The Human Genome Project, and other research projects, has brought to light some explanations of why certain individuals participate in self-destructive behaviors more readily than others. A person’s genetic makeup may be a key factor in determining whether a person will succumb to alcohol abuse, substance abuse or take excessive risks.
Scientists have discovered numerous genes that may influence the way people behave. Five of them, however, stand out as especially important. By understanding the effects these genes have on a person’s mental and physical health, doctors can learn how to help their patients make better choices to live healthier, happier lives.
This is Your Brain on Alcohol, and Other Toxins
An October 2010 study printed in Alcoholism: Clinical and Experimental Research provided supporting evidence for what many researchers already thought: the gene CYPZE1 plays a strong role in whether a person becomes an alcoholic. The gene had already been linked to alcoholism, but its mechanism was poorly understood and the evidence was slim.
Now, the evidence is piling up. A study conducted measured the reactions of undergraduate students to alcohol. Most of the students involved in the study had at least one alcoholic parent. As it turns out, the CYPZE1 gene was present in students who showed fewer effects after three alcoholic drinks.
This provides supporting evidence that the gene influences how the brain perceives alcohol and other toxins. It may also explain why some people become alcoholics while others learn to drink in moderation. Researchers suspect that people who cannot tolerate large amounts of alcohol learn to control their consumption habits because the toxin causes negative effects.
However, those who can tolerate alcohol do not learn how to moderate their drinking habits making them more likely to become alcoholics. CYPZE1 is also linked to brain responses for other addictive chemicals; including nicotine.
Genetic Influence for Alcohol Intensity
Alcoholism can vary from person to person. Some alcoholics have four drinks a day, while others can consume a 12-pack. The gene SLC6A4 could influence how much alcoholics drink. A team of scientists at the University of Virginia School of Medicine found this gene had a significant influence on alcohol intensity (how much alcohol a person consumes in one day).
The study focused on known alcoholics, rather than a general population, that consisted of alcoholics, moderate drinkers, and abstainers. Some of the researchers hypothesize that SLC6A4 could have an impact on drinking by affecting the brain’s serotonin. According to a co-author of the study, drinking acute amounts of alcohol provides a boost in serotonin, thus providing positive, rewarding feelings.
Chronic drinking, however, has the opposite effect – it stunts serotonin production. One of the reasons people with this specific gene may drink excessively, could be that they are using alcohol as a serotonin replacement.
Alcohol, Risk, and Dope (Dopamine, That Is)
Some adolescents seem to take more risks than others. For decades, people have argued over whether this is a result of nature or nurture. Do adolescents take ridiculous risks because this behavior was modeled for them by parents and other adult figures, or do they participate in risky behaviors because they have a genetic predisposition to do so?
Researchers in the Netherlands say that they have found a gene that directly impacts the amount of alcohol that adolescents drink and how willing they are to get involved with other risky behaviors. This study pitted two genes against each other (SLC6A4 and DRD2) to determine which one incited the most risky behavior.
After surveying nearly 300 Dutch children who admitted to drinking alcohol at least once in their lives, the scientists took DNA samples and ran them through the lab. What they found would surprise some researchers; especially those at UVA. The gene DRD2 was a better predictor for alcohol consumption, drinking problems, and other risky behaviors than the gene SLC6A4.
DRD2 affects dopamine receptors in the brain. Dopamine receptors are our brain’s reward system that reinforces certain behaviors.. In some people, the reward system is skewed. When this occurs, people are more likely to binge drink. Researchers believe that binge drinking could help suppress negative emotions.
Additional Evidence in Favor of Nature
Do you still need more evidence that nature has a significant impact on a person’s behavior? A 2009 study conducted by the University of Georgia demonstrated that nature plays a significant role in dictating a person’s behavior. Youth with a certain form of the gene 5-HTTLPR were studied and results showed those with a specific form of this gene were more likely to participate in risky behavior, including binge drinking and other types of alcohol abuse.The study subsequently followed a group of minors undergoing treatment for alcohol, drug use and counseling to curb unsafe sexual practices and other risky behaviors. After completing the program, the researchers tracked the behaviors of the participants. What they found wasn’t surprising. The children with one form of 5-HTTLPR reformed rather well, while the other group continued to participate in risky behaviors.
Case Solved, Right?
If these four genes (plus many more) have such a strong impact on the way that people behave, then the nature versus nurture debate should have been solved by now, right? Far from it.
There are numerous complicating factors that make it difficult to pinpoint whether a gene encourages certain behaviors or people simply mimic the behaviors modeled for them by their family members. In other words, does a child become an alcoholic because he watched his father cope with negative emotions by drinking, or does he become an alcoholic because he inherited his father’s genetic predisposition for alcohol abuse? This is not an easy question to answer.
Most researchers are also careful to remind laymen that genes might influence behavior, but they don’t cause it. Someone with a genetic predisposition for alcoholism has a greater chance of becoming an alcoholic. That gene’s presence, however, does not necessarily mean the person will develop a drinking problem.
Genetic research doesn’t condemn certain individuals to lives of self-destructive behavior. Instead, it provides more information that can help individuals make smarter choices for themselves. For instance, counseling a person with a genetic predisposition to avoid alcohol may effectively prevent that person from becoming an alcoholic. The same could be true of other substances and drugs.
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