Cannabis concentrates impaired movement speed and balance in frequent users, with effects lasting at least an hour
Among 65 frequent concentrate users, dabbing impaired arm speed and balance immediately after use, with arm speed still impaired at 1 hour. Motor impairment was poorly correlated with blood THC levels.
Quick Facts
What This Study Found
Arm speed slowed immediately and remained impaired at 1 hour post-use. Leg speed slowed at 1 hour. Balance decreased immediately but recovered by 1 hour. These effects did not differ between sexes, and acute THC blood level changes were minimally correlated with balance impairment.
Key Numbers
65 participants. THC potency up to 90% in concentrates. Arm speed impaired at both post-use timepoints (p<0.05). Leg speed impaired at 1 hour (p=0.033). Balance impaired immediately (eyes open p=0.017, eyes closed p=0.013) but recovered at 1 hour.
How They Did This
Observational study of 65 experienced concentrate users (46% female, average 17 days/month use) assessed in a mobile lab before, immediately after, and 1 hour after ad-libitum concentrate use. Smartphone sensors measured motor performance. Venous blood THC was measured at each timepoint.
Why This Research Matters
Cannabis concentrates with up to 90% THC are increasingly popular, yet this is one of the first studies to measure motor impairment specifically from concentrate use, relevant to driving and workplace safety.
The Bigger Picture
The poor correlation between blood THC levels and motor impairment challenges the use of blood THC as a proxy for impairment, suggesting that field sobriety-type assessments may be more useful for detecting cannabis-related impairment.
What This Study Doesn't Tell Us
Naturalistic design without controlled dosing. Frequent users may have partial tolerance. The smartphone-based assessment, while novel, is not a validated clinical tool. No placebo control.
Questions This Raises
- ?Are concentrate users at greater driving risk than flower users?
- ?Why does blood THC correlate poorly with motor impairment?
- ?Would infrequent users show more severe impairment?
Trust & Context
- Key Stat:
- Motor impairment lasted 1+ hour and was uncorrelated with blood THC
- Evidence Grade:
- Moderate: naturalistic design with objective measures, though lacking placebo control and standardized dosing.
- Study Age:
- Published in 2020 in Frontiers in Psychiatry.
- Original Title:
- Acute Effects of Cannabis Concentrate on Motor Control and Speed: Smartphone-Based Mobile Assessment.
- Published In:
- Frontiers in psychiatry, 11, 623672 (2020)
- Authors:
- Hitchcock, Leah N, Tracy, Brian L, Bryan, Angela D(19), Hutchison, Kent E, Bidwell, L Cinnamon
- Database ID:
- RTHC-02612
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
How long was motor impairment detected?
Arm movement speed remained impaired at 1 hour after use. Balance was impaired immediately but recovered by 1 hour. The study only measured up to 1 hour, so longer-lasting effects cannot be ruled out.
Why didn't blood THC predict impairment?
The researchers found minimal correlation between changes in blood THC levels and changes in balance performance, suggesting that blood THC is not a reliable indicator of how impaired someone actually is.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02612APA
Hitchcock, Leah N; Tracy, Brian L; Bryan, Angela D; Hutchison, Kent E; Bidwell, L Cinnamon. (2020). Acute Effects of Cannabis Concentrate on Motor Control and Speed: Smartphone-Based Mobile Assessment.. Frontiers in psychiatry, 11, 623672. https://doi.org/10.3389/fpsyt.2020.623672
MLA
Hitchcock, Leah N, et al. "Acute Effects of Cannabis Concentrate on Motor Control and Speed: Smartphone-Based Mobile Assessment.." Frontiers in psychiatry, 2020. https://doi.org/10.3389/fpsyt.2020.623672
RethinkTHC
RethinkTHC Research Database. "Acute Effects of Cannabis Concentrate on Motor Control and S..." RTHC-02612. Retrieved from https://rethinkthc.com/research/hitchcock-2020-acute-effects-of-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.