Why do some people drink so much more than others? Why also are some people able to drink large amounts of alcohol with apparent impunity, while others remain moderate and yet suffer problems as a result of their drinking? This chapter attempts to provide answers to these two questions. However, the complexity of the individual case and the extensiveness of the research literature both indicate that too simple answers should not be expected. Nor should it be imagined that any single factor can provide an adequate explanation. Drinking behaviour and the problems with which it is associated are determined by multiple, interacting factors which concern both the individual and his or her environment.

Drinking and drinking problems

The causes of ‘heavy’ drinking and drinking problems can only be properly understood within the context of an overall view of ‘normal’ drinking in the population as a whole. This is because there is no clear boundary between normal and heavy drinking, and because drinking problems occur in normal as well as heavy drinkers. A graph demonstrating the typical distribution of alcohol consumption within a population is shown in Figure 2.1. It may be seen that while the majority of people drink ‘moderately’, a small percentage drink very heavily indeed (a small percentage can mean a lot of people). However, it is quite arbitrary (on the basis of quantity alone) to choose a point at which to draw the line separating ‘normal’ and ‘heavy’ drinkers.