Classroom know-it-alls may be more likely to experiment with drugs as they enter adulthood, according to a new study.

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mart kids are more likely to use drugs such as marijuana and cocaine when they grow up — and the likelihood is stronger among females than males — according to a new British study published in the Journal of Epidemiology and Community Health. Researchers have previously posited that children with a high IQ can grow up to be heavier drinkers. Now drugs, too? A concise guide to the findings:

What was the study's methodology?
Researchers tracked about 8,000 people across three decades, recording their IQ scores at age 5 and again at age 10, says Makiko Kitamura at Bloomberg Businessweek. As adults, "participants were asked about use of substances including cannabis, cocaine, amphetamines, ecstasy, LSD, hallucinogenic mushrooms, crack and heroin." 

And what did they find?
Subjects "who had high IQs when they were aged 5 and 10 were more likely to use certain illicit drugs at age 16 and at age 30," says Denise Mann at Web MD. In particular, women with high IQ scores at 5 years of age were "more than twice as likely" to have smoked marijuana or tried cocaine by age 30 than women with lower IQs. As for men who tested well as kids, 50 percent were more likely to use amphetamines like speed, 65 percent more likely to have tried ecstasy, and, overall, 57 percent more likely to have used two or more illegal drugs by the time they hit 30.

Why are smart kids more likely to use drugs?
While parents may find the results "surprising at first glance," intelligent children fit the "established" profile of drug experimenters in many ways, says Karen Kaplan at the Los Angeles Times. Among the social factors that can lead individuals to try drugs are boredom and a "tendency to be teased" by peers as a child. (Drugs could be used as a "coping strategy.") Moreover, smarter individuals are typically more willing to try new things. As the researchers note: "High-IQ individuals have also been known to score highly on tests of stimulation seeking and openness to experience" — which illegal drugs can provide.

Sources: Bloomberg Businessweek, LA Times, Web MD