title: Gender and injuries predict stimulant medication use.
abstract: OBJECTIVE
  The purpose of this article was to examine whether injuries in early childhood and gender predict prescriptions of stimulant medication in three groups of children: With attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other psychiatric disorders (OPD).
  
  
  METHODS
  This was a population-based study with prospective and complete follow-up of children with ADHD (n=11,553), ASD (n=9698), and OPD (n=48,468), of whom 61%, 16%, and 3%, respectively, were treated with stimulants. For all 69,719 individual children data on psychiatric diagnoses, injuries, and drug prescriptions were obtained from national registers and merged.
  
  
  RESULTS
  Having sustained an injury before 5 years of age increased the likelihood of later stimulant treatment, in children with ADHD (odds ratio [OR]=1.09; 95% confidence interval [CI]=1.01-1.21), ASD (OR=1.19; 95% CI=1.02-1.40), and OPD (OR=1.24; 95% CI=1.08-1.42), with each injury increasing the likelihood by 3%, 10%, and 7%, respectively. Head injury did not increase the likelihood of later stimulant treatment. Within each of the three groups, ADHD, ASD, and OPD boys were more likely than girls to receive stimulant medication, OR=1.17 (95% CI=1.07-1.28); OR=1.71 (95% CI=1.47-2.01), and OR=2.41 (95% CI=2.16-2.71), respectively.
  
  
  CONCLUSIONS
  To our knowledge, this is the first prospective study assessing early life predictors of later ADHD medication in children with a psychiatric disorder, taken from a national cohort with complete follow-up of all cases. We found that the number of injuries prior to diagnosis was associated with initiation of stimulant treatment in all three groups of patients. In addition, male gender predicted treatment with ADHD medications. Our results suggest that the number of injuries early in life prior to diagnosis is associated with stimulant treatment, and may serve as a proxy for the level of later severity of ADHD symptoms, as it is universally associated with pharmacological treatment for ADHD.
authors.affiliation: 1 National Centre for Register-Based Research, Department of Economics and Business, Aarhus University , Aarhus, Denmark .
authors.forename: Søren
authors.initials: S
authors.lastname: Dalsgaard
authors.forename: James F
authors.initials: JF
authors.lastname: Leckman
authors.forename: Helena Skyt
authors.initials: HS
authors.lastname: Nielsen
authors.forename: Marianne
authors.initials: M
authors.lastname: Simonsen
mesh_terms: D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000188:drug therapy*; D006259:Craniocerebral Trauma / Q000150:complications / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy* / Q000503:physiopathology; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011446:Prospective Studies; D012720:Severity of Illness Index; D012737:Sex Factors; D014947:Wounds and Injuries / Q000150:complications* / Q000453:epidemiology
chemical_list: D000697:Central Nervous System Stimulants