Mediating the Impact of Prenatal Cannabis Exposure on Neurobehavioral Disinhibition: The Role of Delayed Developmental Milestone Attainment

Objective: Environmental perturbations such as prenatal cannabis exposure (PCE) during critical periods may lead to disruptions in biological systems that have downstream consequences on behavior and development. Developmental milestones have served as a measure of normative development that allows providers and parents to identify areas for intervention. However, little is known about the direct impacts of PCE on development milestone attainment and whether failures to attain development milestones mediate later disruptions in executive functioning and behavioral disinhibition. Method: Data from the Adolescent Brain Cognitive Development (ABCD) study were used to examine prenatal cannabis effects on development while using a propensity score approach to control for familial and environmental characteristics. Results: PCE was not significantly associated with any delays in gross motor or language attainment; however, after accounting for confounders via propensity score for PCE (pPCE), PCE was significantly associated with delays in ‘saying his/her first word’ (Odds Ratio = 1.51, 95% Confidence Interval: [1.08, 2.10]). Upon examining the mediating effects, there were no significant total direct or total indirect effects on executive functioning. However, pPCE was associated with behavioral disinhibition and a significant mediation of PCE on behavioral disinhibition via delays in saying his/her first word were observed. Conclusions: This study suggests that delays in saying his/her first word serves as a risk factor for later behavioral disinhibition/externalizing problems. Importantly, the current study didn’t examine language development, rather delays in saying his/her first word can provide insight into the possible impacts prenatal cannabis exposure has on developmental milestone attainment.