Alzheimer's disease

At a glance

  • Alzheimer's disease is the most common cause of dementia. It typically occurs in old age.
  • Memory, sense of orientation and language skills become increasingly impaired.
  • Behavior and mood can also be affected.
  • People who have Alzheimer’s need long-term help and treatment.
  • People close to them also need good support.


Photo of an elderly couple

Alzheimer's disease is the most common cause of dementia. It takes its name from the psychiatrist Alois Alzheimer, who in the early twentieth century was the first person to describe the disease. Over time, people who have Alzheimer’s lose their memory and ability to concentrate. Orientation in space and time become increasingly difficult, and it is also harder for them to manage on their own in everyday life. Those affected need more support as the disease progresses.

The course of Alzheimer’s can be positively influenced by a number of different medications and non-drug treatments – but it is not possible to cure the disease or to keep it from progressing. This makes it even more critical for people with Alzheimer’s to receive good care and support: They need loving and stable relationships and a tolerant environment. Many family members need help and assistance too.

There are other possible causes of dementia besides Alzheimer’s disease. These include problems with the flow of blood in the brain (vascular dementia). Some people – particularly older people – have both Alzheimer’s and vascular dementia. Medical conditions such as Parkinson’s disease, brain injuries or tumors can also cause dementia. Long-term heavy alcohol consumption may lead to dementia too.

There are similarities, but also differences, between the different forms of dementia: The symptoms, the course the disease takes, and the treatment options can all vary. This overview is only about Alzheimer’s.


Most people mainly associate Alzheimer’s disease with forgetfulness. But it can cause many different symptoms and develop in very different ways. Typical symptoms of Alzheimer's disease affect:

  • Memory and cognitive ability: People's memory gradually fades away. Short-term memory is affected more at first, and then later on long-term memory is as well. Their orientation in space and time and ability to concentrate also get worse.
  • Language: People with Alzheimer's disease have more and more difficulties remembering the meanings of words and finding the right words themselves. They often then use filler words or phrases that don't fit the context. This makes it harder for others to understand them. And it makes it increasingly difficult for them to understand others.
  • Mental health and changes in behavior: Lots of people with Alzheimer's become unusually anxious, distrustful, passive or even aggressive. They feel embarrassed and frustrated about forgetting things, regularly making mistakes, and needing help. It is confusing to lose orientation and control. A considerable number of them have depression and trouble sleeping, too. They might also experience euphoric phases.


In Alzheimer’s disease, more and more brain cells are lost as time goes by. It isn't clear why this happens. One thing that is known is that people with Alzheimer’s don't have enough of an important chemical messenger called acetylcholine in their brain. And it has also been shown that small protein particles (for example plaques) build up in their brain. These might cause the nerve cells to die.

But it is still not known what actually causes Alzheimer’s disease. Several factors probably play a role.

Risk factors

The risk of developing Alzheimer’s increases with age, starting at about 65. Many studies have looked at whether particular life circumstances, diseases or behaviors can increase or lower the risk of Alzheimer’s. Although research hasn't yet produced any clear answers, it does suggest that the following factors may play a role:

Potentially preventive factors include:

  • Good education
  • High levels of mental and physical activity
  • Good social network
  • A balanced diet including a lot of fruit and vegetables, legumes and nuts, olive oil and whole grains, more fish than meat, and moderate alcohol consumption

Research has shown that some people are more likely to develop Alzheimer’s than others. But just because there's a relationship between two things, it doesn't necessarily mean that one of them is causing the other. For example, if dementia is known to be more common in people who have a lower level of education, their level of education isn't necessarily the cause of their dementia. People who have a lower level of education might also live in less healthy environments – and that might be what increases their risk of Alzheimer’s disease.

The actual role of different circumstances and behaviors in the development of Alzheimer’s – and whether there are particular measures that can help prevent it – needs to be studied more closely.

Genetic risk

Not many genes are known to influence whether someone gets Alzheimer’s. In some families, several members already develop the disease in middle age. Genetic tests can be used to find out whether they have what is called early-onset Alzheimer’s. If they do, it is very likely that their siblings and children will also develop it.

There are other genetic factors that are often identified as being linked to Alzheimer’s, but they don't make it possible to predict who will develop the disease and who will not. One example is specific types of a gene called the APOE gene, which plays a role in breaking down cholesterol. Testing for these particular genes wouldn't be much help because many of the people who have them don't end up developing Alzheimer’s. So getting tested might give someone a scare for no good reason.

Genetic tests can often be misleading and have serious consequences for those involved. For this reason they should only be done at human genetics institutes where they are given carefully prepared information and consultation.


In Germany there are about 1.4 million people who have dementia. Most of them are women, mainly due to the fact that women tend to live longer than men. Dementia is mostly diagnosed in older people: A little more than 1% of all 65 to 69-year-olds are affected, compared to about 10% of all 80 to 84-year-olds. It is estimated that around 70% of people who have dementia have Alzheimer’s.


Alzheimer’s is a chronic disease that progresses over the course of many years. It typically begins after the age of 65. Alzheimer’s that starts at a younger age will usually progress faster than if it had developed later on.

Alzheimer’s disease has three stages, each of which has its own characteristic symptoms. But the changes that happen, and how fast they happen, can vary from person to person. Some symptoms may appear earlier, and others may not occur at all.

  • Early-stage Alzheimer's: People still manage to lead a largely independent life, even though it becomes increasingly difficult. People in this phase become more and more forgetful and have problems concentrating. They will almost always need help with business and financial matters or official appointments. Behavior and mood can also start to change: Being forgetful and disorientated can cause anxiety, stress, anger, and shame. Severe mood swings are possible.
  • Middle-stage Alzheimer's: People in this stage of Alzheimer’s usually have to give up living independently. They need a lot of help with everyday things. Language and orientation problems and forgetfulness become much worse. Cooking, shopping, keeping their home clean, and going out on a walk are only possible with the help of others. Fits of anger, distrust and aggressive behavior are not uncommon. People’s daily sleep-wake cycle is often affected.
  • Late-stage Alzheimer's: People now need constant help from others. It is often hardly possible to carry on a conversation, and people with Alzheimer's no longer recognize friends or family members. The control of bodily functions and the ability to coordinate movement may also be lost.

On average, people with Alzheimer’s die about six years after being diagnosed.


Alzheimer's is diagnosed if someone has the typical symptoms and no other cause can be found. A number of tests can support the . Looking at the brain using imaging techniques like (CT) or (MRI) is not enough to tell whether or not someone has Alzheimer’s disease. An examination of the brain after death is the only surefire way of finding out.

Because symptoms like forgetfulness, changes in behavior and problems with orientation can have many different causes, it is important not to rush to a of Alzheimer’s.

The symptoms might also be caused by or other physical conditions like meningitis, a stroke or bleeding in the brain. A fluid or vitamin deficiency, or side effects of medication, can sometimes also cause symptoms like these.

There are often good treatments for these things and the symptoms will then improve or disappear completely. Alzheimer’s is diagnosed only if symptoms have lasted for more than six months and any other causes are considered to be unlikely.

This means that comprehensive diagnostic tests are necessary. People generally go to their family doctor first. If it is thought that someone might have Alzheimer’s, other doctors (neurologists, psychiatrists, radiologists) are often involved. It can be helpful to have an appointment at a hospital that specializes in memory problems, particularly when the disease is still in the early stage.

Talk with the doctor

The doctor will first ask about the person’s symptoms, problems in everyday life, and general life situation. They also ask them about their mental state, for example about whether they experience mood swings or whether their emotional state has changed. Medication use, lifestyle, and physical and mental illnesses will also be discussed. It can be helpful for the person being diagnosed to bring someone along to the appointment for support. Relatives or friends often notice changes in behavior that the person affected by the disease doesn’t notice. Or the person may be too ashamed or embarrassed to talk about it.

Psychometric tests

Certain tests are done to get an idea of how far the disease has advanced and how it might progress. There are short tests where a trained specialist asks questions and gives the person short tasks testing their memory, judgment, speech and concentration. These tests usually last about 15 minutes.

Some of the commonly used tests include the mini-mental state examination (MMSE), the clock-drawing test and the dementia detection test (DemTecT). These tests can give an indication of how limiting the disease has become. To get a more exact , though, neuropsychological testing is often needed. This is more extensive.

Medical tests

There are a number of tests that can help show whether other diseases or conditions are possibly causing or influencing the symptoms. These include a physical examination, blood tests or imaging techniques like or (MRI). A lumbar puncture may also be done to take a sample of cerebrospinal fluid.


People who have Alzheimer’s need long-term help and treatment. Depending on their needs, their life situation and the stage of disease, a whole team of people may be involved in providing care. These could include trained doctors, psychologists, nurses and social workers, as well as volunteers. Both treatment with medications and non-drug interventions aim to

  • increase quality of life,
  • keep the ability to do everyday tasks and stay independent for as long as possible,
  • reduce mental health problems, and
  • help family members to cope better.

The most common medications used to treat Alzheimer’s disease include cholinesterase inhibitors, memantine and extracts from the leaves of the Ginkgo biloba tree.

Examples of non-drug treatments include memory and orientation training, doing everyday activities as a group, or art therapy, aromatherapy, and animal-assisted or music therapy. Physical activities and massages can help too. Caregiver training for family members is important too.

Training for people close to those affected is usually key to the treatment and support being successful on a daily basis. Along with care advice and courses, long-term care insurers also offer special, free workshops for people who have a family member with Alzheimer's.

Everyday life

Being diagnosed with Alzheimer’s disease comes as a shock to most people. But sometimes the makes it easier to understand previously inexplicable changes in behavior or personality.

How someone reacts to and deals with the disease not only depends on the changes in their brain, but also on that individual’s personality, their past, and their current circumstances and relationships with other people.

Some people are able to accept the disease and to go on living an active and satisfying life for as long as possible despite having Alzheimer’s. Others have a harder time. Most people need support. The disease is also a major challenge for family and friends. Sharing experiences with others affected by the disease and those close to them, for example in a support group, is often considered to be helpful.

There will be many decisions to be made eventually: about everyday support, but also about treatments, care at later stages of the disease, and the most suitable place to live (at home, in a nursing home or in group living). People with Alzheimer's want to play an active role in the decisions that affect them and their concerns for as long as possible. They want people to talk with them, not just about them.

It is important for those close to them to be involved in treatment plans and to be offered support that matches their personal situation and needs. As well as training, this can include practical matters like financial support and advice on applying for assistance.

People close to someone with late-stage Alzheimer's disease requiring more and more comprehensive care will eventually reach the limits of what they can do. A move to a facility providing care, support and medical treatment by specialists can then be the best solution for everyone. It is often not easy to make the decision to move into a care home or sheltered group living, particularly because it can take some time until a suitable place is found. But there are more and more good options for people with Alzheimer's in particular nowadays, offering dedicated and special care tailored to their needs.

Further information

Many cities in Germany offer support groups and assistance for people with Alzheimer’s in everyday life or help for caregiving family members. This includes services providing daytime care, training courses on how to care for people with Alzheimer’s, as well as self-help groups for family members. The main caregiver also has a legal right to request additional care if they get ill themselves or need some time off.

Many cities across Germany have care support centers [in German: Pflegestützpunkte] which can be contacted for information on nursing care insurance, outpatient care and other support services available in the local area.

More information about care can be found in the "Alzheimer's Disease Advice Brochure" from the German Federal Ministry of Health and the Federal Government. The German Federal Ministry for Family Affairs, Senior Citizens, Women and Youth also offers a guide to Alzheimer's.

Alzheimer Europe. Dementia in Europe Yearbook 2019.

Alzheimer Research Forum (ARF). AlzRisk AD Epidemiology Database. 2018.

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Bunn F, Goodman C, Sworn K et al. Psychosocial factors that shape patient and carer experiences of dementia diagnosis and treatment: a systematic review of qualitative studies. PLoS Med 2012; 9(10): e1001331.

Deutsche Gesellschaft für Psychiatrie und Psychotherapie, Psychosomatik und Nervenheilkunde (DGPPN), Deutsche Gesellschaft für Neurologie (DGN). S3-Leitlinie Demenzen. AWMF-Registernr.: 038 - 013. 2016.

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Ohman A, Josephsson S, Nygard L. Awareness through interaction in everyday occupations: experiences of people with Alzheimer's disease. Scand J Occup Ther 2008; 15(1): 43-51.

Phinney A, Moody EM. Leisure connections: benefits and challenges of participating in a social recreation group for people with early dementia. Activities, Adaptation & Aging 2011; 35(2): 111-130.

Robert Koch-Institut (RKI), Statistisches Bundesamt (Destatis). Altersdemenz. (Gesundheitsberichterstattung des Bundes; Heft 28). 2005.

Stechl E, Lämmler G, Steinhagen-Thiessen E et al. Subjektive Wahrnehmung und Bewältigung der Demenz im Frühstadium - SUWADEM: Eine qualitative Interviewstudie mit Betroffenen und Angehörigen. Z Gerontol Geriatr 2007; 40(2): 71-80.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on March 29, 2022

Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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