Do firstborn children have an increased risk of ADHD?

J Atten Disord. 2014 Oct;18(7):594-7. doi: 10.1177/1087054712445066. Epub 2012 Jul 23.


Objective: Although previous reports have found no birth-order influence on ADHD risk, the authors hypothesize that being the firstborn is a risk factor for developing ADHD.

Method: They selected all of the currently treated ADHD outpatients (n = 748) from our database. Families with adopted sons, nonnuclear families, and families with only one child and with sons (affected or unaffected) younger than 6 or older than 18 years were excluded. A total of 181 families with 213 ADHD sons met the inclusion criteria. We used all siblings without a clinical diagnosis of ADHD and who had no contact with our service as our unaffected controls (n = 173).

Results: The bivariate analysis showed that ADHD was associated with birth order and that firstborn children had nearly twice the ADHD risk of children with other birth orders.

Conclusion: birth order can be an ADHD risk factor in clinical samples.

Keywords: Attention deficit disorder, ADHD; epidemiology; family risk factors; firstborn children.

MeSH terms

  • Adult
  • Attention Deficit Disorder with Hyperactivity / diagnosis*
  • Attention Deficit Disorder with Hyperactivity / epidemiology
  • Birth Order / psychology*
  • Case-Control Studies
  • Child
  • Female
  • Humans
  • Male
  • Parents
  • Prevalence
  • Risk Factors
  • Siblings / psychology*