title: Family history of schizophrenia and bipolar disorder as risk factors for autism.
abstract: BACKGROUND
  The clinical and etiologic relation between autism spectrum disorders (ASDs) and schizophrenia is unclear. The degree to which these disorders share a basis in etiology has important implications for clinicians, researchers, and those affected by the disorders.
  
  
  OBJECTIVE
  To determine whether a family history of schizophrenia and/or bipolar disorder is a risk factor for ASD.
  
  
  METHODS
  We conducted a case-control evaluation of histories of schizophrenia or bipolar disorder in first-degree relatives of probands in 3 samples—population registers in Sweden, Stockholm County (in Sweden), and Israel. Probands met criteria for ASD, and affection status of parents and siblings for schizophrenia and bipolar disorder were established.
  
  
  RESULTS
  The presence of schizophrenia in parents was associated with an increased risk for ASD in a Swedish national cohort (odds ratio [OR], 2.9; 95% CI, 2.5-3.4) and a Stockholm County cohort (OR, 2.9; 95% CI, 2.0-4.1). Similarly, schizophrenia in a sibling was associated with an increased risk for ASD in a Swedish national cohort (OR, 2.6; 95% CI, 2.0-3.2) and an Israeli conscription cohort (OR, 12.1; 95% CI, 4.5-32.0). Bipolar disorder showed a similar pattern of associations but of lesser magnitude.
  
  
  CONCLUSIONS
  Findings from these 3 registers along with consistent findings from a similar study in Denmark suggest that ASD, schizophrenia, and bipolar disorder share common etiologic factors.
authors: Department of Genetics, University of North Carolina at Chapel Hill, USA. pfsulliv@med.unc.edu
authors: Patrick F
authors: PF
authors: Sullivan
authors: Cecilia
authors: C
authors: Magnusson
authors: Abraham
authors: A
authors: Reichenberg
authors: Marcus
authors: M
authors: Boman
authors: Christina
authors: C
authors: Dalman
authors: Michael
authors: M
authors: Davidson
authors: Eyal
authors: E
authors: Fruchter
authors: Christina M
authors: CM
authors: Hultman
authors: Michael
authors: M
authors: Lundberg
authors: Niklas
authors: N
authors: Långström
authors: Mark
authors: M
authors: Weiser
authors: Anna C
authors: AC
authors: Svensson
authors: Paul
authors: P
authors: Lichtenstein
mesh_terms: D000293:Adolescent; D000328:Adult; D020817:Asperger Syndrome / Q000235:genetics; D001714:Bipolar Disorder / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000235:genetics*; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000235:genetics; D007557:Israel; D008297:Male; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D012559:Schizophrenia / Q000235:genetics*; D013548:Sweden