Study: THC Persists in Blood for Extended Periods of Time Post-Abstinence
Vancouver, Canada: The detection of THC in blood at levels greater than 2ng/ml may persist for extended periods of time and therefore it is not necessarily indicative of recent cannabis exposure, according to data published in the journal Drug and Alcohol Dependence.
Investigators affiliated with the University of British Columbia performed a systematic review of the relevant literature assessing residual THC plasma levels in frequent cannabis consumers.
Authors reported: "[I]n all studies where participants were observed for over a day, blood THC [levels] in some participants remained detectable during several days of abstinence," with some subjects continuing to test positive for up to 30 days. Some subjects also demonstrated a so-called "double hump" pattern "where their THC levels rose toward the end of the week after an initial decline."
Researchers concluded, "The studies in our review consistently demonstrate that positive blood THC levels, even levels over 2ng/ml, do not necessarily indicate recent cannabis use in frequent cannabis users."
The study's findings have implications for traffic safety laws, as several US states impose either per se or zero-tolerant per se laws that criminalize the operation of a vehicle by a driver solely based upon the detection of trace levels of THC in one's blood. NORML opposes the imposition of per se limits for cannabis because the presence of THC in blood, especially at low levels, is not a consistent predictor of either recent use or impairment of performance.
Full text of the study, "Residual blood THC levels in frequent cannabis users after over four hours of abstinence," appears in Drug and Alcohol Dependence. Additional information is available from the NORML fact sheet, "Marijuana and Psychomotor Performance."
Marijuana Growing in Popularity Among Seniors
Worchester, MA: The use of cannabis is gaining popularity among those age 65 and older, according to newly published data in the journal Annals of Internal Medicine.
Researchers affiliated with the University of Massachusetts Medical School assessed trends in self-reported cannabis use in a national sampling of over 171,000 seniors. Consistent with prior surveys, they reported: "From 2016 to 2018, cannabis use increased for men in all age groups and in most women. ... Among those aged 65 to 69 years, cannabis use increased from 4.3 percent to 8.2 percent in men and from 2.1 percent to 3.8 percent in women."
Commenting on the findings, NORML Deputy Director Paul Armentano said: "These results are to be expected. Many seniors likely experimented first-hand with cannabis during their youth and are now returning to it as a potential therapy to mitigate many of the health-related symptoms associated with older age, including chronic pain. Many seniors are well aware of the litany of serious adverse side-effects associated with available prescription drugs, like opioids, and they perceive medical cannabis to be a viable alternative."
Several recent studies - such as those here, here, here, and here - have determined that medical cannabis use by seniors is relatively safe and effective at mitigating pain and improving self-reported quality of life.
The increase in seniors' self-reported use of cannabis coincides with rising public support for marijuana legalization among older Americans. According to nationwide polling data compiled by the Pew Research Center, nearly two-thirds (63 percent) of 'Boomers' (those born in the United States between the years 1946 and 1964) now say that marijuana ought to be legal for adults. That percentage is up significantly from a decade ago, when fewer than one-in-three seniors endorsed its legalization.
Armentano added: "This demographic shift holds important implications for marijuana legalization. Not only does it strengthen overall public support in favor of marijuana law reform, but it also galvanizes support amongst arguably the most reliable and powerful voting block - seniors. As their attitudes continue to evolve on cannabis, expect to see many politicians at the state and federal level shift their views as well."
Full text of the study, "Recent trends in cannabis use in older Americans," appears in Annals of Internal Medicine.
Survey: Over Three in Four Cannabis Consumers Prefer Flower Over Concentrates
Tempe, AZ: Nearly eight in ten cannabis consumers say that they prefer herbal cannabis over marijuana-infused concentrates, according to data published in the journal Drug and Alcohol Dependence. Concentrates typically possess significantly higher levels of cannabinoids, in particular THC, than do herbal cannabis products.
Researchers with Arizona State University surveyed 574 US subjects with a history of consuming both herbal cannabis and marijuana concentrates. Seventy-eight percent of respondents selected herbal cannabis over concentrates as their "preferred type of cannabis." Respondents said that the consumption of concentrates was more likely to result in unwanted effects, such as paranoia, memory disruption, and "hangovers." Respondents also said that herbal cannabis was more effective at providing pain relief and that it was a better value for their money than concentrates.
Authors concluded: "Findings showing that marijuana produces greater positive effects than concentrates are consistent with cannabis administration studies documenting that moderate THC doses are preferred to high doses. ... The present study suggests that, contrary to concerns, ultra-high THC cannabis, such as concentrates, might not produce greater positive, reinforcing effects relative to lower-THC cannabis, such as marijuana (flower)."
Commenting on the study's findings, NORML Deputy Director Paul Armentano said: "The conclusion that most marijuana consumers prefer low-to-moderate potency options over high potency options is hardly surprising. Just as the majority of those who consume alcohol prefer relatively low potency beer or wine over hard liquor, most adult-use cannabis consumers gravitate toward herbal cannabis preparations and away from the comparatively stronger alternatives."
Analyses of retail sales data, such as those here and here, report that consumers in legal states are far more likely to purchase herbal cannabis than any other type of marijuana product.
Full text of the study, "A within-person comparison of the subjective effects of higher vs. lower-potency cannabis," appears in Drug and Alcohol Dependence.
Review: Low Doses of THC Hold Value in Mitigating Symptoms of Post-Traumatic Stress
Curitiba, Brazil: Data from available human trials provide evidence that the administration of low doses of THC can safely and effectively mitigate symptoms of post-traumatic stress disorder in some subjects, according to data published in the journal BMC Psychiatry.
Brazilian researchers affiliated with the Federal University of Panama conducted a "qualitative systematic review" of the relevant peer-reviewed literature.
Authors reported, "THC, dronabinol [oral synthetic THC] or nabilone [a synthetic cannabinoid that mimics THC] could help with hyperarousal symptoms, insomnia, anxiety, and extinction deficits related to PTSD."
They concluded, "[D]espite the limited number of published studies, available data suggest that low doses of THC potentiate fear memory extinction in healthy volunteers and reduce anxiety responses in ... PTSD patients without inducing a psychotic effect."
Observational studies assessing the role of cannabinoids in potentially mitigating symptoms of PTSD have yielded mixed results. For instance, a 2014 study published in the Journal of Psychoactive Drugs reported that patients perceived significant reductions in post-traumatic stress symptoms during times when they used cannabis as compared to when they did not. Other studies have shown a relationship between oral THC dosing and a reduction in the frequency of nightmares. By contrast, a study published earlier this year in the journal Psychological Medicine reported, "No evidence of improvement in PTSD-related intrusion symptoms or remission in PTSD diagnosis in association with long-term use of cannabis."
Most recently, clinical study data published in August in the journal Psychopharmacology reported that THC dosing "lowered threat-related amygdala reactivity" in post-traumatic stress patients. Authors concluded: "These preliminary data suggest that THC modulates threat-related processing in trauma-exposed individuals with PTSD, which may prove advantageous as a pharmacological approach to treating stress- and trauma-related psychopathology."
Full text of the study, "Effects of Delta-9-tetrahydrocannabinol on aversive memories and anxiety: A review from human studies," appears in BMC Psychiatry.
Study: Topical Administration of Cannabinoids Treats Intractable Leg Ulcers
Toronto, Canada: The administration of a proprietary blend of topical cannabinoids, terpenes, and flavonoids resulted in wound healing in a pair of elderly patients with treatment-resistant leg ulcers, according to data published in the publication International Wound Journal.
A team of Canadian scientists assessed the daily topical application of cannabinoids on wound healing and wound-related pain in two patients with severe and persistent leg ulcers. In one patient, cannabinoid treatment resulted in complete wound closure in 77 days; in second patient, wound closure was achieved in 74 days. Patients reduced and eventually eliminated their use of conventional analgesics over the course of treatment.
Researchers reported, "This is the first study to report the use of TCBM [Topical Cannabis-Based Medicines] to promote complete integumentary wound closure in human subjects, specifically, two Caucasian females with a mean age of 77 years, with three lower limbs afflicted with intractable and biopsy proven NUC [Non-Uremic Calciphylaxis]."
They concluded: "Topical Cannabis-Based Medicines, applied to both wound beds and peri-wound tissues, represent a promising novel, non-invasive, and safe treatment option for NUC leg ulcers. The ease and simplicity of its application also allows for potential self-application and self-titration by patients. Given that TCBM demonstrated both rapid wound closure and relief of wound-related pain, in very challenging wounds such as NUC, among highly complex patients, they may be poised for an even broader role within overall integumentary and wound management."
A pair of prior case reports have similarly shown that the topical administration of cannabinoids facilitates wound healing and reduces the use of analgesics in patients with the rare skin-blistering disease epidermolysis bullosa.
Full text of the study, "Topical cannabis-based medicines - A novel paradigm and treatment for non-uremic calciphylaxis leg ulcers: An open label trial," appears in International Wound Journal.
Lab Analysis: Some Rolling Papers Contain Unwanted Contaminants
Santa Cruz, CA: Some rolling paper products used by the manufacturers of pre-rolled cannabis cigarettes possess detectable levels of contaminants, including pesticides and heavy metals, according to a laboratory analysis performed by the California-based testing company SC Labs.
Of the 101 products assessed by the lab, eight percent tested positive for potentially dangerous levels of heavy metals, including lead, cadmium, and mercury, while five percent of samples tested positive for the presence of pesticides at levels above those allowable under California law.
While the analysis did not identify any products by brand name, a summary of the study in Forbes.com reported that the products with "very high levels of contamination" typically were "cellulose-based papers - the transparent, gummy papers sold as 'clear' papers in smoke shops." Some "flavored blunt wraps" and so-called "natural hemp-based wraps" also contained detectable levels heavy metals. By contrast, no traditional rolling paper products tested positive for elevated levels of contaminants.
The analysis concluded: "While 11 percent of the rolling papers in this study would fail above the action limits for inhalable products in California, it should be noted that the paper constitutes only a fraction of the overall mass of a cannabis pre roll product. Although the ratio of the mass of paper to cannabis flower varies within pre-roll products depending on a number of factors, it is safe to assume that rolling paper products that fail near the action limit would most likely not cause a compliance failure when combined with 'clean' cannabis."
Consequently, SC Labs President Josh Wurzer told Forbes that, despite the study's results, most cannabis consumers have little reason to be concerned. He stated, "[T]he findings of the study don't support too much alarm; this certainly isn't a, 'Raise the alarm bells now, we have to stop and test all papers.'"
Full text of the study, "Rolling papers tested for heavy metals and pesticides," is available from SC Labs.