the current theory for the reason why the generic markers for making people predisposed to becoming alcoholics are prevelant within societies that have suffered repeated social tragities (such as war) is because it helps them to survive the mental aspects of these events while those who didn't drink tended not to survive very long thereafter. (those markers are prevelant within specific populations because it helped a specific subpopulation within that group to survive). it's a cruel joke that, placed within a decadent society, that those survivors are now at a disadvantage.