title: Measuring autistic traits: heritability, reliability and validity of the Social and Communication Disorders Checklist.
abstract: BACKGROUND
  Autistic traits are widely distributed in the general population, but the boundaries of the autistic spectrum are unclear. Whole-population surveys of unselected samples of children are hampered by the lack of appropriate screening instruments.
  
  
  OBJECTIVE
  To assess whether the Social and Communication Disorders Checklist (SCDC) fulfils the need for a sensitive measure of autistic traits, which can be completed in a few minutes and which measures heritable characteristics in both males and females.
  
  
  METHODS
  A12-item scale, the SCDC, was completed by three independent samples drawn from a twin register, a group with Turner syndrome and children with a diagnosis of autistic-spectrum disorder attending clinics. The data were used to establish the heritability, reliability and validity of the checklist.
  
  
  RESULTS
  Traits measured by the SCDC were highly heritable in both genders (0.74). Internal consistency was excellent (0.93) and test - retest reliability high (0.81). Discriminant validity between pervasive developmental disorder and other clinical groups was good, discrimination from non-clinical samples was better; sensitivity (0.90), specificity (0.69).
  
  
  CONCLUSIONS
  The SCDC is a unique and efficient first-level screening questionnaire for autistic traits.
authors.affiliation: Behavioural and Brain Sciences Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. dskuse@ich.ucl.ac.uk
authors.forename: David H
authors.initials: DH
authors.lastname: Skuse
authors.forename: William P L
authors.initials: WP
authors.lastname: Mandy
authors.forename: Jane
authors.initials: J
authors.lastname: Scourfield
mesh_terms: D000293:Adolescent; D001321:Autistic Disorder / Q000175:diagnosis* / Q000235:genetics / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D004200:Diseases in Twins / Q000235:genetics; D005260:Female; D006801:Humans; D007360:Intelligence; D008297:Male; D008403:Mass Screening / Q000295:instrumentation; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014424:Turner Syndrome / Q000175:diagnosis