A high childhood IQ is linked to subsequent illegal drug use, particularly among women, suggests research published published Monday in the Journal of Epidemiology and Community Health.

The authors base their findings on data from just under 8,000 people in the 1970 British Cohort Study, a large ongoing population based study, which looks at lifetime drug use, socioeconomic factors, and education.

The IQ scores of the participants were measured at the ages of 5 and 10 years and information was gathered on drug use at the age of 16, and again at 30.

Drug use included marijuana, cocaine, amphetamines, sedatives, LSD, and heroin.

When intelligence was factored in, the analysis showed that men with high IQ scores at the age of 5 were around 50 percent more likely to have used amphetamines, ecstasy, and several illicit drugs than those with low scores, 25 years later.

The link was even stronger among women, who were more than twice as likely to have used pot and cocaine as those with low IQ scores.

“Although most studies have suggested that higher child or adolescent IQ prompts the adoption of a healthy lifestyle as an adult, other studies have linked higher childhood IQ scores to excess alcohol intake and alcohol dependency in adulthood,” write the authors.

Although it is not yet clear exactly why there should be a link between high IQ and illicit drug use, the authors point to previous research, showing that highly intelligent people are open to new experiences and need stimulation.

Other research has also shown that brainy children are often easily bored and suffer at the hands of their peers for being different, “either of which could conceivably increase vulnerability to using drugs,” explain the authors.