What topics does this cannabis study cover?

This study covers research on: THC, Mental Health.

Where was this research published?

Published in Neurobiology of disease on October 6, 2026.

Prenatal edible THC linked to brain and behavior changes in macaques

Q: What did this research study find?

MRI showed **white-matter differences** in THC-exposed infant macaques, including higher *fractional anisotropy* in the corpus callosum and centrum semiovale; regional brain volumes did not differ significantly.

Maternal edible THC consumption alters offspring neurodevelopment and emotional behavior in rhesus macaques.

Neurobiology of disease • October 6, 2026 • Highly Relevant

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AI Summary

This study asked whether chronic prenatal THC exposure is associated with changes in offspring brain development and behavior. Researchers compared rhesus macaques given a daily THC edible with controls given a placebo; exposure began before conception and continued through pregnancy and after birth. The abstract reports no significant differences in regional brain volumes, but MRI showed white-matter differences in exposed infants, including higher fractional anisotropy in the corpus callosum and centrum semiovale. The abstract does not report sample size or numerical effect sizes.

In behavioral tests, exposed infants vocalized more and showed less independence. Brain analyses also found DNA-methylation and gene-expression differences related to synaptic organization, brain development, axon development, and glutamatergic synapses. These findings suggest changes associated with exposure in this macaque model, but the abstract cannot establish what the results mean for human pregnancies or prove that THC caused the observed differences. This is an abstract-based summary; the abstract does not provide enough information to assess the full methods or the study’s limitations in detail.

💡 Key Findings

MRI showed white-matter differences in THC-exposed infant macaques, including higher fractional anisotropy in the corpus callosum and centrum semiovale; regional brain volumes did not differ significantly.

Good

60%

THC-exposed infants vocalized more and showed decreased independence in behavioral testing.

Good

60%

Brain analyses found exposure-associated DNA-methylation and gene-expression differences involving genes related to synaptic organization and neurodevelopment.

Moderate

50%

📄 Original Abstract

BACKGROUND: Prenatal cannabis exposure is associated with adverse offspring outcomes including altered neurodevelopment. However, there is insufficient evidence to establish a direct association. We sought to determine the impact of chronic prenatal delta-9-tetrahydrocannabinol (THC) exposure on offspring neurodevelopment and emotional behavior in a translational rhesus macaque model. METHODS: Animals were divided into two groups, control and THC-exposed, with both groups receiving a daily edible (placebo or THC) pre-conception, throughout pregnancy, and postnatally. MRI was performed longitudinally across gestation and infancy to assess volumetric and microstructural brain development. Serial behavioral testing, including motor and emotional assessments, was performed postnatally. At 6 months of age, brain tissue was collected for histology, immunohistochemistry (IHC), whole genome bisulfite sequencing (WGBS), and bulk RNA-sequencing. FINDINGS: Analysis of the MRI images showed white matter changes with higher fractional anisotropy in the corpus callosum (CC) and centrum semiovale in THC-exposed infants. However, there were no significant differences in regional brain volumes. Behavioral testing demonstrated that THC-exposed infants displayed increased vocalizations and decreased independence. WGBS identified differentially methylated regions (DMRs) associated with THC exposure in the cerebellum and prefrontal cortex, annotated to genes involved in synaptic organization and brain development. RNA-sequencing confirmed differential expression of genes related to axon development and glutamatergic synapse, with expression correlating with methylation levels. INTERPRETATION: Chronic prenatal edible THC exposure in the rhesus macaque was associated with changes in white matter development, effects on infant behavior with signs of increased stress and anxiety, and brain DNA methylation and expression of genes involved in neurodevelopment. FUNDING: NIH, March of Dimes, Silver Family Innovation.

Paper Type

📄 Research

Publication

Journal: Neurobiology of disease
Published: October 6, 2026
PMID: 42838264
DOI: 10.1016/j.nbd.2026.107640

Authors (16)

Rahul J D'Mello Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA; Division of Reproductive and Developmental Science, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA.
Lyndsey E Shorey-Kendrick Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA. Electronic address: shorey@ohsu.edu.
Joshua A Karpf Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA.
Chi Ngai Chan Tissues Technologies Unit, Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Marjorie R Grafe Department of Pathology, Oregon Health & Science University, Portland, OR, USA.
+11 more authors