Alzheimer's Disease: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Alzheimer's disease is a common cause of dementia and its associated symptoms. Memory problems that develop slowly over time are often the main or first symptoms of Alzheimer's disease. Later symptoms can include personality changes like apathy, withdrawal, and reduced spontaneity. Trouble with abstract thinking and significant cognitive loss can develop with time. Other symptoms of the mental decline seen in people with Alzheimer's disease can include

  • loss of orientation (to person, place, or time),
  • agitation,
  • irritability,
  • quarrelsomeness, and
  • a diminishing ability to care for him- or herself and to dress appropriately.

Mood changes, wandering, erratic behavior, uncooperativeness, and anger can be seen in the later stages of the disease. Physical symptoms can include loss of bowel control or urinary incontinence.

Causes of Alzheimer's disease

The cause of Alzheimer's disease is unknown. One theory has emerged from the study of early onset inherited (genetic) Alzheimer's disease. Certain genetic mutations associated with Alzheimer's disease have been found in about half of the patients with early onset disease. These mutations result in excess production in the brain of a specific form of a small protein fragment called ABeta (Aβ) that accumulates in the brain. This has been called the "amyloid cascade hypothesis."


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

Medically Reviewed by a Doctor on 6/1/2017

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