Driving under the influence of cannabis is common in patients under medical prescription marijuana in the case of chronic pain, the researchers describe the findings as "worrying".
A study of nearly 800 people who took medical cannabis revealed that more than half of them reported driving within two hours of drinking. About the same proportion of people reported driving "a bit high" and about one in five said they drove "while he was very strong".
"I was particularly interested in understanding how people who use [cannabis] Erin E. Bonar, Ph.D., Center for Addiction of the University of Michigan and Assistant Professor of Psychiatry at the University of Michigan School of Medicine at Ann Arbor, said Medscape Medical News.
"I wanted to see what people are doing [and] Bonar added: "We have found an interesting rate."
A meta-analysis published in 2016 drew attention to the public health risks associated with driving under the influence of cannabis (DUIC), including a potential increase in road accidents.
however, another meta-analysis published last year, it was found that cannabis use was not significantly related to "adverse traffic events", including traffic accidents.
"Although the previous literature on DUIC technology is mixed, the rapidly evolving US cannabis policy deserves more attention for this important public health issue," current researchers write.
"There is an urgent need to better understand the DUIC in order to inform future prevention efforts," they added.
Bonar and his colleagues have recruited participants aged 21 and over who are seeking certification or recertification of marijuana for medical purposes. The 790 patients (mean age, 46 years, 52% male, 81% white) came from three medical cannabis treatment centers in Michigan between February 2014 and June 2015.
Most participants were unemployed (61%) and 32% were receiving disability benefits.
The current study is the first in which people using medical cannabis have been questioned about their behavior, said Bonnar. This is also part of a larger, longer-term study in patients taking marijuana for medical purposes.
"The goal is to track them over time and see what happens to them after getting a card or renewing their card, including health outcomes, mental health outcomes and behaviors," Bonar said. .
The investigators asked questions about cannabis use, for example, in terms of hours of work per day and average amount per week the previous month.
They also asked participants how many times in the last 6 months they had driven "less than two hours after using marijuana," "while it was consuming a little too much marijuana" or "while consuming a lot of marijuana. " Possible answers ranged from "never" to "more than 10 times".
DUIC Majority Report
Nearly three-quarters of participants (73%) reported using cannabis daily or almost daily in the previous 6 months. At the same time, 56% drove within two hours after cannabis use, 51%, a little high, and 21%, while being very high.
Caucasians were more likely to have an IBD within 2 hours or were somewhat higher compared to other participants, indicated logistic regression analysis.
Age also played a role, with younger adults presenting a higher risk of DUIC. In addition, the highest pain scores were associated with lower DUIC probabilities.
"What has interested me the most is not just the number of people who said" Yes, I drove all the way up "or" I drove it. " at the top, but [that] some people did it frequently, "said Bonar.
In the group of people who drove under the influence of cannabis for medical purposes more than 10 times in the previous 6 months, 22% reported having driven at least 2 hours after using cannabis, 19% had drove with a high rate and 7% had driven with very high rates.
Patients who use cannabis for medical purposes may be at particularly high risk of DUIC because of the frequency of their use, the researchers noted.
In addition, 4% of all participants reported a history of arrest against DUIC for life
Although the study focuses on the risks associated with medical cannabis, participants were also asked about consumption of alcohol. One of the goals was to "see if there was an overlap" between DUIC and driving under the influence of alcohol, Bonar said.
The study showed that 8% of group members reported driving after consuming four or more drinks in the previous 6 months. The prevalence of this finding was about 13% among those who drove within two hours and those who drove a bit too high. Prevalence was higher (21%) among participants who drove very high.
Prevention efforts needed
"The results highlight relationships between certain demographic factors (age, race, for example) and related to the use of psychoactive substances, particularly significant episodic consumption and the use of cannabis as markers of DUIC risk. ", write the researchers.
"Prevention efforts may need to specifically target the simultaneous consumption of alcohol and cannabis," they add.
The framework in which participants were asked about driving behavior – the clinical visit for the certification or recertification of medical cannabis – could be an ideal opportunity to counsel patients about the risks, the researchers note.
"Some doctors are already doing this, but we encourage them to inform their patients that they could be at risk if they were driving a car after using marijuana for medical purposes," he said. said Bonar.
For example, patients may not know that they may lose reaction time, especially in the event of unexpected driving, she added.
Consultation on the risks associated with marijuana for medical purposes is also essential because, unlike other prescriptions, cannabis for medical purposes does not carry a warning label.
"If you had a prescription today for an opioid, a small label would warn you to avoid running heavy machinery, which could make you sleepy," Bonar said. "But we do not have this type of regulation for marijuana."
The council is not without difficulties, however, she said. In the absence of much evidence on the potential health risks of marijuana for medical purposes, "we do not know how it affects you or how you consume them. This is to avoid driving – get a ride from someone else, use a trip sharing app, that sort of thing. "
Regulation in constant evolution
Due to changing regulations at the state level, it is difficult for clinicians to track the number of states where medical cannabis and recreational cannabis are considered legal, which adds to the the complexity of the DUIC problem, Bonar said.
"The differences between state and federal regulations are also problematic," she added. "We do not know what will happen – people like to talk about this world as a" Wild West "."
It becomes difficult for science to comply with new regulations when "our society, our country and our policies are changing rapidly," she said.
The researchers noted that future research on a recommended standard "dose" of medical cannabis, whatever the conditions, would be helpful.
Incorporating driving data and / or crash data could also improve the results of subsequent studies, he added.
As for the next steps in their research, "we will continue to look at the results and what happens to people for many years when they consume marijuana for medical purposes," Bonar said.
She added that it would be interesting to know if people drive more or less over time and if those who get a medical cannabis certification versus a new certification behave differently.
"Part of what we are trying to do in our research at the addiction treatment center is identifying the best ways to help people avoid these at-risk situations, the best ways to provide them with information and the information they need. better ways to motivate people to change their behavior, "she says.
"Significant clinical value"
Commenting on the results for Medscape Medical NewsJeramy Peters, DO, a fourth-year resident in psychiatry at Oregon Health Sciences University in Portland, said the study "has significant clinical value" for patients treated with cannabis for medical purposes.
"Informing patients about the risks, benefits and potential interactions of herbal or traditional over-the-counter medicines is an important aspect of the quality of medical care," he said.
"As such, physicians should be able to have an informed discussion with their patients regarding these substances.These data provide a preliminary understanding of the risk of cannabis-impaired driving among cannabis users for medical purposes," he said. Peters, unaffiliated. with the current study but co-wrote a primer for clinicians on cannabis use.
Peters added that although the participants in this study may not necessarily be representative of the general population, it has been shown that more than half of medical cannabis users reported having taken a DUIC course.
"As the CDC reports more than 32,000 deaths and 2 million injuries each year in a traffic accident, the clinical benefit of using the results of this article to provide factual information to patients Probably outweighs the risk of excessive generalization of its results to those of different demographics, "he said.
the The study was funded by the National Institute for Drug Abuse Control (NIDA), including a NIDA Career Development Award, a Career Development Award from the Department of Veterans Affairs, and a Training Award from the Department of Veterans Affairs. National Institute against alcoholism and alcoholism. Bonar and Peters have not reported any relevant financial relationship.
The drug depends on alcohol. Posted online January 9, 2019. Abstract