Korsakoff's psychosis

Korsakoff's syndrome (a.k.a. Korsakoff's psychosis, amnesic-confabulatory syndrome), is a continuum of Wernicke's encephalopathy, though a recognised episode of Wernicke's is not always obvious. Individuals diagnosed with Korsakoff's syndrome usually have symptoms of severe anterograde and retrograde amnesia, as well as confabulation. The syndrome is named for Sergei Korsakoff, the neuropsychiatrist who popularized the theory.

These symptoms are caused by damage to mammillary bodies and other brain regions due to deficiency of thiamine (Vitamin B1). This is most often caused by chronic alcoholism, though other conditions including severe malnutrition have been known to cause it. When Wernicke's encephalopathy accompanies Korsakoff's syndrome, the combined syndrome is called the Wernicke-Korsakoff syndrome.

Pathologically, there is neuronal loss, gliosis, and hemorrhage in mammillary bodies. Damage to the dorsomedial nucleus of the thalamus is also associated with this disorder.

Intravenous (IV) or intramuscular (IM) injection of thiamine is used to treat this condition, though recovery is slow and often incomplete.

A famous case study is recounted by Oliver Sacks in "The Lost Mariner", which can be found in The Man Who Mistook His Wife for a Hat.