Alcoholic presents with psychosis and memory loss. Probable diagnosis is:

Alcoholic patients with chronic thiamine deficiency may also have central nervous system (CNS) manifestations known as Wernicke's encephalopathy, consisting of horizontal nystagmus, ophthalmoplegia (due to weakness of one or more extraocular muscles), cerebellar ataxia, and mental impairment. When there is an additional loss of memory and a confabulatory psychosis, the syndrome is known as Wernicke-Korsakoff syndrome. Ref: Harrison's principle of internal medicine 17th edition, chapter 71.