Prenatal cannabis exposure may harm executive function, behaviour

Children with prenatal exposure to cannabis appears to have poorer executive function and more aggressive behaviour, according to a study.

The study included 250 5-year-old children, of whom 80 (32 percent) had prenatal cannabis exposure, as defined by urine toxicology, maternal self-report, and obstetric record abstraction. Researchers looked at executive function and aggressive behaviour, which were evaluated by staff masked to exposure status.

Maternal use of tobacco, other drugs, and alcohol during pregnancy was common (22–39 percent each). Most mothers were not married or cohabitating during pregnancy (52 percent), and most families earned less than 100 percent of the poverty level (61 percent). More than half of the children were Black/African American, non-Hispanic (62 percent).

Compared with unexposed children, those who were prenatally exposed to cannabis had age-corrected standard scores for children’s attention and inhibitory control (National Institutes of Health Toolbox) that were lower by about 0.4 SD (β, −6.1 points, 95 percent CI, −10.8 to −1.4) in an analysis that applied propensity score weighting and adjustment for confounders. Furthermore, exposed children exhibited poorer task-based planning ability and more observed aggression.

Caregiver ratings of executive function and behaviour and laboratory assessments of other aspects of executive functioning did not differ between the exposed and unexposed groups.

The differences seen in executive function and behaviour in children with prenatal cannabis exposure may be relevant to long-term academic success and adaptive functioning. The present data may be considered in refining clinical recommendations regarding cannabis use during pregnancy, the researchers said.