Bright children are more likely to drink and smoke cannabis in their teenage years, a new study has found.
High academic achievement at the age of 11 has been linked to a lower risk of smoking in adolescence.
But high achievers were more likely to drink alcohol in their teenage years.
They were also more likely to smoke cannabis compared with their less academically gifted peers.
Experts examined data for more than 6,059 young people across England.
Information was gathered on their academic achievement at age 11 and collated with health behaviours from 13/14 to 16/17 - deemed to be early adolescence - and from age 18/19 to 19/20, which are classed as late adolescence.
The study, published in the journal BMJ Open, found that during their early teens, high-achieving pupils were less likely to smoke cigarettes than their less gifted peers. And they were more likely to say they drank alcohol during this period.
During their late teens, brainy children were more than twice as likely to drink alcohol regularly and persistently than those who were not as clever.
Meanwhile, clever pupils were 50% more likely to use cannabis occasionally and nearly twice as likely to use it persistently than their less gifted peers.
They found that these patterns persisted into adulthood and would seem to refute the notion that academic prowess was associated with a greater tendency to 'experiment' temporarily with these substances.
"High childhood academic at age 11 is associated with a reduced risk of cigarette smoking but an increased risk of drinking alcohol regularly and cannabis use," the researchers, from University College London, wrote.
"These associations persist into early adulthood, providing evidence against the hypothesis that high academic ability is associated with temporary 'experimentation' with substance use."