Aggressive behaviour and dementia

Read our information for carers about aggression and dementia, what we mean by aggressive behaviour and why a person with dementia may behave aggressively.

Can dementia cause aggressive behaviour?

As a person’s dementia progresses, they may sometimes behave in ways that are physically or verbally aggressive.

This can be very distressing for the person and for those around them. Looking at what causes this behaviour and being aware of the person’s needs can help to reduce this behaviour or make it easier to manage.

Discussions about Changes in behaviour in our online community, Talking Point...
Discussions about Changes in behaviour...

Aggressive behaviour may be:

  • verbal – for example, swearing, screaming, shouting or making threats
  • physical – for example, hitting, pinching, scratching, hair-pulling, biting or throwing things.

Some people assume that aggressive behaviour is a symptom of dementia itself. This can be true, but it’s more likely that there is another cause. It’s important to see beyond the behaviour and think about what may be causing it. Reasons for the person’s behaviour could include:

  • difficulties to do with dementia – for example, memory loss, language or orientation problems
  • their mental and physical health – for example, they may have pain or discomfort that they are unable to communicate
  • the amount and type of contact they have with another person or other people
  • their physical surroundings – 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
  • frustration and confusion at not being able to do things, or at not being able to make sense of what is happening around them.

Aggression may be linked to the person’s personality and behaviour before they developed dementia. However, people who have never been aggressive before may also develop this type of behaviour. Dementia can affect a person’s personality and habits.

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 impatient or anxious, they may be even more so now that they have dementia. It’s important to think of the person’s point of view – see ‘Preventing and reducing the impact of aggressive behaviour’.

Aggression is one of a number of behaviours – often called ‘behaviours that challenge’ – that can result from dementia. These behaviours can be just as challenging for the person as for those supporting them. Others include agitation and restlessness, walking about, and being sexually inappropriate.

You can read more about changes in behaviour, or listen to an audio version of our factsheet below:

What causes aggressive behaviour in people with dementia?

As human beings, we all have the same basic needs. These include physical, psychological and social needs. We do things consciously and unconsciously to meet these needs. The symptoms of dementia can make it more difficult for someone to do this.

For example, people with dementia can find it hard to understand what’s going on around them. This can be confusing and frightening for them. It is likely that they are trying to stop feeling distressed and to feel calmer again. For example, if someone they do not know well or who they no longer recognise is trying to help them undress, they may feel threatened and try to push the person away.
Aggressive behaviour may be:

  • caused by the person feeling agitated because of a need that isn’t being met
  • the person’s attempt to meet a need (for example, they may remove clothing because they are too hot, and get angry if they are told to stop)
  • the person’s attempt to communicate a specific need to others (for example, they may shout out because they need the toilet).

See below for examples of how different types of needs may cause a person with dementia to act aggressively.

  • The person may be in pain or discomfort. For example, they may be thirsty or need the toilet. They could have an infection, constipation, toothache or have been in one position for too long. This can lead to agitation or anger.
  • The person may experience side effects from medication, such as drowsiness or confusion, which can cause frustration or make it harder for them to communicate their needs.
  • The environment may not be comfortable for the person or appropriate for what they want to do. For example, it could be too noisy for them to be able to have a conversation, or too hot. Make changes to their surroundings if necessary. For example, this could mean reducing background noise, improving the lighting or adjusting the temperature.
  • The person may be disorientated or forget the layout of their home, which can cause frustration. For example, they may forget where the toilet is. Or they may forget where certain items are kept. 
  • The person may have a condition such as sight loss or hearing loss. This can mean that they mistake something they see, hear, smell or touch for something else. This can cause confusion and frustration. The person should have their eyesight and hearing tested. Make sure they wear glasses and a hearing aid that are clean and working properly, if they need them.
  • The person may be having delusions (strongly believing things that aren’t true), or hallucinations (seeing things that aren’t there). This can be confusing and frightening, so the person with dementia may respond in an aggressive way.
  • The person may be sexually frustrated and become agitated as a result. 
  • The person’s dementia may have affected their judgement and self-control. They may have lost their inhibitions or be less aware of what kind of behaviour is appropriate in a given situation.
  • The person may be frustrated by their situation – for example, not being able to do the things they used to. They may also be frustrated if other people assume they can’t do things for themselves and take over. Being left out of decisions may make the person feel angry or upset.
  • The person may be depressed or have another mental health condition.
  • The person may feel threatened or unsettled by an environment that appears strange or unfamiliar. They may think that they are in the wrong place, or that there are strangers in their home, and they need to protect themselves.
  • The person may seem to experience reality differently to you. For example, they may believe they have to go to pick up children from school even though their children are adults. They may become aggressive if they are stopped from doing so.
  • The person may misunderstand the intentions of the person caring for them. For example, they may see personal care as threatening or an invasion of their personal space.

Consider whether they may benefit from psychological therapies with professionals, such as cognitive stimulation therapy or counselling.

  • The person may be feeling lonely or isolated. They might not spend much time with others, or they may not feel included. They may lose confidence and social skills because of this.
  • They may be bored or not have much to stimulate their senses, which may cause irritation or anger.
  • If the person has different visitors, such as care workers, they may all have their own different approaches and routines. This can be confusing for the person. The person may also not like a particular care professional or their approach.
  • The person may be trying to hide their condition from others and become angry if it is mentioned.
  • The person may not be aware of the difficulties they’re having and become irritated if these are mentioned.

The person’s aggressive behaviour may be their response to feeling they’re not able to contribute or are not valued by others. Try to encourage the person to have a daily routine and to do as much as they can for themselves. Support them to be as independent as they are able to be.

Staying connected can help someone feel comforted and stimulated. Help the person to stay in touch with other people. For example, help to arrange visits, or phone or video calls. Social media and messaging apps on tablets or smartphones can also be useful. However, it’s important to ensure the person is safe online and does not share personal details.

Support the person to do things they enjoy or find useful. This can relieve boredom, increase their mood, and keep them engaged and stimulated. For example, they may enjoy activities such as making music or exercising, or activities that engage their senses.

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