In rats with prenatal immune activation (a schizophrenia risk model), adolescent THC exposure impaired sociability but did not interact with or worsen the immune-activation-induced cognitive and sensory deficits.
Psychosis researchers, neuroscientists studying cannabis-schizophrenia relationships, and clinicians interpreting cannabis risk.
What the researchers found
MIA impaired working memory and sensorimotor gating but surprisingly increased sociability. THC alone impaired sociability and social memory. There were no interactions between MIA and THC, meaning THC did not trigger or aggravate schizophrenia-related symptoms in genetically vulnerable animals.
Why it matters
The cannabis-psychosis debate often assumes THC acts as a trigger in vulnerable individuals. This study found no such interaction in a validated model, suggesting the relationship may be more nuanced than a simple trigger mechanism.
The numbers in context
MIA: impaired working memory and sensorimotor gating, increased sociability. THC: impaired sociability and social memory. No MIA x THC interactions on any measure.
How the study worked
Pregnant rats received LPS or vehicle. Offspring were exposed to mild THC during adolescence and tested in adulthood for working memory, sociability, anhedonia, sensorimotor gating, and incidental learning.
What this study cannot tell us
Single animal model with one vulnerability type. Mild THC dose. Rat behavioral assays are imperfect proxies for human psychosis. MIA model captures some but not all schizophrenia aspects.
How to read the evidence
Well-designed animal study with multiple behavioral measures, but limited translational applicability to human psychosis risk.
When this study was published
2024 publication.
The bigger picture
If prenatal immune activation and adolescent THC do not interact, it suggests the two-hit hypothesis may require different vulnerability types, or that the relationship involves mechanisms not captured by this model.
Questions still open
- Would higher THC doses reveal interactions with MIA?
- Do other vulnerability models show different interactions with adolescent THC?
Common questions
Does THC trigger psychosis in vulnerable people?
What is the MIA model?
Read the original research
Lack of interactions between prenatal immune activation and Δ9-tetrahydrocannabinol exposure during adolescence in behaviours relevant to symptom dimensions of schizophrenia in rats.
Progress in neuro-psychopharmacology & biological psychiatry, 129, 110889
Citation
Moreno-Fernández, Mario; Ucha, Marcos; Reis-de-Paiva, Raquel; Marcos, Alberto; Ambrosio, Emilio; Higuera-Matas, Alejandro. (2024). Lack of interactions between prenatal immune activation and Δ9-tetrahydrocannabinol exposure during adolescence in behaviours relevant to symptom dimensions of schizophrenia in rats.. Progress in neuro-psychopharmacology & biological psychiatry, 129, 110889. https://doi.org/10.1016/j.pnpbp.2023.110889
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