Summary: Researchers found that modern high-potency cannabis products do not appear to impair decision-making in experienced users but do produce specific memory effects, including reduced free recall, impaired source memory, and increased false memories.
Source: Washington State University
Researchers at Washington State University used videoconferencing to study the real-world effects of high-potency cannabis products—specifically the types of flower and concentrates that consumers actually buy and use.
Published in Scientific Reports, the study observed experienced cannabis users over Zoom as they consumed high-potency cannabis flower or vaped concentrates purchased from legal dispensaries in Washington state. After consumption, participants completed a battery of cognitive tests administered remotely to measure everyday memory and decision-making.
Overall, the study found no measurable effects on a range of decision-making tasks, including risk perception and confidence in knowledge, when compared with a sober control group. However, specific aspects of memory were affected: free recall, source memory, and susceptibility to false memories showed notable impairments among cannabis users in this sample.
This research addresses a gap in the literature by focusing on products that often exceed 10% tetrahydrocannabinol (THC), the main psychoactive compound in cannabis. Many modern cannabis concentrates can contain THC levels far above what earlier laboratory studies typically examined. This project is one of the few to directly evaluate the acute effects of high-THC concentrates on everyday cognition.
Lead researcher Carrie Cuttler, a psychologist at Washington State University, noted that federal restrictions historically prevented researchers from studying high-potency cannabis. Prior studies were usually limited to low-potency whole-plant material supplied through federal channels. By designing a remote study in which participants procured and consumed their own legally purchased products at home while being observed over video, the team complied with federal guidelines while examining real-world products.
Participants were not reimbursed for product purchases; instead, they received compensation for their time in the form of gift cards. All 80 participants were over age 21, regular cannabis users, and reported no prior adverse reactions such as panic attacks. The study received clearance from the university’s legal and ethical review offices.
The sample was randomly assigned to one of four groups: two groups used high-potency cannabis flower containing 20% or more THC (one of these flower groups included cannabidiol, CBD, and the other did not), a third group vaped concentrates containing at least 60% THC plus CBD, and a fourth group remained sober as a control.
Across the cannabis-using groups there was no detectable impairment on several decision-making measures, including tests of risky choice framing, resistance to sunk costs, and calibration of confidence. Some forms of memory were also unaffected: participants performed similarly to controls on prospective memory (remembering to carry out future tasks) and temporal order memory (recalling the sequence of events).
Nevertheless, the researchers identified specific memory vulnerabilities. Participants who smoked high-potency flower that contained CBD showed reduced performance on verbal free recall tasks, remembering fewer words and images than the sober group. This result contrasts with a limited body of prior work that hinted CBD might have protective effects on memory.
Groups that used high-potency flower without CBD and those who vaped concentrates performed worse on source memory measures, meaning they had more difficulty identifying how or where information had been presented previously. All three cannabis-using groups were more likely to report false memories when presented with novel items—indicating a higher susceptibility to incorrectly recognizing items that had not been shown before.
An unexpected finding was that users who vaped high-potency concentrates performed similarly to those who smoked flower, despite the concentrates’ much higher THC content. The authors suggest this may reflect self-titration: users adjust how much they inhale to achieve a desired level of intoxication, so concentrate users may consume smaller amounts to match the effect of flower.
Cuttler emphasized that these results are not definitive but offer cautious reassurance about concentrates: while certain memory functions were affected, concentrates did not appear to magnify harm relative to high-potency flower in this group of experienced users. She called for more research on widely available high-potency products to draw firmer conclusions.
About this memory research news
Source: Washington State University
Contact: Carrie Cuttler, Washington State University
Image: The image is in the public domain
Original Research: Open access. “Acute effects of high-potency cannabis flower and cannabis concentrates on everyday life memory and decision making” by Carrie Cuttler, Emily M. LaFrance & Amanda Stueber. Scientific Reports
Abstract
Acute effects of high-potency cannabis flower and cannabis concentrates on everyday life memory and decision making
State-level legalization has increased public access to high-potency cannabis flower and concentrates, but federal restrictions have limited researchers’ access to the lower-potency whole-plant cannabis typically used in laboratory studies. This study used a remote, observational design to assess the acute cognitive effects of contemporary high-potency cannabis products.
Eighty regular cannabis users were randomly assigned to remain sober or to purchase and use one of three high-potency products: high-potency flower without CBD (≥ 20% THC), high-potency flower with CBD (≥ 20% THC), or high-potency concentrates with CBD (≥ 60% THC). Participants were observed over videoconference while consuming their product or remaining sober and then completed assessments of everyday memory (prospective, source, temporal order, and false memory) and decision making (risky choice framing, consistency in risk perception, resistance to sunk cost, and confidence calibration).
Results showed that high-potency flower containing CBD impaired free recall; high-potency flower without CBD and concentrates impaired source memory; and all three products increased susceptibility to false memories. CBD did not consistently offset memory impairments, and concentrate users appeared to self-titrate to levels of intoxication and impairment comparable to flower users.