THC-dependent mice showed memory problems during withdrawal, some lasting months
Mice given chronic cannabinoids during late adolescence showed temporary general cognitive impairment but long-lasting spatial memory deficits persisting at least 75 days after stopping.
Quick Facts
What This Study Found
Rats received the cannabinoid agonist WIN55,212-2 daily during late adolescence (postnatal days 45-60) and were tested at 24 hours, 10 days, 30 days, and 75 days after the last injection. Short-term memory in the water maze and object recognition tasks, and synaptic plasticity in the brain's reward pathway, recovered by 10 or 30 days after stopping.
However, hippocampal-dependent spatial memory (tested with the object location task) remained impaired at all timepoints including 75 days, the latest measurement taken. This suggested a specific vulnerability of location-based memory to chronic adolescent cannabinoid exposure.
The researchers interpreted the recoverable deficits as likely due to residual cannabinoids in the brain or acute withdrawal effects, while the persistent spatial memory deficit reflected a more fundamental change in hippocampal function.
Key Numbers
Treatment: postnatal days 45-60 (late adolescence equivalent). Water maze and object recognition: impaired at 24 hrs and 10 days, recovered by 30 days. Object location (spatial memory): still impaired at 75 days.
How They Did This
Rats received WIN55,212-2 (1.2 mg/kg i.p.) daily for 2 weeks during late adolescence. Cognitive testing included Morris water maze, object recognition, and object location tasks at 24 hours, 10 days, 30 days, and 75 days post-treatment. Synaptic plasticity (LTP) was measured electrophysiologically.
Why This Research Matters
The distinction between temporary and persistent effects matters for adolescent cannabis users. Some cognitive deficits cleared with abstinence, but spatial memory impairment persisted well beyond the drug clearance period, suggesting lasting brain changes.
The Bigger Picture
This study contributed to the evidence that adolescent brains may be particularly vulnerable to lasting cannabinoid effects. The finding that different types of memory recovered at different rates has implications for how long cognitive effects persist after people stop using cannabis.
What This Study Doesn't Tell Us
Used a synthetic cannabinoid agonist (WIN55,212-2), not THC. Rat adolescence does not perfectly map to human adolescence. The dosing regimen was high and consistent, unlike typical human use patterns. Only male rats were used.
Questions This Raises
- ?Would the spatial memory deficit eventually recover at later timepoints?
- ?Does this translate to human adolescent cannabis users?
- ?Would intermittent rather than daily dosing produce the same lasting effects?
Trust & Context
- Key Stat:
- Spatial memory still impaired 75 days after stopping
- Evidence Grade:
- Animal study with multiple timepoints and cognitive measures. Well-designed but uses synthetic cannabinoid rather than THC, and rat-to-human translation is uncertain.
- Study Age:
- Published in 2012. Research on adolescent cannabis exposure and lasting cognitive effects has continued to develop.
- Original Title:
- delta(9)-Tetrahydrocannabinol-dependent mice undergoing withdrawal display impaired spatial memory.
- Published In:
- Psychopharmacology, 217(4), 485-94 (2011)
- Authors:
- Wise, Laura E(3), Varvel, Stephen A, Selley, Dana E(5), Wiebelhaus, Jason M, Long, Kelly A, Middleton, Lisa S, Sim-Selley, Laura J, Lichtman, Aron H
- Database ID:
- RTHC-00534
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Do all memory problems from cannabis go away when you stop?
In this rat study, most cognitive deficits recovered within 10-30 days of stopping. But one specific type, spatial memory (remembering where things are located), remained impaired for at least 75 days. This suggests some effects may outlast others.
Why does adolescent exposure matter more?
The adolescent brain is still developing, particularly the hippocampus, which handles spatial memory. Cannabinoid exposure during this critical period may alter development in ways that produce more persistent effects than adult exposure.
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Cite This Study
https://rethinkthc.com/research/RTHC-00534APA
Wise, Laura E; Varvel, Stephen A; Selley, Dana E; Wiebelhaus, Jason M; Long, Kelly A; Middleton, Lisa S; Sim-Selley, Laura J; Lichtman, Aron H. (2011). delta(9)-Tetrahydrocannabinol-dependent mice undergoing withdrawal display impaired spatial memory.. Psychopharmacology, 217(4), 485-94. https://doi.org/10.1007/s00213-011-2305-5
MLA
Wise, Laura E, et al. "delta(9)-Tetrahydrocannabinol-dependent mice undergoing withdrawal display impaired spatial memory.." Psychopharmacology, 2011. https://doi.org/10.1007/s00213-011-2305-5
RethinkTHC
RethinkTHC Research Database. "delta(9)-Tetrahydrocannabinol-dependent mice undergoing with..." RTHC-00534. Retrieved from https://rethinkthc.com/research/wise-2011-delta9tetrahydrocannabinoldependent-mice-undergoing-withdrawal
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.