Archives of Sexual Behavior

, Volume 40, Issue 1, pp 133–142 | Cite as

Sexual Orientation and Psychiatric Vulnerability: A Twin Study of Neuroticism and Psychoticism

  • Brendan P. ZietschEmail author
  • Karin J. H. Verweij
  • J. Michael Bailey
  • Margaret J. Wright
  • Nicholas G. Martin
Original Paper


Recent evidence indicates that homosexuals and bisexuals are, on average, at greater risk for psychiatric problems than heterosexuals. It is assumed with some supporting evidence that prejudice often experienced by nonheterosexuals makes them more vulnerable to psychiatric disorder, but there has been no investigation of alternative explanations. Here we used Eysenck’s Neuroticism and Psychoticism scales as markers for psychiatric vulnerability and compared heterosexuals with nonheterosexuals in a community-based sample of identical and nonidentical twins aged between 19 and 52 years (N = 4904). Firstly, we tested whether apparent sexual orientation differences in psychiatric vulnerability simply mirrored sex differences—for our traits, this would predict nonheterosexual males having elevated Neuroticism scores as females do, and nonheterosexual females having elevated Psychoticism scores as males do. Our results contradicted this idea, with nonheterosexual men and women scoring significantly higher on Neuroticism and Psychoticism than their heterosexual counterparts, suggesting an overall elevation of psychiatric risk in nonheterosexuals. Secondly, we used our genetically informative sample to assess the viability of explanations invoking a common cause of both nonheterosexuality and psychiatric vulnerability. We found significant genetic correlation between sexual orientation and both Neuroticism and Psychoticism, but no corresponding environmental correlations, suggesting that if there is a common cause of both nonheterosexuality and psychiatric vulnerability it is likely to have a genetic basis rather than an environmental basis.


Sexual orientation Personality Neuroticism Psychoticism Twins 



This research was funded by a small grant (R03) to J.M.B. from the National Institute of Mental Health (USA) and a small Commonwealth AIDS Research Grant to N.G.M. Twins participating in this study were drawn from the Australian NHMRC Twin Registry. Thanks go to Geoffrey Miller for helpful feedback on a draft of this article.


  1. American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.Google Scholar
  2. Andrews, G. (1996). Comorbidity and the general neurotic syndrome. British Journal of Psychiatry, 168, 76–84.CrossRefGoogle Scholar
  3. Bailey, J. M. (1999). Homosexuality and mental illness. Archives of General Psychiatry, 56, 883–884.PubMedCrossRefGoogle Scholar
  4. Balsam, K. F., Rothblum, E. D., & Beauchaine, T. P. (2005). Victimization over the life span: A comparison of lesbian, gay, bisexual, and heterosexual siblings. Journal of Consulting and Clinical Psychology, 73, 477–487.PubMedCrossRefGoogle Scholar
  5. Banks, S. J., Eddy, K. T., Angstadt, M., Nathan, P. J., & Phan, K. L. (2007). Amygdala-frontal connectivity during emotion regulation. Social Cognitive and Affective Neuroscience, 2, 303–312.PubMedCrossRefGoogle Scholar
  6. Birley, A. J., Gillespie, N. A., Heath, A. C., Sullivan, P. F., Boomsma, D. I., & Martin, N. G. (2006). Heritability and nineteen-year stability of long and short EPQ-R neuroticism scales. Personality and Individual Differences, 40, 737–747.CrossRefGoogle Scholar
  7. Bozkurt, A., Isikli, H., Demir, F., Ozmenler, K. N., Gulcat, Z., Karlidere, T., et al. (2006). Body image and personality traits of male-to-female transsexuals and homosexuals. Social Behavior and Personality, 34, 927–937.CrossRefGoogle Scholar
  8. Cale, E. M. (2006). A quantitative review of the relations between the “Big 3” higher order personality dimensions and antisocial behavior. Journal of Research in Personality, 40, 250–284.CrossRefGoogle Scholar
  9. Cameron, P., & Cameron, K. (1995). Does incest cause homosexuality? Psychological Reports, 76, 611–621.PubMedGoogle Scholar
  10. Cassin, S. E., & von Ranson, K. M. (2005). Personality and eating disorders: A decade in review. Clinical Psychology Review, 25, 895–916.PubMedCrossRefGoogle Scholar
  11. Claridge, G. (1981). Psychoticism. In R. Lynn (Ed.), Dimensions of personality: Papers in honour of H G Eysenck (pp. 79–109). Oxford: Pergamon Press.Google Scholar
  12. Claridge, G., Robinson, D. L., & Birchall, P. (1983). Characteristics of schizophrenics’ and neurotics’ relatives. Personality and Individual Differences, 4, 651–664.CrossRefGoogle Scholar
  13. Corliss, H. L., Cochran, S. D., & Mays, V. M. (2002). Reports of parental maltreatment during childhood in a United States population-based survey of homosexual, bisexual, and heterosexual adults. Child Abuse and Neglect, 26, 1165–1178.PubMedCrossRefGoogle Scholar
  14. Costa, P. T., & McCrae, R. R. (1994). NEO PI-R Professional Manual: Revised NEO Personality Inventory (NEO PI-R) and NEO Five-Factor Inventory (NEO-FFI). Lutz, FL: Psychological Assessment Resources.Google Scholar
  15. DeLisi, L. E., Svetina, C., Razi, K., Shields, G., Wellman, N., & Crow, T. J. (2002). Hand preference and hand skill in families with schizophrenia. Laterality, 7, 321–332.PubMedGoogle Scholar
  16. Digman, J. M. (1990). Personality structure: Emergence of the 5-factor model. Annual Review of Psychology, 41, 417–440.Google Scholar
  17. Duffy, D. L., & Martin, N. G. (1994). Inferring the direction of causation in cross-sectional twin data: Theoretical and empirical considerations. Genetic Epidemiology, 11, 483–502.PubMedCrossRefGoogle Scholar
  18. Eisinger, A. J., Huntsman, R. G., Lord, J., Merry, J., Tanner, J. M., Polani, P., et al. (1972). Female homosexuality. Nature, 238, 106.PubMedCrossRefGoogle Scholar
  19. Elias, L. J., Saucier, D. M., & Guylee, M. J. (2001). Handedness and depression in university students: A sex by handedness interaction. Brain and Cognition, 46, 125–129.PubMedCrossRefGoogle Scholar
  20. Escorial, S., & Navas, M. J. (2007). Analysis of the gender variable in the Eysenck Personality Questionnaire-Revised scales using differential item functioning techniques. Educational and Psychological Measurement, 67, 990–1001.CrossRefGoogle Scholar
  21. Eysenck, H. J. (1967). Dimensions of personality. London: Routledge & Kegan Paul.Google Scholar
  22. Eysenck, H. J., & Eysenck, S. B. G. (1976). Psychoticism as a dimension of personality. London: Hodder and Stoughton.Google Scholar
  23. Eysenck, S. B. G., Eysenck, H. J., & Barrett, P. (1985). A revised version of the Psychoticism Scale. Personality and Individual Differences, 6, 21–29.CrossRefGoogle Scholar
  24. Fergusson, D. M., Horwood, L. J., & Beautrais, A. L. (1999). Is sexual orientation related to mental health problems and suicidality in young people? Archives of General Psychiatry, 56, 876–880.PubMedCrossRefGoogle Scholar
  25. Friedman, M. S., Marshal, M. P., Stall, R., Cheong, J., & Wright, E. R. (2008). Gay-related development, early abuse and adult health outcomes among gay males. AIDS and Behavior, 12, 891–902.PubMedCrossRefGoogle Scholar
  26. Gangestad, S. W., Bailey, J. M., & Martin, N. G. (2000). Taxometric analyses of sexual orientation and gender identity. Journal of Personality and Social Psychology, 78, 1109–1121.PubMedCrossRefGoogle Scholar
  27. Garcia, J., Adams, J., Friedman, L., & East, P. (2002). Links between past abuse, suicide ideation, and sexual orientation among San Diego college students. Journal of American College Health, 51, 9–14.PubMedCrossRefGoogle Scholar
  28. Grulich, A. E., de Visser, R. O., Smith, A. M. A., Rissel, C. E., & Richters, J. (2003). Sex in Australia: Homosexual experience and recent homosexual encounters. Australian and New Zealand Journal of Public Health, 27, 155–163.PubMedCrossRefGoogle Scholar
  29. Hicks, R. A., & Pellegrini, R. J. (1978). Handedness and anxiety. Cortex, 14, 119–121.PubMedGoogle Scholar
  30. Hughes, T. L., Johnson, T., & Wilsnack, S. C. (2001). Sexual assault and alcohol abuse: A comparison of lesbians and heterosexual women. Journal of Substance Abuse, 13, 515–532.PubMedCrossRefGoogle Scholar
  31. James, W. H. (2006). Two hypotheses on the causes of male homosexuality and paedophilia. Journal of Biosocial Science, 38, 745–761.PubMedCrossRefGoogle Scholar
  32. Joreskog, K. G., & Sorbom, D. (1999). LISREL 8.30 and PRELIS 2.30 for Windows. Chicago: Scientific Software.Google Scholar
  33. Keller, M. C., Coventry, W. L., Heath, A. C., & Martin, N. G. (2005). Widespread evidence for non-additive genetic variation in Cloninger’s and Eysenck’s personality dimensions using a twin plus sibling design. Behavior Genetics, 35, 707–721.PubMedCrossRefGoogle Scholar
  34. Kendler, K. S., Neale, M. C., Kessler, R. C., Heath, A. C., & Eaves, L. J. (1993). A longitudinal twin study of personality and major depression in women. Archives of General Psychiatry, 50, 853–862.PubMedGoogle Scholar
  35. Kendler, K. S., Thornton, L. M., Gilman, S. E., & Kessler, R. C. (2000). Sexual orientation in a US national sample of twin and nontwin sibling pairs. American Journal of Psychiatry, 157, 1843–1846.PubMedCrossRefGoogle Scholar
  36. Khan, A. A., Jacobson, K. C., Gardner, C. O., Prescott, C. A., & Kendler, K. S. (2005). Personality and comorbidity of common psychiatric disorders. British Journal of Psychiatry, 186, 190–196.PubMedCrossRefGoogle Scholar
  37. King, M., Semlyen, J., Tai, S. S., Killaspy, H., Osborn, D., Popelyuk, D., et al. (2008). A systematic review of mental disorder, suicide, and deliberate self harm in lesbian, gay and bisexual people. BMC Psychiatry, 8, 17.CrossRefGoogle Scholar
  38. Kinsey, A. C., Pomeroy, W. B., & Martin, C. E. (1948). Sexual behavior in the human male. Philadelphia: W. B. Saunders.Google Scholar
  39. Kirk, K. M., Bailey, J. M., Dunne, M. P., & Martin, N. G. (2000). Measurement models for sexual orientation in a community twin sample. Behavior Genetics, 30, 345–356.PubMedCrossRefGoogle Scholar
  40. Laurent, A., Gilvarry, C., Russell, A., & Murray, R. (2002). Personality dimensions and neuropsychological performance in first-degree relatives of patients with schizophrenia and affective psychosis. Schizophrenia Research, 55, 239–248.PubMedCrossRefGoogle Scholar
  41. Leach, L. S., Christensen, H., Windsor, T. D., Butterworth, P., & Mackinnon, A. J. (2008). Gender differences in depression and anxiety across the adult lifespan: The role of psychosocial mediators. Social Psychiatry and Psychiatric Epidemiology, 43, 983–998.PubMedCrossRefGoogle Scholar
  42. Lippa, R. A. (2003). Handedness, sexual orientation, and gender-related personality traits in men and women. Archives of Sexual Behavior, 32, 103–114.PubMedCrossRefGoogle Scholar
  43. Lippa, R. A. (2005). Sexual orientation and personality. Annual Review of Sex Research, 16, 119–153.PubMedGoogle Scholar
  44. Lippa, R. A. (2008). Sex differences and sexual orientation differences in personality: Findings from the BBC internet survey. Archives of Sexual Behavior, 37, 173–187.PubMedCrossRefGoogle Scholar
  45. Loehlin, J. C. (1992). Genes and environment in personality development. Newbury Park, CA: Sage.Google Scholar
  46. Loehlin, J. C. (1996). The Cholesky approach: A cautionary note. Behavior Genetics, 26, 65–69.CrossRefGoogle Scholar
  47. Loehlin, J. C., & Martin, N. G. (2001). Age changes in personality traits and their heritabilities during the adult years: Evidence from Australian Twin Registry samples. Personality and Individual Differences, 30, 1147–1160.CrossRefGoogle Scholar
  48. Macaskill, G. T., Hopper, J. L., White, V., & Hill, D. J. (1994). Genetic and environmental variation in Eysenck Personality Questionnaire scales measured on Australian adolescent twins. Behavior Genetics, 24, 481–491.PubMedCrossRefGoogle Scholar
  49. Mays, V. M., & Cochran, S. D. (2001). Mental health correlates of perceived discrimination among lesbian, gay, and bisexual adults in the United States. American Journal of Public Health, 91, 1869–1876.PubMedCrossRefGoogle Scholar
  50. Meyer, I. H. (1995). Minority stress and mental-health in gay men. Journal of Health and Social Behavior, 36, 38–56.PubMedCrossRefGoogle Scholar
  51. Meyer, I. H. (2003). Prejudice, social stress, and mental health in lesbian, gay, and bisexual populations: Conceptual issues and research evidence. Psychological Bulletin, 129, 674–697.PubMedCrossRefGoogle Scholar
  52. Miller, E. M. (2000). Homosexuality, birth order, and evolution: Toward an equilibrium reproductive economics of homosexuality. Archives of Sexual Behavior, 29, 1–34.PubMedCrossRefGoogle Scholar
  53. Miller, J. D., & Lynam, D. (2001). Structural models of personality and their relation to antisocial behavior: A meta-analytic review. Criminology, 39, 765–798.CrossRefGoogle Scholar
  54. Mills, T. C., Paul, J., Stall, R., Pollack, L., Canchola, J., Chang, Y. J., et al. (2004). Distress and depression in men who have sex with men: The urban men’s health study. American Journal of Psychiatry, 161, 278–285.PubMedCrossRefGoogle Scholar
  55. Moffitt, T. E., Caspi, A., Rutter, M., & Silva, P. A. (2001). Sex differences in antisocial behaviour: Conduct disorder, delinquency, and violence in the Dunedin Longitudinal Study. Cambridge: Cambridge University Press.CrossRefGoogle Scholar
  56. Neale, M. C., Boker, S. M., Xie, G., & Maes, H. H. (2006). Mx: Statistical modeling (7th ed.). Richmond, VA: Department of Psychiatry.Google Scholar
  57. Neale, M. C., & Cardon, L. R. (1992). Methodology for genetic studies of twins and families. Boston: Kluwer.Google Scholar
  58. Neale, M. C., Eaves, L. J., & Kendler, K. S. (1994). The power of the classical twin study to resolve variation in threshold traits. Behavior Genetics, 24, 239–258.PubMedCrossRefGoogle Scholar
  59. Nordstrom, P., Schalling, D., & Asberg, M. (1995). Temperamental vulnerability in attempted-suicide. Acta Psychiatrica Scandinavica, 92, 155–160.PubMedCrossRefGoogle Scholar
  60. Ormel, J., Oldehinkel, A. J., & Vollebergh, W. (2004). Vulnerability before, during, and after a major depressive episode: A 3-wave population-based study. Archives of General Psychiatry, 61, 990–996.PubMedCrossRefGoogle Scholar
  61. Phelps, E. A., & LeDoux, J. E. (2005). Contributions of the amygdala to emotion processing: From animal models to human behavior. Neuron, 48, 175–187.PubMedCrossRefGoogle Scholar
  62. Piccinelli, M., & Wilkinson, G. (2000). Gender differences in depression: Critical review. British Journal of Psychiatry, 177, 486–492.PubMedCrossRefGoogle Scholar
  63. Pillard, R. C. (1991). Masculinity and femininity in homosexuality: “Inversion” revisited. In J. C. Gonsiorek & J. D. Weinrich (Eds.), Homosexuality: Research implications for public policy (pp. 32–43). Newbury Park, CA: Sage.Google Scholar
  64. Pillard, R. C., & Bailey, J. M. (1998). Human sexual orientation has a heritable component. Human Biology, 70, 347–365.Google Scholar
  65. Posthuma, D., Beem, A. L., de Geus, E. J. C., van Baal, G. C. M., von Hjelmborg, J. B., Lachine, I., et al. (2003). Theory and practice in quantitative genetics. Twin Research, 6, 361–376.PubMedCrossRefGoogle Scholar
  66. Roy, A. (2002). Childhood trauma and neuroticism as an adult: Possible implication for the development of the common psychiatric disorders and suicidal behaviour. Psychological Medicine, 32, 1471–1474.PubMedCrossRefGoogle Scholar
  67. Sandfort, T. G. M., Bakker, F., Schellevis, F. G., & Vanwesenbeeck, I. (2006). Sexual orientation and mental and physical health status: Findings from a Dutch population survey. American Journal of Public Health, 96, 1119–1125.PubMedCrossRefGoogle Scholar
  68. Sandfort, T. G. M., de Graaf, R., Bijl, R. V., & Schnabel, P. (2001). Same-sex sexual behavior and psychiatric disorders: Findings from the Netherlands Mental Health Survey and Incidence Study (NEMESIS). Archives of General Psychiatry, 58, 85–91.PubMedCrossRefGoogle Scholar
  69. Savic, I., & Lindstrom, P. (2008). PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects. Proceedings of the National Academy of Sciences of the United States of America, 105, 9403–9408.Google Scholar
  70. Sell, R. L., Wells, J. A., & Wypij, D. (1995). The prevalence of homosexual behavior and attraction in the United States, the United Kingdom and France: Results of national population-based samples. Archives of Sexual Behavior, 24, 235–248.PubMedCrossRefGoogle Scholar
  71. Sun, Y. P., Zhang, B., Dong, Z. J., Yi, M. J., Sun, D. F., & Shi, S. S. (2008). Psychiatric state of college students with a history of childhood sexual abuse. World Journal of Pediatrics, 4, 285–290.CrossRefGoogle Scholar
  72. Swaab, D. F. (2008). Sexual orientation and its basis in brain structure and function. Proceedings of the National Academy of Sciences of the United States of America, 105, 10273–10274.Google Scholar
  73. Tomeo, M. E., Templer, D. I., Anderson, S., & Kotler, D. (2001). Comparative data of childhood and adolescence molestation in heterosexual and homosexual persons. Archives of Sexual Behavior, 30, 535–541.PubMedCrossRefGoogle Scholar
  74. Tranah, T., Harnett, P., & Yule, W. (1998). Conduct disorder and personality. Personality and Individual Differences, 24, 741–745.CrossRefGoogle Scholar
  75. Wilson, M. L. (1982). Neuroticism and extraversion of female homosexuals. Psychological Reports, 51, 559–562.PubMedGoogle Scholar
  76. Young, M. S., Harford, K. L., Kinder, B., & Savell, J. K. (2007). The relationship between childhood sexual abuse and adult mental health among undergraduates: Victim gender doesn’t matter. Journal of Interpersonal Violence, 22, 1315–1331.PubMedCrossRefGoogle Scholar
  77. Zietsch, B. P., Morley, K. I., Shekar, S. N., Verweij, K. J. H., Keller, M. C., Macgregor, S., et al. (2008). Genetic factors predisposing to homosexuality may increase mating success in heterosexuals. Evolution and Human Behavior, 29, 424–433.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Brendan P. Zietsch
    • 1
    • 2
    Email author
  • Karin J. H. Verweij
    • 1
    • 2
  • J. Michael Bailey
    • 3
  • Margaret J. Wright
    • 1
  • Nicholas G. Martin
    • 1
  1. 1.Genetic EpidemiologyQueensland Institute of Medical ResearchBrisbaneAustralia
  2. 2.School of PsychologyUniversity of QueenslandBrisbaneAustralia
  3. 3.Department of PsychologyNorthwestern UniversityEvanstonUSA

Personalised recommendations