title: Genetic and environmental influences on psychological traits and eating attitudes in a sample of Spanish schoolchildren.
abstract: BACKGROUND
  The heritability of eating disorders has been estimated to range from 22% to over 62%.The aim of this study is to determine the relative influence of genetics and environment that contribute to the drive for thinness, body dissatisfaction, perfectionism, and ineffectiveness, by evaluating sex differences in a sample of adolescent twins from Valencia, Spain.
  
  
  METHODS
  Five hundred eighty-four pairs of adolescent twins between 13 and 18 years of age completed the study. To determine zygosity, teachers responded to a questionnaire on physical similarity. Psychological traits of eating disorders were assessed with four sub-scales of the Eating Disorder Inventory (EDI); drive for thinness, body dissatisfaction, perfectionism, and ineffectiveness. Twin models were used to assess genetic and environmental (common and unique) factors affecting these four psychological traits.
  
  
  RESULTS
  All four traits showed significant genetic contributions among girls, with heritability estimates of 37.7% for ineffectiveness, 42.8% for perfectionism, 56.9% for drive for thinness, and 65.5% for body dissatisfaction. Among boys, body dissatisfaction showed no additive genetic contributions, indicating significant shared and individual specific environment effects. The three other traits in boys showed significant additive genetic contributions, but were lower than in girls.
  
  
  CONCLUSIONS
  With the exception of body dissatisfaction in boys, psychological traits of eating disorders show heritability patterns that differ according to sex.
authors.affiliation: Servicio de Psiquiatría, Hospital Universitario y Politécnico La Fe, Valencia, España; CIBERESP, España; Departamento de Psiquiatría, Facultad de Medicina, Universidad de Valencia, Valencia, España.
authors.forename: Luis
authors.initials: L
authors.lastname: Rojo-Moreno
authors.affiliation: Servicio de Psiquiatría, Hospital Universitario y Politécnico La Fe, Valencia, España. Electronic address: iranzotatay@hotmail.com.
authors.forename: Carmen
authors.initials: C
authors.lastname: Iranzo-Tatay
authors.affiliation: Grupo de investigación Psiquiátrica, Sección de Psiquiatría Infanto-Juvenil, Hospital Universitario La Fe, Valencia, España.
authors.forename: Natalia
authors.initials: N
authors.lastname: Gimeno-Clemente
authors.affiliation: Servicio de Psiquiatría, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: Maria Antonia
authors.initials: MA
authors.lastname: Barberá-Fons
authors.affiliation: Servicio de Psiquiatría, Hospital Universitario y Politécnico La Fe, Valencia, España.
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Rojo-Bofill
authors.affiliation: Servicio de Psiquiatría, Hospital Universitario y Politécnico La Fe, Valencia, España; CIBERESP, España; Departamento de Psiquiatría, Facultad de Medicina, Universidad de Valencia, Valencia, España.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Livianos-Aldana
mesh_terms: D000293:Adolescent; D001828:Body Image / Q000523:psychology; D003430:Cross-Sectional Studies; D004777:Environment; D001068:Feeding and Eating Disorders / Q000209:etiology* / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D000072639:Perfectionism; D012307:Risk Factors; D020377:Self Efficacy; D012737:Sex Factors; D013030:Spain
keywords: Adolescentes; Adolescents; Eating disorders; Factores de riesgo; Gemelos; Genetics; Genética; Psychological traits; Trastornos de la conducta alimentaria; Twins