Despite a good deal of research into the subject no convincing evidence has been provided to make us believe that the future alcoholic is in some way marked out from his fellows by differences in anatomy, physiology, or pathology or by abnormalities of metabolism or of tissue chemistry.
Among the many theories that have been propounded on these lines, that of an allergic factor receives most attention because the members of Alcoholics Anonymous cleave to it. They contend that there is something in the physical make-up of an alcoholic – even before he has started to drink – which is responsible both for the craving for alcohol and for dependence upon it. This theory, which never found much support among psychiatrists, was convincingly rebutted by the work of Robinson and Voegtlin1 who, after administering alcohol to alcoholics, found none of the characteristic reactions in the tissue fluids which characterize the allergic phenomenon; nor could they induce such responses in laboratory experiments on men or animals where everything was under the optimum condition for their production.
I. Robinson, M. W. and Voegtlin, W/L. (1952). ‘Investigations of an allergic factor in alcohol addiction’. Quarterly Journal ofStudies on Alcohol, 1 /, 196.
Endocrine factors have also been suggested but here again there is a lack of practical evidence to support the theoretical contentions.
Some workers adduce changes in brain structure. These, they claim, are early consequences of excessive drinking and, because brain substance is lost, they result in a lessening of control over future alcohol intake so that addiction can readily develop. However, it has always escaped demonstration that such changes do occur early in the course of excessive drinking. Several workers1 have claimed to find X-ray evidence of loss of brain substance in young alcoholics and this, if it is confirmed, may make further study of the possibility worthwhile.
Nutritional factors have also been widely canvassed. One set of theories implies that certain individuals have a dietary lack of a specific factor (the Nj factor) necessary for metabolism. Rats whose diets lacked this factor were found to take more alcohol than other rats. Later experimental work has cast considerable doubt on what may be concluded from such observations. Another theory is that alcoholics inherit an enzyme abnormality which, because it impairs metabolism of certain substances, increases the need for them and thus sets up a metabolic pattern predisposing to alcoholism. Although some of the research behind this theory has been carried out on alcoholics there is no warrant for the belief that any metabolic disorder is inherited or indeed that it preceded the alcoholism. This last objection applies to many theories which postulate physical factors operating before excessive drinking develops. Craving for alcohol, or dependence on it, has not been shown to occur before drinking has taken place, yet many of the theories require this for their substantiation.
Theories where the pathological or biochemical or endocrinological changes are presumed to be subsequent to heavyi. Lemere,F. (1956). ‘The nature and significance of brain damage from alcoholism’. American Journal of Psychiatry, 11), 361.
drinking but then act to make it get out of control are more plausible. We have already seen that the setting-in of brain damage could be one such factor. There is no doubt that metabolic changes do occur consequent upon heavy drinking although evidence that such changes promote further drinking is still lacking. If it were forthcoming it would show that physical factors played a part in making the drinking take an addictive form but not that they led to excessive drinking in the first place.
The question of inheritance of a predisposition to alcoholism has been repeatedly raised. There is no doubt that it is a familial condition. Sons of alcoholics, for instance, have been shown to have a much higher incidence of alcoholism than other men of the same age.1 But this transmission does not obey biological laws. It works by example. The father provides the son with a pattern of behaviour which he assimilates and on which he subsequendy models his own adult behaviour. The alcoholism is passed on in the same way that money is inherited, not in the way that, say, eye colour is. Genetic inheritance of alcoholism has not been demonstrated.