(See also Drug Use and Abuse.)
Korsakoff psychosis occurs in 80% of people with untreated Wernicke encephalopathy, which is a brain disorder caused by a type of vitamin deficiency that can occur in people who drink large amounts of alcohol for a long time. Korsakoff psychosis is sometimes triggered by a severe bout of delirium tremens, which is a form of alcohol withdrawal, whether a typical attack of Wernicke encephalopathy occurs prior or not. Other causes include head injuries, stroke, bleeding within the brain, and certain brain tumors (rarely).
People with Korsakoff psychosis lose their memory for recent events. Memory of remote events is less affected. Memory can be so poor that people often make up stories, sometimes very convincingly, to try to cover up the inability to remember (called confabulation). They lose all sense of time. People become confused and apathetic and may not respond to events, even frightening ones. People also have all the symptoms of Wernicke encephalopathy, including profound ataxia (wide-based stumbling gait) and difficulty controlling eye movements.
Doctors base a Korsakoff psychosis diagnosis on symptoms, particularly confabulation, in people with conditions that can cause Korsakoff psychosis, such as severe chronic alcohol use disorder. Doctors need to rule out other causes of the symptoms, such as infection.