New study on high potency cannabis shows effects on memory | WSU Insider


PULLMAN, Washington – Even before the pandemic made Zoom ubiquitous, researchers at Washington State University were using the video conferencing app to research an under-researched type of cannabis: the kind people actually use.

For the study, published in Scientific reports, the researchers observed cannabis users on Zoom as they smoked high-potency cannabis flowers or vaping concentrates that they purchased themselves at cannabis dispensaries in Washington state, where recreational use of cannabis is legal. They then gave the subjects a series of cognitive tests.

The researchers found no impact on user performance on decision-making tests compared to a sober control group, but found memory impairment related to free recall, source memory, and false memories.

While the results are in line with previous research on low potency cannabis, this study is one of the few to investigate cannabis that contains significantly more than 10% tetrahydrocannabinol (THC), the plant’s main psychoactive ingredient. This is only the second known study to examine the effect of cannabis concentrates.

“Due to federal restrictions on researchers, it was simply not possible to study the acute effects of these high potency products,” said Carrie Cuttler, WSU psychologist and principal investigator of the study. “The general population of states where cannabis is legal have very easy access to a wide variety of high potency cannabis products, including extremely potent cannabis concentrates that can exceed 90% THC, and we have limited to studying the whole plant. with less than 10% THC.

While 19 states and Washington DC have legalized recreational cannabis, the US federal government still classifies it as a Schedule 1 drug, implying that it has a high potential for abuse and no medical benefit. Until recently, researchers interested in studying cannabis were limited to using plants with a low potency of around 6% THC provided by the National Institute of Drug Abuse. In June, the U.S. Drug Enforcement Administration said it may allow certain companies to start growing cannabis for research purposes.

For this study, which began in 2018, Cuttler and his colleagues found a way to study the effects of high potency cannabis while following federal guidelines. Study participants bought their own products and used them at home. They have never been in a lab on federal property, and the researchers never handled the cannabis themselves. Participants were not reimbursed for their purchase. Instead, they were paid for their time with Amazon gift cards. All of the participants were over 21 and experienced cannabis users who reported no previous negative reactions to cannabis, such as panic attacks. The study method was approved by the WSU division of the attorney general’s office and the university’s research ethics board.

The 80 participants were divided into four groups: two groups used cannabis flowers with more than 20% THC but one containing cannabidiol (CBD), a non-psychoactive component of cannabis, and the other without CBD. Another group vaporized cannabis concentrates that contain over 60% THC and include CBD. A fourth group remained sober.

For all groups of cannabis users, the researchers found no effect on a range of decision-making tests, including risk perception and knowledge confidence. On a few memory tests, there were also no significant differences between the cannabis consuming and sober groups, including prospective memory, the ability to remember to do things later, such as attending a date. you. Participants who used cannabis also scored well on temporal order memory, the ability to remember the sequence of previous events.

However, the groups who smoked cannabis flowers with CBD performed less well in the free verbal recall tests – they were unable to recall as many words or pictures shown to them in comparison. to the sober group. This finding was contrary to a small number of previous studies indicating that CBD may have a protective effect on memory. The groups who used cannabis without CBD and the group who used concentrates performed worse on a measure of source memory, meaning being able to distinguish how previously learned information was presented.

Finally, all three groups of cannabis users scored poorly on a false memory test – when given a new word and asked if it had already been introduced, they were more likely to answer that it was not.

There was also an unexpected discovery: People who vaped the strong concentrates with more than 60% THC had results comparable to those who smoked cannabis flowers. Perhaps this is because they tended to self-titrate – using less of the drug to achieve a similar level of intoxication and debilitation as people who smoked the less potent cannabis flower.

Cuttler said this prompts cautious optimism about little-studied but widely available concentrates.

“There has been a lot of speculation that these very potent cannabis concentrates could amplify the damaging consequences, but there has been almost no research on cannabis concentrates that are freely available to people,” said Cuttler. “I want to see a lot more research before I come to a general conclusion, but it’s encouraging to see that the concentrates didn’t increase the damage.”

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