The findings contradict the conventional wisdom that drug-taking is most prevalent among anxious or insecure youth looking for an escape from poor conditions or a way to feel better about themselves.
Experts say the new research means an overhaul of drug education programmes is necessary.
Unfortunately the results blow a hole in the simple moral fable that young people are led into the paths of righteousness by high self-esteem,' he said. Two factors are thought to explain the results. More confident children are more likely to be sociable, have more money and thus have more opportunity to experiment with drugs. Ashton's research shows that one in five university students says he or she uses cannabis at least once a week. It also shows that a typical cannabis joint in the Sixties contained only 10mg of a potent chemical known as THC which affects the brain.