour, or reduced empathy.

Not everyone will experience these changes, but recognising patterns can help you make sense of what is happening.

Personality changes in dementia can appear at any stage. For some people, they show up long before a formal diagnosis.

You may notice:

• increased irritability

• loss of interest in hobbies

• emotional withdrawal

• uncharacteristic behaviour

These early changes are often confusing and easily misinterpreted.

The most common dementia personality changes affect mood, motivation, and emotional control.

Many people experience anxiety or depression. Some express hopelessness, cry easily, or talk about feeling like a burden.

Others experience fast, extreme mood swings, moving from laughter to tears within minutes. This emotional lability is often seen in those living with vascular dementia.

Some people become:

• short-tempered or aggressive

• less tolerant

• more self-focused

• less aware of social boundaries

Some individuals, there might also be a tendency to appear more self-centred, to lack empathy or insight, and to lose social graces such as tact, or flexibility. Sometimes people can say or do things which might be socially inappropriate or embarrassing to those around them. These changes are symptoms of dementia, not a reflection of their true character.

Aggression in dementia can be frightening or difficult to deal with. Shouting, swearing, or physical outbursts can often come from fear, pain, confusion, or overstimulation.

Triggers may include:

• physical discomfort

• unfamiliar environments

• feeling rushed or controlled

Aggression is a form of communication when language fails. Keeping routines predictable, reducing noise, and approaching calmly can help.

If aggression appears suddenly, seek medical advice. Infections, pain, or medication reactions can worsen behaviour and may be treatable.

Caring for someone whose personality has changed can feel like losing them while they are still alive. This grief is real and valid.

When someone with dementia does not thank you, show affection, or recognise your effort, it can hurt deeply. These responses are caused by the illness, not a lack of love.

Trying to argue, correct, or reason usually does not help. It often increases distress for both of you.

If you do not understand that these responses are unintentional, you will be wasting your time berating, arguing, or reasoning. None of these efforts will work, but they might cause both of you more distress and make a difficult situation even worse.Learning about BPSD in dementia can help you respond in ways that protect your energy and emotional health, and to remember these are symptoms of stress and distress.

Grief does not only happen after death. Many carers experience grief as dementia changes someone’s personality. This is often called ambiguous loss, because the person is still physically present but emotionally different.

You may miss conversations, shared humour, or emotional closeness. You may feel guilty for grieving someone who is still alive. What you are feeling is completely understandable.

Ignoring this grief can lead to burnout, resentment, or depression. Acknowledging it is key to coming to terms with it. Talking about this loss with professionals or peer support groups can help reduce isolation and self-blame.

When dementia affects a parent, the emotional impact can be intense. There is a shift in roles and responsibilities and you can find yourself taking on the role of the grown-up.

You may feel resentment alongside love. It can be difficult to set boundaries. These conflicts are common when caring for a parent with dementia personality changes.

However, clear boundaries, shared responsibility, and outside support are essential. You cannot do this alone, and you should not have to.

If you are feeling overwhelmed, angry, guilty, or emotionally numb, remember you are responding to a very hard situation.

Speak to your GP, seek counselling, and lean on people you trust. Your wellbeing matters.

Try to balance the hard moments with small, positive experiences where possible. Rest when you can. Do things that remind you that you still exist outside the caring role.

Ask about structured support programmes such as START, which are designed to support family members caring for someone with dementia.

Medically reviewed by Dr Jackie Gray, February 2026