Many causes of dementia and dementia-like symptoms are treatable. They may be reversible if they’re caught early enough and if appropriate treatment is given. Some common reversible conditions include:
Deficiencies of thiamine (vitamin B-1) often result from chronic alcoholism and can seriously impair mental abilities, particularly memories of recent events.
Severe vitamin B-6 deficiencies can cause a multisystem illness, known as pellagra, that may include dementia.
Vitamin B-12 deficiencies have been linked to dementia in some cases.
Thyroid hormone imbalances can affect cognition.
Prescribed medications can sometimes lead to reactions or side effects called delirium that mimic dementia. These dementia-like effects can occur in reaction to just one drug or they can result from drug interactions. They may have a rapid onset or they may develop slowly over time.