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SCIENCE

  • by Paul Armentano, NORML Deputy Director May 22, 2019

    Drivers testing positive for the presence of THC in blood do not possess a significantly increased risk of being responsible for a non-fatal motor vehicle accident, according to data published in the journal Addiction.

    Investigators from the University of British Columbia compared the likelihood of crash responsibility in drivers testing positive for THC and/or other substances as compared to drug-free drivers over a six-year period (2010 to 2016).

    Researchers reported, “In this multi-site observational study of non-fatally injured drivers, we found no increase in crash risk, after adjustment for age, sex, and use of other impairing substances, in drivers with THC less than 5ng/ml. For drivers with THC greater than 5ngml there may be an increased risk of crash responsibility, but this result was statistically non-significant and further study is required. … Our findings … suggest that the impact of cannabis on road safety is relatively small at present time.”

    By contrast, authors reported, “There was a significantly increased risk for drivers who used alcohol, sedating medications, or recreational drugs others than cannabis.” Drivers who tested positive for the concurrent use of cannabis and alcohol possessed a higher risk of accident as compared to drivers who tested positive for alcohol alone – a finding that is consistent with other studies.

    The abstract of the study, “Cannabis use as a risk factor for causing motor vehicle crashes: A prospective study,” is online here. Additional information is available in the NORML fact-sheet “Marijuana and Psychomotor Performance.”

  • by NORML May 21, 2019

    The administration of oral CBD reduces cue-induced cravings and anxiety in subjects with a history of heroin use, according to clinical data published in The American Journal of Psychiatry.

    Investigators at The Mount Sinai Health System in New York City assessed the effect of CBD versus placebo in 42 drug-abstinent participants with a history of heroin use. In contrast to placebo, CBD dosing of either 400mg or 800mg “significantly reduced both the craving and anxiety induced by drug cues … in the acute term. CBD also showed significant protracted effects on these measures seven days after the final short-term exposure.”

    Researchers concluded, “CBD’s potential to reduce cue-induced craving and anxiety provides a strong basis for further investigation of this phytocannabinoid as a treatment option for opioid use disorder.”

    In observational models, patients with legal access to cannabis typically reduce or eliminate their use of opioids. In clinical models, CBD administration has been shown to reduce cravings for tobacco. CBD dosing has also been associated with reduced cravings for methamphetamine in preclinical models.

    Commenting on the study’s findings, NORML Deputy Director Paul Armentano said, “These conclusions add to the growing body of evidence that cannabis and its constituents represent an exit away from the use or abuse of other controlled substances rather than a supposed ‘gateway.'”

    The abstract of the study, “Cannabidiol for the reduction of cue-induced craving and anxiety in drug-abstinent individuals with heroin use disorder: A double-blind randomized placebo controlled trial,” appears online here. Additional information is available in NORML’s fact-sheet, “Relationship between marijuana and opioids.”

  • by Paul Armentano, NORML Deputy Director April 15, 2019

    Marijuana FieldMarijuana grown by the University of Mississippi for clinical research purposes is genetically divergent from strains of cannabis commercially available in retail markets, according to an analysis prepared by researchers at the University of Northern Colorado. Since 1968, the University of Mississippi farm, which is governed by the US National Institute on Drug Abuse, has held the only available federal license to legally cultivate cannabis for FDA-approved research.

    Authors reported that samples available via the U-Miss program shared genetics typically associated with industrial hemp, not commercially available cannabis. They concluded: “NIDA research grade marijuana was found to genetically group with hemp samples along with a small subset of commercial drug-type cannabis. A majority of commercially available drug-type cannabis was genetically very distinct from NIDA samples. These results suggest that subjects consuming NIDA research grade marijuana may experience different effects than average consumers.”

    A separate study published in 2017 reported that U-Miss samples contain far lower levels of both THC and CBD than do commercially available cannabis. Clinicians wishing to conduct FDA-approved clinical trials on cannabis have long complained that federally-provided samples are of inferior quality.

    According to the program’s current marijuana menu, no available samples contain more than seven percent THC and all samples contain less than one percent CBD.

    In 2016, the US Drug Enforcement Administration publicly announced that it would, for the first time, begin accepting applications from private entities wishing to grow research-grade cannabis. However, since that time, neither the agency nor the Justice Department have taken any action to move this application process forward.

    Full text of the study, “Research grade marijuana supplied by the National Institute on Drug Abuse is genetically divergent from commercially available Cannabis,” appears online here.

  • by Paul Armentano, NORML Deputy Director March 20, 2019

    A widely reported study appearing today in the British journal The Lancet alleges that an estimated 30 to 50 percent of psychosis cases in Europe are due to cannabis exposure, and that exposure to elevated levels of THC increases this risk.

    NORML has previously written on the data showing a multi-directional association between cannabis and psychiatric illnesses, and we have cautioned that those predisposed to psychosis or other disorders may be at higher risk for adverse events.

    That said, it remains premature at best, and sensational at worst to claim that a causal relationship exists between marijuana use and psychiatric disorders on the basis of this new paper. That is because, by the observational nature of its design, this study at best can only demonstrate a correlation.

    Nonetheless, despite this limitation, the authors boldly “assume causality.” Given the fact that such a cause-and-effect relationship remains unproven and there as of yet exists no consensus among experts that such causation exists, their assumption is, at best, highly questionable.

    Moreover, it is well established that those with psychiatric illness typically use all intoxicants at greater rates than do the general public, so the fact that those admitted to institutions for first-episode psychosis are more likely to consume cannabis than are those in the general population is hardly surprising. But it is not evidence that marijuana in any way causes the condition. Rather, this association may exist because many psychiatric patients are self-medicating with cannabis. Or, this relationship may persist because many people predisposed to psychosis are similarly predisposed to also using cannabis — a theory that is supported by many experts in the field.

    Perhaps most importantly, the fact that cannabis has been used by various populations for decades at disparate rates, yet rates of psychosis and other psychiatric disorders have generally remained static over this same period of time, strongly argues against a direct causal relationship.

    Finally, authors’ presumptions specific to the supposed disparate effects of cannabis based upon THC potency are also highly questionable. This is because subjects in the study self-reported their cannabis use. As a result, authors had no ability to verify the THC content of the marijuana consumed by participants. Further, the cannabis consumed by subjects in the study was largely obtained via black market channels — leaving the users equally in the dark with regard to its actual cannabinoid content.

    Nonetheless, despite these limitations, the concerns raised in this paper and others ought to be taken seriously, and they provide an argument in favor of greater regulation of the plant so that it can be better kept out of the hands of young people and those who may be at higher risk for an adverse reaction. But maintaining cannabis prohibition, unfortunately, achieves neither result. Placed in this context, these latest scare-mongering claims — even if taken at face value — do little to advance arguments in favor of tightening prohibition, and provides ample ammunition to wage for its repeal.

  • by NORML February 22, 2019

    Cannabis exposure is not associated with significant changes in brain morphology in either older or younger subjects, according to a pair of newly published studies.

    In the first study, researchers from the University of Pennsylvania, Perelman School of Medicine compared brain scans of occasional (one to two times per week) and frequent (more than three times per week) marijuana consumers versus nonusers. Subjects were between 14 and 22 years of age.

    Investigators reported: “There were no significant differences by cannabis group in global or regional brain volumes, cortical thickness, or gray matter density, and no significant group by age interactions were found. Follow-up analyses indicated that values of structural neuroimaging measures by cannabis group were similar across regions, and any differences among groups were likely of a small magnitude.”

    They concluded, “In sum, structural brain metrics were largely similar among adolescent and young adult cannabis users and non-users.”

    The findings appear in the journal Neuropsychopharmacology.

    In the second study, researchers from the University of Colorado at Boulder compared magnetic resonance imaging (MRI) scans in 28 cannabis users over the age of 60 versus matched controls. Cannabis consumers, on average, had used marijuana weekly for 24 years.

    Authors reported that long-term cannabis exposure “does not have a widespread impact on overall cortical volumes while controlling for age, despite over two decades of regular cannabis use on average. This is in contrast to the large, widespread effects of alcohol on cortical volumes) that might be expected to negatively impact cognitive performance.” Researchers also reported “no significant differences between groups” with regard to cognitive performance.

    They concluded: “The current study was able to explore cannabis use in a novel older adult population that has seen recent dramatic increases in cannabis use while controlling for likely confounding variables (e.g., alcohol use). The participants in this study were generally healthy and highly educated, and it is in this context that cannabis use showed limited effects on brain structural measures or cognitive performance.”

    The findings appear in the journal Psychiatry Research: Neuroimaging.

    Commenting on the two studies, NORML Deputy Director Paul Armentano said, “These findings dispute the long-standing ‘stoner-stupid’ stereotype and should help to assuage fears that cannabis’ acute effects on neurocognitive behavior may persist long after drug ingestion, or that cannabis exposure is associated with any sort of significant changes in brain morphology.”

    The studies’ conclusions are similar to those of prior trials similarly finding no significant long-term changes in brain structure attributable to cannabis exposure.

    Full text of the study, “Cannabis use in youth is associated with limited alterations in brain structure,” appears in Neuropsychopharmacology. Full text of the study, “Preliminary results from a pilot study examining brain structure in older adult cannabis users and nonusers,” appears in Psychiatry Research: Neuroimaging.

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