Behind The Wheel and Under the Influence
[dropcap class=”kp-dropcap”]R[/dropcap]esearchers at the University of California, San Diego (UCSD) are currently conducting a study entitled “A Randomized, Controlled Trial of Cannabis in Healthy Volunteers Evaluating Simulated Driving, Field Performance Tests and Cannabinoid Levels.” Headed by the Co-Director of the Center for Medicinal Cannabis Research, Thomas Marcotte, Ph.D., along with Barth Wilsey M.D., the study addresses questions that concern cannabis consumers, law enforcement and legislators.
After an online application and initial appointment with researchers, those who are chosen to participate will return at a later date and be instructed to smoke cannabis in the same manner as they do in their personal lives. Participants will be given a cannabis joint containing either 5.9 percent of the psychoactive cannabinoid tetrahydrocannabinol (THC), a joint containing 13.4 percent THC, or a placebo that has had all of the THC removed through a solvent extraction process. The subjects will not be told which sample they have received.
Participants will then spend the next seven hours completing five 25-minute driving simulation tests, iPad-based performance assessments, and bodily fluid draws that will be taken before the cannabis is consumed and then again hourly throughout the rest of the day. Regardless of how well they perform in the simulation, participants are not permitted to drive themselves home after the study. They must get a ride with a sober adult, or arrangements will be made for a taxi. In addition to the free joint, participants will be compensated for their time.
Dr. Marcotte explained the study’s purpose to CULTURE. “[The purpose of the study is to determine] the effects of different strengths of cannabis on driving performance,” he said. It will also determine “if impairing, how long does that impairment last?” Additionally, researchers are interested in learning to what degree different aspects of the field sobriety test are sensitive to the impairing effects of cannabis and how to differentiate between those drivers who are, or who are not, impaired by acute use.
The study also seeks to find out if tablet-based cognitive measures serve as useful adjuncts to field sobriety tests, by testing abilities that are most likely to be impaired by cannabis. Marcotte explained how the results will be used. “[The results will] thus inform the public as to when it is, or is not safe to drive after [cannabis] use. Law enforcement will learn more about the effectiveness of components of the field sobriety test for detecting cannabis related impairment, and whether cannabinoid levels from blood, oral fluid or breath help identify time since use, or relate to actual impairment.” He further explained the aims of the study. “[The study] will also provide valuable information to legislators, as they attempt to design laws that establish when individuals should be considered to be driving under the influence. This is particularly important in jurisdictions where cannabis is legal, as well as where individuals may be using cannabis for medical reasons.”
“[The study] will also provide valuable information to legislators, as they attempt to design laws that establish when individuals should be considered to be driving under the influence.”
The study was authorized by the California State Legislature in Assembly Bill 266, the Medical Marijuana Regulation and Safety Act, and began in early 2017. There are currently 100 people enrolled, and researchers are in the process of adding another 80, making it the largest study of its kind in the United States. While they are not targeting any specific demographic, Marcotte said that they are looking for subjects who are not “cannabis naïve.” This should alleviate the concerns of many cannabis consumers who feared that the study would be stacked unfairly with non-cannabis using participants, thus skewing the results and leading to prohibitively strict laws.
The cannabis used in the study is grown at the University of Mississippi, which is funded by the National Institute on Drug Abuse. It is currently the only legal source of cannabis used for research purposes in the United States. The study is slated to conclude in early spring, and Marcotte told CULTURE that he expects the findings to be published in the spring or summer of 2019.
