A high IQ during childhood may be linked to drug use such as cocaine, cannabis and ecstasy in later life, according to a new survey.
A team of researchers at Cardiff University analysed data from almost 8,000 participants, which revealed that men with a high IQ at the age of five were 50 per cent more likely to have taken drugs such as ecstasy later in life than those with lower IQs.
The study revealed the effect is more pronounced in girls, as those with high IQs in childhood are twice as likely to have tried cocaine or cannabis by the age of 30 than those with low IQs.
The data was collected by analysing data from 8,000 babies who were born in one week in April 1970 and enrolled at the British Cohort Study, which follows participants through life. All the children selected then had their IQs tested between the age of five and 10.
The team then reported on the participants drug use between the ages of 16 and 30.
At age 30, around one in three men (34.4 per cent) and one in six woman (15.9 per cent) had admitted to using cannabis in the last 12 months. During the same period, 8.6 per cent of men and 3.6 per cent of women had used cocaine.
The authors noted in the report in journal BMJ Open: "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."
Study author Dr James White, of Cardiff University's Centre for Development and Evaluation of Complex Interventions for Public Health Understanding, said: "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."
The study did not find any other relationship between those participants who used drug and those who did not in the study, including parental social class, and lifetime household income.
"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," said Dr White.