THC-CBD Combination Did Not Help Alzheimer's Symptoms in Mice
A three-week THC-CBD treatment failed to reverse Alzheimer's-related deficits in transgenic mice, and even worsened some outcomes depending on genotype.
Quick Facts
What This Study Found
Chronic treatment with 3 mg/kg THC and 20 mg/kg CBD did not improve anxiety-like behavior or object recognition deficits in 14.5-month-old Alzheimer's model mice. The treatment had genotype-dependent effects, causing increased anxiety in Alzheimer's mice but reduced anxiety in controls.
Key Numbers
Treatment used 3 mg/kg THC and 20 mg/kg CBD daily for 3 weeks. Alzheimer's mice showed increased anxiety-like behavior with treatment. Control females lost their normal object preference after treatment. THC-CBD significantly decreased body weight and fat deposits across all mice.
How They Did This
Researchers treated 14.5-month-old female APP/PS1 transgenic mice (Alzheimer's model) and control littermates with daily THC-CBD injections for three weeks. They tested anxiety (elevated plus maze, open field), memory (novel object recognition, Y-maze), social interaction, and sensorimotor gating.
Why This Research Matters
Previous research showed CBD alone could reverse some memory deficits in Alzheimer's model mice. Combining THC with CBD was hypothesized to improve outcomes, but this study found the opposite.
The Bigger Picture
The idea that combining cannabinoids produces better therapeutic effects doesn't always hold. Disease state appears to determine whether cannabinoids help or harm, highlighting the complexity of using cannabis-based treatments for neurodegeneration.
What This Study Doesn't Tell Us
Used only female mice. The THC:CBD ratio and doses may not reflect what humans use. IP injection doesn't mimic oral or inhaled routes. APP/PS1 mice don't fully replicate human Alzheimer's disease.
Questions This Raises
- ?Would different THC:CBD ratios produce different results?
- ?Does the disease stage at treatment onset matter?
- ?Would male mice respond differently?
Trust & Context
- Key Stat:
- 0 improvement in Alzheimer's-related deficits
- Evidence Grade:
- Preliminary: animal study using a single transgenic mouse model with only female subjects
- Study Age:
- Published in 2025
- Original Title:
- Combination treatment with medium dose THC and CBD had no therapeutic effect in a transgenic mouse model for Alzheimer's disease but affected other domains including anxiety-related behaviours and object recognition memory.
- Published In:
- Pharmacology, biochemistry, and behavior, 257, 174101 (2025)
- Authors:
- Aumer, Beate, Rosa Porto, Rossana(2), Coles, Madilyn(2), Ulmer, Nina, Watt, Georgia, Kielstein, Heike, Karl, Tim
- Database ID:
- RTHC-05975
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Does this mean cannabis can't help with Alzheimer's?
Not necessarily. Previous studies found CBD alone showed some benefits in similar models. This study specifically tested a THC-CBD combination at particular doses, which didn't work and had some negative effects.
Why did the treatment affect Alzheimer's and control mice differently?
The researchers found genotype-dependent effects, meaning the disease state changed how the brain responded to cannabinoids. This suggests that what works in a healthy brain may not work in a diseased one.
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Cite This Study
https://rethinkthc.com/research/RTHC-05975APA
Aumer, Beate; Rosa Porto, Rossana; Coles, Madilyn; Ulmer, Nina; Watt, Georgia; Kielstein, Heike; Karl, Tim. (2025). Combination treatment with medium dose THC and CBD had no therapeutic effect in a transgenic mouse model for Alzheimer's disease but affected other domains including anxiety-related behaviours and object recognition memory.. Pharmacology, biochemistry, and behavior, 257, 174101. https://doi.org/10.1016/j.pbb.2025.174101
MLA
Aumer, Beate, et al. "Combination treatment with medium dose THC and CBD had no therapeutic effect in a transgenic mouse model for Alzheimer's disease but affected other domains including anxiety-related behaviours and object recognition memory.." Pharmacology, 2025. https://doi.org/10.1016/j.pbb.2025.174101
RethinkTHC
RethinkTHC Research Database. "Combination treatment with medium dose THC and CBD had no th..." RTHC-05975. Retrieved from https://rethinkthc.com/research/aumer-2025-combination-treatment-with-medium
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.