Other disorders affect people of all ages but are more common or more severe or cause different symptoms or complications in the elderly. Elderly people often experience illness differently than do younger adults. A disease may cause different symptoms in elderly people. For example, an underactive thyroid gland usually causes younger people to gain weight and feel sluggish. In the elderly, an underactive thyroid gland may also produce confusion that can be mistaken for dementia.
Depression usually causes younger adults to become tearful, withdrawn, and noticeably unhappy.
In the elderly, depression sometimes causes confusion, loss of memory, and apathy, all of which may be mistaken for dementia. Acute illnesses such as heart attacks, hip fractures, and pneumonia were once likely to result in death for older adults. Now these illnesses are often treatable and controllable even when they are not curable. In turn, a chronic illness no longer necessarily means disability. Many people with diabetes, kidney problems, heart disease, and other chronic illnesses now find that they can remain functional, active, and independent.