My Genes Made Me Do It - There Is no Link between This Gene and Alcoholism!

Written by Stanton Peele

The Blum-Noble discovery was broadcast around the country after being published in the Journal of the American Medical Association and touted by the AMA on its satellite news service. But, in a 1993 JAMA article, Joel Gelernter of Yale and his colleagues surveyed all the studies that examined this allele and alcoholism. Discounting Blum and Noble's research, the combined results were that 18 percent of nonalcoholics, 18 percent of problem drinkers, and 18 percent of severe alcoholics all had the allele. There was simply no link between this gene and alcoholism!

Blum and Noble have developed a test for the alcoholism gene. But, since their own data indicate that the majority of people who have the target allele are not alcoholics, it would be foolhardy to tell those who test positive that they have an "alcoholism gene."

The dubious state of Blum and Noble's work does not disprove that a gene - or set of genes - could trigger alcoholism. But scientists already know that people do not inherit loss-of-control drinking whole cloth. Consider that alcoholics do not drink uncontrollably when they are unaware that they are drinking alcohol - if it is disguised in a flavored drink, for example.

A more plausible model is that genes affect how people experience alcohol. Perhaps drinking is more rewarding for alcoholics. Perhaps some people's neurotransmitters are more activated by alcohol. But although genes can influence reactions to alcohol, they cannot explain why some people continue drinking to the point of destroying their lives. Most people find orgasms rewarding, but hardly any engage in sex uncontrollably. Rather, they balance their sexual urges against other forces in their lives.

Jerome Kagan, a Harvard developmental psychologist, was speaking about more than genes when he noted, "we also inherit the human capacity for restraint."

Of (Fat) Mice and Humans

Public interest was aroused by the 1995 announcement by Rockefeller University geneticist Jeffrey Friedman of a genetic mutation in obese mice. The researchers believe this gene influences development of a hormone that tells the organism how fat or full it is. Those with the mutation may not sense when they have achieved satiety or if they have sufficient fatty tissue, and thus can't tell when to stop eating.

The researchers also reported finding a gene nearly identical to the mouse obesity gene in humans. The operation of this gene in humans has not yet been demonstrated, however. Still, professionals like University of Vermont psychologist Esther Rothblum reacted enthusiastically: "This research indicates that people really are born with a tendency to have a certain weight just as they are to have a particular skin color or height."

Actually, behavior geneticists believe that less than half of total weight variation is programmed in the genes, while height is almost entirely genetically determined. [Table B] Whatever role genes play, America is getting fatter. A survey by the Centers for Disease Control found that obesity has increased significantly over the last 10 years. Such rapid change underlines the role of environmental factors, like the abundance of rich foods, in America's overeating. Complimenting this finding, the Centers have found that teens are far less physically active than they were even a decade ago.

Certainly people metabolize food differently and some people gain weight more easily than others. Nonetheless, anyone placed in a food-rich environment that encourages inactivity will gain weight, whatever fat genes the person may have. At the same time, in nearly all environments, highly motivated people can maintain lower weight levels. We thus see that social pressure, self-control, specific situations - even seasonal variations - combine with physical make-up to determine weight.

Accepting that weight is predetermined can relieve guilt for overweight people. But people's belief that they cannot control their weight can itself contribute to obesity. No test will ever be performed that can tell you how much you must weigh. Personal choices will always influence the equation. And anything that inspires positive efforts at weight control can help people lose weight, or avoid gaining more.

The case of obesity - along with schizophrenia, depression, and alcoholism - raises a striking paradox. At the same time that we now view them as diseases that should be treated medically, their prevalence is growing precipitously. The very reliance on drugs and other medical treatments has created a cultural milieu that seeks external solutions for these problems. Relying on external solutions may itself be exacerbating matters; it may be teaching us a helplessness that is at the root of many of our problems. Instead of reducing our problems, this seems to have fueled their growth.

Harnessing Discoveries

In 1993, the gene that determines the occurrence of Huntington's disease - an irreversible degeneration of the nervous system - was discovered. In 1994, a gene was identified that leads to some cases of breast cancer. Utilizing these discoveries, however, is proving more difficult than anticipated.

Finding a gene for breast cancer was cause for elation. But of all the women with breast cancer, only a tenth have family histories of the disease. Furthermore, only half of this group has a mutation in the gene. Scientists also hoped that breast cancer victims without family histories would show irregularities at this same site on the DNA. But only a small minority do.

The section of the DNA involved in inherited breast cancers is enormously large and complex. There are probably several hundred forms of the gene. The task of determining which variations in the DNA cause cancer, let alone developing therapies to combat the disease, is tremendous. Right now, women who learn that they have the gene defect know they have a high (85 percent) likelihood of developing the disease. But the only decisive response available to them is to have their breasts removed before the disease appears. And even this does not eliminate the possibility of chest cancer.