Girls who go to private schools are three times more likely to suffer from alcohol and drug problems than other young women later in life, an American study has suggested.

"Privileged" students who live in comfortable houses and go to elite schools are at high risk of using cannabis, cocaine and ecstasy, the researchers found.

They were also more likely to abuse drink despite being popular among their peers, performing "exceedingly well" in school and being "highly regarded" by their teachers.

Boys who have grown up in affluent areas and go to "elite" schools are twice as likely as other young men to experience drink and drug addiction in early adulthood.

Study leader Professor Suniya Luthar, of Arizona State University, said: "We found alarmingly high rates of substance abuse among young adults who we initially studied as teenagers.

"Results showed that among both men and women and across annual assessments, these young adults had substantial elevations, relative to national norms, in frequency of several indicators - drinking to intoxication and of using marijuana, stimulants such as cocaine, and club drugs such as ecstasy."

The researchers studied two groups of students in affluent communities as part of the New England Study of Suburban Youth (NESSY).