The symptoms of Alzheimer's disease progress slowly over several years. Sometimes these symptoms are confused with other conditions and may initially be put down to old age.

The rate at which the symptoms progress is different for each individual.

In some cases, other conditions can be responsible for symptoms getting worse.

These conditions include:

• infections
• stroke
• delirium

As well as these conditions, other things, such as certain medicines, can also worsen the symptoms of dementia.

Anyone with Alzheimer's disease whose symptoms are rapidly getting worse should be seen by a doctor so these can be managed.

There may be reasons behind the worsening of symptoms that can be treated.

Generally, the symptoms of Alzheimer's disease are divided into 3 main stages.

Early symptoms

In the early stages, the main symptom of Alzheimer's disease is memory lapses.

For example, someone with early Alzheimer's disease may:

• forget about recent conversations or events
• misplace items
• forget the names of places and objects
• have trouble thinking of the right word
• ask questions repetitively
• show poor judgement or find it harder to make decisions
• become less flexible and more hesitant to try new things

There are often signs of mood changes, such as increasing anxiety or agitation, or periods of confusion.

Middle-stage symptoms

As Alzheimer's disease develops, memory problems will get worse.

Someone with the condition may find it increasingly difficult to remember the names of people they know and may struggle to recognise their family and friends.

Other symptoms may also develop, such as:

• increasing confusion and disorientation – for example, getting lost, or wandering and not knowing what time of day it is
• obsessive, repetitive or impulsive behaviour
• delusions (believing things that are untrue) or feeling paranoid and suspicious about carers or family members
• problems with speech or language (aphasia)
• disturbed sleep
• changes in mood, such as frequent mood swings, depression and feeling increasingly anxious, frustrated or agitated
• difficulty performing spatial tasks, such as judging distances
• seeing or hearing things that other people do not (hallucinations)

Some people also have some symptoms of vascular dementia.

By this stage, someone with Alzheimer's disease usually needs support to help them with everyday living.

For example, they may need help eating, washing, getting dressed and using the toilet.

Later symptoms

In the later stages of Alzheimer's disease, the symptoms become increasingly severe and can be distressing for the person with the condition, as well as their carers, friends and family.

Hallucinations and delusions may come and go over the course of the illness, but can get worse as the condition progresses.

Sometimes people with Alzheimer's disease can be violent, demanding and suspicious of those around them.

A number of other symptoms may also develop as Alzheimer's disease progresses, such as:

• difficulty eating and swallowing (dysphagia)
• difficulty changing position or moving around without assistance
• weight loss – sometimes severe
• unintentional passing of urine (urinary incontinence) or stools (bowel incontinence)
• gradual loss of speech
• significant problems with short- and long-term memory

In the severe stages of Alzheimer's disease, people may need full-time care and assistance with eating, moving and personal care.

Read more about how Alzheimer's disease is treated.

If you're worried about your memory or think you may have dementia, it's a good idea to see a GP.

If you're worried about someone else's memory problems, encourage them to make an appointment and perhaps suggest that you go along with them.

Memory problems are not just caused by dementia – they can also be caused by depression, stress, medicines or other health problems.

A GP can carry out some simple checks to try to find out what the cause may be, and they can refer you to a specialist for more tests if necessary.

Read more about diagnosing Alzheimer's disease.