When Dementia Changes Behaviour: What to Look For and What to Do

This article has been reviewed by clinicians from Sussex Partnership NHS Foundation Trust.

If you are caring for someone living with dementia, you may start to notice changes in their behaviour over time. These changes can creep up slowly, so slowly that you do not realise how much has shifted until you suddenly feel overwhelmed.

There is an old story about a frog in slowly warming water, not noticing the danger until it is too late. Caring can sometimes feel like that. You adapt to small changes day by day without realising how serious or risky things have become until it feels like too much.

It is important to remember: these changes are not personal.

Dementia affects the brain and the way a person understands and interprets the world around them. This can lead to behaviours that feel very different from the person you knew before.

Why does behaviour change?

Dementia can damage different parts of the brain. Depending on where this happens, you may notice changes in:

• Senses: Trouble recognising sights, sounds, smells or touch.

• Movement: Difficulty starting, coordinating or controlling actions.

• Communication: Struggles with finding words, understanding others or expressing thoughts.

• Memory: Forgetting recent events, names or how to do familiar tasks.

• Emotions and behaviour: Changes in mood, personality or social awareness.

• Thinking and judgement: Challenges with planning, making decisions or solving problems.
  

What these changes can look like

When these areas are affected, everyday life can look very different. Carers often describe things like:

• Repeating questions again and again, which can feel frustrating and draining.

• Social changes that may be embarrassing or uncomfortable, sometimes making you avoid going out.

• Disorientation that leads the person to follow you constantly, even into the bathroom, leaving you with little space for yourself.

• Communication breakdowns where they cannot understand your words or express themselves clearly, leaving you unsure how best to respond.

• Frustration or anger, sometimes directed at you, which can feel hurtful, aggressive or frightening.

• Loss of connection, where conversations become difficult and the person no longer engages in the same way, leaving you lonely even when you are together.

• Risks to daily life, such as forgetting to eat or drink, leaving the oven on, taking medication incorrectly or losing awareness of danger when crossing the road.

Caring in these circumstances can be emotionally and physically exhausting. Symptoms may change not only from day to day but hour to hour, which can leave you doubting what you are seeing or wondering if the person is "putting it on". In reality, these fluctuations are often part of the condition.

However, a sudden or significant change in behaviour is not always caused by dementia. 

Infections (particularly urinary or chest infections), dehydration, constipation, pain, medication side effects or delirium can all cause rapid changes in confusion or behaviour. These should always be assessed promptly by a healthcare professional.

Understanding why behaviours happen does not necessarily make them easier, but it can help protect your heart.

The behaviour is a symptom of the condition, not a reflection of the person they have always been.

When to ask for help

You do not have to wait for a crisis. If you notice any of these signs, it is time to reach out for support:

• Verbal or physical aggression.

• Severe anxiety, distress or low mood (for either of you).

• Hallucinations or delusions that are causing distress.

• Increased risk of leaving home unsafely.

• Not eating, drinking or taking medication regularly.

• Repeated falls or a sudden worsening in mobility.

• Risky behaviours such as fire hazards or giving away large sums of money.

• A sudden worsening in confusion or behaviour.

• You feeling exhausted, unsafe or at breaking point.

If you notice worrying changes, contact your GP for a review.

If you ever feel unsafe, remove yourself to a safe place, call a trusted friend or family member, or dial 999 in an emergency.

Even if you never need to use this advice, being prepared matters.

Practical Resources

There are specialist services and organisations that can help.

• Your GP is usually the first point of contact for assessment, referrals and medication reviews.

• Neighbourhood Mental Health Teams (including Specialist Older Adults Mental Health Services) provide specialist assessment and support for people with more complex dementia-related needs.

• Admiral Nurses are dementia specialist nurses who support families across the UK.

• Dementia UK offers practical advice, a national helpline and guidance on creating a personal safety plan.

• Carer support groups can reduce isolation and provide practical ideas from people who understand what you are experiencing.

East Sussex Support

In East Sussex, specialist mental health support for older adults is provided through the Neighbourhood Mental Health Teams, which include the Specialist Older Adults Mental Health Service (SOAMHS).

These teams support older adults (typically aged 70 and over, or younger people with significant frailty or complex needs) who are experiencing moderate to severe mental health difficulties, including dementia.

Support may include:

• A comprehensive assessment.

• A personalised care plan.

• Support from mental health nurses, psychiatrists, psychologists, occupational therapists and support workers.

• Advice and education for families and carers.

• Ongoing review where specialist support is needed.

Your GP is usually the first point of contact and can make a referral if specialist support is appropriate.

If you are finding it difficult to access your GP, you can also contact Health and Social Care Connect at East Sussex County Council for advice about local services and support.

The specialist team will still liaise with your GP because physical health problems such as infections, delirium, dehydration or vitamin deficiencies can sometimes cause sudden changes in behaviour and should always be ruled out.

A Final Thought

Behaviour changes can be one of the most challenging aspects of dementia, but they are also one of the clearest signs that the brain is struggling to make sense of the world.

You are not expected to manage this alone. Reaching out for help early can make life safer and less overwhelming for both you and the person you care for. Looking after yourself is not a luxury but an essential part of providing good care.