Researchers are using a video conferencing app to study the memory effects of highly potent cannabis

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Even before the pandemic made Zoom ubiquitous, Washington State University researchers used the video conferencing app to study a type of cannabis that has been little explored: the type that people actually use.

For the study, published in Scientific Reports, researchers used Zoom to monitor cannabis users while they smoked high potency cannabis flowers or vaporized concentrates they had bought themselves at cannabis dispensaries in Washington state, where recreational cannabis use is legal. They then gave the subjects a series of cognitive tests.

The researchers found no effect on user performance on decision tests compared to a sober control group, but found some memory impairments 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 looking at cannabis that contains much more than 10% tetrahydrocannabinol (THC), the plant’s main psychoactive ingredient. This is only the second known study that examines the effects of cannabis concentrates.

Government restrictions on researchers simply made it impossible to study the acute effects of these highly potent products. The general population in states where cannabis is legal have very easy access to a wide range of highly potent cannabis products, including extremely potent cannabis concentrates that can exceed 90% THC, and we have limited ourselves to examining the entire plant with below 10% THC. “

Carrie Cuttler, Senior Researcher and Psychologist, WSU

While 19 states and Washington DC have legalized recreational cannabis, the US federal government still classifies it as a List 1 drug, meaning it has high potential for abuse and no medicinal benefit.

Until recently, researchers interested in cannabis were limited to the use of low potency plants of around 6% THC supplied by the National Institute of Drug Abuse. In June, the US Drug Enforcement Administration announced that it may allow some companies to grow cannabis for research purposes.

For this study, which began in 2018, Cuttler and her colleagues found a way to study the effects of highly potent cannabis while complying with federal guidelines. Study participants bought their own products and used them at home. They were never in a federally owned laboratory, and the researchers never handled the cannabis themselves.

The participants were not reimbursed for their purchases. Instead, they were compensated for their time with Amazon gift cards. All participants were over 21 and experienced cannabis users who did not report any negative reactions to cannabis such as panic attacks in the past. The method of the study was cleared by the WSU division of the attorney general and the university’s research ethics committee.

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

For all cannabis user groups, the researchers found no effects on a range of decision tests, including risk perception and confidence in knowledge. In some memory tests, there were also no significant differences between the cannabis user and the fasted group, including prospective memory, the ability to remember to do things at a later point in time, such as making an appointment. The participants who used cannabis also did well for memory of temporal order, the ability to remember the sequence of previous events.

However, the groups who smoked cannabis flowers with CBD fared worse on verbal free reminders – they were unable to remember as many words or pictures they were shown compared to the sober group. This finding contrasted with a small number of previous studies that suggested that CBD might have protective effects on memory. The groups who consumed cannabis without CBD and the group who consumed concentrates performed worse on source memory, meaning they were able to distinguish the way previously learned information was presented.

Finally, all three cannabis-using groups did badly on a false memory test – if they were given a new word and asked if it had been presented before, they were more likely to say it was when it wasn’t.

There was also an unexpected finding: people who vaped the highly potent concentrates containing more than 60% THC performed similarly to those who smoked cannabis flowers. This could be because they had a tendency to titrate themselves – they consumed less of the drug in order to achieve similar levels of intoxication and impairment as the people who smoked the less potent cannabis flower.

Cuttler said this gives cause for cautious optimism about the under-studied but widely used concentrates.

“There has been a lot of speculation that these really potent cannabis concentrates might increase the harmful effects, but there has been almost no research on cannabis concentrates that are freely available to the people,” said Cuttler. “I’d like to see a lot more research before we get to a general conclusion, but it’s encouraging to see that the concentrates didn’t add to the harm.”

Source:

Washington State University

Journal reference:

Cuttler, C., et al. (2021) Acute effects of highly potent cannabis flowers and cannabis focus on everyday memory and decision-making. Scientific reports. doi.org/10.1038/s41598-021-93198-5.