导读：加拿大不列颠哥伦比亚大学研究人员发布最新研究报告称，同一年级但晚几个月出生的学生更易被误诊为多动症。
研究人员在3月5日出版的《加拿大医学协会期刊》（Canadian Medical Association Journal）上发表论文说，他们用11年时间在不列颠哥伦比亚省调查了超过93万名6岁至12岁儿童，发现在同龄儿童组成的班级里，当年12月出生的孩子被诊断为多动症的几率，比当年1月出生的孩子高出39%，接受药物治疗的几率也比后者高出48%。
研究人员深入分析这一现象后发现，在同一年级中，晚几个月出生的孩子表现出相对不成熟的特征，但人们却使用对待较大孩子的同一标准看待他们，这使他们较容易被误诊为多动症。
“这项研究对临床医生、教师和家长都提出了一个意味深长的问题，”研究人员简·加兰说，“我们在诊断儿童多动症时需要更多注重他们的校外表现。”
治疗多动症的药物包括利他林和安非他明等，会带来睡眠紊乱、增加患心血管疾病风险和延缓发育进程等问题。同时，被诊断为“多动症”的孩子也会遭到老师和家长区别对待，这对他们的自我认知产生消极影响。
对是否存在儿童多动症，医学界本来就存在一定争议。一些医生认为这属于一种精神失调症，患儿往往难以长时间集中注意力或保持安静，时常烦躁不安，情绪易冲动，或伴有学习困难等。
Influence of relative age on diagnosis and treatment of attention-deficit/hyperactivity disorder in children
Richard L. Morrow, Jane Garland, James M. Wright, Malcolm Maclure, Suzanne Taylor, Colin R. Dormuth
Background: The annual cut-off date of birth for entry to school in British Columbia, Canada, is December 31. Thus, children born in December are typically the youngest in their grade. We sought to determine the influence of relative age within a grade on the diagnosis and pharmacologic treatment of attention-deficit/ hyperactivity disorder (ADHD) in children.
Methods: We conducted a cohort study involving 937 943 children in British Columbia who were 6–12 years of age at any time between Dec. 1, 1997, and Nov. 30, 2008. We calculated the absolute and relative risk of receiving a diagnosis of ADHD and of receiving a prescription for a medication used to treat ADHD (i.e., methylphenidate, dextroamphetamine, mixed amphetamine salts or atomoxetine) for children born in December compared with children born in January.
Results: Boys who were born in December were 30% more likely (relative risk [RR] 1.30, 95% confidence interval [CI] 1.23–1.37) to receive a diagnosis of ADHD than boys born in January. Girls born in December were 70% more likely (RR 1.70, 95% CI 1.53–1.88) to receive a diagnosis of ADHD than girls born in January. Similarly, boys were 41% more likely (RR 1.41, 95% CI 1.33–1.50) and girls 77% more likely (RR 1.77, 95% CI 1.57–2.00) to be given a prescription for a medication to treat ADHD if they were born in December than if they were born in January.
Interpretation: The results of our analyses show a relative-age effect in the diagnosis and treatment of ADHD in children aged 6–12 years in British Columbia. These findings raise concerns about the potential harms of overdiagnosis and overprescribing. These harms include adverse effects on sleep, appetite and growth, in addition to increased risk of cardiovascular events.
文献链接：https://www.cmaj.ca/content/early/2012/03/05/cmaj.111619.abstract
