Birth months as predictor of ADHD medication use in Dutch school classes

Several international studies have shown that pupils who are comparatively young within their year group have a greater likelihood of being diagnosed with ADHD and receiving ADHD medication. The findings suggest that comparatively young but age-appropriate behaviour some pupils show in school may be confused with ADHD. This study investigates whether this noted association between birth month and ADHD medication is also found in the Netherlands; and if so, whether GPs (general practitioners) and teachers are aware of this association. Over 2000 birth dates of children between the ages of 5 and 12 were collected from GP client files. The data included whether children are prescribed methylphenidate, the most commonly used medication for ADHD. These data were analysed by descriptive statistics (graphs) and evaluative statistics (logistic regression analysis and relative risk). GPs and teachers were invited by questionnaire to report whether they knew of the association between birth month and ADHD. A significant correlation between birth month and methylphenidate prescription are found. Relatively young pupils are 2.43 times more likely to be prescribed methylphenidate than their older classmates. A majority of GPs and teachers report not being aware of an association between birth month and ADHD medication.