There are many potential causes of personality changes in the elderly. One possibility is that changes in brain structure and function may lead to alterations in personality. For example, research has shown that dementia can cause personality changes, and that these changes are often related to specific areas of the brain that are affected by the disease. Another possibility is that medications taken by the elderly can cause personality changes. Some drugs, such as those used to treat depression or anxiety, can have side effects that alter a person's mood and behavior. Finally, it's also possible that physical illnesses or other health problems may lead to personality changes. For instance, someone who experiences a stroke may have difficulty controlling their emotions due to damage to the parts of the brain responsible for processing emotion. Personality changes can also be a normal part of aging, and don't always indicate an underlying health problem. However, if you notice sudden or drastic personality changes in an elderly loved one, it's important to talk to their doctor to rule out any potential medical causes.