Korsakoff's disease, or rather Korsakoff's disease, is characterized by incurable and severe memory loss (amnesia) of both retrograde and anterograde nature. Typically, the memories lost during conversations or interrogations are replaced by imaginary statements: conffabulation.
The disease picture was first described in the late 1800s. Its underlying cause is thiamine (vitamin B1) deficiency. Since severe vitamin deficiency is often linked to severe alcoholism (as an effect of a lack of normal nutrition), Korsakoff's disease, somewhat misleadingly, has usually been explained as a direct consequence of alcohol abuse.
The typical finding in the brain of the Korsakoff patient is hemorrhages and degenerations in the medial mammillary nucleus of the hypothalamus.