Medical Specialties: Family practice, Internal medicine, Neurology

Clinical Definition

Dementia is not a specific disease but a descriptive term for a collection of symptoms severe enough to interfere with daily life, such as a decline in memory, judgment or other thinking skills. These symptoms occur in many different disorders. Dementia is not a normal part of aging but is common in very elderly individuals, a result of damage to the brain cells. Alzheimer's disease is the most common type of dementia.

In Our Own Words

Dementia describes a collection of symptoms, including problems with thinking and memory that hamper regular everyday activities. Memory loss by itself does not mean that a person has dementia. Most dementias tend to be permanent and worsen over time; this is in contrast to delirium, which can lift like a fog. Many individuals have both delirium and dementia.


Alzheimer's disease is the most common cause of dementia. Vascular dementia is also relatively common and can occur after a stroke or after a series of small strokes. Other causes include boxer’s syndrome (i.e., “dementia pugilistica”), which boxers may experience after years of blows to the head. Certain brain disorders such as Huntington's disease and Creutzfeldt-Jakob disease also cause dementia.


Diagnosis depends upon medical history, lab tests and observation; treatment depends on the dementia’s cause. For most progressive dementias, there is not yet a known cure, but in some cases, today’s therapies can help improve symptoms temporarily.

Relevant Conditions
Common Types
Side Effects
  • Memory problems
  • Less ability to focus and pay attention
  • Deficits in reasoning, judgment
  • Personality changes and emotional disturbance
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  • Harvard Health Publications. "Medical Dictionary of Health Terms." Accessed August 2013.
  • American Academy of Neurology. "Dementia." Accessed August 2013.
  • Centers for Disease Control and Prevention. "Dementia/Alzheimer's Disease." Mental Health Basics. Updated December 2011. Accessed August 2013.
  • Alzheimer's Association. "What Is Dementia?" Accessed August 2013.
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