The scientific consensus on the use of stimulants to treat "hyperactive" or ADHD-diagnosed children amounts to recognizing a calming effect on children's disruptive behavior and better performance of repetitive tasks, both in the short-term. Long-term effects remain unknown. Still, in Québec, prescription of stimulants to children of welfare recipients nearly tripled between 1990 and 1994, reaching a prevalence of 11.9%. Using a systemic model integrating three approaches (medicalization of deviance, political economy, and strategic analysis), we conceptualized the decision to prescribe as the result of interactions involving different actors holding unequal power and seeking to further their interests. We attempted to establish the defendability of this model by means of in-depth interviews with five parents, four primary school teachers and three physicians in prolonged contact with a hyperactive child receiving stimulant medication. Data from the interviews reveal the omnipresence of the medical model in the hyperactivity treatment system, although teachers rather than physicians appear as the engine of this medicalization. According to parents and physicians, teachers identify and "diagnose" children, propose the use of medication to parents and, in some cases, the school requires that doctors write a prescription. Doctors admit that medical evaluation of referred children is often inadequate. For their part, teachers stress the growing difficulties of their task and the lack of psychosocial supports in the schools. Our respondents' comments highlight the divergent interests of the actors involved as well as each actor's own perception that he or she wishes to act differently but lacks any real choice other than opting for medication. These limited observations should be validated in further studies. They suggest that the current system functions irrationally and that we should not expect it to act in the best interests of children.