Several illnesses or injuries can cause dementia. And the mental impairment can be mild to severe.
Natural history
A variety of illnesses or injuries may cause dementia. Mental impairment may range from mild to severe. It may also cause personality changes.
Some types of dementia are progressive. Progressive means they get worse over time. Some types are treatable or even reversible. Some experts restrict the term “dementia” to irreversible mental deterioration.