Alzheimer’s disease is a brain disorder and type of dementia primarily characterized by memory loss and confusion. Some people with Alzheimer’s or other dementias may experience significant personality changes, which may include irritable or aggressive behavior.

“These changes can be difficult to manage for people with Alzheimer’s and their loved ones. Here are some things we know about Alzheimer’s and how to deal with it.”

How common is Alzheimer’s disease?

Alzheimer’s is a top 10 cause of death for adults in the United States. As of 2020, 5.8 million Americans ages 65 and older had the disease.

“Alzheimer’s disease symptoms include memory loss and difficulty with everyday tasks. This could be trouble remembering appointments or even getting lost in your own neighborhood. When the disease starts to affect the way someone behaves, it is often referred to as a change in personality.”

Initially, personality changes include apathy, increased anxiety, and moments of unexplained sadness. People with mild to moderate Alzheimer\’s are more impatient and less “filtered” in their behavior. They may make comments that feel out of character.

As Alzheimer’s progresses, the likelihood of agitation and irritability increases. A 2016 study suggests that as many as 90% of Alzheimer’s cases include these types of behavioral changes.

“Shouting and pushing may occur. People with Alzheimer’s disease may be reluctant to be helped. These behaviors can be distressing to loved ones and interfere with care, which is one of the most upsetting aspects of Alzheimer’s.”

“If you are a family member or other person looking after a person with Alzheimer’s, it is important to remember that the behavior changes are the result of the disease and not directed towards you.”

“It is not always clear why an individual with Alzheimer’s disease starts to show aggressive or violent behavior. There are some factors that are considered to be part of Alzheimer’s related personality changes. Let’s see what we can learn.”

Physical factors

“Alzheimer’s disease can affect the ability to communicate simple concepts clearly, which is frustrating for the individual with the disease and their caregivers.”

“Someone with Alzheimer’s may be uncomfortable in pain but unable to articulate it.”

Such sensations could be the symptoms of a urinary tract infection (UTI), a condition that commonly accompanies Alzheimer’s disease, or of another infection or injury. Maybe the person is simply hungry or thirsty.

The inability to clearly communicate a physical state can cause more pain, anger, and frustration.

“Poor sleep is one of the main causes of Alzheimer’s.”

“A person with Alzheimer’s may lash out in these situations because they feel out of control or are resistant.”

Medication side effects

Individuals with Alzheimer’s disease are often on a variety of dementia medications, as well as drugs to treat other co-occurring health conditions such as heart disease or arthritis.

Benadryl and Tylenol PM are both used for pain and allergies, and may cause problems with memory and confusion.

In some cases, the interaction of several medications can cause side effects.

Environmental factors

“Alzheimer’s disease and other types of dementia can change an individual’s ability to handle crowded or noisy environments. Having several people in a small room can make someone with Alzheimer’s feel stressed or uncomfortable.”

“Alzheimer’s disease can cause someone to feel lost or unsure of their surroundings, even in places they spend a lot of time in. This can lead to fear and anger.”

Time of day can also be a major factor influencing behavior in people with Alzheimer’s. In many dementias, late afternoons and early evenings are associated with worsened symptoms and increased aggressiveness. This phenomenon is known as sundowning.

A 2016 report suggests that as many as 20% of people with Alzheimer’s disease experience sundowning on a regular basis, particularly in the winter and fall.

Alzheimer’s disease is a chronic, progressive disease, in which symptoms worsen over time. If you’re a caregiver or family member, you can’t blame yourself for personality and behavioral changes thatare beyond your control and the control of the individual with Alzheimer’s.

Mood changes

Depression and anxiety commonly follow the onset of Alzheimer’s disease as a response to the life changes it brings.

“A person may be aware of their memory problems early on in Alzheimer’s. They are losing their grasp on their sense of self as their condition gets worse. This creates feelings of grief, fear, and anger.”

“Someone with Alzheimer’s will miss being able to drive and engage in hobbies. When someone with Alzheimer’s is still aware of the loss of independence, it can be traumatizing. Feelings of helpless can cause people to lose control over their lives.”

“When you notice behavioral and personality changes in someone with Alzheimer’s disease, look at some of the more obvious causes. Take note of possible events. Did the behaviors start after a new medication was introduced? Is aggressive behavior usually late in the day or when there is too much activity?”

“If your loved one is in a skilled nursing facility, you should talk to the facility’s healthcare professionals about any patterns or triggers they have noticed. Ask about the strategies that may be effective and the drugs that may help.”


“There are many drugs that can be used to treat Alzheimer’s disease. There are no approved drugs for its symptoms, which include paranoia, delusions, and other psychosphintic symptoms.”

“The medications used to treat Alzheimer’s include donepezil, rivastigmine, and galantamine, which help improve communication between nerve cells.”

“The brain of people with Alzheimer’s and other neurodegenerative diseases is vulnerable to damage.”

A 2021 study examining the effects of cholinesterase inhibitors and memantine in people with moderate Alzheimer’s suggests that the combination of the two drugs may be helpful in reducing impulsive and aggressive behavior. Further study is needed, as these results have yet to be replicated.

It is important to keep in mind that medications may help in other ways. Depression can be treated with anti-depressants, but they can also help with insomnia and improve sleep quality.

“Discuss your loved one’s medication regimen with a healthcare professional. Ask that it be reviewed to look for possible interactions or instances in which a drug may be eliminated, given at a lower dose or a different time of day.”

Health checkups

You want to rule out any medical concerns, such as nausea or dizziness, as soon as possible. Any kind of physical pain can lead to aggressive behavior.

Ask whether the individual has been tested for a UTI or other infection or injury, such as a bedsore. Try to see that your loved one has regular health assessments, and be attuned to nonverbal signs of discomfort.

Schedule adjustments

“Changing parts of a person’s daily routine is enough to make a difference.”

  • adjusting to sleep
  • Changing times for meals to be served.
  • Instead of the afternoon or evening, schedule appointments in the morning.

“It is important to update other loved ones when a person with Alzheimer’s is having serious personality and behavior changes. This can make sure that everyone is on the same page.”

Calming surroundings and activities

“Approaches to make someone with Alzheimer’s feel more secure at home.”

  • Adding family photos and familiar items in a new environment is a good idea.
  • A person should avoid too much space in their space.
  • The person likes music.
  • Spending time with a therapy dog is one of the enjoyable activities that can be made.
  • Time with loved ones.

If one activity is causing anxiety or other symptoms, be prepared to shift things around. It may take a while to figure out what times of the day are best for certain activities.

“It is important to use a calm, reassuring voice when caring for someone with dementia. If you are in a tense situation with a person with Alzheimer’s disease, try not to escalate it by yelling or physical actions.”

You can learn more about how to manage sundowning and aggressive behavior in people with Alzheimer’s from the National Institute on Aging.

“As the disease progresses, it is important to understand that aggressive or violent behavior is possible for some people with Alzheimer’s. When caring for a person with Alzheimer’s, you need to be aware of personality changes and be prepared to manage them.”

“Alzheimer’s can make it difficult for a person to communicate when they are tired, hungry or in pain.”

“People with Alzheimer’s can become upset and frustrated by these challenges. In some cases, this may look like resistance to your help, while in other cases, a person may lash out.”

“Mental health concerns, medications, and environmental factors can all contribute to aggressive behavior in people with Alzheimer’s. People can respond with resistance or violence if they feel powerless or confused.”

“It is important that you keep yourself safe while caring for others. If you no longer feel you can care for a loved one who is showing signs of aggression and violence due to Alzheimer’s, talk to a care team.”