Meda Shashwath A, Stevens Michael C, Boer Erwin R, Pittman Brian, Gueorguieva Ralitza, Huestis Marilyn A, Pearlson Godfrey D
Olin Neuropsychiatry Research Center, Institute of Living at Hartford Healthcare, Hartford, CT, USA.
Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
J Psychopharmacol. 2025 Apr;39(4):364-372. doi: 10.1177/02698811251324379. Epub 2025 Mar 12.
In the context of increasing cannabis use, understanding how cannabis affects specific driving behaviors is crucial in mitigating risks and ensuring road safety.
The current study included 38 adults aged 18-40 years, administered a single 0.5 g acute dose of vaporized cannabis (5.9% Tetrahydrocannabinol (THC), 13% THC or placebo) in a randomized, within-subject, double-blind, counterbalanced design. Throughout each of the three, 8-h assessment days, at 4 time points, participants underwent simulated driving tests, including lane-keeping, car following, and overtaking tasks, capturing 19 behavioral metrics. An SPSS linear mixed model assessed the main effects of dose, time, and dose × time.
During lane-keeping, participants exhibited reduced steering reversal rates up to 5.5 h following 13% THC and 3.5 h for 5.9%. For car following, participants showed reduced pedal peak-to-peak deviation and reversal rates, persisting for 1-3 h post-dose (only at 13% THC). During overtaking, following 13% THC, subjects demonstrated a shorter median gap to passed cars, lower time-to-potential collision, and more time in the oncoming lane. Drug effects on driving metrics improved gradually, to varying degrees over time. Approximately 66% of participants reported willingness to drive, despite subjective awareness of being impaired and objectively worse driving performance.
Our study reveals for the first time long-lasting cannabis-induced impairments across multiple driving behaviors, that extend beyond the typical 3-h window explored in most previous research. The observed discrepancy between participants' willingness to drive and their actual impairment highlights an important public safety concern. In addition, the lack of correlation between cannabinoid metabolite concentrations and driving performance challenges the reliability of blood THC levels as impairment indicators, emphasizing the need for a multifaceted approach to assessing cannabis-impaired driving risk.
在大麻使用日益增加的背景下，了解大麻如何影响特定驾驶行为对于降低风险和确保道路安全至关重要。
本研究纳入了38名年龄在18至40岁之间的成年人，采用随机、受试者内、双盲、平衡设计，给予单次0.5克的雾化大麻急性剂量（5.9%四氢大麻酚（THC）、13%THC或安慰剂）。在三个为期8小时的评估日中，每个评估日的4个时间点，参与者都要进行模拟驾驶测试，包括车道保持、跟车和超车任务，记录19项行为指标。使用SPSS线性混合模型评估剂量、时间以及剂量×时间的主要影响。
在车道保持过程中，服用13%THC后长达5.5小时以及服用5.9%THC后3.5小时，参与者的转向反转率降低。在跟车过程中，参与者的踏板峰峰值偏差和反转率降低，在给药后持续1至3小时（仅在13%THC时）。在超车过程中，服用13%THC后，受试者与被超越车辆的中位间距缩短，潜在碰撞时间降低，且在对向车道的时间增加。药物对驾驶指标的影响随时间逐渐改善，程度各异。尽管参与者主观意识到自己受到影响且客观驾驶表现更差，但仍有大约66%的参与者表示愿意开车。
我们的研究首次揭示了大麻对多种驾驶行为造成的长期损害，这种损害超出了以往大多数研究所探讨的典型3小时窗口期。参与者驾驶意愿与实际受损情况之间的差异凸显了一个重要的公共安全问题。此外，大麻素代谢物浓度与驾驶表现之间缺乏相关性，这对血液THC水平作为受损指标的可靠性提出了挑战，强调需要采用多方面方法来评估大麻影响下的驾驶风险。
