What is Alzheimer’s Disease? Causes and Symptoms

Alzheimer's Disease

Alzheimer’s disease is a progressive neurologic disorder that leads to the brain shrinking (atrophying) and brain cells dying. Alzheimer’s disease affects a person’s ability to function independently by causing a gradual decline in mental, behavioral and social abilities.

According to the Alzheimer’s Association, 5.8 million Americans 65 and older are living with Alzheimer’s disease. Nearly 80% are over 75 years old. Alzheimer’s disease is estimated to be the cause of dementia in 60% to 70% of the 50 million people worldwide who have it.

Alzheimer’s disease displays early symptoms such as forgetting recent events or conversations. The impact of Alzheimer’s disease on daily tasks and memory impairment progresses as the disease progresses.

Temporarily improving symptoms or slowing the progression may be possible with medication. Alzheimer’s patients may benefit from these treatments by maximizing function and maintaining independence for a time. People with Alzheimer’s disease and their caregivers can be supported by a variety of programs and services.

Alzheimer’s disease cannot be cured or altered by any treatment. Death occurs from severe impairment of the function of the brain in advanced stages of the disease, such as dehydration, malnutrition or infection.

Read: Parkinson’s Disease

How common is Alzheimer’s disease?

It is estimated that Alzheimer’s disease causes 60 percent to 80 percent of all dementia cases. The United States has the sixth highest mortality rate due to Alzheimer’s disease.

There is a 20% chance of developing Alzheimer’s disease among people over 65 and nearly 50% chance of developing it among people over 85. People in their 40s can also be affected by Alzheimer’s disease. Every decade, the number of people with Alzheimer’s disease increases. In 2050, 106 million people worldwide will be living with Alzheimer’s disease due to the aging population and the absence of successful treatments, according to the Alzheimer’s Association.

Dementia vs. Alzheimer’s

There is some confusion between dementia and Alzheimer’s disease. It is important to understand that these two conditions are not the same. There are many types of dementia, but Alzheimer’s is one of them.

The term dementia covers a large range of conditions that cause memory loss, including forgetfulness and confusion. It is possible to develop these symptoms as a result of dementia and other conditions, such as Alzheimer’s disease, Parkinson’s disease, and traumatic brain injury.

It is possible for these conditions to have different causes, symptoms, and treatments.

Younger onset Alzheimer’s

People over 65 are more likely to suffer from Alzheimer’s disease. People can develop this disease as young as their 30s, 40s, or 50s. Earlier onset Alzheimer’s is known as younger onset. The type of Alzheimer’s that causes this is a rare illness that affects fewer than 10 percent of people.

It can take a long time for doctors to diagnose Alzheimer’s in younger adults because doctors don’t always look for signs. Alzheimer’s symptoms vary depending on the stage at the time of onset. Memory loss, difficulty concentrating, and trouble finishing daily tasks can all be early signs. Words can be difficult to find and time may slip away.

Alzheimer’s disease can be diagnosed in its early stages in people at least 50 years old when they are experiencing certain changes in their vision and eyes.

Alzheimer’s is more likely to develop in people with a family history of the disease. It is believed that some families suffer from groups of cases that are caused by several rare genes. It is recommended that people with a family history of Alzheimer’s talk to their doctors.

Alzheimer’s and genetics

Alzheimer’s is not caused by a single factor, but genetics may be a factor. There is one gene in particular that researchers are interested in. Older adults with APOE are more likely to develop Alzheimer’s symptoms.

This gene increases the risk of developing Alzheimer’s if you have a certain version of it in your blood. Alzheimer’s may not affect someone even if they carry this gene.

It’s also true that someone with a gene for Alzheimer’s may still develop the disease. Alzheimer’s can’t be anticipated with any degree of certainty.

It is also possible for other genes to increase Alzheimer’s risk. It is believed that certain cases of young onset have been linked to several rare genes.

Alzheimer’s disease symptoms

Memory loss is the most prominent symptom of Alzheimer’s disease. Recent events or conversations can be difficult to recall in the early stages. Symptoms such as memory loss and other conditions develop as the disease progresses.

An Alzheimer’s patient may experience difficulties recalling things and organizing thoughts at first. The symptoms may be more apparent to a family member or friend.

Alzheimer’s disease changes the brain in such a way that it causes:


We all forget things occasionally, but Alzheimer’s disease causes persistent and worsening memory loss, affecting the ability to function at work or at home.

The following are possible symptoms of Alzheimer’s:

  • Keep repeating statements and questions
  • Not remember conversations, appointments or events later on
  • Place possessions in illogical locations, misplacing them regularly.
  • Lose things in familiar surroundings
  • Fail to recall names of family and things around us
  • Have difficulty identifying objects, expressing thoughts or taking part in conversations

Read: Mixed Dementia

Thinking and reasoning

It is difficult for an Alzheimer’s patient to concentrate or think abstractly, especially about numbers.

You may find it difficult to manage your finances, balance your checkbook and pay your bills on time when multitasking. Alzheimer’s patients may eventually lose their ability to recognize and deal with numbers.

Making judgments and decisions

A person with Alzheimer’s disease loses their ability to make sensible decisions and judgments. People can make poor social choices or dress inappropriately for the weather, or they may not behave as they usually do in social interactions. Some situations are more difficult to handle on a daily basis, such as food burning on the stove or driving in an unexpected location.

Planning and performing familiar tasks

The disease progressively makes it harder and harder to perform routine activities that require sequential steps. Advanced Alzheimer’s patients often have difficulty performing basic tasks, such as dressing and bathing.

Changes in personality and behavior

Moods and behaviors can be affected by brain changes caused by Alzheimer’s disease. These issues include:

  • Depression
  • Apathy
  • Social withdrawal
  • Mood swings
  • Distrust in others
  • Irritability and aggressiveness
  • Changes in sleeping habits
  • Wandering
  • Loss of inhibitions
  • Having delusions about something being taken from you

Read: Vascular Dementia

Preserved skills

When symptoms worsen, many skills are maintained for longer periods. There are various skills that can be preserved such as reading or listening to books, reminiscing, telling stories, dancing, drawing or doing crafts.

It is likely that these skills will remain intact for a longer period of time because they are controlled by areas of the brain that are affected later in the disease process.

Alzheimer’s disease causes

Researchers do not fully understand the causes of Alzheimer’s disease. In the basic sense, when brain proteins malfunction, they disrupt the work of brain cells (neurons) and provide a pathway for toxic events to take place. The neurons break down, lose contact with each other and ultimately die.

Generally, Alzheimer’s disease is thought to be caused by a combination of genetic, lifestyle and environmental factors over an extended period of time.

A person is likely to develop Alzheimer’s disease if certain genetic differences occur less than 1% of the time. People with these genetic differences usually develop the disease during middle age.

In most cases, the damage begins in the region of the brain responsible for memory. However, the damage begins well before symptoms appear. There is a somewhat predictable pattern in which neurons are lost in different parts of the brain. The brain has shrunk considerably by the end of the illness.

Currently, researchers are examining the role of two proteins in Alzheimer’s disease:

  • Plaques: A beta-amyloid fragment is part of a larger protein. These fragments then appear to impede cell-to-cell communication by clustering together and having a toxic effect on neurons. They form larger deposits known as amyloid plaques, which also contain other types of cellular debris.
  • Tangles: Neurons carry nutrients and other essential materials within their walls using tau proteins. Tau proteins alter shape and form neurofibrillary tangles in Alzheimer’s disease. They disrupt transport systems and cause cellular damage.

Check: How to Avoid Alzheimer’s Disease

Alzheimer’s disease risk factors


Growing older is the most important risk factor for Alzheimer’s. The incidence of Alzheimer’s disease does not increase with age, but it increases as you get older.

According to one study, yearly there are four new diagnoses for every 1,000 people in the 65-74 age group, 32 diagnoses for people in the 75-84 age group, and 76 diagnoses for people 85 and older.

Genetics and family history

It is somewhat more likely that you will develop Alzheimer’s if you have a first-degree relative with the disease – a parent or sibling. Alzheimer’s genetic mechanisms are largely unknown among families, and there are likely several genetic factors involved.

Apolipoprotein E (APOE) gene is one better understood genetic factor. APOE e4 is a gene variant associated with Alzheimer’s disease. The APOE e4 allele is inherited by approximately 25% to 30% of the population, however, not every person with this gene variation develops the disease.

Researchers have discovered three rare genetic changes (mutations) that virtually guarantee someone inheriting one of them will develop Alzheimer’s disease. There are fewer than 1% of people with Alzheimer’s disease who have these mutations.

Down syndrome

Alzheimer’s disease is common in people with Down syndrome. There is likely a connection between having three copies of chromosome 21 and having three copies of the gene that causes beta-amyloid to be made. When compared with the general population, people with Down syndrome tend to show signs and symptoms of Alzheimer’s 10 to 20 years earlier.

Read: Frontotemporal Dementia


The risk of a woman getting this disease is similar to that of a man, but, overall, women are more likely to have it due to their long lives.

Mild cognitive impairment

The term mild cognitive impairment (MCI) refers to a decline in memory or other thinking skills that is greater than normal for an individual’s age, but the decline doesn’t interfere with a person’s ability to function socially or at work.

Dementia is a significant risk for people with MCI. MCI with memory impairment has a higher risk of progressing to Alzheimer’s disease. When diagnosed with MCI, patients are encouraged to adopt healthy lifestyles, develop strategies to compensate for memory loss, and schedule regular doctor appointments.

Head trauma

Alzheimer’s disease is more likely to develop in people who have had severe head trauma. People 50 years of age or older who have experienced a traumatic brain injury (TBI) are at increased risk for developing dementia and alzheimer disorder. Multiple and more serious TBIs increase the risk. It has been found that the risk post-TBI may be greatest between the six-month and two-year mark.

Read: Lewy Body Dementia

Air pollution

Air pollution particulates have been shown to speed the degeneration of neurons in animals. Researchers have found that exposure to air pollution – particularly from the exhaust from traffic and wood burning – is linked to an increased risk of dementia.

Excessive alcohol consumption

The effects of drinking a lot of alcohol on the brain are well known. There is a link between alcohol use disorders and dementia, especially early-onset dementia, according to several large studies and reviews.

Poor sleep patterns

Sleep problems that make it difficult to fall asleep and stay asleep are associated with a higher risk of Alzheimer’s.

Lifestyle and heart health

A variety of risk factors have been linked to heart disease and Alzheimer’s disease. Examples include:

  • Lack of exercise
  • Obesity
  • Excessive smoking
  • High blood pressure
  • High cholesterol
  • Poorly controlled type 2 diabetes

It is possible to change all of these factors. Thus, lifestyle changes can alter your risk of certain diseases. An active lifestyle and a healthy low-fat diet enriched with fruits and vegetables help reduce the risk of Alzheimer’s disease.

Check: Hoarding Disorder

Lifelong learning and social engagement

There is evidence linking mental and social stimulation with a reduced risk of Alzheimer’s disease. An education level less than a high school diploma appears to be associated with an increased risk of Alzheimer’s disease.

Alzheimer’s medication

Alzheimer’s disease has no known cure. The symptoms of the disease can, however, be eased by medications and other treatments your doctor may recommend delaying the progression of the disease.

Donepezil (Aricept) or rivastigmine (Exelon) may be prescribed by your doctor as a treatment for Alzheimer’s in the early to moderate stages. Acetylcholine levels in your brain can be maintained with these drugs. Your brain’s nerve cells can receive and send signals more efficiently if you do this. The symptoms of Alzheimer’s may then be eased as a result.

Those with early Alzheimer’s are recommended aducanumab (Aduhelm), a newer medication. According to some studies, it reduces protein plaques in the brain associated with Alzheimer’s disease. The potential benefits of the drug, however, are not outweighed by its risks.

The two most common medications for Alzheimer’s disease are donepezil (Aricept) and memantine (Namenda). It is possible to block the effects of excess glutamate with memantine. Alzheimer’s disease damages brain cells by releasing high amounts of glutamate, a brain chemical.

If you are suffering from symptoms of Alzheimer’s, your doctor may also prescribe antidepressants, antianxiety medications, or antipsychotics. Variable symptoms can be experienced as the disease progresses, including:

  • Depression
  • Sleeping problems
  • Agitation
  • Hallucinations

People with Alzheimer’s will have different symptoms throughout their lifetime, even though the care needs will increase.

Other Alzheimer’s treatments

It is also possible to manage your condition through lifestyle changes, along with medication. You or a loved one might be able to benefit from the following strategies developed by your doctor:

  • Simplify tasks
  • Avoid confusion
  • Make sure you get enough sleep every day
  • use relaxation techniques
  • Make the environment calm

You can maintain your quality of life as you progress through Alzheimer’s with the help of a team of healthcare professionals. There may be a variety of members on the Alzheimer’s care team, including:

  • Staying active can be helped by a physical therapist
  • Maintain a balanced, nutritious diet with the help of a dietician
  • Medication monitoring can be done by a pharmacist
  • Professionals who work with caregivers and people with Alzheimer’s
  • Providing support and resources through a social worker
  • Someone with Alzheimer’s can seek short-term respite care in a respite care center when their caregiver is temporarily unavailable
  • Hospice care centers are designed to help patients manage their symptoms at the end of their lives in a comfortable and supportive environment

Taking vitamin E with medications like donepezil, which increases acetylcholine in the brain, may help slow the loss of function in Alzheimer’s. The study did not find any benefits when vitamin E was taken for Alzheimer’s disease. It is still necessary to gather more evidence.

Whenever you take vitamin E or any other supplement, make sure to ask your doctor first. Alzheimer’s disease medications can be affected by it.

Your doctor can recommend alternative and complementary therapies as well as lifestyle changes.

Are there any newer medications being studied?

Currently, all medications approved for treating Alzheimer’s disease target it after it develops. Alzheimer’s disease is currently being researched for ways to slow its progression or stop it altogether.

Monoclonal antibodies are some of the drugs currently being investigated at the late stage of development. Brain cells accumulate amyloid protein, which is targeted by these drugs. As they float in the brain, they attach to the amyloid proteins and remove them, preventing plaques and tangles from forming and interfering with the brain’s functions.

Food and Drug Administration approval of these drugs is several years away in the United States because they are still in clinical trials. There has been a mixed response to the early results of some studies, with some showing no improvement in brain function, while others showed a slight improvement (less decline in brain function). It is still thought that this new approach to modifying disease processes may offer some promise despite the mixed results.


It can be difficult to treat other health conditions when Alzheimer’s leads to loss of memory and language, confusion, and impaired judgment. The following might not be possible:

  • Tell him or her that you are experiencing pain
  • Tell them about another illness you have
  • Make sure you follow the prescription
  • Let them know how the medication affects you

Alzheimer disorder affects a number of functions related to the body as it progresses, including swallowing, balance, and controlling bowel and bladder function. Additional health problems can arise as a result of these effects, such as:

  • Consuming food and liquids by inhaling them into our lungs (aspiration)
  • Infections such as influenza and pneumonia
  • Falls
  • Fractures
  • Bedsores
  • Malnutrition or dehydration
  • Constipation or diarrhea
  • Dental problems such as tooth decay or mouth sores

Read: How to Help Someone with Hoarding Disorder

Alzheimer’s disease prevention

Alzheimer illness cannot be prevented. However, Some lifestyle factors are modifiable and can be modified to reduce the risk of Alzheimer’s. A change in diet, exercise, and habits – all of which can decrease your risk of developing cardiovascular disease – may also help you prevent Alzheimer’s and other types of dementia.

Some heart-healthy lifestyles can help reduce the risk of Alzheimer’s disease.

  • Maintaining a regular exercise routine
  • Fresh produce and healthy oils, such as a Mediterranean diet, lead to a diet low in saturated fats
  • Maintaining blood pressure, diabetes, and cholesterol levels according to treatment guidelines
  • Seeking help from your physician to quit smoking

Studies have shown that cognitive skills are preserved later in life when people participate in social events, read, dance, play board games, create art, play an instrument, read and take part in social activities.

Read: Short-Term Memory Loss

When to see a doctor

Memory loss or other symptoms of dementia can be caused by many conditions, including treatable ones. Get a thorough assessment and diagnosis from your doctor if you have concerns about your memory or other thinking skills.

When you see a family member or friend struggling with thinking skills, let them know you are concerned and ask if you can make an appointment together with a doctor.

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