Not all cannabis strains affect memory equally

October, 2010

Current strains of cannabis may put users at greater risk of cognitive impairment.

A study involving 134 cannabis users aged 16-23 has found that when they were smoking cannabis containing a low percentage of cannabidiol they performed much worse on the memory tests. In contrast, those smoking cannabis high in cannabidiol performed just as well on the tests when they were intoxicated as when they were sober. There were no differences in the THC content of the cannabis smoked by any of the participants (THC is the main psychoactive ingredient, which gives the characteristic ‘stoned’ feeling, and feelings of paranoia).

For the study, the participants were tested on two separate occasions — once while they were smoking their own preferred type of cannabis and were intoxicated, and once when they had not smoked for the last 24 hours and were sober.

Levels of cannabidiol in cannabis can range from virtually none to 40%. This study suggests that cannabidiol can counteract the memory-impairing effects of THC. Unfortunately, low-cannabidiol strains (like skunk) now dominate the market of street cannabis, suggesting current users will be more at risk of cognitive impairment.



I'm sorry but there is no way

I'm sorry but there is no way almost half the mass of the plant material is CBD, that's preposterous. THC content is at most 30%, and that's pushing it. And THC degrades into CBD with light, so it's really hard to believe CBD content would exceed that of THC.

Re: I'm sorry but there is no way

I don't have any expertise in chemistry so can't speak to the absurdity of it, but the paper advises that CBD and THC are the main constituents of cannabis, and that in the UK, "on average, cannabis resin contains approximately equal levels of THC and cannabidiol, whereas herbal cannabis contains only moderate levels of THC and almost no cannabidiol. By contrast, sinsemilla, or skunk, contains high levels of THC and almost no cannabidiol." The 40% figure I quoted was taken from the press release.


Related News

A new MRI technique has revealed that it is the structural integrity of the

An examination of the brains of three groups of deceased individuals (13 cognitively normal, aged 20-66; 16 non-demented older adults, aged 70-99; 21 individuals with Alzheimer's, aged 60-95) has found that amyloid starts to accumulate and clump inside basal

A year-long study involving young adults has compared those who engaged in either tai chi or brisk walking or no exercise. Those who practiced tai chi had a significantly higher number of CD 34+ cells compared with those in the other groups.

I’ve reported often on the perils of multitasking. Here is yet another one, with an intriguing new finding: it seems that the people who multitask the most are those least capable of doing so!

I’ve spoken before about the effects of motivation on test performance.

I have reported previously on research suggesting that rapamycin, a bacterial product first isolated from soil on Easter Island and used to help transplant patients prevent organ rejection, might improve learning and memory.

I’ve talked before about Dr Berman’s research into Attention Restoration Theory, which proposes that people concentrate better after nature walks or even just looking at nature scenes.

Is there, or is there not, a gender gap in mathematics performance? And if there is, is it biological or cultural?

Math-anxiety can greatly lower performance on math problems, but just because you suffer from math-anxiety doesn’t mean you’re necessarily going to perform badly.

Research has shown that younger adults are better decision makers than older adults — a curious result. A new study tried to capture more ‘real-world’ decision-making, by requiring participants to evaluate each result in order to strategize the next choice.


Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news