Aims: To describe the connections among the likelihood of attention deficit/hyperactivity disorder (ADHD), medical and non-medical methylphenidate and amphetamine use and the diversion of prescribed methylphenidate in the general adolescent population.

Design: Cross-sectional self-reported anonymous data from the 2002 Student Drug Use Survey in the Atlantic Provinces.

Setting: The Atlantic provinces of Canada.

Participants: A total of 12,990 students participated.

Measurements: The outcomes were a positive ADHD screening test, medical and non-medical use of methylphenidate, medical and non-medical use of amphetamine and the giving and selling of methylphenidate medication by students with a prescription. The Ontario Child Health Study Hyperactivity Scale was used to screen for ADHD.

Findings: The prevalence of a positive ADHD screening test was 6% with no significant gender difference. The prevalence of medical and non-medical methylphenidate use and medical and non-medical amphetamine use was 2.0%, 6.6%, 1.2% and 8.7%, respectively. A positive ADHD screening test was independently predictive of these four patterns of use. About 26% of students with prescribed methylphenidate gave or sold some of their medication. Students in a class where at least one student had given or sold some of their prescribed pills had a 1.52-fold increased risk of non-medical methylphenidate use than their counterparts in classes where no giving or selling had taken place.

Conclusions: Connections were demonstrated at the population level between ADHD, medical methylphenidate use, the diversion of prescribed methylphenidate and the non-medical use of methylphenidate. The appropriate assessment and management of ADHD are essential to minimize both the risk of diversion and of substance use associated with unrecognized or untreated ADHD.