What causes changes in behaviour?

When a person with dementia starts to behave in ways that seem out of character, some people wrongly assume this is just another symptom of the condition.

It’s important to see beyond the behaviour itself and think about what may be causing it. There may be specific reasons why the person with dementia is behaving differently, such as:

  • difficulties relating to dementia (such as memory loss, language or orientation problems)
  • their mental and physical health
  • whether they’re interacting with other people and the environment around them and how they are doing this. For example, if the room is too dark the person may become confused and distressed because they can’t work out where they are
  • a sense of being out of control, frustration with the way others are behaving, or a feeling that they’re not being listened to or understood.

Dementia can have an impact on a person’s personality and habits, which may lead to changes in behaviour.

Knowing the person – how they react to and deal with things, their preferences, routines and history – can help when it comes to supporting them.

For example, if the person has always been stubborn or anxious, they may be even more so now they have dementia.

Communicating unmet needs

We all have the same basic needs – a mix of physical, psychological and social factors. People with dementia may be less able to recognise their needs, know how to meet them, or communicate them.

Changes in their behaviour may be:

  • caused by them having needs that aren’t being met
  • their attempt to meet a need (for example – they may remove clothing because they are too hot)
  • their attempt to communicate a need to others (for example – they may shout out because they need the toilet).

Because of their dementia they may also find it more difficult to tell you what they need using words. Their behaviour may be the best way for them to communicate what they want.

Our helpline advisers are here for you.

Examples of how the different types of needs may affect someone’s behaviour

Physical needs

  • The person may be in pain or discomfort – they may be constipated or thirsty, or in pain from an infection such as a urinary tract infection (UTI) or from being in one position for too long.
  • Too many medications or the side effects of medication may lead to a person becoming drowsy and confused. This can make it harder for the person to meet their needs or communicate them.
  • The environment may not be supporting the person. For example, it could be too hot or too noisy, or there might not be enough for the person to do.
  • Other conditions (such as sight or hearing loss) might mean the person misunderstands or misperceives things in their environment (mistaking something they see, hear, smell or touch for something else).
  • The person may be having delusions (strongly believing things that aren’t true) or hallucinations (seeing things that aren’t really there). These can be confusing and frightening and may affect how the person reacts to a situation.

Psychological needs

  • The person may be frustrated by their situation and not being able to do the things they used to. They may be frustrated if other people assume they can’t do things for themselves and take over or leave them out of decisions.
  • The person may be depressed or have other mental health problems.
  • They may feel threatened by an environment that doesn’t seem right or familiar. They may think they are in the wrong place.
  • They may not be able to understand and work out the world around them. Their sense of reality may be different to those around them. For example, they may believe they have to go to work even though they’re no longer working.
  • The person may not understand the intentions of those caring for them. For example, they may see personal care as threatening or an invasion of their personal space. It can be especially confusing and frightening if the person doesn’t understand what is happening.

Social needs

  • The person may be feeling lonely or isolated. They might not spend much time with others or they may not feel included.
  • They may be bored and not have much to stimulate them or their senses (sight, hearing, touch, smell and taste).
  • If the person has different people coming into their home, such as care workers or neighbours, they may all have their own approaches and routines. This can be confusing.
  • The person may be trying to ‘hide’ their condition from others or may not be aware of the difficulties they’re having.

Think of the person’s point of view

People with dementia sometimes struggle to understand what’s going on around them, and this can be confusing and frightening.

You might not understand their behaviour, and this can be frustrating for you – but the behaviour will have meaning for the person with dementia. It is likely to be their attempt to stop feeling confused or distressed and to feel well again. Always try to see things from the person’s perspective.

Sight, perception and hallucinations

Some people with dementia may encounter problems with their sight, which might cause them to misunderstand or misperceive things in their environment.

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