title: Klinefelter syndrome and risk of psychosis, autism and ADHD.
abstract: BACKGROUND
  Schizophrenia, bipolar disorder, autism spectrum disorders and ADHD might be overrepresented in Klinefelter syndrome, but previous investigations have yielded inconclusive results.
  
  
  METHODS
  We compared a national sample of 860 Klinefelter patients in Sweden with 86 000 matched population controls. To assess the risks of schizophrenia, bipolar disorder, autism spectrum disorder and ADHD in Klinefelter patients, we estimated odds ratios and 95% confidence intervals using conditional logistic regressions.
  
  
  RESULTS
  Klinefelter patients had almost four times higher risks of schizophrenia, odds ratio (OR) = 3.6, 95% confidence interval (CI) 2.0-6.7 and bipolar disorder (OR = 3.8, CI 1.8-7.6) and about six times higher risk of autism spectrum disorder (OR = 6.2, CI 4.0-9.4) and ADHD (OR = 5.6, CI 4.0-7.8).
  
  
  CONCLUSIONS
  The risk of psychosis, autism and ADHD is increased in Klinefelter patients. These findings indicate an X chromosome-related factor in the etiology of the studied psychiatric disorders, and may also have implications for treatment of patients with Klinefelter syndrome.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, SE-171 77 Stockholm, Sweden. Electronic address: Martin.Cederlof@ki.se.
authors.forename: Martin
authors.initials: M
authors.lastname: Cederlöf
authors.forename: Agnes
authors.initials: A
authors.lastname: Ohlsson Gotby
authors.forename: Henrik
authors.initials: H
authors.lastname: Larsson
authors.forename: Eva
authors.initials: E
authors.lastname: Serlachius
authors.forename: Marcus
authors.initials: M
authors.lastname: Boman
authors.forename: Niklas
authors.initials: N
authors.lastname: Långström
authors.forename: Mikael
authors.initials: M
authors.lastname: Landén
authors.forename: Paul
authors.initials: P
authors.lastname: Lichtenstein
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology*; D001321:Autistic Disorder / Q000453:epidemiology*; D002648:Child; D006801:Humans; D007713:Klinefelter Syndrome / Q000453:epidemiology*; D008297:Male; D011618:Psychotic Disorders / Q000453:epidemiology*; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: ADHD; Autism spectrum disorder; Bipolar disorder; Epidemiology; Klinefelter syndrome; Schizophrenia