Ever go into the kitchen and forget why you went in there? Forget where you put your keys? Forget what you were saying mid-sentence? Ever do all that stuff while high? You’re not alone – the forgetful stoner is probably one of the most common conceptions of cannabis consumers.
Now, stereotypes sometimes exist for a reason. Science shows that, yes, cannabis use almost certainly affects memory. One study indicates that tetrahydrocannabinol (THC) impairs recall of information presented after, but not before, use of cannabis. That might be one reason the plot of Game of Thrones is so hard to follow after a toke or two (to say nothing of the fact that basically every character is named some riff of “Bran” or “Bronn”).
Memory can be broken down into three groups: Sensory, short-term and long-term. Sensory memory is incredibly fast; information is held for less than a second after something is perceived. Short-term memory (also known as working memory) lasts a little longer – several seconds to a minute without rehearsal; things like remembering telephone numbers can be placed in this category. Finally, long-term memory is much longer lasting, like remembering that embarrassing thing you did that one time in Grade 2 well into adulthood. Cannabis consumption is believed to affect all three, depending on the study.
But it’s not all bad news. First, the effects of THC seem to wane relatively quickly, according to this study, which says that “no effects of [THC] were found 24 or 48 hours following ingestion.”
Another study on the neuropsychological performance in long-term cannabis users suggests that even the heaviest of users – those who had smoked cannabis at least 5,000 times in their lives and were daily smokers – had “virtually no significant differences [in neuropsychological performance]” from a control group after a 28-day abstinence period.
Although many suggest that cannabis affects working memory (memorizing a small series of numbers, for example), others suggest possibly not. One three-year longitudinal study from 2016, that used functional magnetic resonance imaging (fMRI), found no changes in working memory function between chronic cannabis users and a control group, while another one also found that working memory wasn’t particularly affected by THC.
If a cannabis consumer is looking to reduce the effects of memory loss, one study from 2010 suggests that higher levels of cannabidiol (CBD) in a particular strain may help stem memory impairment. Conversely, it says low-cannabidiol strains, like those from the “skunk” family, might actually increase the effect of memory impairment.
Memory impairment caused by cannabis consumption might also even be beneficial, like in the case of post-traumatic stress disorder (PTSD). Research from one 2015 study shows that THC and/or CBD may be helpful in reducing “aversive memory” in PTSD patients. Other studies highlight the connection between a higher level of cannabinoid receptors (CB1 receptors) and PTSD, especially women. These findings are still in their infancy and require more study but may be an interesting avenue for those with PTSD to pursue under medical guidance.
Overall, the lesson seems to be that if a cannabis consumer wants to bridge a memory gap, that stopping – even if only for 24 hours – can make a difference.
Story by Fraser Abe
Illustration by Adrian Forrow
The preceding is for informational purposes only. It is not meant to condone the use or consumption of the term being defined. For more information, please refer to our disclaimer.