After adjusting for sociodemographic and clinical factors, prenatal marijuana exposure was not associated with worse neuropsychological test scores at age 10 or autistic traits at ages 19-20.
Prenatal health researchers, pediatric neuropsychologists, and obstetricians counseling patients about cannabis.
No significant associationsbetween prenatal marijuana exposure and any neuropsychological outcomes after adjusting for parental characteristics
What the researchers found
Exposed children scored similarly to unexposed children on language (CELF Total -0.33 points, 95% CI -4.71, 4.05) and all secondary neuropsychological outcomes. No associations with clinical deficit risk were found.
Why it matters
This well-controlled longitudinal study challenges assumptions about prenatal marijuana harm, suggesting that observed effects in other studies may be confounded by parental characteristics rather than cannabis itself.
The numbers in context
2,804 children (285 exposed, 10.2%). No significant differences in CELF Total, Receptive, or Expressive scores at age 10. No associations with PPVT, CBCL, MAND, CPM, SDMT, or AQ scores.
How the study worked
Propensity score matching with optimal full matching, multiple imputation for missing covariates, and inverse probability of censoring weighting for missing outcomes. Linear regression within matched sets.
Who was studied
2,804 children from the Raine Study, born 1989-1992 in Western Australia, followed to age 10 (and 19-20 for autism traits).
What this study cannot tell us
Maternal self-report of cannabis use may be underreported. Cannabis potency and frequency of use were not detailed. The Raine Study cohort (born 1989-1992) may not reflect current, higher-potency cannabis.
How to read the evidence
Well-designed cohort with propensity score matching and multiple adjustment methods; strong negative finding.
When this study was published
Raine Study cohort born 1989-1992; cannabis potency was lower than current products.
The bigger picture
This null finding is important because it suggests that after careful adjustment for confounders, the independent effect of prenatal marijuana on child neurodevelopment may be smaller than previously thought.
Replication
Important null finding; replication with modern higher-potency cannabis exposures needed.
Funding
Not specified in abstract
Conflicts of interest
Not specified in abstract
Questions still open
- Would results differ with today higher-potency cannabis?
- Are there more subtle cognitive effects not captured by these standardized tests?
Read the original research
Neurodevelopmental outcomes in children after prenatal marijuana exposure.
Paediatric and perinatal epidemiology, 37(6), 536-546
Citation
Isik, Oliver G; Guo, Ling; Whitehouse, Andrew J O; Li, Guohua; Ing, Caleb. (2023). Neurodevelopmental outcomes in children after prenatal marijuana exposure.. Paediatric and perinatal epidemiology, 37(6), 536-546. https://doi.org/10.1111/ppe.12987