Benefits and risks of cannabinoids

Cannabis is used by an estimated 219 million adults globally (4.3% of the population) with a particularly high prevalence in North America (17.4% of the population).1 The 1961 UN Single Convention on Narcotic Drugs included cannabis with opioids and cocaine as a controlled substance whose use was prohibited, but policies have changed considerably in recent decades. Medical use of cannabis is now permitted in large parts of North and South America, Europe, and Oceania; although, patient access varies considerably across jurisdictions. The use of cannabis for non-medical purposes is also now permitted in Canada, 22 US states, and Uruguay, and several other countries are considering allowing adult use in some form (eg, Germany, Luxembourg, Malta, the Netherlands, and Switzerland). In this rapidly changing policy climate, high quality evidence on benefits and risks are needed to inform policy and clinical practice

'Standard THC Units':a proposal to standardise dose across all cannabis products and methods of administration

Background and Aims Cannabis products are becoming increasingly diverse, and vary considerably in concentrations of ∆9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Higher doses of THC can increase the risk of harm from cannabis, while CBD may partially offset some of these effects. Lower Risk Cannabis Use Guidelines currently lack recommendations based on quantity of use, and could be improved by implementing standard units. However, there is currently no consensus on how units should be measured or standardized among different cannabis products or methods of administration. Argument Existing proposals for standard cannabis units have been based on specific methods of administration (e.g. joints) and these may not capture other methods, including pipes, bongs, blunts, dabbing, vaporizers, vape pens, edibles and liquids. Other proposals (e.g. grams of cannabis) cannot account for heterogeneity in THC concentrations among different cannabis products. Similar to alcohol units, we argue that standard cannabis units should reflect the quantity of primary active pharmacological constituents (dose of THC). On the basis of experimental and ecological data, public health considerations and existing policy, we propose that a ‘standard THC unit’ should be fixed at 5 mg THC for all cannabis products and methods of administration. If supported by sufficient evidence in future, consumption of standard CBD units might offer an additional strategy for harm reduction. Conclusions Standard ∆9-tetrahydrocannabinol (THC) units can potentially be applied among all cannabis products and methods of administration to guide consumers and promote safer patterns of use

Using the standard THC unit to regulate THC content in legal cannabis markets [Commentary]

Abstract not available

Estimating the location of the open-closed magnetic field line boundary from auroral images

The open-closed magnetic field line boundary (OCB) delimits the region of open magnetic flux forming the polar cap in the Earth’s ionosphere. We present a reliable, automated method for determining the location of the poleward auroral luminosity boundary (PALB) from far ultraviolet (FUV) images of the aurora, which we use as a proxy for the OCB. This technique models latitudinal profiles of auroral luminosity as both a single and double Gaussian function with a quadratic background to produce estimates of the PALB without prior knowledge of the level of auroral activity or of the presence of bifurcation in the auroral oval. We have applied this technique to FUV images recorded by the IMAGE satellite from May 2000 until August 2002 to produce a database of over a million PALB location estimates, which is freely available to download. From this database, we assess and illustrate the accuracy and reliability of this technique during varying geomagnetic conditions. We find that up to 35% of our PALB estimates are made from double Gaussian fits to latitudinal intensity profiles, in preference to single Gaussian fits, in nightside magnetic local time (MLT) sectors. The accuracy of our PALBs as a proxy for the location of the OCB is evaluated by comparison with particle precipitation boundary (PPB) proxies from the DMSP satellites. We demonstrate the value of this technique in estimating the total rate of magnetic reconnection from the time variation of the polar cap area calculated from our OCB estimates

The effect of conflicting public health guidance on smokers' and vapers’ e-cigarette harm perceptions

BACKGROUND: E-cigarettes are increasingly being viewed, incorrectly, as more harmful than cigarettes. This may discourage smokers from switching to e-cigarettes. One potential explanation for these increasingly harmful attitudes is conflicting information presented in the media and online, and from public health bodies. AIMS AND METHODS: In this prospectively registered online study, we aimed to examine the impact of conflicting public health information on smokers’ and vapers’ e-cigarette harm perceptions. Daily UK smokers who do not vape (n = 334) and daily UK vapers (n = 368) were randomized to receive either: (1) a consistent harm reduction statement from two different public health bodies (Harm Reduction), (2) a consistent negative statement about e-cigarette harms from two different public health bodies (Negative), (3) a harm reduction statement from one public health body and a negative statement from another (Conflict), and (4) a statement of the risks of smoking followed by a harm reduction statement from one public health body and a negative statement from another (Smoking Risk + Conflict). Participants then answered questions regarding their perceptions of e-cigarette harm. RESULTS: The Negative condition had the highest e-cigarette harm perceptions, significantly higher than the Smoking Risk + Conflict condition (MD = 5.4, SE = 1.8, p < .016, d = 0.3 [CI 0.73 to 10.04]), which did not differ from the Conflict condition (MD = 1.5, SE = 1.8, p = .836, d = 0.1 [CI −3.14 to 6.17]). The Conflict condition differed from the Harm Reduction condition, where harm perceptions were lowest (MD = 5.4, SE = 1.8, p = .016, d = 0.3 [CI 0.74 to 10.07]). CONCLUSIONS: These findings are the first to demonstrate that, compared to harm reduction information, conflicting information increases e-cigarette harm perceptions amongst vapers, and smokers who do not vape. IMPLICATIONS: This research provides the first empirical evidence that conflicting information increases smokers’ and vapers’ e-cigarette harm perceptions, compared to harm reduction information. This may have a meaningful impact on public health as e-cigarette harm perceptions can influence subsequent smoking and vaping behavior. Conflicting information may dissuade smokers, who have the most to gain from accurate e-cigarette harm perceptions, from switching to e-cigarettes. These findings indicate that public health communications that are consensus-based can lower harm perceptions of e-cigarettes, and have the potential to reduce morbidity and mortality attributable to tobacco smoking

Effects of increasing cannabis potency on adolescent health

Cannabis is the most prevalent illicit drug used by adolescents worldwide. Over the past 40 years, changes in cannabis potency through rising concentrations of Δ-9-tetrahydrocannabiol (THC), decreases in cannabidiol, or both, have occurred. Epidemiological and experimental evidence demonstrates that cannabis with high THC concentrations and negligible cannabidiol concentrations is associated with an increased risk of psychotic outcomes, an effect on spatial working memory and prose recall, and increased reports of the severity of cannabis dependence. However, many studies have failed to address cannabis use in adolescence, the peak age at which individuals typically try cannabis and probably the most vulnerable age to experience its harmful effects. In this Review, we highlight the influence that changing cannabis products have on adolescent health and the implications they carry for policy and prevention measures as legal cannabis markets continue to emerge worldwide.</p

Acute and chronic effects of Δ⁹-tetrahydrocannabinol (THC) on cerebral blood flow:A systematic review

Acute and chronic exposure to cannabis and its main psychoactive component, Δ 9-tetrahydrocannabinol (THC), is associated with changes in brain function and cerebral blood flow (CBF). We therefore sought to systematically review the literature on the effects of THC on CBF following PRISMA guidelines. Studies assessing the acute and chronic effects of THC on CBF, perfusion and volume were searched in the PubMed database between January 1972 and June 2019. We included thirty-four studies, which altogether investigated 1259 humans and 28 animals. Acute and chronic THC exposure have contrasting and regionally specific effects on CBF. While acute THC causes an overall increase in CBF in the anterior cingulate cortex, frontal cortex and insula, in a dose-dependent manner, chronic cannabis use results in an overall reduction in CBF, especially in the prefrontal cortex, which may be reversed upon prolonged abstinence from the drug. Future studies should focus on standardised methodology and longitudinal assessment to strengthen our understanding of the region-specific effects of THC on CBF and its clinical and functional significance. </p