Aim To discuss the current status of gene–environment interaction research with regard to alcohol use and dependence. Further, we highlight the difficulties concerning gene–environment studies.
Methods Overview of the current evidence for gene–environment interactions in alcohol outcomes, and of the associated challenges in gene–environment studies.
Results Attention to the causative roles of gene–environment interactions in alcohol use and dependence is increasing. Studies with twin designs are beginning to examine gene-shared environment effects, and animal studies have investigated gene–environment interaction effects on alcohol intake in primates. Thirteen studies incorporated gene–environment interactions in examining alcohol use or dependence in humans. These studies held a variety of candidate genes and environmental risk factors and their heterogeneity made it impossible to draw firm general conclusions.
Conclusions Challenges for future gene–environment studies are abundant, and consist of, for example, the development of clear theoretical assumptions about neurobiological mechanisms and the recruitment of large longitudinal samples that already start in childhood. Replication is essential to prevent an overload of false-positive results. Despite the difficulties, it is crucial to include gene–environment interactions in future studies in order to unravel the aetiological factors of human alcohol outcomes.