Nadler Jacobus Rabin, 2024

Our primary outcomes of interest were derived from the CBCL [Child Behavioral Checklist].⁴⁶ The CBCL is a parent-reported questionnaire that describes their child’s behaviour and emotional problems. Parents answer 118 questions scored on a 3-point Likert scale (0 = absent, 1 = occurs sometimes, 2 = occurs often). Each behaviour assessed was classified into one of eight syndromes: anxious/depressed, depressed, somatic complaints, social problems, thought problems, attention problems, rulebreaking behaviour, and aggressive behaviour.

We used the Child Behavioral Checklist (CBCL), to identify and categorize the key behaviours that are affected by prenatal tobacco and cannabis exposure in pre-teen children. The CBCL is a questionnaire, completed by parents, that is used to describe behavioural and emotional problems they may see in their child. Parents answered 118 questions/scenarios by rating each on a three-point scale (0 = absent, 1 = occurs sometimes, 2 = occurs often). The questionnaire is built to group these answers to highlight different clinical syndromes that may reflect their child’s problem areas. The 8 syndromes that are the focus of this analysis include: anxious/depressed, depressed, physiological complaints, social problems, thought problems, attention problems, rule breaking behaviour, and aggressive behaviour.

Using data from the Adolescent Brain Cognitive Development (ABCD) study and controlling for confounding factors, Paul et al.¹⁷ reported that prenatal cannabis exposure was associated with greater externalizing problems in middle childhood (∼10 years old) relative to unexposed children. Using the same dataset, but controlling for different covariates, Cioffredi et al.¹⁸ similarly reported that children with prenatal cannabis exposure had greater externalizing problems compared to children matched on prenatal tobacco and alcohol exposure and unexposed children.

The Adolescent Brain Cognitive Development (ABCD) study is a long-term study that follows a large number of children across time, as they grow and develop.  This large data set has been used in several previous studies to evaluate the effects of prenatal exposures to different substances, including alcohol, tobacco, and cannabis. One study (Paul et al., 2017) found that in, ~10-year old children, prenatal cannabis exposure was linked to more problems with outwardly expressed behaviours, like aggression toward others and high-risk behaviors, as compared with unexposed children. While another study (Cioffredi et al., 2022), controlling for different interacting variables (such as coincidental exposure to multiple substances), found that cannabis exposure was linked to greater outwardly expressed problem behaviours, when compared to children who were exposed to tobacco or alcohol or who were not exposed prenatally at all.

We found a significant main effect for prenatal cannabis exposure (F1,9545 = 4.702, p = 0.03) and prenatal tobacco exposure (F1,9545 = 28.959, p < 0.001) on externalizing scores. The interaction effect between prenatal cannabis exposure and prenatal tobacco exposure was also significant (F1,9545 = 4.615, p = 0.032).

We found that prenatal exposure to both cannabis and tobacco individually affected the scores of outwardly expressed behaviours, and these differences were statistically significant when compared with unexposed children. Furthermore, we show that there is a statical interplay between tobacco and cannabis, such that the effect on these behaviours appeared greater in combination.

Findings from this study demonstrated both main and interaction effects of prenatal cannabis exposure and prenatal tobacco exposure on externalizing symptoms in middle childhood. We found that children with prenatal cannabis and tobacco co-exposure had greater externalizing symptoms compared to all other groups: children with prenatal cannabis-only exposure, children with prenatal tobacco-only exposure, and unexposed children.

This study found that the primary variables of prenatal cannabis exposure alone and prenatal tobacco exposure alone are associated with outwardly expressed troubling behaviors (main effect) in pre-teenage children. They also found that when mothers smoked both cannabis and tobacco during pregnancy their children showed even greater expression of aggressive and risk-taking behaviours than children exposed to either drug alone or compared with unexposed children (interaction effect).

1. There will hopefully be follow-up longitudinal analyses of these children as they go through puberty and into early adulthood.
2. As the authors suggest, this study calls for the need for interventions to address substance use/abuse in pregnant woman.

While I had to look up the terms for internalizing and externalizing behaviors, I don’t really understand the details of the statistical analyses used, especially what the Bonferroni correction does to help understand the differences between groups or why it was used.

“Bonferroni corrected post-hoc tests revealed that the CT group (M = 8.88, SD = 8.6) had significantly higher externalizing scores compared to the CAN group (M = 5.66, SD = 6.7) (p < 0.001), the TOB group (M = 6.20, SD = 7.2) (p = 0.013), and the CTL group (M = 3.97, SD = 5.3) (p < 0.001).”