Scientists injected people with pure THC and gave them a series of tests to learn how marijuana affects basic motor functions.
What, you don’t normally consume cannabis intravenously? Moving on…
With a majority of states having passed laws legalizing marijuana in some form, there’s strong interest in determining how its components impact motor skills. To that end, researchers at Yale School of Medicine recruited 23 former cannabis consumers, administered low- and high-THC infusions and and had them perform several psychomotor tests.
The results, released online on Wednesday, are set to be published in the Journal of Psychopharmacology.
What the researchers found is generally consistent with earlier studies: the THC infusion “resulted in robust and significant deficits in motor performance” in a dose-dependent manner.
There was one test—where participants were asked to recognize a numeric sequence displayed on a screen and then press a response pad—that showed no significant difference in performance with or without THC. But when it comes to fine motor skills and response time, the study showed evidence that THC impaired the participants. The higher dose (0.03 mg/kg) led to poorer performance compared to the low dose (0.015 mg/kg).
The dosing was based on previous research into the blood plasma concentration of THC after smoking a standard joint. The higher dose is roughly equivalent to three-quarters of a joint and the lower dose is equivalent to one-quarter of a joint, according to the study.
Impairment from THC has been soundly established in earlier research. But what stood out to the researchers wasn’t that THC seemed to impair psychomotor skills; it was that participants who received the low and high dose THC reported feeling equally high.
“Perhaps even more concerning is the fact that even though the high dose of THC produced greater psychomotor deficits, subjects were not able to distinguish between levels of intoxication across the low- and high-dose conditions. This suggests that it may be difficult for individuals to gauge their level of psychomotor impairment based upon subjective feelings of intoxication, which could lead to greater risk during psychomotor-dependent behaviors.”
The subjective self-reports seemed to reinforce the idea that the “high” effects “plateau with increased doses of THC, while subjective alertness and postural sway continue to worsen.”
“Taken together, these data suggest that while several domains of motor function are disrupted by THC, subjective feelings of intoxication are dissociable from cannabinoid-induced psychomotor effects,” the researchers wrote.
There were a couple limitations to the study. First, it was designed to test how THC alone impacts motor function, whereas most consumers are exposed to numerous cannabinoids, including CBD, when they use marijuana. Second, the participants hadn’t used cannabis in at least the past three months, which means the effects were likely more pronounced than they would be in a frequent users whose developed a tolerance.
“These limitations notwithstanding, to our knowledge, this is the first controlled study examining a range of psychomotor functions in humans during the administration of several doses of IV THC,” the researchers wrote.
“These results suggest that THC exhibits robust effects on fine motor control and motor timing in a dose-dependent manner, which have implications for real world psychomotor-dependent behaviors such as driving, weapon use, operating machinery, work-related tasks, and skilled labor.”
(The researchers each reported potential conflicts of interest, including receiving grants from major pharmaceutical companies.)
Photo courtesy of Chris Wallis/Side Pocket Images.
Scientists Actually Did A Study To Confirm That Marijuana Causes The Munchies
Science has confirmed that marijuana really does cause the munchies.
More precisely, a new study found that sales of commonly munched on products like ice cream, cookies and chips tend to go up after states legalize cannabis.
To do so, a team of researchers developed complicated mathematical formulas like the one featured below and analyzed a trove of retail scanner data.
The study indicates that the “widespread urban myth” that cannabis stimulates hunger and drives people to gorge on goodies is a myth no longer. The researchers looked at retail scanner data in more than 2,000 counties across the U.S. from 2006 to 2016 to determine whether states that legalize marijuana for adult use experience increases in the sale of high-calorie food items.
Past studies on the munchies have relied on data that’s “correlational and indirect,” they wrote. This paper, meanwhile, tested the hypothesis by factoring in the “differences in timing of the legalization of recreational marijuana across states” and specifically comparing “retail food purchases for the subsample of contiguous counties across [recreational marijuana law] and non-[recreational marijuana law] shared borders only.”
The study found causal evidence that legalizing cannabis was associated with higher so-called “junk food purchases.
Shortly after a state’s legal marijuana system became effective, average monthly sales of ice cream, cookies and chips jumped 3.1 percent, 4.1 percent and 5.3 percent, respectively. And that was the case even after the researchers accounted for “state- and pair-specific time trends.”
“The increase in sales starts at the time of the legislation becomes effective,” the study authors wrote. “The effect slightly decreases in the semesters thereafter for ice cream and chips, but not for cookies.”
That’s probably a welcome finding for Girl Scouts in Colorado. The state’s chapter recently lifted a ban on selling cookies outside of “adult-oriented businesses” such as marijuana stores, where the scouts can rest assured they’ll find a hungry customer base.
Study Shows That Bees Like Hemp, And That’s Great News For The Environment
Farmers (and Sen. Mitch McConnell) aren’t the only ones who are excited about hemp. According to a recent study, the crop also attracts a variety of bees—and that can help inform ecologically sustainable agriculture practices.
For the study, published this month in the journal Biomass and Bioenergy, researchers at Colorado State University set up 10 traps at industrial hemp fields in northern Colorado and collected bees over the course of five days during peak flowering season.
There are few other crops that pollinate in the region during the same timeframe, so the team wanted to know whether the non-psychoactive cannabis cousin of marijuana represented “a potentially valuable source of pollen for foraging bees,” which play a critical role in maintaining “sustainable productivity in natural and agricultural ecosystems.”
When the researchers looked at their collection, they found almost 2,000 bees from 23 different bee genera. Most of those (38 percent) were classic honeybees, but there were also specialized genera such as Melissodes bimaculata and Peponapis pruinosa that turned up in surprisingly “high proportions.”
The sample also indicated that hemp flowers are uniquely attractive to bees because previous reports looking at bee abundance and diversity for crops like genetically modified canola flowers didn’t produce the same volume or variety.
“Industrial hemp can play an important role in providing sustained nutritional options for bees during the cropping season.”
The study could prove helpful as ecologists attempt to address declining bee populations. The insects “continue to face debilitating challenges due to a number of different stressors,” the researchers wrote, but chief among them is the overall health of their respective habitats.
Finding a suitable pollinating crop to improve their habitats is, therefore, critical to the lives of bees and the ecosystems they occupy. Hemp “can thus be an ecologically valuable crop whose flowers are attractive to managed honey bees and a wide range of wild bees,” the researchers concluded.
“In addition, access to crucial phytochemicals through pollen and nectar from diverse plant sources is important for improved survival and pathogen tolerance in honey bees,” the team wrote. “Further studies analyzing the nutritive value of hemp pollen, would provide strong evidence in support of the ecological benefits.”
But the study also includes a warning: as hemp cultivation expands, which experts expect it will significantly since it has recently been federally legalized, there will be an increased risk of insect pests infecting the crop. And so the researchers said they “strongly urge that the information generated in this study on the diversity and abundance of bees on hemp be used to develop an integrated pest management plan designed to protect pollinators while controlling pests.”
Photo courtesy of Pixabay.
States With Legal Medical Marijuana Have Lower Teen Use Rates, Large-Scale Study Finds
Contrary to often-expressed fears of marijuana legalization opponents, teens living in states that allow medical cannabis are actually less likely to use the drug compared to those in non-legal states.
That’s the result of a new study published in The American Journal of Drug and Alcohol Abuse.
Researchers at Boston College looked at national youth drug surveys from 1999 to 2015—a data set that involved more than 860,000 adolescents across the United States. They investigated how self-reported marijuana use changed in states that have either decriminalized cannabis possession or legalized it for medical purposes.
And while opponents of legalization have long argued that loosening marijuana laws would drive more youth to consume cannabis, the study showed the opposite. The enactment of medical cannabis laws was associated with 1.1 percentage point reduction in marijuana use among teens.
“We found that for every group of 100 adolescents, one fewer will be a current user of marijuana following the enactment of medical marijuana laws,” study author Rebekah Levine Coley said in a press release.
That decline was even more pronounced within certain subgroups. For example, 3.9 percent fewer black adolescents and 2.7 percent fewer Hispanic adolescents used marijuana in legal medical cannabis states.
The trend also held true after researchers accounted for factors such as state demographics and economic trends. What’s more, the reductions in youth marijuana use were more significant the longer a state had a medical cannabis system in effect.
“Some people have argued that decriminalizing or legalizing medical marijuana could increase cannabis use amongst young people, either by making it easier for them to access, or by making it seem less harmful,” Coley said. “However, we saw the opposite effect.”
“We were not able to determine why this is, but other research has suggested that after the enactment of medical marijuana laws, youths’ perceptions of the potential harm of marijuana use actually increased. Alternatively, another theory is that as marijuana laws are becoming more lenient, parents may be increasing their supervision of their children, or changing how they talk to them about drug use.”
States that have simply decriminalized cannabis possession did not experience the same reductions in youth marijuana use, the study also found. There were slight declines in usage among 14-year-olds and Hispanic youth, but the broader reductions were only seen in medical marijuana states.
Photo courtesy of Nicholas C. Morton.