Dementia is actually not a disease but a variety of symptoms associated with a decline in memory or other thinking skills which has a large impact on a person's ability to perform everyday activities. If these symptoms persist for six months or longer, than it is given the diagnosis of dementia.
Alzheimer's disease accounts for 60 to 80 percent of cases. Vascular dementia (which occurs after a stroke), thyroid problems, and vitamin deficiencies also may cause problems in cognitive behavior under the umbrella of dementia, but these account for less than 10% of patients with this disorder.
Dementia usually starts with problems involving short term memory and tends to progress inhibiting routine activities and independence. The later stages of dementia are characterized by depression, anxiety, psychosis, being easily agitated, or being disoriented about the present time, surroundings, or people they are interacting with. For 90% of cases, there is no reversal.
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