Getting behind the wheel after cannabis use is on the rise in the US, and THC, not alcohol, is now the most commonly detected intoxicant in US drivers. Detecting levels of THC, however, is challenging and the methods used so far cannot accurately determine a person's level of impairment.
The article "Driving While Stoned: Issues and Policy Options" by Mark A.R. Kleiman, Tyler Jones, Celeste J. Miller, and Ross Halperin, published in De Gruyter's Journal of Drug Policy Analysis, looks at current issues associated with cannabis intoxication when driving and the options available in testing for THC levels.
The research suggests that, due to the recent legalization of the production and sale of cannabis in some US States, the number of people driving under the influence of cannabis is likely to rise, which is unsettling since there is a widespread belief among marijuana users that THC does not have an effect on driving. Americans now spend an estimated 15 billion hours under the influence of cannabis per year, with no sign of consumption slowing down soon.
Unlike breath alcohol detection tests, which are cheap, reliable and can be easily administered at the roadside, a breath test for cannabis remains to be developed.
Oral-fluid testing can demonstrate recent use but not the level of impairment and thus a blood test must be carried out by health professionals at a medical facility. A further challenge is that blood THC levels drop very sharply even after minutes. A blood test is also a poor indicator of how recently the drug was used or the extent of impairment, and other tests are also not completely accurate.
Research on the risk of driving under the influence of cannabis is still preliminary and subject to fierce debate. However, a few facts are certain: stoned-driving adds to accident risk, especially in combination with alcohol and other drugs. Also, while it is certain that the risk of driving under the influence of cannabis alone is much lower than under the influence of high levels of alcohol, it is difficult to determine levels of impairment after cannabis use.
Stoned driving, the article posits, should be discouraged by making it a traffic offense with the promotion of anti-stoned driving messages highlighting the dangers and risks.
"Even assuming that an acceptable test can be developed, stoned driving alone and not involving alcohol or other drugs, should be treated as traffic infraction rather than as a crime, unless aggravated by recklessness, aggressiveness, or high speed," said study author Professor Mark A.R Kleiman of New York University.
Studies show that Legalized medical cannabis lowers opioid use
States that have approved medical cannabis laws saw a dramatic reduction in opioid use, according to a new study by researchers at the University of Georgia.
In a document published in the Journal of the American Medical Association, Internal Medicine, researchers examined the number of all opioid prescriptions filled between 2010 and 2015 under Medicare Part D, the prescription drug benefit plan available to Medicare enrollees.
Research has shown that's states with medical cannabis dispensaries, the researchers observed almost 15 percent reduction in the use of prescription opioids and nearly a 7 percent reduction in opiate prescriptions filled in states with home-cultivation-only medical cannabis laws.
"Some of the states we analyzed had medical cannabis laws throughout the five-year study period, some never had medical cannabis, and some enacted medical cannabis laws during those five years," said W. David Bradford, study co-author and Busbee Chair in Public Policy in the UGA School of Public and International Affairs.
"So, what we were able to do is ask what happens to physician behavior in terms of their opiate prescribing if and when medical cannabis becomes available."
Since California approved the first medical cannabis law in 1996, 29 states and the District of Colombia have approved some form of medical cannabis law.
"Physicians cannot prescribe cannabis; it is still a Schedule I drug," Bradford said.
"We're not observing that prescriptions for cannabis go up and prescriptions for opioids go down. We're just observing what changes when medical cannabis laws are enacted, and we see big reductions in opiate use."
The researchers examined all common prescriptions opiates, including hydrocodone, oxycodone, morphine, methadone, and fentanyl. Because heroin is not a legal drug, it was not included as part of the study.
Recently, the U.S. Department of Health and Human Services declared a public health emergency related to the abuse of opiates. Opioid overdoses accounted for over 42,000 deaths in 2016, more than any previous year on record, and more than 40 percent of opioid overdose deaths involved a prescription opioid, according to HHS.
Opioid prescription rates increased from about 148 million prescriptions in 2005 to 206 million prescriptions by 2011, Bradford said. This coincided with an increase in the number of opioid-related deaths.
"There is a growing body of studies that suggest cannabis may be used to manage pain in some patients, and this could be a major component of the reductions we see in the use of opiates," he said.
The researchers did not, however, see any significant reductions in the number of non-opioid drugs prescribed during the study period.
"In other studies, we examined prescription rates for non-opioid drugs such as blood thinners, flu medications, and phosphorus stimulants, and we saw no change," said Ashley Bradford, lead author of the study and graduate student in UGA's department of public administration and policy.
"Medical cannabis wouldn't be an effective treatment for flu or for anemia, so we feel pretty confident that the changes we see in opioids are because of cannabis because there is a legitimate medical use."
The researches concede that if medical cannabis is to become an effective treatment, there is still much work to be done. Scientists are only just beginning to understand the effects of the compounds contained in cannabis, and an effective "dose" of cannabis would need to be defined clearly so that each patient receives a consistent dose.
"Regardless, our findings suggest quite clearly that medical cannabis could be one useful tool in the policy arsenal that can be used to diminish the harm of prescription opioids, and that's worthy of serious consideration," David Bradford said.
Materials provided by the University of Georgia, School of Public and International Affairs. Note: Content may be edited for style and length.
1. Ashley C. Bradford, W. David Bradford, Amanda Abraham, Grace Bagwell Adams. Association Between US State Medical Cannabis Laws and Opioid Prescribing in the Medicare Part D Population. JAMA Internal Medicine, 2018; DOI: 10.1001/jamainternmed.2018.0266
Newly published research from UBC's Okanagan campus has found that many strains of cannabis have virtually identical levels of tetrahydrocannabinol (THC) and cannabidiol (CBD), despite their unique and various street names.
" It is estimated that there are several hundred or perhaps thousands of strains of cannabis currently being cultivated," says Professor Susan Murch, who teaches chemistry at UBC Okanagan. " We wanted to know how different they truly are, given the variety of unique and exotic names."
Cannabis breeders have historically selected strains to produce THC, CBD or both, she explains. But the growers have had limited access to different types of plants and there are few records of the parentage of different strains.
" People have had informal breeding programs for a long time," Murch says. " In a structured program we would keep track of the lineage, such as where the parent plants came from and their characteristics. With unstructured breeding, which is the current norm, particular plants were picked for some characteristic and then given a new name."
Until now, the chemical breakdown of many strains has been unknown because of informal breeding.
Elizabeth Mudge, a doctoral student working with Murch and Paula Brown, Canada Research Chair in Phytoanalytics at the British Columbia Institute of Technology, examined the cannabinoid -- a class of chemical compounds that include THC and CBD -- profiles of 33 strains of cannabis from five licensed producers.
The studies show that most strains, regardless of their origin or name, had the same amount of THC and CBD. They further discovered that breeding highly potent strains of cannabis impacts the genetic diversity within the crop, but not THC or CBD levels.
However, Mudge says that they found differences in a number of previously unknown cannabinoids -- and these newly discovered compounds, present in low quantities, could be related to pharmacological effects and serve as a source of new medicines.
"A high abundance compound in a plant, such as THC or CBD, isn't necessarily responsible for the unique medicinal effects of certain strains," says Mudge. " Understanding the presence of the low abundance cannabinoids could provide valuable information to the medical cannabis community."
Currently licensed producers are only required to report THC and CBD values. But Murch says her new research highlights that the important distinguishing chemicals in cannabis strains are not necessarily being analyzed and may not be fully identified.
Murch says while patients are using medical cannabis for a variety of reasons, they actually have very little information on how to base their product choice. This research is a first step towards establishing an alternative approach to classifying medical cannabis and providing consumers with better information.
Murch's research was recently published in Nature's Scientific Reports.
Materials provided by University of British Columbia Okanagan campus. Original written by Patty Wellborn.
Advanced Studies reveal that adults prefer to consume marijuana in states where it is legal.
Daily use of marijuana, as well as past month rates, rose for both men and women aged 26 and older in states with medical marijuana laws in effect, according to researchers at Columbia University's Mailman School of Public Health.
Marijuana use among individuals younger than 26 years old was generally unaffected by changes in the law. The results of the study are published online in Prevention Science.
In states with medical marijuana laws, daily marijuana use for male users age 26 and older increased from 16.3 percent to 19.1 percent, and for women, from 9.2 percent to 12.7 percent. Past month use among men in the same age bracket increased from 7.0 percent before the laws passed to 8.7 percent following their passage, and for women rose from 3.0 percent before to 4.3 percent after. There were no significant increases in past-year marijuana use disorder (continuing to use despite significant behavioral or psychological changes) for any age or gender group following passage of the laws.
The research also documents a spike in males ages 18-25 consuming marijuana daily compared to females. "Among past month users, more than one in five young men ages 18-25 living in states with medical marijuana laws said they used marijuana every day," said Christine Mauro, Ph.D., assistant professor of Biostatistics at Columbia's Mailman School of Public Health, and first author.
Daily use was generally higher among individuals aged 18-25 compared with those ages 12-17 and those 26 or older, regardless of their state's laws around Cannabis. "Daily marijuana use raises health concerns as the brain doesn't fully mature until age 25," noted Mauro.
The researchers analyzed state-level survey data from the National Survey on Drug Use and Health for the years 2004-2013, including more than 17,500 youth (12-17 years old), 17,500 young adults (18-25 years old), and 18,800 adults 26 and older per year studied.
Since 1996, more than half of the United States have passed medical marijuana laws, with 28 states legalizing medical marijuana use as of November 2016; eight states have legalized recreational marijuana. "As more states enact laws and more years of data are available, future research should examine how legalization of recreational marijuana and other local rules contribute to changes in marijuana use," said Mauro.
Rising rates of Cannabis use raises concerns regarding associated increases in the heavy use of marijuana and marijuana use disorder. Earlier research by Columbia researchers estimated that 16.2 percent and 57.2 percent of daily marijuana users meet criteria for DSM-IV abuse and dependence diagnosis, respectively.
"The advent of medical marijuana laws has been proposed as one potential cause of the increased prevalence of marijuana use, but there is now a general consensus that passage of the laws has not affected rates of use in adolescents," said Silvia Martins, MD, PhD, associate professor of Epidemiology at the Mailman School, and senior author. Until this most recent data, studies by Martins and colleagues found past-year individual use rose among all adults 26+ in states with medical marijuana laws but had not investigated changes in daily marijuana use and marijuana use disorder.
In fact, despite public health concerns regarding the increased use of pot and enactment of marijuana laws, some positive outcomes have been associated with the laws, including decreased opioid use and decreased alcohol consumption -- the latter tied to declining rates of traffic injury fatalities at the state level.
"Research shows the impacts of medical marijuana law, both positive and negative," noted Martins.
"Because most states in our sample more recently passed medical marijuana laws, it is possible that not enough time has elapsed to observe more significant changes in marijuana use disorder across age-gender subgroups," said Mauro.
"Given the impact, the disorder may have on individuals, families, and society, marijuana use should continue to be monitored regularly. Building the evidence base by age and gender is critical in helping public health professionals better understand which groups, may be most affected by medical marijuana laws and target public health programming accordingly."
Materials provided by Columbia University's Mailman School of Public Health. Note: Content may be edited for style and length.
1. Christine M. Mauro, Paul Newswanger, Julian Santaella-Tenorio, Pia M. Mauro, Hannah Carliner, Silvia S. Martins. Impact of Medical Marijuana Laws on State-Level Marijuana Use by Age and Gender, 2004–2013. Prevention Science, 2017; DOI: 10.1007/s11121-017-0848-3