Brief intervention, consisting in an intervention with the adolescent and a session with parents or mentors. The session with the adolescent lasted 60 minutes. Materials related to the interview were developed according to previous reports on the subject. After building a good rapport the interviewer involved the patient in an initial discussion about the results of the evaluation. This led to a review of the drugs used by the subject and an elicitation of positives and negatives of drug use. The relationship between drug use and current and long-term goals was explored. Discrepancies and problems in the future related to substance use were examined, and information and counseling was offered. The basic components of the motivational interview approach were contemplated, and several skills were used by the interviewers. The individual session with parents or mentors consisted in the presentation of educational materials and a brief counseling intervention on parenting skills.

Treatment as usual (TTU): Individuals assigned to this group and their parents or tutors received standard care and no further intervention other than completion of the assessment protocol. After completing the assessment individuals and their families went on to receive standard care at the Child and Adolescent Psychiatry and Psychology Department according to the primary diagnosis

Brief intervention, consisting in an intervention with the adolescent and a session with parents or mentors. The session with the adolescent lasted 60 minutes. Materials related to the interview were developed according to previous reports on the subject. After building a good rapport the interviewer involved the patient in an initial discussion about the results of the evaluation. This led to a review of the drugs used by the subject and an elicitation of positives and negatives of drug use. The relationship between drug use and current and long-term goals was explored. Discrepancies and problems in the future related to substance use were examined, and information and counseling was offered. The basic components of the motivational interview approach were contemplated, and several skills were used by the interviewers. The individual session with parents or mentors consisted in the presentation of educational materials and a brief counseling intervention on parenting skills.