Cannabis Consumption and Driving Impairment Assessment on a Closed Course
试验速览
- 阶段
- 2 期
- 状态
- 招募中
- 发起方
- 入组人数
- 300
- 试验地点
- 1
- 主要终点
- Modified Driving Performance Examination (MDPE)
研究概览
简要总结
In a true experiment, roughly 300 volunteer participants will smoke active cannabis, a corresponding placebo, or no substance at all (control). Next, participants will complete a drive test and then be observed by actual California Highway Patrol (CHP) officers who will attempt to classify participants as impaired or unimpaired. CHP Officers will evaluate participants in the context of driving (i.e., while following participants in an actual patrol car), as part of a roadside behavioral assessment (i.e., the Advanced Roadside Impaired Driving Enforcement, or ARIDE, battery, which includes Standardized Field Sobriety Tests, or SFSTs), and as part of a Drug Recognition Expert (DRE) evaluation conducted indoors.
详细描述
The easing of restrictions on the use of cannabis for recreational purposes presents a new challenge for policing of impaired driving, which is to say Driving Under the Influence of Drugs (DUI-D), specifically cannabis. In particular, it is not entirely clear how well the tools used by law enforcement officers to detect driving impairment (e.g., behavioral instruments such as the SFSTs, as included in the ARIDE battery) work for identifying cannabis-induced driving impairment specifically. While these instruments are designed to help officers identify driving impairment in general (irrespective of cause), prior empirical validation work has almost exclusively involved alcohol-induced impairment. This study will be conducted within a realistic, closed-course driving environment and it seeks to validate the same instruments currently used by law enforcement to detect cannabis-induced driving impairment against a second, independent, behavioral standard for driving impairment: a comprehensive driver evaluation adapted from the same set of driver tests that Californians must pass upon application for an original license, or (in certain instances) when referred to the Department of Motor Vehicles (DMV) for evaluation of their ability to safely operate a non-commercial class of motor vehicle (here referred to as the Modified Driver Performance Evaluation or MDPE).
This study seeks to answer the following research questions:
I. How accurately do behavioral assessments used by officers distinguish between drivers impaired by cannabis and drivers not impaired by cannabis?
II. How does cannabis affect real-world (as opposed to simulated) driving performance?
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Other
- 盲法
- Triple (Participant, Investigator, Outcomes Assessor)
盲法说明
Participants are blind to condition assignment, meaning they are not told in advance which version of the procedure they will experience. While those assigned to the true control condition will obviously realize this during the session, remaining participants are not informed whether the cigarette they smoke contains active cannabis or placebo.
Similarly, the experimenters will necessarily become aware of which individuals are in the control conditions, however, they do not know which of the remaining participants are assigned to active cannabis versus placebo conditions (i.e., the active vs. placebo cannabis cigarettes are not labeled as such).
Most importantly, outcome assessors such as the officers and driving evaluators who supply the ratings that comprise the focal dependent variables will be completely blind to experimental condition, so that there is no straightforward means by which experimenter bias could affect data collected for those variables.
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
- •Possessing a valid California driver's license
- •Cannabis use in the past six months
- •Willing and able to abstain from alcohol, cannabis, and other recreational drugs for 24 hours prior to scheduled participation
- •Willing and able to avoid driving and operating heavy machinery for at least four hours after participation
- •Residence within approximately 15 miles of the study site
- •Possessing the capacity to provide informed consent
排除标准
- •Completion of a roadside sobriety test during the previous 12 months
- •Physical or psychological conditions that can be exacerbated by cannabis use, or for which cannabis use is contraindicated
- •Potential presence of Cannabis Use Disorder as assessed by a modified version of the Cannabis Use Disorder Identification Test
- •Potential presence of Substance Use Disorder as assessed by a modified version of the Drug Abuse Screening Test
- •Pregnancy or breastfeeding reported
- •Unwillingness to be transported by taxi
- •Having been convicted of Driving Under the Influence (DUI) within five years prior to scheduled participation
- •Parole or probation status
- •One or more felony convictions on record involving aggressive or dangerous criminal activity
- •Any of the following at the time of the experimental session: breath alcohol content of .01% or greater; positive pregnancy test; cannabis consumption considered unsafe following medical checkup by the study nurse; or driving test behavior considered hazardous by the driving examiner
研究组 & 干预措施
Active Smoked Cannabis
Participants in this arm will smoke an active cannabis cigarette containing 18.16% Δ9-tetrahydrocannabinol (THC). The smoking will occur at each participant's preferred pace, but will be limited to a maximum ten-minute period. While individual doses vary in this type of paradigm (ad libitum dosing), the anticipated dose of THC within the cannabis condition can be approximated by the following formula: (700 mg of cannabis) x [% of cigarette smoked; maximum of 70% (allowing room to hold the cigarette)] x (% THC). Therefore, the maximum dose in this arm is 700 mg x 70% x 18.2% = 89.18 mg of THC. Individual participants will only take part in the study under a single condition and receive the active cannabis once.
Bulk cannabis for this arm will be provided by the National Institute on Drug Abuse Drug Supply Program; cannabis cigarettes will be prepared and prescribed by the Research Pharmacy of the University of California, San Diego.
干预措施: Active smoked cannabis (Drug)
Placebo Smoked Cannabis
Participants in this arm will smoke a placebo cannabis cigarette containing <.01 THC. The smoking will occur at each participant's preferred pace, but will be limited to a maximum ten-minute period. Individual participants will only take part in the study under a single condition and receive the placebo cannabis once.
Bulk placebo for this arm will be provided by the National Institute on Drug Abuse Drug Supply Program; placebo cannabis cigarettes will be prepared and prescribed by the Research Pharmacy of the University of California, San Diego.
干预措施: Placebo smoked cannabis (Drug)
结局指标
主要结局
Modified Driving Performance Examination (MDPE)
时间窗: Conducted an average of 35 minutes after the assigned intervention is completed.
The MDPE driving test, developed for this study, is administered once per participant per experimental session. It occurs after the assigned intervention (i.e., drug administration) and it is primarily scored dichotomously (pass versus fail).
Advanced Roadside Impaired Driving Enforcement (ARIDE) battery
时间窗: Conducted an average of 65 minutes after the assigned intervention is completed.
The ARIDE battery is not a scale but a series of roadside behavioral assessments used by law enforcement officers to help them detect impaired driving: (1) pulse check, (2) Horizontal Gaze Nystagmus or HGN, (3) a test of distinct and sustained nystagmus, (4) vertical nystagmus, (5) lack of convergence test, (6) a check to see if eyes are bloodshot or watery, (7) Modified Romberg Balance Test, (8) Walk and Turn Test or WAT, (9) One Leg Stand Test or OLS, and some additional observations. The ARIDE battery occurs once per participant following the Modified Driving Performance Examination. The ARIDE battery is scored overall as pass versus fail by the officer conducting the test (in real-time).
Drug Recognition Expert (DRE) evaluation
时间窗: Conducted an average of 90 minutes after the assigned intervention is completed.
The DRE evaluation is designed to help law enforcement officers identify whether an individual is generally impaired and, if so, which class of substance caused the impairment. The DRE evaluation occurs once per participant, following the ARIDE battery. It is scored by the officer conducting it in real-time as a judgment about state of impairment (impaired versus unimpaired), and, in the case of impairment, a judgment about the class of substance.
次要结局
- First blood draw (baseline)(Conducted 15 minutes before the assigned intervention.)
- Second blood draw (change from baseline)(Conducted immediately after the assigned intervention is completed.)
- Third blood draw (change from baseline and second blood draw)(Conducted an average of 85 minutes after the assigned intervention is completed.)
研究者
Bayliss J. Camp, PhD
Chief, Research & Development Branch
California Department of Motor Vehicles