2.47 THE DOPAMINE D4 RECEPTOR GENE, BIRTH WEIGHT, EARLY MATERNAL CARE, MATERNAL DEPRESSION OVER THE POSTNATAL TIME PERIOD, AND THE PREDICTION OF DISORGANIZED ATTACHMENT AT 36-MONTHS OF AGE: A PROSPECTIVE GENE X ENVIRONMENT ANALYSIS

Objectives: Efforts to understand the developmental pathways for disorganized (D) attachment reflect the importance of D attachment on the prediction of future psychopathology. The inconsistent findings on the prediction of D attachment from the dopamine D4 receptor (DRD4) gene, birth weight, and maternal depression, as well as the evidence supporting early maternal care as a mediator or moderator of more distal environmental effects, suggest the importance of exploring a Gene by Environment model. Methods: Our sample group is from the Maternal Adversity, Vulnerability and Neurodevelopment project, consisting of 655 mother-child dyads. Birth weight was cross-referenced with normative data to calculate birth weight percentile. Infant DRD4 genotype was obtained with buccal swabs and categorized according to the presence of the seven-repeat allele. Maternal depression was assessed with the Center for Epidemiologic Studies Depression Scale at the prenatal, 6-, 12-, 24-, and 36-month assessments. Early maternal care was measured at 6 months using a videotaped session of a 20-minute nonfeeding interaction. Attachment was assessed at 36 months using the Strange Situation Procedure. Results: Infant DRD4 genotype (β = -1.11, OR = 0.329, P < 0.001) and chronic maternal depression (β = 1.01, OR = 2.74, P < 0.01) showed significant main effects on D attachment. One measure of early maternal care, looking away frequency, showed significant interactions with maternal depression at the prenatal assessment (b = 0.00312, OR = 1.003, P < 0.05) and at 24 months (β = 0.00367, OR = 1.004, P < 0.05), whereas maternal education also showed a separate contribution (college level, β = -1.76, OR = 0.173, P < 0.0001, and university level or higher, β = -1.15, OR = 0.316, P < 0.01). Conclusions: Our models support the contribution of biological (DRD4 genotype) and multiple environmental factors (the chronicity of maternal depression, maternal education, and the interaction between maternal depression and early maternal care) in the complex prediction of D attachment at 36 months.