Four international studies have found that the youngest children in a school class are more likely than their classmates to receive pharmacological treatment for attention deficit/hyperactivity disorder (ADHD).1-4 We investigated whether this late birth date effect applies to children in Western Australia. We compared the proportions of WA children born in the early and late months of a recommended school-year intake who received at least one Pharmaceutical Benefits Scheme prescription for an ADHD medication in 2013 (Box).
- 1. Elder TE. The importance of relative standards in ADHD diagnoses: evidence based on exact birth dates. J Health Econ 2010; 29: 641-656.
- 2. Evans WN, Morrill MS, Parente ST. Measuring inappropriate medical diagnosis and treatment in survey data: the case of ADHD among school-age children. J Health Econ 2010; 29: 657-673.
- 3. Morrow RL, Garland J, Wright JM, et al. Influence of relative age on diagnosis and treatment of attention-deficit/hyperactivity disorder in children. CMAJ 2012; 184: 755-762.
- 4. Chen MH, Lan WH, Bai YM, et al. Influence of relative age on diagnosis and treatment of attention-deficit/hyperactivity disorder in Taiwanese children. J Pediatr 2016; 172: 162-167.e1.
- 5. Frances A. Don’t throw out the baby out with the bathwater. Aust N Z J Psychiatry 2015; 49: 577.
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