Sex moderated and RSA mediated effects of prenatal cocaine exposure on behavior problems at age 7.

This study was designed to assess whether prenatal cocaine exposure (PCE) is associated with sex differences in behavior problems in middle childhood and whether there are sex differences in the way in which parasympathetic functioning mediates the relations between PCE and behavior problems within a diverse low-income sample. Participants included 164 high risk mother-child dyads including 89 PC exposed children and 75 control children participating in an ongoing longitudinal study. Respiratory sinus arrhythmia (RSA) was measured to assess parasympathetic functioning at 13 months of age and maternal reports of child behavior problems were collected at 7 years of age. Results revealed no significant association between PCE and behavior problems for the full sample. A 2 × 2 Anova revealed a significant interaction between PCE and child sex on internalizing, externalizing, and total behavior problems (F (3, 160) = 13.45, p < .001) with cocaine exposed females averaging the highest behavior problem scores. Results also revealed a statistically significant indirect effect linking cocaine exposure to lower externalizing problems via lower baseline RSA among males. Findings indicate that cocaine exposed females may be more vulnerable to developing behavior problems than cocaine exposed males and that high baseline RSA may present a sex specific risk factor for externalizing problems among exposed males.