My Genes Made Me Do It - Alcohol's Addictive Effects

Written by Stanton Peele

Among drinkers who are potentially vulnerable to alcohol's addictive effects, most will nonetheless find alternatives to drinking to deal with anxiety. Perhaps their social group disapproves of excessive drinking, or their own values strongly rule out drunkenness. Thus, although people who finds alcohol redresses their anxiety are more likely to drink addictively than others, they are not programmed to do so.

Table C. A Path to Alcoholism

Mirror, Mirror

The goal of determining what proportion of behavior is genetic and environmental will always elude us. Our personalities and destinies don't evolve in this straightforward manner. Behavioral genetics actually shows us how the statistical plumbing of the human spirit has reached its limits. Claims that our genes cause our problems, our misbehavior, even our personalities are more a mirror of our culture's attitudes than a window for human understanding and change.*

SIDEBAR A: Twins "Separated At Birth"

An especially fascinating natural genetic experiment is the comparison of identical twins reared apart, which was the object of a project headed by psychologist Thomas Bouchard at the University of Minnesota. Findings from the project reporting uncanny similarities among the reared-apart twins were often broadcast to the press prior to the publication of any formal results. Yet, Northeastern psychologist Leon Kamin showed that most British twins supposedly separated at birth in another study actually spent considerable periods of time together.

The Bouchard team introduced to the press two twins who claimed to have been brought up separately as, respectively, a Nazi and a Jew. However, both twins claimed they thought it funny to sneeze in crowds and flushed the toilet before urinating! In another case, British sisters showed up in Minnesota wearing seven rings distributed identically on their fingers. Bouchard's colleague David Lykken suggested a genetic predisposition might exist for "beringedness"!

Few, if any, geneticists would agree that genes influence the order in which people urinate and flush the toilet. Kamin waggishly suggested the researchers might use some of their grant money to hire a private investigator to see whether such twins had been playing a "trick" on the researchers. After all, such twins must have realized, amazing similarities between twins sell much better than differences between them. Identical twins who are substantially different are just not as newsworthy.

SIDEBAR B: How to Interpret Genetic Discoveries

We often need help in interpreting newspaper or television accounts about genetic "discoveries." Here are factors readers can use to evaluate the validity of a genetic claim:

1. Nature of the study. Does the study involve human beings or laboratory animals? If animal, additional critical factors will almost certainly affect the same aspect of human behavior. If human, is the study a statistical exercise or an actual investigation of the genome? Statistical studies which apportion variation in behavior between genes and environment cannot tell us whether individual genes actually cause a trait.
2. Mechanism. How exactly is the gene claimed to affect the proposed trait to which it is linked? That is, does the gene affect people in a way that leads logically to the behavior or trait in question? For example, to say that a gene makes some people welcome alcohol's effects does not explain why they would regularly drink until they become unconscious, destroying their lives along the way.
3. Representativeness. Are the populations studied large and diverse, and does the same genetic result appear in different families and groups? Are those studied selected randomly? Early claims about manic depression, schizophrenia, and alcoholism were made with extremely limited groups and did not hold up. Findings about homosexuality will likely suffer a similar fate.
4. Consistency. Are the results of the study consistent with other studies? Have other studies found a similar genetic loading for the behavior? Have gene studies identified the same gene or area of the chromosome? If every positive study implicates a different section of DNA as the major determinant of the behavior, the likelihood is that none will hold up.
5. Predictive power. How closely linked are gene and trait? One measure of power is the likelihood a syndrome or disease will appear given a genetic disposition. With Huntington's gene, the disease may be inevitable. In other cases, only a small minority with a claimed genetic predisposition may express a trait. For example, accepting the original Blum-Noble figures for the A1 Allele, many more of those with the gene would not be alcoholic than would be.
6. Usefulness. What use can be made of the proposed discovery? Simply warning people they will have a problem may be little help to them. Teenagers with an "alcoholism gene" who are told they are genetically predisposed to alcoholism may believe they cannot drink normally. Since most of them nonetheless will drink, they are then set up for a self-fulfilling prophecy in which they act as they had been told they would. If a proposed genetic discovery is not useful, it is merely a curiosity or, worse, a distraction from real solutions.

Ruth Hubbard assisted Stanton and Rich DeGrandpre in the preparation of this article. She is the author, with Elijah Wald, of Exploding the Gene Myth.

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