Your 75-year-old father has always been healthy and active. But lately, he forgets names and dates. And he doesn't act quite like himself. You're worried these may be signs of Alzheimer disease, a brain disorder. But these symptoms may not always be Alzheimer disease. If you're concerned about a loved one, talk with a doctor. They can help find the source of the problem.

Many factors can cause symptoms that mimic Alzheimer disease. These symptoms are known as reversible dementias. Unlike Alzheimer disease, they can be cured with correct treatment. Some factors that may lead to reversible dementias include:

• Depression. People who are depressed feel intense sadness. As a result, they may seem tired, listless, and withdrawn.
• Medicines. Older adults often take a number of medicines. Sometimes these medicines stay in the body too long. Or they may interact with each other. This may cause some people to become confused and forgetful.
• Poor eating habits. Often, older adults may not feel like eating. It may also be hard for them to chew or digest food. This can lead to poor nutrition, lack of key vitamins such as B-12 and folate, or low blood sugar. These issues can affect the brain.
• Heart or lung disease. These problems can prevent the brain from getting enough oxygen.
• Diseases of the thyroid, parathyroid, or other glands. Many glands and hormones affect the way people think and feel. Sometimes they don't function as they should. This may cause changes in thought or mood.
• Infections. Syphilis and Lyme disease have been known to cause dementia.
• Illegal drug use.
• Alcohol use.

Don't ignore mental changes in a parent or other loved ones. Sometimes these changes can be reversed once the cause is found. A doctor can help.