A meta-analysis of 14 studies involving 203,783 participants found prenatal cannabis exposure associated with increased ADHD symptoms and a 30% higher risk of autism spectrum disorder in offspring.
Obstetricians, child psychiatrists, and families
30% higher ASD risk with prenatal cannabis exposure
What the researchers found
Prenatal cannabis exposure was associated with increased ADHD symptoms (B=0.39, p=0.001) and a 30% higher risk of ASD (RR=1.30, p<0.05). Stratified analysis showed elevated ADHD symptom scores (B=0.54) and a marginally significant increase in diagnosed ADHD (RR=1.13, CI: 1.01-1.26) among exposed offspring.
Why it matters
ADHD and ASD are among the most common neurodevelopmental disorders, and identifying modifiable risk factors is a public health priority. This meta-analysis provides pooled evidence that prenatal cannabis exposure may be one such factor.
The numbers in context
14 studies, 203,783 participants. ADHD symptoms: B=0.39 (CI: 0.20-0.58), I2=66.85%. ASD: RR=1.30 (CI: 1.03-1.64), I2=45.5%. ADHD symptom score in stratified analysis: B=0.54 (CI: 0.26-0.82). Diagnostic ADHD: RR=1.13 (CI: 1.01-1.26).
How the study worked
Systematic review and meta-analysis with preregistered PROSPERO protocol. Searched PubMed/Medline, Scopus, EMBASE, Web of Science, PsycINFO, and Google Scholar. 14 primary studies included (10 on ADHD, 4 on ASD) with 203,783 total participants. Inverse variance weighted random effects model.
What this study cannot tell us
Moderate heterogeneity for ADHD outcome (I2=66.85%). Only 4 studies on ASD limits that analysis. Underlying studies vary in how cannabis exposure was measured. Confounders including concurrent substance use and socioeconomic factors are variably controlled.
How to read the evidence
Preregistered meta-analysis with appropriate methods, though limited by moderate heterogeneity and small number of ASD studies.
When this study was published
2024 meta-analysis
The bigger picture
These findings add to the growing picture of prenatal cannabis risks. Combined with evidence on birth defects, birth weight, and attention problems, the body of evidence increasingly suggests that cannabis exposure during fetal development has measurable neurodevelopmental consequences.
Questions still open
- Is the ADHD association driven by a specific gestational window of exposure? Does the 30% ASD risk increase hold up in larger studies? Would controlling for all confounders eliminate the associations?
Common questions
Does cannabis use during pregnancy increase ADHD risk?
Is prenatal cannabis linked to autism?
Read the original research
Prenatal cannabis use and the risk of attention deficit hyperactivity disorder and autism spectrum disorder in offspring: A systematic review and meta-analysis.
Journal of psychiatric research, 171, 142-151
Citation
Tadesse, Abay Woday; Dachew, Berihun Assefa; Ayano, Getinet; Betts, Kim; Alati, Rosa. (2024). Prenatal cannabis use and the risk of attention deficit hyperactivity disorder and autism spectrum disorder in offspring: A systematic review and meta-analysis.. Journal of psychiatric research, 171, 142-151. https://doi.org/10.1016/j.jpsychires.2024.01.045
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