Background: Little is known about genetic and environmental contributions to the inter-relationship between DSM-III-R antisocial personality disorder (ASPD), major depressive disorder (MDD) and nicotine dependence (ND). The present study investigated genetic and environmental influences common and unique to ASPD, MDD and ND using a large population-based male twin sample. Methods: Data were analyzed from 3,360 middle aged male-male monozygotic and dizygotic twin pairs from the Vietnam Era Twin registry who were administered the DIS (version IHR) by telephone in 1992. A multivariate genetic model was fitted to estimate additive genetic, shared environmental, and nonshared environmental influences common and specific to lifetime DSM-III-R ASPD. MDD, and ND. Results: Structural equation modeling yielded heritability estimates for ASPD, MDD, and ND of 69%, 42%, and 61% respectively. Genetic influences on ASPD accounted for 11 % and 23% of the total phenotypic variance in risk for MDD and ND, respectively. After controlling for the genetic influences of ASPD, the partial geneuc correlation of MDD with ND was not significant. Genetic effects specific to MDD (30%) and ND (35%) remained statistically significant. Nonshared environmental contribution to the comorbidity between MDD and ND was not significant. Conclusions: In these male veterans, the shared genetic risk between MDD and ND could be explained by genetic influences on ASPD, which in turn was associated with increased risk of each of the other disorders. Both shared and nonshared environmental influences on comorbidities among ASPD, MDD and ND were not significant.
|Number of pages||1|
|Journal||American Journal of Medical Genetics - Neuropsychiatric Genetics|
|State||Published - Oct 8 2001|