A disease of central nervous system metabolism due to a lack of vitamin B1 (thiamine) seen in chronic alcoholism. Wernicke’s disease features irregularities of eye movements, in-coordination, impaired thinking, and often sensorimotor deficits. Korsakoff’s psychosis is characterized by confabulation and, more importantly, by a short-term, but not immediate, disturbance that leads to gross impairment in memory and learning. Wernicke’s disease and Korsakoff’s psychosis begin suddenly and are often found in the same person simultaneously.