THE RELATIONSHIP AMONG PRENATAL DRUG EXPOSURE AND SOCIAL FEAR, INHIBITORY CONTROL, AND HEAD CIRCUMFERENCE

Drug use during pregnancy is a growing concern in the US, as prenatal drug exposure (PDE) predicts negative outcomes in child development. One such outcome is physical, as existing research supports a relationship between PDE and head circumference at birth. Other outcomes include temperament-related behaviors, such as inhibitory control. Inhibitory control, which is the inability to resist impulses to heed a command, has been negatively correlated with PDE. Further, there is a small body of research suggesting a positive relationship between PDE and general fearfulness. Within this, research on social fear and PDE is even more limited. Findings from one study indicate infants with cocaine PDE experience more distress around others than infants without cocaine PDE. Following these lines of research, the current study investigated relationships among PDE, head circumference at birth, and temperament-related outcomes (e.g., social fear and inhibitory control). Participants consisted of 215 mothers from South-Central Appalachia. PDE was operationalized using scores on the self-report substance use questionnaire, which measures use of a broad range of drug use. Inhibitory control and social fear were operationalized using parental report TBAQ subscale scores. We hypothesized that there would be statistically significant differences between infants with PDE and those without PDE with regards to head circumference at birth, inhibitory control at 15 months of age, and social fear at 15 months of age. We also hypothesized that PDE would be negatively correlated with head circumference at birth, negatively correlated with inhibitory control at 15 months of age, and positively correlated with social fear at 15 months of age. Based on independent samples t-tests, after Bonferroni correction (p = .0125), no statistically significant differences were found between PDE and non-PDE infants with regards to head circumference at birth t(213) = -0.41, p = 0.68), parental report of social fear in children at 15 months of age t(213) = 2.24, p = 0.026), or parental report of inhibitory control in children at 15 months of age t(213) = -.204, p = .839). Bivariate Pearson product-moment correlations revealed a statistically significant negative relationship between amount of PDE and social fear at 15 months of age r(215) = -.187, p = .006. No statistically significant linear relationships were found between amount of PDE and inhibitory control r(215) = .005, p = .947, or between amount of PDE and head circumference at birth r(215) = -.027 p = .691. With the exception of the negative relationship between PDE and social fear, our hypotheses were not supported by our findings. The inverse relationship between social fear and PDE indicates a need for further research. The inconsistency between findings from the current study and existing literature may, to some degree, be accounted for by the limitations of retrospective self-report of substance use. Additionally, with a predominantly Caucasian sample, a more diverse sample is needed. Nonetheless, findings from the current study point to a need for additional research on the relationships among PDE, temperament-related behaviors, and physical outcome variables to further explore inconsistencies with existing research.