FEATURE ARTICLE
Predicting Addiction
Behavioral genetics uses twins and time to decipher the origins of addiction and learn who is most vulnerable
Lisa Legrand, William Iacono, Matt McGue
Much Left to Learn
Although the MCTFR data have resolved some addiction-related questions, many others remain, and our team has just begun to scratch the surface of possible research. Our work with teenagers indicates that externalizing is a key factor in early-onset substance-use problems, but the path to later-life addiction may be distinct. Some evidence suggests that genes play a lesser role in later-onset addiction. Moreover, the markers of risk may vary. Being prone to worry, becoming upset easily and tending toward negative moods may, with age, become more important indicators. We don't yet know. However, the MCTFR continues to gather information about its participants as they approach their 30s, and we hope to keep following this group into their 40s and beyond.
Meanwhile, the evidence suggests that for early-onset addiction, most relevant genes are not specific to alcoholism or drug dependence. Instead, the same genes predispose an overlapping set of disorders within the externalizing spectrum. This conclusion has significant implications for prevention: Some impulsive risk-takers, frequent rule-breakers and oppositional children may be just as much at risk as early users.
At the same time, many kids with a genetic risk for externalizing don't seem to require any sort of special intervention; as it is, they turn out just fine. DNA may nudge someone in a certain direction, but it doesn't force them to go there.
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