When it comes to the negative effects of cannabis use, it’s often touted that it leads to memory loss—especially when consumption begins during adolescence. However, a new study finds that potency actually plays a significant role in how cannabis affects our memory.
Over a series of Zoom calls, Washington State University researchers performed cognitive tests on subjects who had just smoked high-potency cannabis flower or vaped concentrates they purchased from cannabis dispensaries located in Washington.
The researchers primary interest was comparing their study to previously-reported research on cannabis and cognitive ability. They felt that the kind of cannabis being used in research wasn’t accurate compared to what people were actually smoking, which is the fault of the Drug Enforcement Administration (DEA) who had control over what cannabis is harvested for research until recently.
The study concluded that high-potency cannabis had no impact on decision-making, but did impair a person’s memory when it came to free recall, source memory and false memories.
All of the cannabis used in this study was legally purchased by the participants. Furthermore, researchers never touched the cannabis used and they never brought the subjects into a laboratory for study. Beyond a placebo-controlled sober group, these researchers tried to interfere with participants as little as possible. The only control they had was they made sure everyone was an experienced cannabis user with no past negative experiences with cannabis, such as “greening out.”
Since the study began in 2018, there have been 80 participants divided into four groups. The first two groups smoked cannabis flower with a minimum of 20 percent tetrahydrocannabinol (THC). The third group vaped cannabis concentrates with a minimum of 60 percent THC. And the final group was sober.
The Results: Cannabis Does Affect Memory, But It’s Complicated
As mentioned, researchers discovered cannabis had no significant impact on decision-making tests. This includes risk perception and confidence in one’s own knowledge. Furthermore, there were little-to-no differences when looking into a few memory tests, such as prospective memory and the ability to remember later tasks (i.e. deadlines, attending appointments, etc.).
Interestingly, those who used cannabis had better results when it came to temporal order memory. This is how well a person is able to remember a sequence of previous events rather than an event as a whole.
Still, those who smoked cannabis were found to do worse when it came to a few areas of memory.
The first were free recall trials. This is when a group is presented with an image or series of words (i.e. essay) and asked to remember as much as possible. Those who were sober tended to remember more. The significance of these results is that previous studies concluded that cannabidiol (CBD) had a protective effect on memory.
The second was source memory where groups had to distinguish how previously learned information was presented.
The final was a false memory test. This is when all groups would be presented with a new word and questioned on whether or not they had heard it before. Most of those who consumed cannabis would say they had heard it before even if they hadn’t.
However, one of the most striking takeaways from this study was the fact that both the flower smokers and concentrate vapers showed almost identical results even though concentrates are noticeably more potent. Carrie Cuttler, WSU psychologist and lead researcher on the study, claims:
“There’s been a lot of speculation that these really high-potency cannabis concentrates might magnify detrimental consequences, but there’s been almost zero research on cannabis concentrates which are freely available for people to use. I want to see way more research before we come to any general conclusion, but it is encouraging to see that the concentrates didn’t increase harms.”
Still, it has been noted that those concentrate users tend to consume less than flower smokers as they reach a satisfactory “high” at a much quicker rate. With that, we need more research to determine if even high potencies of cannabis products leads to memory issues.