Dementia can have a very big effect on the person affected. They may fear their loss of memory and thinking skills, but they also fear the loss of who they are.

They may also find they do not understand what's going on or why they feel they're not in control of what's happening around them or to them. All of this can affect their behaviour.

In the middle to later stages of most types of dementia, a person may start to behave differently. This can be distressing for both the person with dementia and those who care for them.

Some common changes in behaviour include:

• repeating the same question or activity over and over again
• restlessness, like pacing up and down, wandering and
  fidgeting
• night-time waking and sleep disturbance
• following a partner or spouse around everywhere
• loss of self-confidence, which may show as apathy or disinterest in their usual activities

If you're caring for someone who's showing these behaviours, it's important to try to understand why they're behaving like this, which is not always easy.

You may find it reassuring to remember that these behaviours may be how someone is communicating their feelings. It may help to look at different ways of communicating with someone with dementia.

Sometimes these behaviours are not a dementia symptom. They can be a result of frustration with not being understood or with their environment, which they no longer find familiar but confusing.

Although changes in behaviour can be difficult to deal with, it can help to work out if there are any triggers.

For example:

• Do some behaviours happen at a certain time of day?
• Is the person finding the home too noisy or cluttered?
• Do these changes happen when a person is being asked to do something they may not want to do?

Keeping a diary for 1 to 2 weeks can help identify these triggers.

If the change in behaviour comes on suddenly, the cause may be a health problem. The person may be in pain or discomfort from constipation or an infection.

Ask a GP for an assessment to rule out or treat any underlying cause.

Keeping an active social life, regular exercise, and continuing activities the person enjoys, or finding new ones, can help to reduce behaviours that are out of character.

Read more about activities for dementia.

Other things that can help include:

• providing reassurance
• a quiet, calming environment
• activities that give pleasure and confidence, like listening to music or dancing
• therapies, such as animal-assisted therapy, music therapy, and massage

Remember also that it's not easy being the person supporting or caring for a person with behaviour changes. If you're finding things difficult, ask for support from a GP.

Repeating the same question or activity may be a result of memory loss where the person cannot remember what they've said or done.

It can be frustrating for the carer, but it's important to remember that the person is not being deliberately difficult.

Try to:

• be tactful and patient
• help the person find the answer themselves, for example, if they keep asking the time, buy an easy-to-read clock and keep it in a visible place
• look for any underlying theme, such as the person believing they're lost, and offer reassurance
• offer general reassurance, for example, that they do not need to worry about that appointment as all the arrangements are in hand
• encourage someone to talk about something they like talking about, for example, a period of time or an event they enjoyed

People with dementia often develop restless behaviours, such as pacing up and down, wandering out of the home and agitated fidgeting.

Try to:

• make sure the person has plenty to eat and drink
• have a daily routine, including daily walks
• accompany them on a walk to shops or consider tracking devices and alarm systems (telecare) to keep them safe
• give them something to occupy their hands if they fidget a lot, such as worry beads or a box of items that mean something to them

Dementia can cause problems with the person's body clock, or sleep-wake cycle.

A person with dementia may get up repeatedly during the night, unaware that it's night time.

This can be particularly hard on carers, as their sleep is disturbed, too.

Try to:

• provide plenty of activity and exposure to daylight
• make sure the bedroom is comfortable and provide a nightlight or blackout blinds if needed
• cut down on caffeine and alcohol in the evening

Dementia makes people feel insecure and anxious. They may "shadow" their partner or carer as they need constant reassurance they're not alone and they're safe.

They may also ask for people who died many years ago, or ask to go home without realising they're in their own home.

Try to:

• have the person with you if you're doing chores such as ironing or cooking
• reassure them that they're safe and secure if they're asking to go home
• avoid telling them someone died years ago and talk to them about that period in their life instead

Dementia can make people feel less confident about going out or doing other activities. This may seem like they've lost interest in people or activities they usually enjoy.

Try to:

• remember they may still be interested in an activity but feel they'll have trouble coping with it
• reassure them the activity, or getting there, will be straightforward
• explain clearly where they are going and who they may be seeing
• consider simpler activities or social occasions, as, for example, joining in a conversation among a large group of people may be too difficult

In the later stages of dementia, some people with dementia will develop what's known as behavioural and psychological symptoms of dementia (BPSD).

The symptoms of BPSD can include:

• increased agitation
• aggression (shouting or screaming, verbal abuse, and sometimes physical abuse)
• delusions (unusual beliefs not based on reality)
• hallucinations (hearing or seeing things that do not exist)

These types of behaviours and psychological symptoms are very distressing for the carer and for the person with dementia.

It's very important to ask your doctor to rule out or treat any underlying causes, such as:

• uncontrolled pain
• untreated depression
• infection, such as a urinary tract infection (UTI)
• side effects of medicines

If the person you're caring for behaves in an aggressive way, try to stay calm and avoid confrontation. You may have to leave the room for a while.

If none of the coping strategies works, an antipsychotic medicine can be prescribed as a short-term treatment. This should be prescribed by a consultant psychiatrist.

Your needs as a carer are as important as the person you're caring for.

To help care for yourself:

• join a local carers' support group or a specialist dementia organisation – for more details, call the Carers Direct helpline on 0300 123 1053; lines are open 9am to 8pm Monday to Friday, and 11am to 4pm at weekends
• call Dementia UK's Admiral Nurse Dementia Helpline free on 0800 888 6678 to talk to a registered specialist dementia nurse; lines are open 9am to 9pm Monday to Friday, 9am to 5pm at weekends
• share your experiences with other carers on online forums, such as Alzheimer's Society's Dementia Support Forum and the Carers UK forum
• try to make some time for yourself, but if it's difficult to leave the person alone, ask if someone can be with them for a while, such as a friend, relative, or someone from a support group
• consult a GP if you're feeling low or depressed as you may benefit from counselling or other talking therapies

Read more about caring for someone with dementia.

Get more advice on managing challenging behaviour from the Alzheimer's Society.

Find dementia information and support.