There are a number of reasons why behavior and personality changes might occur in an aging parent. It’s natural for people to change as they age, and these changes can be physical, mental, or emotional.

Daughter holding hands elderly woman's

Aging Parent’s Behavior May Have Changed

Sometimes, the changes are a result of disease or illness, and other times they’re simply a part of the aging process. Here are some possible explanations for changes in your aging parent’s behavior:

Dementia or Alzheimer’s disease

There are many possible reasons for changes in your aging parent’s behavior. One reason may be dementia or Alzheimer’s disease. A decline in mental capacity brought on by illness or trauma is generally referred to as dementia.  The most prevalent form of dementia is Alzheimer’s disease. Symptoms of dementia can include:

  • Memory loss
  • Problems with language
  • Difficulty with problem-solving and planning
  • Changes in mood or behavior 

If you notice a changing personality in your aging parent, it’s important to talk to their doctor. Dementia is a disease that progresses over time, meaning it gets worse. Dementia cannot be identified by a single test. Instead, doctors will look at the person’s medical history, do a physical exam, and order tests to assess brain function. 


Depression is a real and serious medical condition that affects millions of Americans, including older adults. While depression is not a normal part of aging, it can be a common problem in later life. Many older adults with depression do not seek treatment, but there are many effective treatments available.

  • As people age, they may experience more losses, such as the death of friends or loved ones. These losses can trigger feelings of sadness, loneliness, and grief—all symptoms of depression. 
  • Additionally, many older adults face challenging life circumstances, such as retirement or chronic health problems. These stressors can also lead to depression. 
  • Finally, some medications used to treat other conditions can cause depressive side effects. 

Side effects of medication

It’s not unusual for aging parents to experience changes in their behavior. And while some of these changes may be due to the aging process itself, others may be the result of medications they’re taking. Common side effects of medications that can cause changes in behavior include:

  • Drowsiness: Many medications, particularly those used to treat anxiety or depression, can cause drowsiness. If your parent is taking medication that makes them drowsy, they may appear more withdrawn or confused than usual.
  • Agitation: Some medications, such as those used to treat Parkinson’s disease, can cause agitation. This may manifest as restlessness, pacing or fidgeting. If you notice your parent’s behavior changing, it is important to talk to their doctor to see if the medication they are taking may be the cause. 

Loneliness or social isolation

Loneliness is a feeling of being alone, even when surrounded by people. It can lead to feelings of sadness, depression, and anxiety. Social isolation is a state of being socially isolated from others. It can be caused by physical or mental disabilities, living in a rural area, or not having any close friends or family members.

Loneliness and social isolation can have a negative impact on your parents’ health. They are at increased risk for high blood pressure, heart disease, stroke, and other chronic conditions. They may also have a higher risk for dementia and Alzheimer’s disease. 


If you are concerned about a change in your aging parent’s behavior, the best thing to do is to talk to them about it. If they are able to communicate, they may be able to tell you what is causing the change and whether or not they are experiencing any distress. If your parent is unable to communicate, you may want to consult with their physician to rule out any medical causes for the change in behavior.