Causes
Conditions resulting in the vitamin deficiency and its effects include chronic alcoholism, and severe malnutrition. Alcoholism is often an indicator of poor nutrition, which in addition to inflammation of the stomach lining, causes thiamine deficiency.[4] Other causes include dietary deficiencies, prolonged vomiting, eating disorders, or the effects of chemotherapy. It can also occur in pregnant women who have a form of extreme morning sickness known as hyperemesis gravidarum.[5] Mercury poisoning can also lead to Korsakoff's syndrome.[citation needed] It has also been caused by centipede (mukade) bites in Japan.[6]

There is no specific treatment because the previous thiamine deficiency produces irreversible damage to the medial thalamic nuclei and mammillary bodies. Mammillary body atrophy may be visible on high-resolution MRI.[7]

The most effective method of preventing Korsakoff's syndrome is to avoid B vitamin/thiamine deficiency. In Western nations the most common causes of such deficiency are alcoholism and weight disorders. Thiamine was introduced to alcoholic beverages in the U.S. for a time,[citation needed] but this does not appear to have an effect on Korsakoff's syndrome, as the cause of Korsakoff's syndrome in chronic alcoholics is not a deficiency of thiamine in the diet, but rather a reduction in the body's ability to absorb thiamine in the intestine.[5] In the U.S., government mandates to adding thiamine to alcoholic beverages have been blocked for this reason and also by political groups asserting that such supplementation would encourage alcohol use.[citation needed]

Also, alcohol is, by itself, neurotoxic. It will cause neural damage taken in excess, especially in the hippocampus. The body responds to alcohol ingestion by releasing cortisol as a neuroprotective mechanism (animals that have been adrenalectomized [i.e. had their adrenal gland removed] may be killed by a fraction of the dose of alcohol that an unadrenalectomized animal may tolerate). Cortisol, specifically, has been shown to cause irreversible damage to the hippocampus when present in large amounts for extended periods of time.[8] Alcohol in excess may be causal in and of itself in Korsakoff dementia regardless of thiamine addition to spirits. Alcohol toxicity is cumulative; cessation of its use, or never having used it, will reduce risk of korsakoff and other dementias