Intrauterine cannabis exposure leads to more aggressive behavior and attention problems in 18-month-old girls
Background: The development of the fetal endocannabinoid receptor system may be vulnerable to maternal cannabis use during pregnancy and may produce long-term consequences in children. In this study, we aimed to determine the relationship between gestational cannabis use and childhood attention problems and aggressive behavior. Methods: Using a large general population birth cohort, we examined the associations between parental prenatal cannabis and tobacco use and childhood behavior problems at 18 months measured using the Child Behavior Checklist in N= 4077 children. Substance use was measured in early pregnancy. Results: Linear regression analyses demonstrated that gestational exposure to cannabis is associated with behavioral problems in early childhood but only in girls and only in the area of increased aggressive behavior (B= 2.02; 95% CI: 0.30-3.73; p= 0.02) and attention problems (B= 1.04; 95% CI: 0.46-1.62; p< 0.001). Furthermore, this study showed that long-term (but not short term) tobacco exposure was associated with behavioral problems in girls (B= 1.16; 95% CI: 0.20-2.12; p= 0.02). There was no association between cannabis use of the father and child behavior problems. Conclusions: Our results suggest that intrauterine exposure to cannabis is associated with an increased risk for aggressive behavior and attention problems as early as 18 months of age in girls, but not boys. Further research is needed to explore the association between prenatal cannabis exposure and child behavior at later ages. Our data support educating future mothers about the risk to their babies should they smoke cannabis during pregnancy.