Korsakoff syndrome is a neuro disorder associated with deficiency of which vitamin?

• A. Thiamine (B1)
• B. Cobalamin (B12)
• C. Niacin (B3)
• D. Riboflavin (B2)

Answer: (A)

Thiamine deficiency is what underlies Korsakoff syndrome. Thiamine, or vitamin B1, is essential for brain energy production. In chronic alcohol use, malnutrition, or poor absorption, thiamine levels drop, leading to damage in memory-related brain regions such as the mammillary bodies. The resulting disorder is characterized by profound anterograde and retrograde amnesia and often confabulation. It’s commonly a sequela of Wernicke encephalopathy, and in clinical practice you’d treat suspected Korsakoff with thiamine administration (ideally before glucose) to prevent further neurologic injury. Other vitamins listed are linked to different deficiency syndromes—B12 deficiency causes neuropathy and anemia, niacin deficiency causes pellagra, and riboflavin deficiency causes mouth and skin findings—which is why thiamine deficiency best explains Korsakoff syndrome.