Mice with reduced levels of the brain development protein Reelin showed more severe social, behavioral, and stress-related impairments after chronic adolescent THC exposure compared to normal mice.
Neuroscience researchers studying gene-environment interactions, and clinicians interested in cannabis vulnerability factors.
Reelin-deficient mice showed worse behavioral outcomes from same THC exposure
What the researchers found
Heterozygous Reeler mice (reduced Reelin) treated with THC during adolescence showed impaired social behaviors, elevated disinhibitory phenotypes, and increased stress reactivity compared to wild-type mice given the same THC treatment. These effects were sex-specific. Wild-type mice showed less severe behavioral changes from the same THC exposure.
Why it matters
Reelin is implicated in brain development and psychiatric disorders including schizophrenia. This study suggests that genetic variations affecting Reelin levels could make some individuals more vulnerable to lasting behavioral effects from adolescent cannabis use.
The numbers in context
THC dose: 10 mg/kg chronic during adolescence. Two-week washout before testing. HR mice showed impaired social behavior, elevated disinhibition, and increased stress reactivity compared to WT mice with same THC exposure. Effects were sex-specific.
How the study worked
Heterozygous Reeler (HR) mice and wild-type littermates received chronic high-dose THC (10 mg/kg) during adolescence. Two weeks after the last injection, mice underwent multiple behavioral tests: working memory, social interaction, locomotor activity, anxiety-like responses, stress reactivity, and pre-pulse inhibition.
What this study cannot tell us
High THC dose (10 mg/kg) may not reflect typical human use. Mouse behavior may not translate to human psychiatric outcomes. Only chronic high-dose regimen tested. Two-week follow-up may miss longer-term effects.
How to read the evidence
Well-controlled animal study with genetic model. Preliminary because mouse behavioral tests have limited human translation.
When this study was published
2021 preclinical study.
The bigger picture
Not everyone who uses cannabis as a teenager develops problems. Gene-environment interaction studies like this one help explain individual vulnerability. If Reelin-related genetic variants predict cannabis sensitivity in humans, it could eventually enable personalized risk assessment.
Questions still open
- Do human Reelin gene variants predict vulnerability to cannabis-related psychiatric outcomes? Would lower THC doses produce similar gene-environment interactions? Are the behavioral effects reversible with longer abstinence?
Common questions
What is Reelin and why does it matter?
Were male and female mice affected the same way?
Read the original research
Reelin deficiency contributes to long-term behavioral abnormalities induced by chronic adolescent exposure to Δ9-tetrahydrocannabinol in mice.
Neuropharmacology, 187, 108495
Citation
Iemolo, Attilio; Montilla-Perez, Patricia; Nguyen, Jacques; Risbrough, Victoria B; Taffe, Michael A; Telese, Francesca. (2021). Reelin deficiency contributes to long-term behavioral abnormalities induced by chronic adolescent exposure to Δ9-tetrahydrocannabinol in mice.. Neuropharmacology, 187, 108495. https://doi.org/10.1016/j.neuropharm.2021.108495
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