Tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, could have significantly different effects on older brains than on those of younger animals.  Recent studies are showing that a low daily dose of cannabis could improve your memory.

Cannabis has gotten its own studies lately thanks to the growing desire for not only its medicinal properties but its recreational usage as well.  If any of the positive impacts on mice extend to human beings, cannabis could help doctors treat the cognitive decline that comes with old age, including dementia.

The study took place over a period of four weeks. Neurobiologist Andreas Zimmer of the University of Bonn in Germany and his team administered small doses of THC via a drip to mice aged two months old (young), 12 months old (mature), and 18 months old (elderly).

The quantity of THC administered was small, 3 mg per kilogram of body weight per day.  This was too low of a dose to intoxicate the animals, but the researchers wanted to see what the effects were on the mice’s endocannabinoid system.  This is the system of receptors in the brain and nervous system that help regulate appetite, mood, and memory, and which also respond to THC.  The results were nothing short of astounding, especially in the elderly mice.

“The treatment completely reversed the loss of performance in the old animals,” Zimmer said. “It looked as though the THC treatment turned back the molecular clock.”

In cognition tests with control animals using a water maze to assess spatial awareness, object recognition, and partner recognition, the young mice outscored their mature and elderly counterparts, as was expected. But when the animals were given the same dose of THC, the mature and elderly mice vastly boosted their performance in the learning and memory tests, doing as well as young, drug-free animals in the control group.

The good news doesn’t end there, either.  The positive effects on cognitive function lasted for several days.  The tests on the mice were conducted 5 days after they finished a 28-day daily administration of the THC. But the young mice did see their performance decline during testing.  It was the older mice that really benefited from the daily dosage.

“It seems that the young brain becomes old and the old brain becomes young,” one of the team members, Andras Bilkei-Gorzo, told The Scientist. “At first sight. it was totally illogical, but I realized when we gave the same drug to a young [animal], it overdrives the cannabinoid system – it’s [non-typical] hyperactivity and they have to bear the consequences. [But] in the old, the same treatment normalizes pathological low activity.”

But the team thinks that there’s a perfectly acceptable reason for that, although it’s just a hypothesis right now.  It could be because THC imitates the effect of naturally occurring cannabinoids produced in the body. Too much of this could create an intoxicating effect, but when animals are older, the THC supplement seems to restore cannabinoid levels back to those of young mice.

“With increasing age, the quantity of the cannabinoids naturally formed in the brain reduces,” Zimmer explains in a press release.  “When the activity of the cannabinoid system declines, we find rapid aging in the brain.”

Of course, there is no proof that this could benefit humans, but that’s the next step, according to this team. A clinical trial on humans is expected later this year.  With similar results, we could see cannabis help lead us to a cure for dementia.