A total of 726 youths presenting a severe addiction were evaluated at the time of their request for services in an addiction rehabilitation center. Results show that the more delinquent youths have a more severe profile of substance use, thus confirming the strong association between psychoactive substance (PAS) use severity and delinquency. Girls being treated for addiction present a more severe profile of substance use than boys treated. No interaction effect was found between gender and level of delinquency. It also appears important that the history of sexual abuse be considered as one of the variables associated with the severity of PAS use.