TUESDAY, Dec. 28 (HealthDay News) -- Preteens with conduct disorders are much more likely to be involved in serious violence and delinquency when they are teens, finds a new Canadian study.

It followed 4,125 Canadian youngsters for two years who were ages 12 to 13 at the start of the study.

Those who stole, destroyed property, fought and bullied as preteens were six times more likely to sell illicit drugs, nine times more likely to join a gang, 11 times more likely to carry a weapon, and eight times more likely to be arrested when they were teens, said the University of Montreal researchers.

"Children with conduct disorders who are not violent are also more likely to adopt serious delinquent behaviors as teenagers. More specifically, this group is three times as likely to sell illicit drugs, four times as likely to join a gang, and three times as likely to mug someone using a weapon," principal author Eric Lacourse said in a university news release.

The study appears in the December issue of the Journal of Child Psychology and Psychiatry.

"At ages 12 and 13, the behaviors that lead to delinquency are well documented. However, intervention programs are mostly targeted to younger children and very little help is available for kids [who are] preteens," Lacourse said.

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