Due to alcohol abuse brain related disease Korsakoff's syndrome...

Alcohol interferes with the metabolism of thiamine in the liver. Thus, alcohol intake with deficiency of vitamin- $\mathrm{B}_1$ is the basis of brain related diseases called Wernicke's syndrome and Korsakoff's syndrome. Both the syndromes are associated with the destruction of cells in brain with the memory loss even of recent events and mental confusion along with the impairment of speech.