By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – There has always been a sense that alcoholism runs in families and researchers have studied the topic quite often.

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Some of the theories are very interesting. In particular work from the University of Iowa has raised interesting theories.

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These researchers studied the relationship between alcohol consumption and variations in a gene involved in processing the brain chemical serotonin in 275 people, largely men, who had an alcohol dependency. They found that those with a particular variation in one gene involved in serotonin processing were more likely to drink more alcohol than those with a different variation.

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Researchers theorize that the chronic alcoholics may drink, in part, to alleviate a deficit in serotonin. Those with particular variations may experience a greater or lesser degree of deficit.