A 14-day THC course in adolescent rats and mice caused profound, sex-specific deficits in hippocampal synaptic plasticity and memory that persisted into adulthood, with females more severely affected through disrupted estrogen signaling.
Neuroscientists, adolescent health researchers, and clinicians counseling young women about cannabis risks.
Females more severely affected via disrupted estrogen-synaptic signaling
What the researchers found
Adolescent THC exposure produced selective, lasting deficits in synaptic plasticity in two hippocampal pathways, primarily in females. In females, THC disrupted endocannabinoid-dependent long-term potentiation, impaired estrogen effects on synaptic responses, and caused deficits in both episodic-like and spatial memory. Effects were sexually dimorphic and pathway-specific.
Why it matters
This study identifies a specific mechanism for sex-specific adolescent cannabis vulnerability: THC disrupts the interaction between the endocannabinoid system and estrogen signaling in the hippocampus, with lasting consequences for memory.
The numbers in context
14-day adolescent THC treatment. Effects confirmed in both rats and mice (cross-species validation). Lateral perforant path LTP disrupted in females of both species and male mice. Schaffer-commissural LTP disrupted in females only.
How the study worked
Rats and mice received 14 days of daily THC during adolescence. In adulthood, researchers measured synaptic plasticity (long-term potentiation) in hippocampal brain slices and tested episodic and spatial memory behavior.
What this study cannot tell us
Animal study with uncertain human translation. Single THC dose regimen. Specific hippocampal pathways may not capture all relevant cognitive effects. Estrogen interaction mechanism needs confirmation in humans.
How to read the evidence
Cross-species validation (rats and mice) with mechanistic depth, but animal model limitations.
When this study was published
Published in 2022.
The bigger picture
The finding that adolescent THC disrupts estrogen's role in synaptic plasticity provides a mechanistic explanation for why female cannabis users may be particularly vulnerable to memory impairment, with implications for the growing number of young women using cannabis.
Questions still open
- Could estrogen-related treatments reverse these effects? Do hormonal contraceptives interact with cannabis to worsen or protect against these effects? Are human females similarly more vulnerable?
Common questions
Does teen cannabis use cause lasting brain damage?
Are girls more vulnerable to cannabis brain effects?
Read the original research
Persistent sexually dimorphic effects of adolescent THC exposure on hippocampal synaptic plasticity and episodic memory in rodents.
Neurobiology of disease, 162, 105565
Citation
Le, Aliza A; Quintanilla, Julian; Amani, Mohammad; Piomelli, Daniele; Lynch, Gary; Gall, Christine M. (2022). Persistent sexually dimorphic effects of adolescent THC exposure on hippocampal synaptic plasticity and episodic memory in rodents.. Neurobiology of disease, 162, 105565. https://doi.org/10.1016/j.nbd.2021.105565
Explore the wider topic
- How to Talk to Your Teenager About Weed (Without Losing Them)
- My Kid's Friends Smoke Weed: A Parent's Guide
- I Smoke Weed But Don't Want My Kids To: Navigating the Hypocrisy
- Quitting Weed as a Parent: Why It Is the Hardest and Most Important Quit
- Quitting Weed as a Teen or Young Adult
- My Kid Is Smoking Weed: A Parent's Guide