Daily cannabis users show tolerance to some acute cognitive effects but not all
Occasional cannabis users showed slowed reaction time and impaired memory after smoking, but daily users showed tolerance to these effects while still taking longer on a driving-related decision task.
Quick Facts
What This Study Found
Occasional users showed significant decrements in reaction time and short-term memory after smoking cannabis. Daily users did not show these impairments (consistent with tolerance) but did take more time on a gap acceptance driving task, though their accuracy remained unchanged.
Key Numbers
Occasional users: n=23. Daily users: n=31. Non-users: n=32. Ages 25-45. THC concentration: 15-30%. Testing occurred approximately 60 minutes after smoking. Daily users took more time on gap acceptance but maintained accuracy.
How They Did This
Participants aged 25-45 completed an iPad-based test battery before and 60 minutes after smoking cannabis. Three groups compared: occasional users (n=23), daily users (n=31), and non-users (n=32). Cannabis was self-supplied flower with 15-30% THC, self-administered ad libitum.
Why This Research Matters
Understanding how tolerance affects cannabis impairment is critical for assessing driving safety and workplace policies. This study suggests daily users develop tolerance to some cognitive effects but may still show subtle changes in real-world decision tasks.
The Bigger Picture
Cannabis impairment testing is a major policy challenge because tolerance makes effects highly variable across users. This study supports the idea that frequent users are less acutely impaired on some measures but still show changes on tasks that mimic real-world driving decisions.
What This Study Doesn't Tell Us
Small sample sizes per group. Self-administered, self-supplied cannabis means doses varied. Only one time point (60 minutes) measured. iPad-based tests may not fully capture real-world driving complexity. No blood THC levels reported.
Questions This Raises
- ?Does the daily users finding on gap acceptance (slower but equally accurate) represent impairment or a deliberate compensation strategy?
- ?Would tolerance findings hold at higher THC doses?
- ?How long do these acute effects last in occasional versus daily users?
Trust & Context
- Key Stat:
- Daily users showed tolerance to reaction time and memory effects
- Evidence Grade:
- Controlled experimental design with appropriate comparison groups, though limited by small sample sizes, self-dosed cannabis, and single-timepoint assessment.
- Study Age:
- Published in 2024 in Journal of Cannabis Research.
- Original Title:
- Effects of acute cannabis inhalation on reaction time, decision-making, and memory using a tablet-based application.
- Published In:
- Journal of cannabis research, 6(1), 3 (2024)
- Authors:
- Brooks-Russell, Ashley(20), Wrobel, Julia(9), Brown, Tim(4), Bidwell, L Cinnamon, Wang, George Sam, Steinhart, Benjamin, Dooley, Gregory, Kosnett, Michael J
- Database ID:
- RTHC-05163
Evidence Hierarchy
Frequently Asked Questions
Do daily cannabis users develop tolerance to impairment?
This study found daily users showed tolerance to acute effects on reaction time and short-term memory. However, they still took longer on a driving-related gap acceptance task, suggesting tolerance may not fully protect against all forms of impairment.
Were daily users more accurate on the driving task despite being slower?
Yes. Daily users took more time to complete the gap acceptance task after smoking but did not make more errors, suggesting they may have prioritized accuracy over speed.
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Cite This Study
https://rethinkthc.com/research/RTHC-05163APA
Brooks-Russell, Ashley; Wrobel, Julia; Brown, Tim; Bidwell, L Cinnamon; Wang, George Sam; Steinhart, Benjamin; Dooley, Gregory; Kosnett, Michael J. (2024). Effects of acute cannabis inhalation on reaction time, decision-making, and memory using a tablet-based application.. Journal of cannabis research, 6(1), 3. https://doi.org/10.1186/s42238-024-00215-1
MLA
Brooks-Russell, Ashley, et al. "Effects of acute cannabis inhalation on reaction time, decision-making, and memory using a tablet-based application.." Journal of cannabis research, 2024. https://doi.org/10.1186/s42238-024-00215-1
RethinkTHC
RethinkTHC Research Database. "Effects of acute cannabis inhalation on reaction time, decis..." RTHC-05163. Retrieved from https://rethinkthc.com/research/brooks-russell-2024-effects-of-acute-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.