Cognomen Demented (Demented 
, Demento 
) , worldwide, is a very rare last name. The cognomen Demented is characteristic of Israel, where it is a very rare surname, the United States, and the United Kingdom, where it is an extremely rare surname. Very seldom, Demented is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Demented | United States |
| Demento | United States, Israel, United Kingdom |