THC’s Impact on Memory and Learning Ability
Recently, a fascinating article appeared in scientific journals discussing the effects of cannabinoids on memory, titled “Preventing Symptoms of Senile Dementia with Marijuana Consumption.” This property of cannabis could potentially be a real breakthrough in addressing currently incurable age-related memory loss and cognitive decline. Surprisingly, instead of clouding the mind, THC may actually strengthen the brain, helping it maintain cognitive function even in old age.
Although the study made interesting observations about the effects of THC on mice of different ages, it’s important to note that marijuana smoke was not used in the experiment. So, what did scientists discover, and how might this information help in developing treatments for dementia?
Cannabinoids and Aging: What Does Science Know?
Before this study, there were three basic facts known about THC’s effects on memory. First, young animals have a greater ability to learn and retain memory than older ones, which is fairly obvious. Second, after consuming THC, young mice performed worse in memory and learning tests compared to a sober control group and older mice under the influence of THC. Finally, it’s known that the endocannabinoid system directly affects aging processes and the regeneration of brain nerve cells, and that the activity of receptors and endogenous cannabinoids decreases with age.
Dr. Andreas Bilkei-Gorzo, the author of the study, explained the experiment’s premise: “It was previously established that a decline in cannabinoid receptors in the brain signals the activation of the aging process. We hypothesized that boosting the body’s natural system with external compounds could help preserve and improve brain function in old age.”
The logic is simple: if memory dysfunction is linked to a lack of endogenous cannabinoids, supplementing them with exogenous THC could help protect the brain from age-related diseases or even reverse their progression.
Overview and Key Findings
The study involved a series of experiments comparing the cognitive abilities and memory of young and old mice. Both age groups received a daily dose of THC for 28 days. Their test results were compared to those of control groups. The concentration of THC in the animals’ bodies was not measured; instead, scientists focused on the effects of daily consumption on cognitive abilities and memory.
The two age groups responded differently to the substance. After a month-long THC regimen, older animals significantly outperformed young mice in the tests. Overall, the older mice demonstrated behavior and cognitive abilities similar to young animals in the control group.
In addition to behavioral changes, scientists observed structural changes in the hippocampus. In simple terms, the brains of older mice that underwent THC therapy were identical to those of young control mice. New endings appeared on neurons in the hippocampus. Researchers also noted interesting genetic changes: older mice that received THC showed increased expression of genes responsible for neuron plasticity and longevity, and decreased activity of genes that destroy neural connections.
Chronic THC consumption increased the regeneration of nerve endings in the brains of older mice. Each brain cell has a “spine” structure: a main neuron connects it to neighboring cells. Compared to young mice (left column), older mice (middle) had fewer connections between neurons. After THC treatment (right), new connections appeared in the nerve cells of older animals, improving their conductivity.
The Role of the Endocannabinoid System in Aging
As we age, the body loses CB1 receptors. This receptor, typically activated by psychoactive cannabinoids, becomes less prominent in older organisms. Scientists believe that THC consumption increased CB1 sensitivity, allowing the body to compensate for endocannabinoid system deficiencies. This idea was confirmed in the mouse experiment.
“THC helps compensate for CB1 receptor deficiency in older mice. Compared to young animals (top left), older mice (top right) had suppressed CB1 receptor expression. Regular activation of the endocannabinoid system corrected this deficiency. Each red arrow indicates CB1. Different cannabinoids can activate receptors in specific body parts (yellow aura) without activating other receptor clusters.”
In short, the study concludes that cannabinoids, especially THC, can have very different effects on the body depending on age. Age-related suppression of the endogenous cannabinoid system can be addressed with THC extract therapy.
Future researchers should take this into account and consider the age of subjects when selecting volunteers for experiments. Also, given the unique properties of cannabinoids, effects observed in animals cannot be directly applied to humans.
Differences in THC Metabolism
According to the study, “chronic low-dose THC consumption restores cognitive function and memory in older mice.” But what exactly is a “low” dose?
Researchers calculated a daily dose of 3 milligrams of THC per kilogram of body weight for the test animals. For a 150-pound (68 kg) person, the equivalent dose would be 204 milligrams of THC. Spread evenly throughout the day, this would mean about 8.5 milligrams of THC per hour. A standard cannabis edible sold in medical dispensaries contains about 10 milligrams of THC. This means the animals received a dose equivalent to a cannabis edible every hour for a month.
While this is a large dose for a human, mice process the substance differently. “Compared to rodents, our bodies are much more sensitive to psychoactive substances. For example, test doses of antidepressants and sedatives for mice are 100 times higher than the human standard. The same goes for THC: mice are less sensitive to it.”
Mice metabolize exogenous compounds differently than humans, which is why scientists are cautious about drawing conclusions regarding THC’s effects on people.
The substance was administered to the animals via a chip implanted under the skin, ensuring a regular and uninterrupted supply. In other words, the animals did not inhale marijuana smoke or consume edibles, which is a significant difference from real-world use.
Questions for the Future
Despite these caveats, the study clearly demonstrated that THC has different effects on brain function depending on the user’s age. Science knows that CB receptor concentration decreases with age, but their function in the human body has not yet been studied.
For this reason, the global community should consider conducting large-scale clinical trials with cannabinoids. In particular, scientists need to find out whether patients can achieve cognitive improvements by consuming commercially available cannabis products. It’s possible that a special pharmaceutical concentrate of cannabis oils will be needed for therapeutic effects.
Currently, the study’s authors are preparing a clinical trial involving elderly volunteers suffering from dementia. “The plan for such an experiment is already in development,” says Dr. Bilkei-Gorzo. “Ideally, we’ll be able to start testing by the end of this year. The trial will use a THC extract to determine the effective therapeutic dose for humans.”
Although cannabinoid extracts are often used in lab tests, the human body reacts differently to a single compound than to the full spectrum of substances present when smoking cannabis. “Of course, the effects of pure THC can’t be compared to those of cannabis. Patients generally tolerate smoking better than extracts, but pure THC is easier to dose.”
It’s also worth mentioning where the research was conducted. The study was carried out by a team from the University of Bonn, Germany, and their colleagues from the Hebrew University of Israel. Notably, Israel is currently a recognized world leader in medical marijuana research, while Germany and Canada are planning major reforms regarding cannabis status.
Unfortunately, U.S. scientists cannot participate in clinical cannabis trials due to ongoing strict federal criminalization. While the Trump administration tries to undermine medical research and eliminate the medical cannabis market, Israel, Canada, and Germany are conducting advanced studies to become leaders in the global industry.