BACKGROUND: For irrational fears and their associated phobias, epidemiological studies suggest sex differences in prevalence and twin studies report significant genetic effects. How does sex impact on the familial transmission of liability to fears and phobias? METHODS: In personal interviews with over 3000 complete pairs (of whom 1058 were opposite-sex dizygotic pairs), ascertained from a population-based registry, we assessed the lifetime prevalence of five phobias and their associated irrational fears analysed using a multiple threshold model. Twin resemblance was assessed by polychoric correlations and biometrical model-fitting incorporating sex-specific effects. RESULTS: For agoraphobia, situational and blood/injury fear/phobia, the best fit model suggested equal heritability in males and females and genetic correlations between the sexes of less than +0.50. For animal fear/phobias by contrast, the best fit model suggested equal heritability in males and females and a genetic correlation of unity. No evidence was found for an impact of family environment on liability to these fears or phobias. For social phobias, twin resemblance in males was explained by genetic factors and in females by familial-environmental factors. CONCLUSION: The impact of sex on genetic risk may differ meaningfully across phobia subtypes. Sex-specific genetic risk factors may exist for agoraphobia, social, situational and blood-injury phobias but not for animal fear/phobia. These results should be interpreted in the context of the limited power of twin studies, even with large sample sizes, to resolve sex-specific genetic effects.
BACKGROUND: For irrational fears and their associated phobias, epidemiological studies suggest sex differences in prevalence and twin studies report significant genetic effects. How does sex impact on the familial transmission of liability to fears and phobias? METHODS: In personal interviews with over 3000 complete pairs (of whom 1058 were opposite-sex dizygotic pairs), ascertained from a population-based registry, we assessed the lifetime prevalence of five phobias and their associated irrational fears analysed using a multiple threshold model. Twin resemblance was assessed by polychoric correlations and biometrical model-fitting incorporating sex-specific effects. RESULTS: For agoraphobia, situational and blood/injury fear/phobia, the best fit model suggested equal heritability in males and females and genetic correlations between the sexes of less than +0.50. For animal fear/phobias by contrast, the best fit model suggested equal heritability in males and females and a genetic correlation of unity. No evidence was found for an impact of family environment on liability to these fears or phobias. For social phobias, twin resemblance in males was explained by genetic factors and in females by familial-environmental factors. CONCLUSION: The impact of sex on genetic risk may differ meaningfully across phobia subtypes. Sex-specific genetic risk factors may exist for agoraphobia, social, situational and blood-injury phobias but not for animal fear/phobia. These results should be interpreted in the context of the limited power of twin studies, even with large sample sizes, to resolve sex-specific genetic effects.
Authors: Benjamin B Lahey; Robert F Krueger; Paul J Rathouz; Irwin D Waldman; David H Zald Journal: Psychol Bull Date: 2016-12-22 Impact factor: 17.737
Authors: C Hohoff; K Domschke; K Schwarte; G Spellmeyer; C Vögele; G Hetzel; J Deckert; A L Gerlach Journal: J Neural Transm (Vienna) Date: 2008-07-16 Impact factor: 3.575
Authors: Kenneth S Kendler; Charles O Gardner; Peter Annas; Michael C Neale; Lindon J Eaves; Paul Lichtenstein Journal: Arch Gen Psychiatry Date: 2008-04
Authors: Marijn A Distel; Jacqueline M Vink; Gonneke Willemsen; Christel M Middeldorp; Harald L G J Merckelbach; Dorret I Boomsma Journal: Behav Genet Date: 2007-12-12 Impact factor: 2.805