Early onset Alzheimer’s disease (AD) affects people in their 40s and 50s. However, an early AD diagnosis is difficult because a decline in memory, cognitive, or physical abilities may be attributed to life events.

Alzheimer’s disease (AD) is a type of dementia that affects more than 5 million people in the United States and over 50 million people worldwide.

Although it’s commonly known to affect adults 65 years and older, about 5 percent of those with the diagnosis have early onset AD, sometimes called “younger onset.” This generally means that the person with the diagnosis is in their 40s or 50s.

It can be difficult to obtain a true diagnosis at this age because many symptoms may appear to be a result of typical life events, such as stress.

As the disease affects the brain, it can cause a decline in memory, reasoning, and thinking abilities. The decline is typically slow, but this can vary on a case-by-case basis.

AD is the most common form of dementia. Dementia is a general term for the loss of memory functions or other mental abilities that affect your daily life.

You or a loved one may be developing early onset AD if you experience any of the following:

Memory loss

You or a loved one may begin to appear more forgetful than usual. Forgetting important dates or events can occur.

If questions become repetitive and frequent reminders are required, you should contact your doctor.

Difficulty planning and problem solving

AD may become more apparent if you or a loved one has difficulty developing and following a plan of action. Working with numbers may also become difficult.

This can often be seen when you or a family member begins to demonstrate problems maintaining monthly bills or a checkbook.

Difficulty completing familiar tasks

Some people may experience a greater problem with concentration. Routine day-to-day tasks requiring critical thought may take longer as the disease progresses.

The ability to drive safely may also be called into question. If you or a loved one gets lost while driving a commonly traveled route, this may be a symptom of AD.

Difficulty determining time or place

Losing track of dates and misunderstanding the passage of time as it occurs are also two common symptoms. Planning for future events can become difficult because they aren’t immediately occurring.

As symptoms progress, people with AD can become increasingly forgetful about where they are, how they got there, or why they’re there.

Vision loss

Vision problems can also occur. This may be as simple as an increased difficulty in reading.

You or a loved one may also begin to have problems judging distance and determining contrast or color when driving.

Difficulty finding the right words

Initiating or joining in on conversations may appear difficult. Conversations may randomly be paused in the middle, as you or a loved one may forget how to finish a sentence.

Because of this, repetitive conversations can occur. You may have difficulty finding the right words for specific items.

Misplacing items often

You or a loved one may begin putting items in unusual places. It may become more difficult to retrace your steps to find any lost items. This may lead you or a loved one to think that others are stealing.

Difficulty making decisions

Financial choices may demonstrate troubles with judgment. This symptom often causes detrimental financial effects. An example of this is donating large amounts of money to telemarketers.

Physical hygiene also becomes less of a concern. You or a loved one may experience a rapid decline in bathing frequency and a lack of willingness to change clothing on a daily basis.

Withdrawing from work and social events

As symptoms appear, you may notice that you or a loved one becomes increasingly withdrawn from common social events, work projects, or hobbies that were previously important. Avoidance can increase as symptoms worsen.

Experiencing personality and mood changes

Extreme swings in mood and personality may occur. A noticeable change in moods may include:

You may notice that you or your loved one is increasingly irritated when something outside a typical routine takes place.

Although AD isn’t an expected part of advancing age, you’re at increased risk as you get older. More than 32 percent of people over age 85 have AD.

You may also have an increased risk of developing AD if a parent, sibling, or child has the disease. If more than one family member has AD, your risk increases.

A 2016 study showed that African Americans, Native Americans, and Native Alaskans are at higher risk for developing early onset AD compared to white people.

Prevalence of early onset AD

Early onset AD affects approximately 220,000 to 640,000 people in the United States.

The exact cause of early onset AD hasn’t been fully determined. Many researchers believe that this disease develops as the result of multiple factors rather than one specific cause.

Researchers have discovered rare genes that may directly cause or contribute to AD. These “deterministic genes” are:

  • amyloid precursor protein (APP) on chromosome 21
  • presenilin-1 (PS1) on chromosome 14
  • presenilin-2 (PS2) on chromosome 1

These genes may be carried from one generation to the next within a family. Carrying these genes can result in adults younger than age 65 developing symptoms much earlier than expected.

Mutations in these genes account for only 5 to 10 percent of all Alzheimer’s cases but a majority of early onset AD cases.

Apolipoprotein E (APOE-e4) is another gene associated with AD. It’s more commonly a factor in people who develop AD after age 65.

Early onset AD cannot be prevented, but you can reduce your risk. People who take steps to reduce their risk of early onset AD can still develop the disease.

Lifestyle changes that help reduce risk include:

Talk with a doctor if you or a loved one is finding it increasingly difficult to perform day-to-day tasks, or if you or a loved one is experiencing increased memory loss. They may refer you to a doctor who specializes in AD.

Especially in the case of early onset AD, symptoms may seem to be related to other causes, like stress.

There’s no one test to diagnose AD. Your doctor may use many different tools to arrive at a diagnosis. These include:

Recent research has focused on blood tests that can identify proteins associated with AD in the blood. While these show promise, more research is needed.

There’s no cure for AD at this time. Detecting the disease early on can help with treatment options and managing symptoms.

Symptoms of AD can sometimes be treated with medications meant to help improve memory loss or decrease sleeping difficulties. These medications include

Research is still being done on possible alternative treatments.

Some activities and habits can help both the person with AD and their caregiver to manage symptoms and behavioral problems. These include:

  • maintaining a familiar environment
  • getting exposure to sunlight
  • eating a healthy diet
  • reducing or eliminating alcohol consumption
  • doing relaxation techniques to reduce stress
  • doing aerobic exercises

Since early onset AD can affect people in their 40s and 50s, symptoms can sometimes be more disruptive to work, social, and family life. Managing symptoms of early onset AD often focuses on more age-appropriate support.

Specific support may include:

  • occupational therapy
  • speech therapy
  • vision therapy

Receiving an early onset AD diagnosis can be worrying. Now is the time to put together a plan so that you have peace of mind for the future when symptoms appear or intensify.

Try creating a plan together with your family, friends, and medical team. It can also be beneficial to meet with a financial planner and a lawyer.

Here are some key things to consider:

  • Education. You may find it helpful to learn more about AD and how it progresses. Talk with your doctor and learn about what your care plan could look like in the future.
  • Health insurance. Find out which medications and treatments are covered by your plan.
  • Future care costs. What will your medical and care expenses be? This may include professional home care of safety equipment for the home.
  • Disability insurance. What is covered by your employer? What documentation is needed?
  • Loss of income. Will you be able to keep working? If so, for how long? Will someone in your family need to stop working in order to become a caregiver?
  • Power of attorney. Who will have the authority to make health, financial, and legal decisions for you when you can’t any more?
  • Support. Try finding a support group specifically for people with early onset AD and their caregivers. Their life situations are likely to be more similar to yours.

It’s important to have a detailed, realistic plan for your future care. This will allow you to be more confident as you navigate through the stages of AD.

The symptoms of AD may worsen over time. For many people, a period of 2 to 4 years will pass between the onset of symptoms and receiving an official diagnosis from their doctor. This is considered to be the first stage.

After receiving a diagnosis, you or a loved one may enter the second stage of the disease. This period of mild cognitive impairment can last anywhere from 2 to 10 years.

During the final stage, Alzheimer’s dementia may occur. This is the most severe form of the disease. You or a loved one may experience periods of total memory loss and may need help with tasks such as financial management, self-care, and driving.

If you or a loved one has AD, there are many resources available that can provide you with more information or connect you with face-to-face support services.

The National Institute on Aging offers an extensive literature database and has information about the most current research.

The Alzheimer’s Association also provides valuable information for caregivers about what to expect at each stage of the disease.