title: A multivariate genetic analysis of specific phobia, separation anxiety and social phobia in early childhood.
abstract: BACKGROUND
  Comorbidity amongst anxiety disorders is very common in children as in adults and leads to considerable distress and impairment, yet is poorly understood. Multivariate genetic analyses can shed light on the origins of this comorbidity by revealing whether genetic or environmental risks for one disorder also influence another. We examined the genetic and environmental influences on the comorbidity between three common childhood anxiety disorders: Specific Phobia, Separation Anxiety and Social Phobia.
  
  
  METHODS
  Using a two-phase design 4,662 twin-pairs were screened in the first phase and 854 pairs were assessed in the second phase by maternal-informant diagnostic interview using DSM-IV criteria.
  
  
  RESULTS
  Multivariate genetic analysis revealed significant shared environmental over-lap between Specific Phobia and Separation Anxiety and significant familial and non-shared environmental over-lap between Specific Phobia and Social Phobia.
  
  
  CONCLUSIONS
  Familial influences, especially shared environment, are central to the comorbidity between Specific Phobia and both Separation Anxiety and Social Phobia.
authors.affiliation: Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Kings College London, De'Crespigny Park, London SE5 8AF, UK. t.eley@iop.kcl.ac.uk
authors.forename: Thalia C
authors.initials: TC
authors.lastname: Eley
authors.forename: Fruhling V
authors.initials: FV
authors.lastname: Rijsdijk
authors.forename: Sean
authors.initials: S
authors.lastname: Perrin
authors.forename: Thomas G
authors.initials: TG
authors.lastname: O'Connor
authors.forename: Derek
authors.initials: D
authors.lastname: Bolton
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000453:epidemiology / Q000235:genetics; D001010:Anxiety, Separation / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D010698:Phobic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D014427:Twins / Q000235:genetics*; D055815:Young Adult