Alzheimer’s disease: Symptoms and outlook

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Most people mainly associate Alzheimer’s disease with forgetfulness. But it can cause many different symptoms. Even though it develops very individually, there are three different main stages.

The symptoms and course of Alzheimer’s disease depends not only on changes in the brain but also on the person's general physical fitness, their personality, and their life history. Current life circumstances and relationships with other people can affect how Alzheimer's develops.

What are the typical symptoms of Alzheimer’s disease?

Memory and cognitive ability

Most people’s memory and other cognitive abilities gradually get worse as they get older. No longer being able to react as quickly and flexibly to new situations is a natural part of aging. It often becomes harder to recognize and solve problems in new areas. But it is still possible to access the knowledge that has been gained over the years, and stay oriented, independent, and able to make sound judgments.

This is different in people who have Alzheimer’s disease. Their memory gradually fades away. At first, short-term memory is affected more. This means that they forget about events that have just happened, but can still remember experiences from long ago. But long-term memory also fades with time. The ability to concentrate is affected too, making it more and more difficult to maintain orientation in time and space.

It becomes harder to link things that were learned in the past to new situations or impressions. There comes a point when it is no longer possible to understand contexts or assess information, formulate an opinion and then decide what to do. An example: A person who has late-stage Alzheimer’s can see that it's raining outside, and can express this fact in words. But they will not be able to draw conclusions for their own actions. They may then go out to do their shopping in an undershirt instead of putting on a raincoat or taking an umbrella.

Activities that are made up of several steps (like shopping or cooking) become more and more difficult as someone’s memory, comprehension and planning skills start to fade. In early-stage Alzheimer’s, completing more complex business matters can be a problem. For instance, doing taxes may become an insurmountable challenge. Forgetfulness might not only mean forgetting things like what you wanted to buy or why you left the house, but can also make you more likely to get lost and have problems finding your way home again.


We all have to search for the right word or feel tongue-tied now and then. But forgetting individual words more and more frequently is a different matter. As dementia progresses, it becomes more difficult to remember the right words, and people use words or phrases that do not match the context instead. This makes it difficult for others to understand them. And people with dementia also forget the meaning of words and are then often no longer able to follow conversations. This makes it increasingly harder to communicate verbally.

Mental health and changes in behavior

Many people with Alzheimer’s go through noticeable changes in their behavior. Later on their personality may also change considerably. They can become unusually fearful, distrustful or passive, or may become aggressive as well. These changes can happen suddenly, and might cause fits of rage – or they may develop gradually, as with listlessness. Abnormal behavior like this may be related to the disease. But fear, passivity or aggression can sometimes be perfectly normal reactions to the circumstances of living with the disease: After all, a person who has Alzheimer’s keeps finding themselves in situations that are confusing and in which they behave “wrongly.”

Plus there is the shame and frustration of forgetting more and more, being wrong a lot of the time, and gradually losing your independence. Many people who have Alzheimer’s feel that others are being patronizing, and are worried about being seen only as a sick and needy person. A considerable number of people with Alzheimer’s have depression and trouble sleeping, too. They might also experience unusually euphoric phases.

How does Alzheimer’s disease develop?

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

In early-stage (mild) Alzheimer’s, people have a bit more trouble managing their lives on their own, but they can usually still lead independent lives. It's often difficult to tell the difference between early-stage symptoms and normal forgetfulness due to aging. There is no clear cut-off point between the normal problems associated with aging and mild Alzheimer's. But forgetfulness, absentmindedness and trouble concentrating mean that more complex everyday tasks are difficult to perform.

People who have early-stage Alzheimer’s will almost always need help with business and financial matters or official appointments. Driving and taking medication regularly are two other critical areas.

Behavior and mood can already change in early-stage Alzheimer’s. The limitations resulting from the disease can cause fear, stress, anger, or even feelings of shame: It can be embarrassing to forget things and lose your orientation. And it takes a lot of strength to find strategies to deal with these problems.

A person’s inner drive and interest in hobbies or other activities may fade. Some people feel down or irritable, or they may have intense mood swings. These mood swings – making people suddenly burst into tears for no apparent reason, for example – are often puzzling as well as draining for other family members.

Middle-stage Alzheimer's

People with middle-stage (moderate) Alzheimer’s usually have to give up living independently. They can still eat, drink and wash themselves, and perhaps do simple tasks around the home or garden, but may have to be reminded and asked to do so. Cooking, shopping, keeping their home clean, and going out on a walk are only possible with the help of others.

They are more likely to get lost, not find their way back home, leave the stove on and endanger themselves or others. Patterns of behavior such as frantic pacing, seemingly meaningless rummaging through drawers and fiddling with clothing become more frequent. Fits of rage, distrust and aggressive behavior are also consequences of problems associated with Alzheimer’s that affect the person’s perception and limit their abilities.

People’s daily sleep-wake cycle is often affected. It becomes more difficult for them to express things in words and understand what other people say. They also confuse the past with the present. For instance, they may falsely believe that their parents are still alive and are expecting them to come back home.

Late-stage Alzheimer's

In late-stage (severe) Alzheimer’s, people need constant help from others. Speech and language problems may start making conversation barely possible. They now even need help to accomplish simple everyday activities, and to eat and drink.

People who have late-stage Alzheimer’s are often restless, hallucinate or confuse the past with the present. They no longer recognize people who they used to know very well. 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.

Ballard C, Gauthier S, Corbett A et al. Alzheimer's disease. Lancet 2011; 377(9770): 1019-1031.

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

Livingston G, Sommerlad A, Orgeta V et al. Dementia prevention, intervention, and care. Lancet 2017; 390(10113): 2673-2734.

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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Created on March 29, 2022

Next planned update: 2025


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

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