Effects of Cannabis/Alcohol on Driving Performance and Field Sobriety Tests
试验速览
- 阶段
- 1 期
- 状态
- 撤回
- 主要终点
- Composite Drive Score
研究概览
简要总结
The overarching aim of this study is to examine the impact of acute cannabis and alcohol administration on driving performance, as well as identify methods for detecting driving under the influence of these substances. One-hundred twenty-five healthy volunteers will be randomized into one of 5 conditions; those who receive 1) low dose alcohol and placebo cannabis, 2) low dose alcohol and tetrahydrocannabinol (THC), 3) high dose alcohol and placebo cannabis, 4) placebo alcohol and THC, and 5) double placebo. Cannabis inhaled ad libitum and/or ingested alcohol will take place at the beginning of the day followed by the completion of driving simulations, components of the Drug Recognition Expert (DRE) evaluations, and bodily fluid draws (e.g., blood, oral fluid/saliva, breath) over the subsequent 4 hours after ingestion. The purpose of this study is to determine (1) the impact of Δ9-THC on driving performance with and without concurrent alcohol ingestion (2) the duration of driving impairment in terms of hours from initial use, (3) the relationship between performance on the DRE measures and cannabis/alcohol ingestion, and 4) if saliva or expired air can serve as a useful adjunct to the field for blood sampling.
详细描述
Driving under the influence of alcohol and cannabis presents significant safety risks. In the real world, impairment is usually determined via the standardized field sobriety tests (SFSTs), a series of psychophysiological tests conducted by law enforcement officers. These include the Horizontal Gaze Nystagmus (HGN; eye movements when following the officer's fingers in space), Walk and Turn (WAT; walking nine steps, turning, and walking back), and One Leg Stand (OLS; holding each leg in the air for a designated period of time).
Despite a vast literature documenting impaired driving behavior due to alcohol consumption, much less is known regarding driving under the influence of cannabis, and even less about how the combination of alcohol and cannabis may affect driving behavior. This study will examine whether either, or both, conditions significantly impact performance in a driving simulator, on cognitive measures, and during the comprehensive Drug Recognition Expert evaluations (which includes SFSTs, as well as additional measures).
Alcohol studies. Higher blood alcohol levels (BACs) have been consistently related to impaired driving. BACs greater than .08% have been associated with 5.5 times higher crash risk compared to those without alcohol or drugs. In terms of detecting alcohol-related impairment, SFSTs have consistently been shown to be predictors of a blood alcohol concentration of .08%.
Cannabis studies. Several studies suggest higher doses of whole-blood or plasma delta-9 tetrahydrocannabinol (THC) concentration are associated with increased crash risk and crash culpability. However, attempts to define a cut-off point for blood THC levels have proven to be challenging. Unlike alcohol, for which a level can be reasonably measured using a breathalyzer (and confirmed with a blood test), detection of a cut-off point for intoxication related to THC concentration has eluded scientific verification. Most recently, we did not find any correlation between blood THC concentrations and driving performance. To date, the relationship between SFSTs and cannabis use/impairment have been mixed across studies.
Cannabis and Alcohol. There have been a limited number of studies examining the combination of cannabis and alcohol on driving and/or field sobriety test performance.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Screening
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
Cannabis will be dispensed from the Research Pharmacy. Alcohol will be dispensed by a research staff member who is not involved in any assessments. All assessors, investigators, and participants are blinded to the THC and alcohol content.
入排标准
- 年龄范围
- 21 Years 至 55 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Aged 21 to 55
- •Must be a licensed driver and driven a minimum of 1,000 miles in the past year
- •Experience with cannabis and alcohol
排除标准
- •At the discretion of the examining physician, individuals with significant cardiovascular, hepatic or renal disease, uncontrolled hypertension, and chronic pulmonary disease (eg, asthma, COPD) will be excluded.
- •Unwillingness to abstain from cannabis for 2 days prior to screening and experimental visits
- •Positive pregnancy test
- •A positive result on toxicity screening for cocaine, amphetamines, opiates, and phencyclidine (PCP) will exclude individuals from participation.
- •Unwilling to refrain from driving or operating heavy machinery after consuming study medication.
研究组 & 干预措施
Cannabis, No alcohol
18.16% THC, placebo alcohol
干预措施: Cannabis (Drug)
Cannabis, Low dose alcohol
18.16% THC, .07 breath alcohol concentration
干预措施: Cannabis (Drug)
Placebo cannabis, High dose alcohol
<.1% THC, .10 Breath alcohol concentration
干预措施: Alcohol (Drug)
Placebo
Placebo cannabis and placebo alcohol
干预措施: Cannabis (Drug)
Placebo
Placebo cannabis and placebo alcohol
干预措施: Alcohol (Drug)
Cannabis, No alcohol
18.16% THC, placebo alcohol
干预措施: Alcohol (Drug)
Cannabis, Low dose alcohol
18.16% THC, .07 breath alcohol concentration
干预措施: Alcohol (Drug)
Placebo cannabis, High dose alcohol
<.1% THC, .10 Breath alcohol concentration
干预措施: Cannabis (Drug)
Placebo cannabis, Low dose alcohol
<.1% THC, .07 breath alcohol concentration
干预措施: Cannabis (Drug)
Placebo cannabis, Low dose alcohol
<.1% THC, .07 breath alcohol concentration
干预措施: Alcohol (Drug)
结局指标
主要结局
Composite Drive Score
时间窗: Participants are assessed pre-smoking/drinking, and then approximately 30 minutes, 1 hour 30 minutes, and 3 hours 30 minutes post-smoking
The Composite Drive Score (CDS) is a z-score comprised of key variables from the simulator tasks (SDLP, speed deviation, and task accuracy during the modified Surrogate Reference Task (mSuRT); coherence from the car following task). This outcome reflects the change in CDS from the pre-smoking assessment, at each timepoint. The z-score indicates the number of standard deviations away from the mean from the baseline performance for the entire group. A Z-score of 0 is equal to the mean of a reference population (in this case the pre-smoking performance for the entire group). Higher z-scores at each timepoint indicate worse performance (variables that went in the opposite direction were reflected in order to have all variables have the same direction). When examining the change in Composite Drive Score (this outcome variable), a higher score indicates a decline in performance (e.g., Time 2 minus Time1).
次要结局
- DRE Impairment(Approximately 1.5 hours and 2.5 hours after alcohol/cannabis administration)
- Whole blood THC concentration(Approximately 30 minutes after alcohol/cannabis administration)
- Oral Fluid THC concentration(Approximately 30 minutes after alcohol/cannabis administration)
- Breath THC concentration(Approximately 30 minutes after alcohol/cannabis administration)
研究者
Thomas D. Marcotte, PhD
Professor
University of California, San Diego