RT Journal
A1 True WR, Xian H, Scherrer JF, et al
T1 COmmon genetic vulnerability for nicotine and alcohol dependence in men
JF Archives of General Psychiatry
JO Archives of General Psychiatry
YR 1999
FD July 1
VO 56
IS 7
SP 655
OP 661
DO 10.1001/archpsyc.56.7.655
UL http://dx.doi.org/10.1001/archpsyc.56.7.655
AB Background 
    Nicotine and alcohol dependence often occur together. We examined data from male twin pairs to determine whether there are genetic or environmental influences common to nicotine and alcohol dependence, and, if so, to estimate the magnitude and correlation of these influences.Methods 
    Subjects were 3356 male-male twin-pair members of the Vietnam Era Twin Registry who participated in a 1992 telephone administration of the Diagnostic Interview Schedule Version 3 Revised. Genetic model fitting was performed to estimate the magnitude and correlation of genetic and environmental contributions to lifetime nicotine and alcohol dependence.Results 
    The heritability of nicotine dependence was 60.3% (95% confidence interval [CI], 55.4%-65.2%); that of alcohol dependence, 55.1% (95% CI, 49.7%-60.5%). The best-fitting model for the co-occurrence of lifetime nicotine and alcohol dependence included a substantial genetic correlation between both disorders (r=0.68; 95% CI, 0.61-0.74) and a modest unique environmental correlation (r=0.23; 95% CI, 0.14-0.32).Conclusions 
    These data suggest a common genetic vulnerability to nicotine and alcohol dependence in men. This common genetic influence may partially explain the clinical and epidemiological observations that alcoholics are often dependent smokers.