major depressive disorder associated_with regular smoking

assess whether MD, regular tobacco use and ND are influenced by shared genetic and/or environmental factors

genetic correlation between MD and regular smoking in males is comparable with (but lower than) other reports

lower estimates have also been reported (ra = 0.17–0.25)

genetic correlation between MD and RUC (ra = 0.13) indicates shared liability between MD and tobacco use

allows for shared genetic and environmental liability between MD and both tobacco-related variables

Kendler et al. (1993) reported a substantial genetic correlation between MD and regular smoking in women (ra = 0.56).

MD, regular tobacco use and ND share a common liability... genetic correlation between MD and regular tobacco use...