What Causes Dementia?


Dementia is the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that it interferes with a person’s daily life and activities. There are several stages of dementia which range in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others.

According to the National Institute on Aging, many conditions and diseases cause dementia. Two of the most common causes of dementia in older people are Alzheimer’s Disease and vascular dementia, which is caused by a series of strokes or changes in the brain’s blood supply. Other conditions that may cause memory loss or dementia include:

  • Medication side effects
  • Chronic alcoholism
  • Tumors or infections in the brain
  • Blood clots in the brain
  • Vitamin B12 deficiency
  • Some thyroid, kidney, or liver disorders


Many of these conditions are temporary and reversible, but they can be serious and should be treated by a doctor as soon as possible. The National Institute on Aging also notes emotional problems, such as stress, anxiety, or depression, can make a person more forgetful and can be mistaken for dementia. For instance, someone who has recently retired or who is coping with the death of a spouse may feel sad, lonely, worried, or bored. Trying to deal with these life changes leave some people confused or forgetful. The emotional problems can be eased by supportive friends and family, but if these feelings last for a long time, it is important to get help from a doctor or counselor.