UW ADAI - Symposium - 2022 - Acute Effects of High Potency Cannabis Flower and Concentrates on Cognition
(September 16, 2022) - Summary

Cannabis and Memory...
[ Event Details ]

A WSU researcher described results of two studies she conducted on cannabis consumption and memory, sharing that her hypothesis on the impacts of concentrates hadn’t been validated.

Here are some observations from the Friday September 16th University of Washington Addictions, Drugs, and Alcohol Institute (UW ADAI) 2022 Symposium on “High-THC Cannabis in Legal Regulated Markets.”

My top 3 takeaways:

  • Cuttler presented “Acute Effects of High Potency Cannabis Flower and Concentrates on Cognition,” her research with subjects who independently purchased cannabis products and consumed them while video conferencing as a workaround to federal restrictions before completing various cognitive tests (audio - 22m, video) 
    • Cuttler established that adults stopping by “one of the hundreds of cannabis dispensaries serving our state…would see that they carry an enormous variety of high potency cannabis products, including cannabis flower that typically exceeds 20% [tetrahydrocannabinol] THC, edibles sold in 10 milligram (mg) doses in our state, tinctures that you can place under your tongue, lotions you can apply to your skin, suppositories that I won't further describe, and cannabis concentrates that I will further describe.” She suggested that “research has focused almost exclusively on the effects of cannabis flower and edibles. There has been an absolute dearth of research examining the effects of all these other products, including cannabis concentrates.”
    • “Now as their name implies cannabis concentrates are a highly concentrated form of the drug,” stated Cuttler, “typically produced using chemical solvents like butane, and the end product is an oil, wax, or resin-like substance.”
      • Such products “typically have over 60% THC, but can also exceed 90% THC,” she continued, reporting that more than “half of cannabis users say they have used concentrates and 13 to 37% report using them on a regular basis.”
      • She pointed to research, Variation in cannabis potency and prices in a newly legal market: evidence from 30 million cannabis sales in Washington state, showing concentrate sales “increased by almost 150% while flower shares in our state showed a slight decrease” in the first 18 months of legal retail in Washington.
        • The study, which was initiated in October 2014, stated that after the nearly 150% increase in concentrates, they comprised 21.2% of the market. Part of this increase may be attributed to limited product choice during the initial months of retail operations before cannabis concentrates became more widely available.
      • The increase in concentrate sales made some people “very concerned because we know that higher doses of cannabis increase the detrimental outcomes of cannabis use so we assume that higher potency versions of the drug will also increase these detrimental outcomes,” said Cuttler. She understood this concern was part of why the symposium had been organized.
    • Study of high concentration cannabis products had been hindered by the plant’s federal Schedule I status, explained Cuttler, as it “imposes numerous legal restrictions and hurdles that have impeded research.”
    • Cuttler reviewed recent THC Lab research with graduate students Emily LaFrance and Aria Petrucci attempting to “examine which aspects of cognition are detrimentally affected by the chronic use of these high potency cannabis products” along with “whether concentrate users would demonstrate objectively worse cognitive test performance than exclusive flower users.” She relayed the “inclusion and exclusion criteria” for her participants, including the type and frequency of cannabis products used, their overall physical health, and they “couldn't be heavy drinkers or smokers.”
      • Cuttler said their study “recruited 98 non-users and 100 cannabis users that met these criteria,” with 46 using cannabis flower only, and “54 reported using both flower and concentrates regularly.”
      • Participants were “well balanced with respect to gender, but…predominantly White and young” with the “average age around 24” though “both groups of cannabis users report[ed] lower levels of education than non-users…there were no other significant group differences, and I statistically control for these differences in education in the upcoming results.” They completed a 90 minute “battery of cognitive tests in the controlled laboratory environment while sober,” she commented, and were asked “to try to remember to rate how difficult they found each test immediately after completing” them. “They were told they wouldn't be reminded to do this, it'd be up to them to do this on their own,” she added, and the same went for requesting “their $50 compensation towards the end of the study.”
      • Cuttler’s study found “both groups of cannabis users performing worse than non-users, and the difference between flower users and concentrate users” wasn’t significant. This pattern continued in a verbal memory test, which she said involved “both the immediate and delayed recall trials of this test” and “the difference between the concentrate and flower users is not significant.” Concentrate consumers did score worse than flower and non-consumers in a “simple episodic recall” test which asked “participants to briefly describe each of the tests that they had to complete at the end of the study,” Cuttler added. Finally, flower consumers scored worst at “the incidental recall trial of the digit symbol substitution test…and now the concentrate users are not significantly different from either of the other two groups.”
      • Her study found “no significant effects of regular use of high potency flower or concentrates on measures of visual spatial memory, temporal order memory, source memory, working memory, or three different measures of executive functioning.” Cuttler also believed this to be “the first study to attempt to examine the chronic effects of cannabis on either temporal order memory or source memory.” And “most critically, we found no significant differences in the performance of the groups who reported the exclusive use of flower relative to the group who reported using both flower and concentrates. Thereby providing no real evidence for the notion that regular use of concentrates is associated with worse cognitive outcomes, than exclusive use of flower,” she explained.
    • LaFrance and graduate student Amanda Stuber had joined Cuttler in another research effort “to examine the acute effects of high potency cannabis, which we defined as having at least 20% THC, on prospective, source, false, and temporal order memory as well as non-normative decision making.” This involved a comparison of “cannabis concentrates to cannabis flower and we also wanted to compare the acute effects of cannabis flower with CBD, to flower without CBD, to see if it actually might be protective,” she stated.
      • They had avoided “all of the legal restrictions on acute cannabis research by having participants purchase and administer their own cannabis in their own environment off federal property while we simply observe them over Zoom video chat,” which Cuttler said amounted to “an observational field experiment.” She stressed that she and her research team “didn't purchase the drug. I didn't administer. I didn't even touch the drug. We just observed [a federally] illegal act.” Cuttler said participants were “randomly assigned to purchase and use one of three different product types” and researchers “compensated participants for their time, but not their cannabis purchase, using Amazon gift cards because at least as of today, you can't buy cannabis on Amazon.”
        • The preparation section of the study elaborates that “Those in the three cannabis-using groups were informed that we are interested in studying the effects of specific products and were sent a list of products available at local recreational cannabis dispensaries that met criteria for the group to which they were assigned (e.g., participants randomly assigned to the THC flower group were emailed a list of pre-rolled joints with ≥ 20% THC and 0% CBD available at local dispensaries). Prior to testing, participants in the cannabis-using groups purchased a product off the list using their own funds.”
        • Consumption methodology stipulated that “Participants in the three cannabis-using groups were asked to show the researcher the cannabis product they purchased for the study. The brand, strain, and cannabinoid content (%THC and %CBD) were recorded. The vast majority of participants used the list they were sent to purchase the product-type to which they had been randomly assigned to use.”
      • She briefly addressed participant criteria of being “very healthy, [they] couldn't use other drugs, couldn't be heavy drinkers or smokers, couldn't be breastfeeding or pregnant” and “had to report that they had never previously experienced any adverse events with cannabis” and had previously consumed “both concentrates and flower.” 80 people were found that fit this standard, conveyed Cuttler, with 20 being assigned to flower, concentrates, and products containing THC and CBD categories, along with “a sober control group.” On the day of the tests, the “average period of abstinence” for subjects who would consume cannabis products on camera “was closer to 24 hours.”
      • For cannabis products containing CBD, they required at least 0.7% of the cannabinoid. Although “we initially aimed for way higher level” of the compounds, “it proved exceptionally difficult to find in such high potency flower,” she acknowledged. The researchers “recorded the number of puffs participants took and we time the durations of their inhalations and holds, and we found that participants randomly assigned to use an extremely high potency concentrate took significantly fewer puffs than those smoking flower joints,” Cuttler said. She reported this enabled subjects to achieve the same “subjective high as those inhaling high potency flower…with no significant differences in the intoxication ratings of any of the three cannabis used in groups at any time.”
      • There “was a medium-sized effect with the participants who smoked the joint containing both THC and CBD recalling significantly fewer pictures than the control group,” she commented, and a source memory evaluation showed “THC flower and concentrate groups had worse source memory for pictures.” A false memory test described by Cuttler “found a medium size affected group on free recall with participants who smoked a joint containing both THC and CBD once again having worse free recall” and “all three cannabis using groups had more false memories…relative to the sober control group.” She told attendees “we found no significant effects” on “two tests of prospective memory, a couple measures of temporal order memory, and four measures of non-normative decision making” cautioning that “we might have been underpowered to detect some of these effects.” Cuttler concluded that their tests ”found no significant differences between the performance of those who are randomly assigned to use cannabis flower relative to those who were assigned to use a concentrate.” She further speculated this “failure to detect effects on these domains of cognition may pertain to our use of highly experienced cannabis users” as “it's apparent that some people will habituate to some of the effects of cannabis over time.”
      • The research offered no evidence “that CBD offset the detrimental effects of THC. In fact, the group that smoked the joint containing both THC and CBD had more memory impairments than the group that smoked just the THC flower joint,” Cuttler indicated. She expressed some surprise that “one of the most important and encouraging findings from these studies is the lack of evidence that cannabis concentrates are more detrimental to cognition than flower. This was not my hypothesis.” She claimed there had been “a lot of speculation that concentrates would magnify the harms of cannabis. My studies instead indicate that neither the chronic use of concentrates, nor acute intoxication on concentrates is worse for cognition than flower” as consumers chose to “self-titrate their use of extremely high potency concentrates.”
  • Cuttler responded to several attendee questions related to cannabis dosage, compensatory effects, studies of specific cultivars, and THC tolerance.
    • “High potency consumers seem to self-titrate. Were you able to estimate the actual THC dose by the puff/inhale/hold times in any way?” (audio - 1m, video)
      • Cuttler said they hadn’t been estimating that as it was a “hard thing to catch here in such a naturalistic setting over Zoom.”
      • Prior research indicated “there was little evidence that response to marijuana was a function of breathhold duration.”
    • “How much do you think your findings on acute memory effects were due to compensatory behavior in consumption of the different forms of cannabis?” (audio - 1m, video)
    • “Most of the cannabis research has been focused on THC concentration, has there been any significant studies on how different cannabis strains affect different cognitive effects and lineages?” (audio - 1m, video)
      • Cuttler replied that she’d been interested in addressing the “common folklore propagated by budtenders” that “everything is a hybrid nowaday.” Her study had focused on levels of THC and CBD, but she hoped to “do research on some of the minor phytocannabinoids. We're doing a study right now looking at the effects of cannabigerol (CBG) because we do think that some of these are going to produce different effects.” She doubted that “we're going to see much of this on cognition specifically” as she was certain it was “THC that is implicated in the cognitively impairing effects of cannabis.”
    • “The [Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition] DSM-5 diagnostic criteria for cannabis use disorder (CUD) has to do with increased…THC tolerance and dependence. Is there any inclination…or intuition that the use of high potency products indicates higher THC tolerance and may predict some level of dependency?” (audio - 2m, video)
    • Cuttler believed that “higher potency versions of the drug are more likely to increase” risks of dependency, and that those with CUD would be “more likely to use higher potency versions of the drug.” She felt this made any “cross-sectional survey looking at this and linking the two is problematic because there’s a huge chicken-and-egg problem here, and probably a bi-directional relationship.”

Information Set