What Causes Agitation in Dementia?

We will discuss four problems that can cause agitation: physical and medical problems, environmental stresses, sleep problems, and psychiatric syndromes (psychosis, anger and aggression, depression, and anxiety). Remember that, in all these situations, a person with dementia is more easily agitated because the brain has physically changed and no longer functions in a healthy manner.

Physical and medical problems

If a person with dementia has recently become agitated for the first time or has a change from his or her usual behavior, the first thing to look for is a medical or physical problem.

Sudden illnesses may weaken the brain, causing worsened agitation. Your doctor might use the term delirium to describe an episode of agitation and confusion that begins suddenly because of a medical illness. Delirium improves when the medical problem gets better. The most common medical problems that can cause agitation or delirium are bladder infections, bad colds, bronchitis or pneumonia, and dehydration or poor nutrition (especially in people who forget to eat or can’t feed themselves). It is also very important to make sure that someone who has become more agitated has not recently had a new stroke or been injured in a fall. Finally, flare-ups of chronic diseases such as diabetes or diseases of the heart, liver, or kidneys can cause agitation or delirium, especially if a person with dementia cannot take medications reliably or follow a special diet. A toxic reaction to medication is an important cause of sudden confusion and agitation. Older people often take many different medications that can interact with each other. It is crucial to find out if side effects of a new prescription, interactions between medicines, or taking the wrong dose have led to a bad reaction. Common physical problems that cause pain, discomfort, worry, or lack of sleep can lead to agitation by making the person upset or fatigued. Examples of such problems include arthritis, sitting all day in an uncomfortable position, constipation, and impaired vision or hearing.

Environmental Stresses

People with dementia are very sensitive to the environment they live in. They are less able to handle changes, uncertainty, and other situations that they could manage when they were well. The ideal environment for a person with dementia provides clear, calm, com-forting structure—often not an easy situation to arrange. Routine is very important, since changes in schedule or rushing can cause extreme disappointment, frustration, or fear. A physically comfort-able environment is important. Noisy, poorly lit, or improperly heated areas can cause increased agitation.

Extremes in the social environment can also cause problems (for example, if someone is left alone for long periods or is overwhelmed by being around too many people). Medical or dental procedures, and especially hospitalization, are particularly disruptive and can lead to sudden agitation or confusion in a person who was calm at home.

Sleep Problems

Sleep problems are common in dementia. One type of problem is insomnia—trouble falling asleep at night or waking up throughout the night. Although the cause is often unclear, it is sometimes possible to pinpoint a reason that can be corrected, such as busy activities just before bedtime, using caffeine or alcohol, or drinking fluid before bedtime and then having to urinate. Conditions such as depression, nervousness, or physical pain can also cause insomnia. It also helps to keep in mind that many people need less sleep as they age, but that the person with dementia has a very hard time finding purposeful things to do during longer waking hours.

“Sundowning” is another type of sleep problem. Sleep patterns are controlled by an internal clock in our brain that senses day and night, telling us when to rest and when to be active. This clock is often damaged in dementia. The person may be awake and overactive at night, thinking it should be daytime and trying to get dressed and out of bed. This type of confusion, disorientation, and agitation is called sundowning because it usually begins in the early evening in a person who might otherwise be fairly clearheaded when awake during the daylight hours.

Psychiatric Syndromes

Psychosis, aggression or anger, depression, and anxiety are common psychiatric syndromes seen in agitated persons suffering from dementia.
  • Psychosis means being out of touch with reality in an irrational way. The person imagines things and is convinced these things are real. There are two types of psychotic symptoms: delusions (believing things that are not true) and hallucinations (hearing, seeing, or smelling things or feeling physical sensations on the skin that are not there). You cannot convince a person with psychosis that his or her beliefs are untrue. The most common delusions are believing that one is in danger from criminals, that others have stolen items or money, that a spouse is unfaithful, that unwelcome guests are living in the house, or that a relative is an imposter and not really the person he or she claims to be. These are also sometimes referred to as paranoid delusions and reflect fear and insecurity that result from being confused. Visual hallucinations such as seeing nonexistent visitors or burglars can cause a person to fearfully report events that have not actually occurred.


  • Anger and aggression. Dementia causes the brain to lose its normal ability to control angry impulses, a problem called disinhibition. Anger becomes aggression when the person acts on these feelings by verbally or physically threatening another person or attacking objects. It may occur because the person with dementia often misunderstands or misinterprets the actions of others, and then lashes out because he or she feels ignored, in danger, or mistreated. Another cause of anger is frustration at being unable to complete tasks that were once easy, such as fixing something that is broken, using the stove, or going to the bathroom. Sometimes there is no obvious cause of frustration. Anger and aggression can include verbal accusations and insults, aimless screaming, refusal to cooperate with requests to eat or bathe, and even physical assaults. Aggression can also include self-injury such as head banging or biting oneself. When a person with dementia becomes angry and aggressive, it is important to evaluate the person’s environment to be sure it is safe and to see if some simple adjustments might reduce the problem. Although aggression is among the most distressing problems for caregivers, it can usually be helped with extra attention and sometimes medication; it should not be ignored in the hopes it will go away by itself.


  • Depression. A person with depression feels sad or loses interest in things he or she normally enjoys. Although depression is an understandable reaction to an illness such as dementia, it is a treatable symptom, not a “normal” reaction, and should not be ignored. Successful treatment of depression helps individuals with dementia enjoy time with their families and other pleasurable activities. A diagnosis of depression should be considered if a person is often sad, tearful, or unable to enjoy anything or expresses constant thoughts of discouragement, failure, being a burden, or wanting to die or commit suicide. Depression often includes physical symptoms such as loss of appetite and weight, trouble sleeping, or complaints of physical pain. If no other medical cause is found for these physical symptoms, depression should be considered, even if the person denies feeling sad but just seems more withdrawn, apathetic, or disinterested. Agitation in depression can include extreme tearfulness, hand-wringing, an excessive need for reassurance, and other signs of extreme unhappiness. Depression can also cause delusions, most often guilty feelings about having done terrible things in the past.


  • Anxiety means being very worried, overly fearful, nervous, fidgety, shaky, or frightened, either because of exaggerated fears or some-times for no apparent reason. An important cause of anxiety maybe the diagnosis of dementia itself, especially in the early stages when a person can feel embarrassed by making mistakes, forgetting things, or having trouble joining a conversation. An anxious person may not always be able to put the feelings into words, but instead may appear tense or have physical symptoms such as racing heart, nausea, or “butterflies in the stomach.” Anxious people worry about things such as being alone, or they may fear that visitors will be late, that loved ones have been harmed, or that plans will be disrupted. They may become especially nervous when they are separated from caregivers, when schedules are changed, or when they are rushed or tired.