Physical Causes of Challenging Behaviors in Dementia

Difficult behaviors can make caring for someone with Alzheimer's and other kinds of dementia a challenge. One way to approach this is to try to determine the cause of those behaviors so that we can respond more appropriately. All behaviors have meaning, so by figuring out what may be causing the behavior, we can hopefully address the unmet need underneath it.

As we look at various causes, consider these physical causes. Physical (or biological) issues, such as discomfort or hunger, can cause people with dementia to act out or resist care.

Pain Can Be One Physical Cause of Challenging Behaviors in Dementia
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Discomfort or Pain

Sometimes behaviors are caused by physical discomfort or pain. For example, if your mother has pain that is unnoticed, she may become restless, anxious, or resist being cared for or moved.

Hunger or Thirst

Some people with Alzheimer’s wander around, searching for a snack or a drink. If your loved one needs more snacks or drinks, keep food out on the counter that's safe and easy to eat. You can also fill a covered cup with ice water and a straw and set it out on the counter. This may prevent wandering or restlessness.

Poor Nutrition

As opposed to actively seeking food or drinks, some people don't take in enough food. Perhaps your father lives on his own and is trying to be as independent as possible. He may report that all is well, but unexplained weight loss or a tour of his kitchen may reveal this isn’t the case. Poor nutrition can increase confusion and cause such behaviors as apathy or resistance to care. People with early-stage dementia often struggle with planning and making meals, and may not be getting adequate nutrition. If your father is still able to manage the other areas of living independently, try looking into such services as senior meals or meals-on-wheels to assist with meeting his nutritional needs.


Dehydration is closely linked with poor nutrition. Some people intentionally avoid drinking lots of water because they struggle with incontinence. Others simply forget to drink water throughout the day. Dehydration can cause decreased awareness, disorientation, and increased confusion, increasing the risk of wandering and other behaviors. Depending on what medications your loved one is taking, proper hydration can be especially important because some medications can build up in the body and become toxic.


Being overly tired can also result in challenging behaviors. We all have less patience and tolerance when we’re tired, and it’s the same for the person with dementia. Poor sleep can certainly trigger behavior challenges in dementia, especially because people may lack the inhibition to temper their feelings of irritation or crankiness.

A Need for Exercise

Did your mother get some exercise today? If not, she may need to go for a walk or stretch her legs. Building in a time for exercise, even if it’s just walking through the house or the halls, can decrease restlessness.

A Need to Use the Bathroom/Incontinence

Perhaps your loved one is attempting to get up again out of her chair after you’ve reminded her many times to stay seated so she won’t fall. Rather than getting frustrated with her and viewing her as stubborn, consider that she might not be able to find the words to express her need for the bathroom or to convey that she is uncomfortable, wet and in need of a new incontinence pad and change of clothes.

Urinary Tract Infection

A urinary tract infection (UTI), sometimes called a bladder infection, can dramatically affect behavior. If someone shows a sudden change in behaviors, be sure to investigate this as a possible cause. Other symptoms of a UTI include cloudy urine, pain while urinating (so watch for grimacing while your loved one is using the bathroom), foul smell and fever.

Sensory Impairments

Does the person you’re caring for have a deficit in hearing or vision? This can increase his anxiety since he might be startled by your nearness or touch. Be aware of this deficit and compensate for it by approaching the person from the front, speaking into the ear that has better hearing or gently touching him on the arm to indicate your presence.

Decreased Ability to Communicate Needs or Preferences

Deficits in communication can range from mild difficulties with finding the right words to a complete inability to make needs known. This can cause feelings of helplessness and frustration, which in turn can trigger a behavior problem. Being intentional in adhering, as much as possible, to preferences and routines can help minimize this frustration.

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By Esther Heerema, MSW
Esther Heerema, MSW, shares practical tips gained from working with hundreds of people whose lives are touched by Alzheimer's disease and other kinds of dementia.