Male started alcohol at 20 years, presently taking 3 quarters daily over 30 years, now complains that he gets the kick in 1 quarter, diagnosis is:

Ans. c. Reverse tolerance (Ref: Kaplan and Sadock's 9/e p1271; Mellanby effect)People with a lot of alcoholic liver damage can no longer metabolize alcohol very well, these people can get very intoxicated on small quantities of alcohol -much smaller quantities than are needed to affect the person who rarely drinks. This phenomenon is known as Reverse Tolerance.Reverse ToleranceReverse Tolerance occurs when a heavy drinker develops liver damage and the liver no longer produces as great a quantity of the enzymes needed to break down alcohol in the body as it did before.Since people with a lot of alcoholic liver damage can no longer metabolize alcohol very well, these people can get very intoxicated on small quantities of alcohol -much smaller quantities than are needed to affect the person who rarely drinks. This phenomenon is known as Reverse ToleranceQ.It is important to note that most heavy drinkers do NOT develop liver damage or Reverse Tolerance.The majority of heavy drinkers will not suffer liver damage and hence will not develop Reverse Tolerance.The way that Reverse Tolerance can develop over a lifetime is illustrated by the curve in Figure.Healthy Tolerance Reversal which occurs when a heavy drinker does a period of abstinence from alcohol or a period of moderate drinking.The essential difference between Reverse Tolerance and Healthy Tolerance Reversal is that Reverse Tolerance is caused by damage to the liver which is often irreversible.In Healthy Tolerance Reversal the liver is actually becoming more healthy than it was during the period of heavy drinking and the reason why the tolerance is dropping is that the excessive and unhealthy levels of liver enzymes associated with heavy drinking are now returning to normal and healthy levels.Mellanby Effect( style="font-family: Times New Roman, Times, serif"> Mellanby effect)*The most widely used acute tolerance measure in human research is often called the Mellanby effect* Involves the comparison of responses at the same blood alcohol concentrations on the ascending and descending limbsa of the blood alcohol curve