Titled, “Multi-Polygenic Analysis of Nicotine Dependence in Individuals of European Ancestry,” the current study employed a multi-trait model with the aim of genetically correlating traits and diseases to increase the accuracy of predicting one’s nicotine dependence.
Genes that increase the risk of addiction
The results indicated that polygenetic scores for the different traits and disorders,such as a risk for schizophrenia, depression, neuroticism, self-reported risk-taking, a high body mass index and alcoholism, raised the risk for that dependence. On the other hand other polygenetic scores such as ones associated with higher education attainment, lowered the risk for nicotine dependence.
Interestingly, reported the study, the number of cigarettes smoked per day, self-perceived risk-taking, and educational attainment were the most robust predictors. “If you look at the joint effect of all of these characteristics, our model accounts for nearly 4 percent of the variation in nicotine dependence, or nearly four times as much as what we learn when relying solely on a genetic index for the number of cigarettes someone smokes daily,” said Rohan Palmer, Senior Author, and Assistant Professor at the Behavioral Genetics of Addiction Laboratory at Emory University.
Palmer added that the situation seems more complex than previously thought. “What we’re finding, is that to better leverage genetic information, we need to go beyond individual human traits and disorders and think about how risk for different behaviors and traits are interrelated. This broader approach can give us a much better measure for whether someone is at risk for a mental disorder, such as nicotine dependence.”
“All of the traits and diseases we looked at are polygenic, involving multiple genes,” adds Victoria Risner, first author of the study, who did the work as an Emory undergraduate majoring in neuroscience and behavioral biology. “That means that millions of genetic variants likely go into a complete picture for all of the heritable risks for nicotine dependence.”
The role of habitability
The multi-variant, polygenetic model used in this study offers an opportunity and road map for future studies. For instance, it gives a clearer picture of the role of heritability in addiction, which researchers can zoom further on by adding more risk associations to the model (such as nicotine metabolism) and clusters of polygenic traits (such as anxiety along with neuroticism).
“As we continue to zero in on who is most at risk for becoming nicotine dependent, and what inter-related factors, whether genetic or environmental, may raise their risk, that could help determine what intervention might work best for an individual,” concluded Palmer.
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