Gene-environment interactions reexamined: does mother's marital stability interact with the dopamine receptor D2 gene in the etiology of childhood attention-deficit/hyperactivity disorder?

Potential candidate Gene x Environment interactions in the etiology of childhood attention-deficit/hyperactivity disorder (ADHD) are examined between the dopamine receptor D2 gene (DRD2) and putative family environmental risk factors that reflect mothers' marital stability. Specifically, interactions were tested between DRD2 and mothers' marital status, number of marriages or cohabiting relationships, and age at first marriage. Moderate relations were found among the marital stability measures, and mother's marital status and number of marriages or cohabiting relationships (but not age at first marriage) were risk factors for their children's ADHD. All three mother's marital stability variables were associated with either the child's or mother's DRD2 genotypes. Gene x Environment interactions were found for children's ADHD diagnoses between children's DRD2 genotypes and mother's marital status and number of marriages or cohabiting relationships. It is of interest that these interactions were strengthened with the progressive addition of sets of covariates intended to control for alternative causal pathways that represent background genetic and environmental context confounds. The present findings highlight the importance of considering both the nexus of putative environmental risk factors and whether their etiology and effects are truly environmental in future Gene x Environment interaction research.