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Might cannabis rejuvenate the minds of older people?

Cannabis was found to improve memory and learning in older mice. Photo: Thomas Quine
Cannabis was found to improve memory and learning in older mice. Photo: Thomas Quine

A study has been conducted where cannabis rejuvenated the minds of older mice. If it works on older mice, it could work on older people. The mice were given a small amount of tetrahydrocannabinol (THC), the ingredient of cannabis that gets you stoned, in quantities much less than would get them stoned. Learning and memory skills improved, making them as good as those of considerably younger mice. Andrew Zimmer, a professor at the Institute of Molecular Psychiatry at the University of Bonn who led the study in conjunction with staff from the Hebrew University of Jerusalem, described his reaction as “Complete disbelief, basically.”

What happened

For four weeks, osmotic mini-pumps, tiny pumps implanted under the skin, delivered a constant amount of THC. Treatment ceased for a week and then the mice’s learning and memory were tested. One such test saw mice required to find a hidden platform. The THC-blessed mice remembered where the platform was as well as younger animals, which Zimmer described as “quite staggering.” Other tests involved navigating a water maze and recognising partners.

Old mice

The older mice were 12 to 18 months old, which is extremely old for a mouse, while the younger ones were only two months of age. No other substance has the same effect: it is, as Zimmer declared, “very unique to cannabis.” Onder Albayram, a co-author of the study, summed up the situation as “It’s like the brain goes back to the good old days, when the animals were younger and the cannabinoid system was higher in activity.”

Just what’s going on?

The precise effect is that THC affected cell plasticity and signalling. There was more klotho, a protein that has a drastic anti-ageing effect and shores up synapses, which are used for communication between neurons.

Research into cannabis to date has concentrated on younger rather than older people, as they’re considered to be at greater risk. While the number of younger cannabis users has been stable over the last decade, the number of older ones has increased as the drug’s stigma faded. Cannabis is known to worsen the memory of young mice – and people – for as long as they are under its influence.

Results were published in the journal Nature Medicine. In the United Kingdom, Oxford University launched a £10 million programme aiming to “identify new medical therapies through research into the molecular, cellular and systems mechanisms of cannabinoids.” This benefit of THC could well prove useful in the treatment of such diseases as Alzheimer’s and Parkinson’s disease where older people suffer cognitive impairment, as well as multiple sclerosis and epilepsy.

People are enthused!

Dr. Michael Bloomfield, who lectures in psychiatry at University College London, professed that the study was “particularly exciting,” but the chance of older people being prescribed THC or something along those lines was “still a long way off.” Svenja Schulze, the science minister of North Rhine-Westphalia, spoke similarly.