The genetic epidemiology of irrational fears and phobias in men

Arch Gen Psychiatry. 2001 Mar;58(3):257-65. doi: 10.1001/archpsyc.58.3.257.


Background: Much of our knowledge of the role of genetic factors in the etiology of phobias comes from one population-based sample of female twins. We examined the sources of individual differences in the risks for phobias and their associated irrational fears in male twins.

Methods: In personal interviews with both members of 1198 male-male twin pairs (707 monozygotic [MZ] and 491 dizygotic [DZ]) ascertained from a population-based registry, we assessed the lifetime history of agoraphobia and social, animal, situational, and blood/injury phobias as well as their associated irrational fears. Twin resemblance was assessed by means of probandwise concordance, odds ratios, tetrachoric correlations, and univariate and multivariate biometrical model fitting.

Results: The suggestive results obtained by analysis of phobias only were supported by analyzing both fears and phobias. All 5 phobia subtypes aggregate within twin-pairs. This aggregation is due largely or solely to genetic factors with heritability of liabilities ranging from 25% to 37%. Multivariate analysis revealed a common genetic factor, genetic factors specific to each subtype, and a common familial-environmental factor.

Conclusions: In male subjects, genetic risk factors, which are partially common across all subtypes and partially subtype specific, play a moderate role in the etiology of phobias and their associated irrational fears. Family environment probably has an impact on risk for agoraphobia and social phobia. The genetic liability to blood/injury phobias is not distinct from those of the more typical phobias.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Agoraphobia / diagnosis
  • Agoraphobia / epidemiology
  • Agoraphobia / genetics
  • Comorbidity
  • Diseases in Twins / diagnosis
  • Diseases in Twins / epidemiology
  • Diseases in Twins / genetics
  • Fear / classification*
  • Fear / psychology
  • Humans
  • Male
  • Middle Aged
  • Odds Ratio
  • Phobic Disorders / diagnosis
  • Phobic Disorders / epidemiology*
  • Phobic Disorders / genetics*
  • Registries
  • Reproducibility of Results
  • Risk Factors
  • Sex Factors
  • Twins, Dizygotic / genetics
  • Twins, Dizygotic / statistics & numerical data
  • Twins, Monozygotic / genetics
  • Twins, Monozygotic / statistics & numerical data