Original analyses on the connections between school entry age and ADHD diagnoses for children in Quebec

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In Quebec, children must be 5 years old before October1st to be admitted to kindergarten. In the same class, the youngest students are therefore up to one year younger than the oldest. In this study, the authors show that children born in September have 35% higher rates of ADHD diagnosis and medication than those born in October. ADHD could be confused with inattentive or more turbulent behaviors. Based on unpublished data from the RAMQ, including the medical services records of nearly 800,000 young people born between 1996 and 2005, the authors draw unequivocal conclusions about the extent of the phenomenon and sound the alarm on an issue of great concern.