Clever children more likely to end up on drugs

Intelligent girls and boys are much more likely than average to take illegal drugs like cocaine, cannabis and ecstasy when they grow up, a study has found.

Scientists think they do so in part as a "coping strategy" to avoid bullying from their peers, and partially because they find life boring.

The effect is more pronounced in girls than boys, with those exhibiting high IQs as children more than twice as likely to have tried cocaine or cannabis by the age of 30, as those of lower intelligence.

The effect in boys with high IQs is also marked, with them being around 50 per cent more likely to have done so by that age as their less intelligent former classmates.

A team at Cardiff University analysed data from almost 8,000 people born in one week in April 1970, who were enrolled at birth in the ongoing British Cohort Study, which follows participants through life. All these children had their IQs tested between the age of five and 10.

Drug use, as reported by the participants themselves, was then recorded at 16 and 30 years of age.

At 16, 7.0 per cent of boys and 6.3 per cent of girls had used cannabis. This minority had "statistically significant higher mean childhood IQ scores" than non-users, according to the authors of the report, published in the Journal of Epidemiology and Community Health.

At 30, 35.4 per cent of men and 15.9 per cent of women had used cannabis, while the figures for cocaine were 8.6 and 3.6 per cent respectively.

The authors noted: "Across most drugs (except amphetamine in men), men and women who reported using in the past 12 months had a significantly higher childhood IQ score than those who reported no use."

They concluded: "High childhood IQ may increase the risk of substance abuse in early adulthood."

The study did not look into why this was the case, although it did not fine any relationship between the social class of the participants' parents and future drug use.

However, the authors noted that other studies suggested "intellectually 'gifted children' [with an IQ higher than 130] report high levels of boredom and being stigmatised by peers, either of which could conceivably increase vulnerability to using drugs as an avoidant coping strategy".

Dr James White of Cardiff University's Centre for Development and Evaluation of Complex Interventions for Public Health Understanding, said: "Although it is not yet clear exactly why there should be a link between high IQ and illicit drug use, previous research has shown that people with a high IQ are more open to new experiences and keen on novelty and stimulation."

The Telegraph 15/11/2011