In a naturalistic lab study, 22 regular cannabis users who consumed their usual edibles (averaging 7.3 mg THC) showed impaired verbal learning and memory but no effects on executive function, visual attention, or trail-making performance, with blood THC levels unrelated to cognitive outcomes.
People who use cannabis edibles and want to understand cognitive effects at typical consumer doses.
Verbal memory impaired but trail-making and visual attention unaffected at 7.3 mg THC edible dose
What the researchers found
At 150 minutes after consuming a cannabis edible averaging 7.3 mg THC, participants showed decreased performance on two verbal free recall measures. No effects were found on the useful field of view test or trail making test. Significant subjective intoxication was reported. Blood THC was not correlated with any cognitive outcomes.
Why it matters
Edible cannabis use is rising rapidly, yet almost all cognitive research has focused on smoked cannabis. This study provides rare data on how edibles at typical consumer doses affect thinking, finding a narrower cognitive impact than typically seen with smoking.
The numbers in context
22 participants. Mean edible THC dose: 7.3 +/- 2.9 mg. Cognitive testing at 150 and 270 minutes. Two verbal free recall measures impaired at 150 minutes. Trail making and useful field of view unaffected. Blood THC did not correlate with any cognitive outcome.
How the study worked
Observational study where 22 participants consumed their own legally sourced cannabis edibles in the lab. Cognitive testing (verbal free recall, trail making, useful field of view) and subjective experience measures were administered at 150 and 270 minutes post-ingestion. Blood THC and metabolites were measured and correlated with cognitive outcomes.
What this study cannot tell us
Very small sample (n=22) of regular users who may have tolerance. Naturalistic dosing means no placebo control. Participants knew they were taking cannabis, so expectancy effects cannot be ruled out. The relatively low average dose (7.3 mg) may not reflect all consumer patterns.
How to read the evidence
Small observational study (n=22) with naturalistic dosing and no placebo control, though with objective cognitive and blood measures.
When this study was published
Published in 2025.
The bigger picture
The finding that blood THC levels do not predict cognitive performance with edibles mirrors similar findings with smoked cannabis in older adults. This disconnect may reflect the complex pharmacokinetics of oral THC, including first-pass metabolism producing 11-OH-THC (which is more psychoactive), variable absorption rates, and individual differences in metabolism.
Questions still open
- Would higher edible doses affect a broader range of cognitive functions? Does the cognitive impact differ between smoked and edible cannabis at equivalent THC exposure? Why does blood THC fail to predict cognitive effects with oral consumption?
Common questions
Are edibles safer for cognition than smoking cannabis?
Why didn't blood THC predict cognitive effects?
Read the original research
Effects of naturalistic doses of cannabis edibles on cognition and association with blood THC.
Psychopharmacology
Citation
Di Ciano, Patricia; Zhao, Sampson; Kaduri, Pamela; Patel, Siddhi; Bhakta, Kruti; Wickens, Christine M; Chen, Sheng; Le Foll, Bernard; Brands, Bruna. (2025). Effects of naturalistic doses of cannabis edibles on cognition and association with blood THC.. Psychopharmacology. https://doi.org/10.1007/s00213-025-06863-2
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