The trope of the forgetful stoner with short term memory loss may give weed a bad rap, but in reality researchers have found that small doses of cannabis extract might actually reverse cognitive decline, especially in old age.
In a study with mice published in the journal Nature Medicine, researchers found that small, consistent doses of THC, the main psychoactive compound in cannabis, compromised memory and learning in younger test subjects, but improved memory and learning in older ones. To determine whether this finding holds true for human subjects, the researchers are planning a clinical trial later this year.
During the study, the researchers gave THC every day to two-month-old, one-year-old, and 18-month-old mice. Then they observed how fast the mice could solve a water maze and how quickly they recognized objects and other mice they had previously met or been exposed to. The younger mice performed the best out of all the test subjects, but only when they didn’t have any THC in their systems. Meanwhile, with the help of THC, the older mice were able to match the performance of the THC-free younger mice. These results lasted even weeks after the researchers stopped dosing the mice with THC. The results of the study reveal “profound, long-lasting improvement of cognitive performance” from low THC treatments in elderly animals, the study authors wrote.
The research team posits that the THC is so useful because it stimulates the endocannabinoid system, a network throughout the body that regulates various physiological functions, including sleep, appetite, emotions, and memory. Further research has illustrated that THC restores gene transcription patterns in the hippocampus, which is related to memory and learning, to states similar to those in younger mice.
“I’m sure that what we are seeing are the long-term consequences of normalizing the system,” says Andras Bilkei-Gorzo, a researcher at the University of Bonn in Germany. “If we can rejuvenate the brain so that everybody gets five to ten more years without needing extra care then that is more than we could have imagined.”
If the same findings apply in humans, they could lead to treatments that prevent cognitive deterioration in the elderly. “{Cannabis preparations and THC} have an excellent safety record and do not produce adverse side-effects when administered at a low dose to older individuals,” the researchers wrote. “Thus, chronic, low-dose treatment with THC or cannabis extracts could be a potential strategy to slow down or even to reverse cognitive decline in the elderly.”
