Researchers at the Yale School of Public Health have identified a gene associated with multiple cases of alcoholism, drug abuse and other addictive behaviors in white women of European origin. The research appears in this week's Online Early Edition of the Proceedings of the National Academy of Sciences.

The research used data collected in genome-wide studies and found a strong and significant association between a gene located on chromosome 11-known as PKNOX2-and multiple dependencies among white women involving nicotine, alcohol, marijuana, cocaine, opiates and other drugs. The women with this gene were almost twice as likely as white men, black women or black men to have two or more of the addictions.

While genes on other chromosomes have previously been associated with alcoholism and drug abuse in prior studies, this is believed to be the first time that PKNOX2 has been linked to addiction in humans, said Heping Zhang, Ph.D., professor in the division of Biostatistics at the Yale School of Public Health and the paper's senior author. The gene identified by the researchers had previously been associated with addictive behavior in mice.

Addiction can only occur when an individual is exposed to the habit-forming substance. Therefore, if and when a gene such as PKNOX2 is identified, scientists can use that information to estimate how many people are vulnerable to addictions and the extent to which an individual with the gene is at risk.

"This information can be used to design preventive and/or treatment strategies for addiction by controlling the environment exposure in the targeted group and/or by exploring and developing medications that modify the expression of the gene," Zhang said. "Findings such as ours have the potential of great clinical significance, but this is a beginning instead of the end, because understanding addiction is very complex and challenging. The people who are likely to be affected most are those who are addicted to one substance, and they can be genotyped for a risk gene in order to prevent elevated risk of multiple dependences."

Different ethnic groups have very different underlying genetics for many complex diseases, Zhang said. Previous research has found racial differences in the prevalence of substance abuse.

Zhang's research team included Xiang Chen and Kelly Cho of the Yale School of Public Health and Burton H. Singer of Princeton University.

Yale University