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, both for those with Alzheimer’s and their loved ones and caregivers. Here’s how to recognize aggressive behavioral symptoms in people with Alzheimer’s, what we know about why these occur, and current coping and management strategies.

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.

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The earliest symptoms of Alzheimer’s disease are usually memory lapses and difficulty with everyday tasks. This could look like trouble remembering appointments or even getting disoriented in your own neighborhood. When the disease begins to impact the way someone usually acts and behaves, it’s often referred to as a “change in personality.”

Initially, personality changes tend to include apathy, increased anxiety, or moments of unexplained sadness. People with mild to moderate Alzheimer’s often become more impatient and less “filtered” in the things they say and do. They may deliver inappropriate comments or hurtful accusations that feel very 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, at times, physical violence such as pushing or kicking may occur. People with Alzheimer’s disease may physically resist being helped while changing clothes or taking medication. These behaviors can be some of the most upsetting aspects of Alzheimer’s, as they’re emotionally distressing to loved ones and interfere with care.

If you’re a caregiver, family member, or other looking after a person with Alzheimer’s, it’s important to remember that these behavior changes are the result of the disease and aren’t personally directed toward you.

It’s not always clear why an individual with Alzheimer’s disease starts to show aggressive or violent behavior. But there are some factors widely considered to be common components of Alzheimer’s-related personality changes. Let’s overview.

Physical factors

One of the more frustrating aspects of Alzheimer’s disease, both for the individual with the disease and their caregiver, is that the cognitive changes caused by the disease can impact the ability to communicate simple concepts clearly.

For example, someone with Alzheimer’s may be uncomfortable or in pain but be unable to articulate those sensations verbally.

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 or need can create further discomfort, anger, and frustration.

Poor sleep, another common complication of Alzheimer’s, may make the individual especially irritable during the day.

A person with Alzheimer’s in these kinds of situations may lash out due to feeling out of control or unheard, becoming resistant, or even violent.

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.

Medications containing the antihistamine diphenhydramine (such as Benadryl and Tylenol PM), often used for pain and allergies, may worsen problems with memory and confusion.

In some cases, it’s the interaction of several medications that leads to side effects such as irritability.

Environmental factors

An individual’s ability to handle a crowded or noisy environment can change with the onset of Alzheimer’s disease or another type of dementia. Having several people in a small room, or having the lights too bright, can cause someone with Alzheimer’s to feel stressed, overwhelmed, or uncomfortable.

The disorientation created by Alzheimer’s disease can cause someone to feel lost or unsure of their surroundings, even in spaces they spend a lot of time in. This can lead to anxiety, fear, and outbursts of 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.

Early on in Alzheimer’s progression, a person may be aware of their memory problems, confusion, and communication difficulties. They’re often aware their condition is worsening, and they’re losing grasp of their sense of self. This creates deep, complex feelings of grief, fear, and anger.

Someone with Alzheimer’s will likely miss being able to drive or engage in hobbies and other activities they once enjoyed. Loss of independence due to a health condition can be traumatizing, especially when someone with Alzheimer’s is still aware of that loss. Feeling helpless can cause people to lash out in frustration or in order to regain some type of control.

When you notice behavioral and personality changes in someone with Alzheimer’s disease, start looking at some of the more obvious and manageable causes. Take note of possible triggers and patterns. For example, did the behaviors begin after a new medication was introduced? Does aggressive behavior usually occur late in the day or when there’s too much activity?

If your loved one is in a skilled nursing or assisted living facility, talk with the facility’s healthcare professionals about any patterns or triggers they have noticed. Ask about what strategies may be effective and whether medications or schedule changes may help.


There are many medications used to treat the symptoms of Alzheimer’s disease and slow its progression. However, there are currently no medications approved by the Food and Drug Administration (FDA) to treat its neuropsychiatric symptoms in particular.

Medications used to treat Alzheimer’s include cholinesterase inhibitors (such as donepezil, rivastigmine, and galantamine), which help improve communication between nerve cells, and memantine, part of a class of medications called NMDA receptor antagonists.

Memantine slows the neurotoxicity in the brain of people with Alzheimer’s and other neurodegenerative diseases, meaning it reduces nerve system 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.

Keep in mind that medications designed for one purpose may help in other ways. Antidepressants, for example, can help treat depression but have also been shown to ease problems with insomnia and improve sleep quality and quantity.

Talk with a healthcare professional about your loved one’s medication regimen. 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 given at a different time of day.

Health checkups

You want to rule out pain or other medical concerns, such as nausea or dizziness, as soon as possible. Any kind of physical discomfort can lead to angry and 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

In some cases, changing parts of a person’s daily routine is enough to make a difference:

  • adjusting bedtime
  • changing times at which meals are served
  • scheduling appointments or activities in the morning instead of the afternoon or evening

It’s important to update other loved ones when a person with Alzheimer’s is experiencing serious personality and behavior changes. This can prevent surprising friends and family and make sure that everyone is on the same page.

Calming surroundings and activities

Approaches to make someone with Alzheimer’s feel more secure and at home include:

  • adding family photos and familiar items in a new environment, such as a care facility
  • avoiding too much clutter in a person’s space
  • playing the person’s favorite music
  • making time for enjoyable activities, such as making art, walking, or spending time with a therapy dog
  • scheduling time with loved ones

Be prepared to shift things around if one activity is somehow causing irritability or anxiety. It may take several attempts before you figure out what times of the day are best for certain activities.

Using a calm, reassuring voice is important when spending time with or caring for someone with dementia. If in a tense situation with a person who has Alzheimer’s disease, try not to escalate it by yelling or becoming physical yourself, unless in self-defense.

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

While not everyone with Alzheimer’s displays aggressive or violent behavior, it’s important to understand that these symptoms are possible as the disease progresses. When living with or caring for a person with Alzheimer’s, you need to be prepared to recognize personality and behavioral changes and manage them.

The mental impacts of Alzheimer’s can make it difficult for the person to understand their situation, express themselves, and communicate when they’re in pain, tired, or hungry.

These challenges can cause people with Alzheimer’s to become frustrated and upset. In some cases, this may look like resistance to your help, while in other cases, a person may lash out physically.

Mental health concerns, medications, and environmental factors can all contribute to aggressive behavior in people with Alzheimer’s. Feeling helpless or disoriented can make people respond with resistance or violence in order to feel in control again.

It’s important you keep yourself safe, even when caring for others. If you no longer feel you can handle caring for a loved one who’s showing signs of aggression and violence due to Alzheimer’s, discuss this with a care team immediately.