title: A twin study of body dysmorphic concerns.
abstract: BACKGROUND
  Dysmorphic concern refers to an excessive preoccupation with a perceived or slight defect in physical appearance. It lies on a continuum of severity from no or minimal concerns to severe concerns over one's appearance. The present study examined the heritability of dysmorphic concerns in a large sample of twins.
  
  
  METHODS
  Twins from the St Thomas UK twin registry completed a valid and reliable self-report measure of dysmorphic concerns, which also includes questions about perceived body odour and malfunction. Twin modelling methods (female twins only, n=3544) were employed to decompose the variance in the liability to dysmorphic concerns into additive genetic, shared and non-shared environmental factors.
  
  
  RESULTS
  Model-fitting analyses showed that genetic factors accounted for approximately 44% [95% confidence intervals (CI) 36-50%] of the variance in dysmorphic concerns, with non-shared environmental factors and measurement error accounting for the remaining variance (56%; 95% CI 50-63%). Shared environmental factors were negligible. The results remained unchanged when excluding individuals reporting an objective medical condition/injury accounting for their concern in physical appearance.
  
  
  CONCLUSIONS
  Over-concern with a perceived or slight defect in physical appearance is a heritable trait, with non-shared environmental factors also playing an important role in its causation. The results are relevant for various psychiatric disorders characterized by excessive concerns in body appearance, odour or function, including but not limited to body dysmorphic disorder.
authors: Department of Psychosis Studies, King's College London, Institute of Psychiatry, London, UK. benedetta.monzani@kcl.ac.uk
authors: B
authors: B
authors: Monzani
authors: F
authors: F
authors: Rijsdijk
authors: M
authors: M
authors: Anson
authors: A C
authors: AC
authors: Iervolino
authors: L
authors: L
authors: Cherkas
authors: T
authors: T
authors: Spector
authors: D
authors: D
authors: Mataix-Cols
mesh_terms: D000328:Adult; D000368:Aged; D057215:Body Dysmorphic Disorders / Q000235:genetics*; D005260:Female; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D014429:Twins, Dizygotic / Q000523:psychology; D014430:Twins, Monozygotic / Q000523:psychology