The μ‐opioid receptor gene A118G polymorphism is associated with insecure attachment in children with disruptive mood regulation disorder and their mothers

BACKGROUND: The A118G single nucleotide polymorphism (SNP) of the μ‐opioid receptor gene, with high expression of the A allele and low expression of the G allele, has been associated with emotional/behavioral dysregulation and depressive disorders and is recognized as a mediator of affiliative behavior. No study has thus far investigated this SNP in school‐age children with disruptive mood regulation disorder (DMDD). This study compared a sample of healthy children and their mothers with a sample of children with DMDD and their mothers, evaluating whether insecure attachment and psychopathological symptoms are associated with A allele‐ or G allele‐carrying mothers and children and whether caregiving capacities are associated with A allele‐ or G allele‐carrying mothers. METHODS: For evaluation of their psychopathological symptoms and attachment styles, mothers filled out the CBCL/6‐18, the SCL‐90‐R, and the ECR. To evaluate the types of relationship children were experiencing with their mothers, children filled out the ECR‐revised child version and the PBI. Genotypic analyses were conducted on DNA samples obtained by buccal swabbing from children and mothers. RESULTS: An insecure attachment style was more frequent in mothers and children carrying the G allele (G/G + A/G genotypes). In the clinical sample, G allele‐carrying children scored higher than homozygous A/A ones on the subscales of Withdrawal and Conduct Problems. G‐carrying mothers showed higher interpersonal sensitivity, depression, hostility, and paranoid ideation and provided less care than A/A mothers. CONCLUSIONS: This study offers new insights into the associations between the A118G SNP of the μ‐opioid receptor gene and emotional/behavioral functioning, attachment style in children, and psychopathology and caregiving ability in mothers.