Mapping the acute effects of cannabis on multiple memory domains: A randomized, double-blind, placebo-controlled study.
Carrie Cuttler, Ryan J Mclaughlin
Journal of Psychopharmacology March 1, 2026 DOI: 10.1177/02698811261416079 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Placebo-controlled Double-blind Preregistered Peer reviewed |
|---|---|
| Sample size | 120 |
| Population | Cannabis-using participants |
| Dose | 0 mg, 20 mg, or 40 mg THC |
| Topics | Cannabis |
| Keywords | False memory Prospective memory Source memory Temporal order memory |
| Registration | NCT05488509 |
| Key findings | Acute cannabis use broadly impairs most domains of memory, including prospective and temporal order memory, with no significant difference between moderate and high doses. |
Abstract
One of the most robust acute effects of cannabis is impaired memory. Although memory is not a unitary construct, most cannabis research has focused on verbal memory. Less is known about its effects on more ecologically valid domains of memory, such as prospective and temporal order memory. We conducted a randomized, double-blind, placebo-controlled study to map out which aspects of memory are impaired following acute cannabis use. Cannabis-using participants (N = 120) were randomly assigned to vaporize flower containing 0 mg Δ-9-tetrahydrocannbinol (THC; placebo), 20 mg THC (moderate dose) or 40 mg THC (high dose) before completing a battery of memory tests, including tests of verbal memory (immediate, delayed, short-term, working), visuospatial memory (immediate, delayed, short-term, working), prospective memory (event-cued, time-cued), source memory, false memory, episodic content memory, and temporal order memory. Relative to placebo, cannabis increased susceptibility to false memories and detrimentally impacted verbal memory (immediate, delayed, working), visuospatial memory (immediate, delayed), event-cued prospective memory, source memory, and temporal order memory. There were no significant differences between the moderate and high dose groups. This is the first study to detect acute effects of cannabis on prospective memory and temporal order memory, which is important because these tests better reflect everyday memory and predict daily functioning. Collectively, these results indicate that acute cannabis use has broad detrimental effects on most domains of memory rather than selectively impairing a limited number of these domains. The study was pre-registered on clinicaltrials.gov (#NCT05488509) at https://clinicaltrials.gov/study/NCT05488509.
Comparable studies
Other randomized controlled trials on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Healthy participants | 2012 | Randomized controlled trial | n = 48 |
| Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing Healthy, English-native, right-handed men who had used cannabis 15 times or less in... | 2009 | Double-blind, randomized, placebo-controlled crossover trial | n = 15 |
| Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Healthy male subjects | 2012 | Randomized controlled trial | n = 16 |
| Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol Healthy, native English-speaking, right-handed men of white race/ethnicity who had used... | 2009 | Randomized controlled trial | n = 15 |
| Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition Healthy volunteers with a history of light cannabis use | 2019 | Randomized, double-blind, within-subjects crossover | n = 14 |
Citations in the library
Cites 9
- Cannabis increases susceptibility to false memory Proceedings of the National Academy of Sciences February 10, 2020
- Psychoactive drugs and false memory: comparison of dextroamphetamine and delta-9-tetrahydrocannabinol on false recognition Psychopharmacology 2012
- False memory formation in cannabis users: a field study Psychopharmacology June 27, 2019
- Δ9-Tetrahydrocannabinol (THC) impairs visual working memory performance: a randomized crossover trial. Neuropsychopharmacology October 1, 2020
- Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: a systematic meta-review of meta-analyses. Addiction January 19, 2022
and 4 more in the library