Mobile phone cognitive tests detected slight impairment from marijuana in young adults' daily lives
Young adults who reported feeling more high from marijuana performed slightly worse on mobile phone cognitive tests in their natural environments, with slower reaction times and fewer correct responses.
Quick Facts
What This Study Found
Higher subjective marijuana ratings were associated with slower reaction times on all three mobile tasks (Flowers: B=2.29, p=.008; Stroop: B=2.74, p=.01; DSST: B=3.08, p=.03) and fewer correct responses on two of three tasks. Distraction moderated the association for some tasks.
Key Numbers
60 participants; 2,703 data points; 451 (16.7%) marijuana use reports. Significant slowing on all 3 tasks. Significant accuracy decreases on 2 of 3 tasks. Effects described as "slight" decreases in cognitive functioning.
How They Did This
Observational study of 60 young adults (aged 18-25) who used marijuana at least twice weekly. Mobile cognitive tasks (visuospatial working memory, attentional bias, processing speed) delivered 3 times daily plus self-initiated during marijuana use, for up to 30 days. 2,703 data points collected including 451 marijuana use reports.
Why This Research Matters
Traditional lab studies of cannabis impairment may not capture real-world effects. Mobile assessment in natural environments provides ecologically valid data on how marijuana affects daily cognitive functioning.
The Bigger Picture
Real-time mobile cognitive monitoring could eventually provide immediate feedback to cannabis users about their functional impairment, helping them make decisions about driving or other activities.
What This Study Doesn't Tell Us
Small sample; self-reported marijuana ratings; no objective THC measurement; participants were regular users who may have developed tolerance; "slight" effects may not be clinically meaningful.
Questions This Raises
- ?Could real-time cognitive monitoring apps serve as practical impairment self-checks?
- ?Would effects be larger in less frequent users?
Trust & Context
- Key Stat:
- Higher subjective marijuana high linked to slower reaction times on all 3 mobile tasks
- Evidence Grade:
- Observational study with ecological validity but no controlled dosing or objective impairment measures.
- Study Age:
- Published in 2020.
- Original Title:
- Mobile Assessment of Acute Effects of Marijuana on Cognitive Functioning in Young Adults: Observational Study.
- Published In:
- JMIR mHealth and uHealth, 8(3), e16240 (2020)
- Authors:
- Chung, Tammy(3), Bae, Sang Won, Mun, Eun-Young, Suffoletto, Brian, Nishiyama, Yuuki, Jang, Serim, Dey, Anind K
- Database ID:
- RTHC-02467
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
How impaired were people who felt high?
The effects were described as "slight" decreases in cognitive functioning. Higher subjective ratings of being high were associated with a few milliseconds slower reaction time and slightly fewer correct answers. These are statistically significant but may not represent major functional impairment.
Could a phone app detect marijuana impairment?
This study provides proof-of-concept that mobile cognitive tasks can detect acute marijuana effects in real-world settings. However, the effects were small and there was considerable overlap between impaired and non-impaired performance, so practical application would need further development.
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Cite This Study
https://rethinkthc.com/research/RTHC-02467APA
Chung, Tammy; Bae, Sang Won; Mun, Eun-Young; Suffoletto, Brian; Nishiyama, Yuuki; Jang, Serim; Dey, Anind K. (2020). Mobile Assessment of Acute Effects of Marijuana on Cognitive Functioning in Young Adults: Observational Study.. JMIR mHealth and uHealth, 8(3), e16240. https://doi.org/10.2196/16240
MLA
Chung, Tammy, et al. "Mobile Assessment of Acute Effects of Marijuana on Cognitive Functioning in Young Adults: Observational Study.." JMIR mHealth and uHealth, 2020. https://doi.org/10.2196/16240
RethinkTHC
RethinkTHC Research Database. "Mobile Assessment of Acute Effects of Marijuana on Cognitive..." RTHC-02467. Retrieved from https://rethinkthc.com/research/chung-2020-mobile-assessment-of-acute
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.