Alcoholic dementia. Coloured magnetic resonance imaging (MRI) scan of the brain of a patient with alcoholic dementia. The brain has atrophied (shrunk), shown by the enlarged gap (black) between the brain and the skull. Alcoholic dementia is caused by excessive alcohol drinking over a prolonged period. It causes memory loss, confusion, impaired judgement and personality changes. If caught at an early stage the dementia can be reduced or even reversed if the patient abstains from alcohol and has a healthy diet supplemented with vitamin B1.