familial effects on alcohol and tobacco in males and females, but limited familial effects on cannabis (more so in males (Δχ2 = 1.57, Δdf = 2, P = 0.45, ΔAIC = −2.43) than females (Δχ2 = 4.26, Δdf = 2, P = 0.12, ΔAIC = 0.26)). Model-wide tests of differences in the magnitude of substance-specific genetic and environmental effects between males and females indicated that the genetic and environmental effects specific to tobacco and alcohol could not be equated; however, there was evidence to suggest that cannabis-specific effects could be equated across genders.
