Tuesday, July 21, 2015
What's In Your Weed?
Australia has one of the highest rates of marijuana use in the world, but until recently, nobody could say for certain what, exactly, Australians were smoking. Researchers at the University of Sydney and the University of New South Wales recently analyzed hundreds of cannabis samples seized by Australian police, and put together comprehensive data on street-level marijuana potency across the country. They sampled police seizures and plants from crop eradication operations. The mean THC content of the samples was 14.88%, while absolute levels varied from less than 1% THC to almost 40%. Writing in PLoS one, Wendy Swift and colleagues found that roughly ¾ of the samples contained at least 10% total THC. Half the samples contained levels of 15% or higher—“the level recommended by the Garretsen Commission as warranting classification of cannabis as a ‘hard’ drug in the Netherlands.”
In the U.S., recent studies have shown that THC levels in cannabis from 1993 averaged 3.4%, and then climbed to THC levels in 2008 of almost 9%. By 2015, marijuana with THC levels of 20% were for sale in Colorado and Washington.
CBD, or cannabidiol, another constituent of cannabis, has garnered considerable attention in the research community as well as the medical marijuana constituency due to its anti-emetic properties. Like many other cannabinoids, CBD is non-psychoactive, and acts as a muscle relaxant as well. CBD levels in the U.S. have remained consistently low over the past 20 years, at 0.3-0.4%. In the Australian study, about 90% of cannabis samples contained less than 0.1% total CBD, based on chromatographic analysis, although some of the samples had levels as high as 6%.
The Australian samples also showed relatively high amounts of CBG, another common cannabinoid. CBG, known as cannabigerol, has been investigated for its pharmacological properties by biotech labs. It is non-psychoactive but useful for inducing sleep and lowering intra-ocular pressure in cases of glaucoma.
CBC, yet another cannabinoid, also acts as a sedative, and is reported to relieve pain, while also moderating the effects of THC. The Australian investigators believe that, as with CBD, “the trend for maximizing THC production may have led to marginalization of CBC as historically, CBC has sometimes been reported to be the second or third most abundant cannabinoid.”
Is today’s potent, very high-THC marijuana a different drug entirely, compared to the marijuana consumed up until the 21st Century? And does super-grass have an adverse effect on the mental health of users? The most obvious answer is, probably not. Recent attempts to link strong pot to the emergence of psychosis have not been definitive, or even terribly convincing. (However, the evidence for adverse cognitive effects in smokers who start young is more convincing).
It’s not terribly difficult to track how ditch weed evolved into sinsemilla. It is the historical result of several trends: 1) Selective breeding of cannabis strains with high THC/low CBD profiles, 2) near-universal preference for female plants (sinsemilla), 3) the rise of controlled-environment indoor cultivation, and 4) global availability of high-end hybrid seeds for commercial growing operations. And in the Australian sample, much of the marijuana came from areas like Byron Bay, Lismore, and Tweed Heads, where the concentration of specialist cultivators is similar to that of Humboldt County, California.
The investigators admit that “there is little research systematically addressing the public health impacts of use of different strengths and types of cannabis,” such as increases in cannabis addiction and mental health problems. The strongest evidence consistent with lab research is that “CBD may prevent or inhibit the psychotogenic and memory-impairing effects of THC. While the evidence for the ameliorating effects of CBD is not universal, it is thought that consumption of high THC/low CBD cannabis may predispose users towards adverse psychiatric effects….”
The THC rates in Australia are in line with or slightly higher than average values in several other countries. Can an increase in THC potency and corresponding reduction in other key cannabinoids be the reason for a concomitant increase in users seeking treatment for marijuana dependency? Not necessarily, say the investigators. Drug courts, coupled with greater treatment opportunities, might account for the rise. And schizophrenia? “Modelling research does not indicate increases in levels of schizophrenia commensurate with increases in cannabis use.”
One significant problem with surveys of this nature is the matter of determining marijuana’s effective potency—the amount of THC actually ingested by smokers. This may vary considerably, depending upon such factors as “natural variations in the cannabinoid content of plants, the part of the plant consumed, route of administration, and user titration of dose to compensate for differing levels of THC in different smoked material.”
Wendy Swift and her coworkers call for more research on cannabis users’ preferences, “which might shed light on whether cannabis containing a more balanced mix of THC and CBD would have value in the market, as well as potentially conferring reduced risks to mental wellbeing.”
Swift W., Wong A., Li K.M., Arnold J.C. & McGregor I.S. (2013). Analysis of Cannabis Seizures in NSW, Australia: Cannabis Potency and Cannabinoid Profile., PloS one, PMID: 23894589
(First published at Addiction Inbox Sept. 3 2013)
Graphics Credit: https://budgenius.com/marijuana-testing.html
Monday, July 13, 2015
Study sheds potential light on indica vs. sativa debate.
[Thanks to Ivan Oransky (@ivanoransky) for alerting me to this study.]
Anyone who has smoked marijuana more than a couple of times knows that cannabis can alter how you sleep. The effect of cannabis on sleep is even part of the never-ending debate over Cannabis indica vs. Cannabis sativa, the two major species of the marijuana plant. Indica smokers typically report a marijuana high that is body-intensive and often soporific, sometimes leading to the condition aptly known as “couch lock.” Whereas sativa smokers, according to marijuana lore, experience a more cerebral, energetic “head high,” with fewer somatic effects. Not surprisingly, hybrid strains incorporating the alleged characteristics of both indica and sativa strains are popular in the medical marijuana community.
Although there is no official sanction for it in the medical community, marijuana is often dispensed medically for sleep problems. One piece of common wisdom holds that the higher the THC content of marijuana, the more helpful it will be in promoting sleep and improving poor sleep. The stronger the better, in other words. Similarly, indica strains are assumed to promote sleep more than sativa strains.
In an effort to clear the air, so to speak, a group of researchers, writing in Addictive Behaviors, sought to “document naturalistic choice of particular medical cannabis types among individuals who self-report using cannabis for the treatment of sleep problems…. Little research has documented species or cannabinoid concentration preferences among individuals who use medical cannabis for particular conditions…. We also evaluated the interaction between the type of cannabis used and diagnosis of cannabis use disorder among study participants.”
The researchers recruited participants from a medical cannabis dispensary in California under procedures approved by the VA and Stanford University review boards. 163 people with a mean age of 40, who used cannabis twice a day on average, provided self-reported information on their cannabis use for the study. 81 participants reported using cannabis for the management of insomnia, and another 14 reported using cannabis to reduce nightmares. (Frequent smokers insist they dream less. THC does appear to decrease the density of REM cycles, leading to more restful, dream-free sleep, according to some studies. )
So what did they find?
—“Individuals who reported using cannabis for nightmares, compared to those who did not, preferred sativa to indica.” (Small effect.)
Indica, considered the “heavier” high, might have seemed the likely choice here.
—"Individuals who self-report using cannabis to treat symptoms of insomnia and those with greater self-reported sleep latency reported using cannabis with significantly higher concentrations of CBD.” (Large effect.)
Again, a somewhat counterintuitive finding, since it is widely believed that CBD conduces toward a more wakeful state than THC alone.
—“Individuals who used sleep medication less than once/week used cannabis with higher THC concentrations than those who used sleep medication at least once a week.” (Large effect.) “There were no differences in THC concentration as a function of self-reported sleep quality, or use for insomnia or nightmares.”
Pretty straightforward finding: THC makes you sleepy. It is not clear, however, that above a certain threshold, more THC makes you even sleepier. In fact, some researchers would consider this finding unexpected, given that high THC concentrations have been shown to have a stimulating effect.
—“Older individuals were less likely to have cannabis use disorder compared to those younger….
No surprise about the older folks, since prior studies show a decrease in the prevalence of cannabis use disorders with age.
—“Individuals who preferred sativa or primary sativa hybrid strains were less likely to have cannabis use disorder compared to those who preferred indica or primary indica hybrid strains.” (Small effect.)
If replicated, this finding could have significant implications; both in strengthening programs to reduce marijuana smoking among the very young, and it warning consumers that some evidence suggests indica strains may be more addictive than sativa strains in plants with similar THC/CBD levels and ratios.
—“Neither concentration of THC nor CBD were associated with cannabis use disorder.”
Common sense, but useful to remember. In other addictive behaviors, such as heroin and alcohol abuse, the relative strength of the drug is not the primary determinant of its addictive potential.
Caveats and design limitations: The survey relied on retrospective reports of sleep quality and pot preferences. Also lacking is an examination of additional variables such as PTSD and co-occurring substance abuse.