It makes most people a little foggy-headed, but scientists are investigating whether an active ingredient in cannabis could actually stave off dementia.
A team from Neuroscience Research Australia is in the early stages of research examining if one of the main active ingredients in cannabis, called cannabidiol, could reverse some of the symptoms of memory loss in animals.
Tim Karl, a senior research fellow with the group, said cannabidiol does not have the same psychoactive effects as the main component of marijuana, THC, but it has been found to have anti-inflammatory, antioxidant and other effects that could be beneficial for the brain.
“Back in the day cannabis was used for medical purposes, I'm talking 200 years, 100 years back, then at some point people discovered it had other effects and, as quite often happens in our society, people decided it was a bad drug,” he said.
“But it's not one compound, it is a mixture of 60 different compounds, and you just have to look at those different compounds because some of them might be good for you.”
His study involved injecting cannabidiol into mice that had been bred to have similar symptoms as those seen in Alzheimer's, as well as examining what would happen to brain cells treated with the drug.
Dr Karl found that when the mice were given the cannabidiol they showed drastic improvement on parts of the tests that were related to recognising and remembering objects and other mice.
“It basically brings the performance of the animals back to the level of healthy animals,” he said. “You could say it cured them, but we will have to go back and look at their brains to be sure.”
The study was done as part of the PhD of student David Cheng, who has also collected the brains of the mice and intends to examine them to see if they showed physical improvements.
As part of the research, which is being presented at the Australian Neuroscience Society annual meeting in Melbourne this week, the team also treated animal brain cells that produced a protein linked to the development of plaques in the brain in humans with Alzheimer's disease, amyloid precursor protein.
The cell research, done at the University of Wollongong, found treating the cells with cannabidiol also reduced the amount of the harmful protein that they produced.
Dr Karl said there had been case reports in medical literature of marijuana smokers who had developed Alzheimer's disease, only to find their smoking seemed to relieve some of their symptoms.
“Most of the components [of marijuana] are detrimental, they worsen your cognitive performance and have psychoactive effects… cannabidiol seems to not have any of these negative effects,” he said.
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