What if a molecule from cannabis could prevent the brain from sliding into Alzheimer’s-type decline? A preclinical study published in 2025 in the journal
Neuropsychopharmacology describes how the
cannabidiol blocked the onset of memory and sociability disorders in rats, while modulating key mechanisms involved in the disease.
Cannabidiol and Alzheimer’s: an experimental model where memory is preserved
There Alzheimer’s disease does not only affect memories: it also damages reasoning and social relationships, with a role increasingly attributed to neuroinflammation. Cannabidiol (CBD), a cannabis compound that has no psychotropic (“high”) effect, is of interest to researchers for its anti-inflammatory properties. In this work, a very low dose of CBD was enough to prevent rats from developing a behavioral profile close to the onset of Alzheimer’s.
The team of Roni Shira Toledano and Irit Akirav (University of Haifa, Israel) used adult male rats to which they injected a toxin, streptozotocin, into the brain. This model reproduces several characteristics of sporadic Alzheimer’s: accumulation of amyloid beta protein, abnormal tau protein and inflammation in the hippocampus, a key region for memory. Some of the animals then received a low dose of CBD daily for two weeks.
The researchers assessed spatial memory, object recognition and social interaction, while verifying that motor skills and anxiety remained stable. Rats exposed to streptozotocin without CBD showed marked forgetfulness and social withdrawal. Those treated with cannabidiol behaved like healthy animals on both memory and sociability tests, suggesting that CBD prevented the disorders from appearing rather than camouflaging them.
The CB1 receptor and inflammation in the spotlight
Analysis of brain tissue reveals that streptozotocin increases typical markers of Alzheimer’s in the hippocampus: amyloid beta protein, phosphorylated tau protein, but also immune activation signals such as TREM2, APOE ε4 and pro-inflammatory cytokines (TNF-α, IL-1β, NF-κB1). Under CBD, these markers drop significantly. To put it simply, cannabidiol appears to have “cooled the inflammatory fire” in a crucial area of the brain for memory.
The authors also targeted cannabinoid type 1 (CB1) receptors, which are very abundant in the brain and involved in learning. When they blocked CB1 with another molecule, CBD’s protection on memory and sociability almost disappeared. On the other hand, blocking CB2 did not change these effects. The study therefore points to a central role for CB1 receptors in the way cannabidiol protects the brain from this Alzheimer’s-type decline in rats.
What this discovery changes for Alzheimer’s
The authors summarize their work as follows: “As current treatments for Alzheimer’s disease are limited, our study highlights cannabidiol as a promising candidate, showing for the first time that a low dose can prevent behavioral and molecular deficits in a mouse model of the disease.“, conclude Roni Shira Toledano and Irit Akirav in the article published in Neuropsychopharmacology. The study, however, remains limited to male rats, over a short period, in a model which imitates but does not perfectly reproduce the human disease.
For patients and their loved ones, these results do not mean that CBD prevents Alzheimer’s in humans. The doses used in rats do not translate into the number of drops of oil, self-medication can interact with existing treatments and only clinical trials will be able to say whether cannabidiol has a therapeutic future in the face of Alzheimer’s disease. This work, however, reinforces the idea that targeting neuroinflammation very early, possibly via the endocannabinoid system, could be one of the avenues to follow in the years to come.