In an alcoholic man, Blackout is seen in

Acute Intoxication After a brief period of excitation, there is a generalised central nervous system depression with alcohol use. With increasing intoxication, there is increased reaction time, slowed thinking, distractibility and poor motor control. Later, dysahria, ataxia and incoordination can occur. There is a progressive loss of self-control with frank disinhibited behaviour. The duration of intoxication depends on the amount and the rapidity of ingestion of alcohol. With blood alcohol levels of 300-450 mg%, increasing drowsiness followed by coma and respiratory depression develop. Death occurs with blood alcohol levels between 400 to 800 mg%. Occasionally a small dose of alcohol may produce acute intoxication in some persons. This is known as pathological intoxication. Another feature, sometimes seen in acute intoxication, is the development of amnesia or blackouts. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 37