Finally, we examined whether there were sex differences in these G × E effects. We found no evidence of sex differences in the G × E effect for drinking frequency or AD symptoms. However, the G × E effect for intoxication frequency was driven primarily by the effect in males. Simulations revealed modest power (~60%) to detect this three-way interaction. Previous work in social epidemiology has documented how males tend to ‘over-benefit’ from relationships in terms of health [32]. This may reflect the tendency for women in relationships to be the emotional and social support providers, of which men are the receivers [59]. In the current study, we see that this effect may be due in part to limiting genetic liability among a riskier drinking group. This difference does not appear in AD symptoms, which may be due to the fact that these symptoms capture aspects of both consumption and problems. Relationship status may only limit genetic liability in regards to heavy consumption. Additionally, our AD measure was a life-time measure. It is possible that current levels of misuse may differ from life-time symptomology.
