In male rats, THC+CBD self-administration caused stress responses to generalize to neutral stimuli by altering astrocyte-synapse connections in the nucleus accumbens.
Neuroscience researchers and clinicians interested in the cannabis-PTSD relationship and sex differences in cannabinoid effects.
Stress generalization and neural changes occurred only in male rats after THC+CBD self-administration
What the researchers found
THC+CBD self-administration followed by withdrawal caused male rats to show stress-coping behaviors in response to a neutral stimulus unrelated to the original stressor. This generalization was linked to astrocyte retraction from synapses and decreased Synapsin-I density in the nucleus accumbens core. Effects were observed only in males.
Why it matters
Cannabis use disorder and PTSD frequently co-occur. Understanding how cannabinoid exposure might alter brain circuits involved in stress generalization could point to new treatment targets for both conditions.
The numbers in context
Rats self-administered THC+CBD for 10 days with 10 days of withdrawal. MMP-2 was the primary driver of matrix metalloproteinase activation. Effects on stress generalization and neural plasticity were observed only in male rats.
How the study worked
Rats were restraint-stressed with an associated odor (stress-CS), then self-administered THC+CBD for 10 days followed by 10 days of withdrawal. Stress responses to the conditioned and neutral odors were measured in a defensive burying task. Brain changes were assessed via in vivo zymography and confocal microscopy.
What this study cannot tell us
Animal study results may not translate directly to humans. The THC+CBD combination and dosing may not reflect typical human consumption patterns. Only examined one brain region. The sex difference mechanism was not fully explained.
How to read the evidence
Animal study with specific brain mechanisms identified, but unclear translation to human cannabis use patterns and PTSD.
When this study was published
2025 preprint (Research Square), not yet peer-reviewed.
The bigger picture
The finding that cannabinoid exposure can cause stress responses to spread beyond their original triggers mirrors a key feature of PTSD. The sex-specific nature of these effects adds to growing evidence that cannabis affects male and female brains differently.
Questions still open
- Why did these neuroadaptations occur only in males?
- Would these effects persist with longer withdrawal periods?
Read the original research
Cannabinoid use generalizes stress responses by altering the astrocyte plasticity through extracellular matrix signaling in the nucleus accumbens core.
Research square
Citation
Hodebourg, Ritchy; Duncan, Lillian; Dereschewitz, Eric; Kalivas, Peter. (2025). Cannabinoid use generalizes stress responses by altering the astrocyte plasticity through extracellular matrix signaling in the nucleus accumbens core.. Research square. https://doi.org/10.21203/rs.3.rs-7254957/v1
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