Does variation in the μ-opioid receptor gene (OPRM1) moderate the association between maternal sensitivity and child attachment? A preregistered attempted replication and extension of Tchalova et al. (2024).

Initial molecular genetic studies identified specific genes that contribute to variation in associations between maternal sensitivity and infant attachment, but these findings from small samples failed to replicate in larger-sample investigations. A recent study shifted attention to a genetic marker of the opioid system, OPRM1 rs1799971, providing evidence for its role in moderating the association between maternal insensitivity and resistant attachment assessed via the Modified Strange Situation. This preregistered report attempted to replicate these results leveraging data from the NICHD Study of Early Child Care and Youth Development (SECCYD). We also examined robustness to other attachment assessments (i.e. Strange Situation Procedure, Attachment Q-Sort) and more comprehensive assessments of maternal sensitivity utilizing data from the SECCYD and the Generation R Study. The previously reported results did not replicate, providing another replication failure in the candidate gene literature. We discuss avenues forward by highlighting genetically-informed research designs derived from current best practices.