Query: Cannabis

title: The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU GEI) a multicentre case control study
abstract: Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder.  We included patients aged 18 64 years who presented to psychiatric services in 11 sites across Europe and Brazil with first episode psychosis and recruited controls representative of the local populations. We applied adjusted logistic regression models to the data to estimate which patterns of cannabis use carried the highest odds for psychotic disorder. Using Europe wide and national data on the expected concentration of D9 tetrahydrocannabinol (THC) in the different types of cannabis available across the sites, we divided the types of cannabis used by participants into two categories: low potency (THC <10% and high potency (THC =10% Assuming causality, we calculated the population attributable fractions (PAFs) for the patterns of cannabis use associated with the highest odds of psychosis and the correlation between such patterns and the incidence rates for psychotic disorder across the study sites.  Between May 1, 2010, and April 1, 2015, we obtained data from 901 patients with first episode psychosis across 11 sites and 1237 population controls from those same sites. Daily cannabis use was associated with increased odds of psychotic disorder compared with never users (adjusted odds ratio [OR] 3*2, 95% CI 2*2 4*1) increasing to nearly five times increased odds for daily use of high potency types of cannabis (4*8, 2*5 6*3) The PAFs calculated indicated that if high potency cannabis were no longer available, 12*2% (95% CI 3*0 16*1) of cases of first episode psychosis could be prevented across the 11 sites, rising to 30*3% (15*2 40*0) in London and 50*3% (27*4 66*0) in Amsterdam. The adjusted incident rates for psychotic disorder were positively correlated with the prevalence in controls across the 11 sites of use of high potency cannabis (r 0*7; p=0*0286) and daily use (r 0*8; p=0*0109)  Differences in frequency of daily cannabis use and in use of high potency cannabis contributed to the striking variation in the incidence of psychotic disorder across the 11 studied sites. Given the increasing availability of high potency cannabis, this has important implications for public health.

title: Association of Cannabis Use in Adolescence and Risk of Depression, Anxiety, and Suicidality in Young Adulthood: A Systematic Review and Meta analysis
abstract: Importance Cannabis is the most commonly used drug of abuse by adolescents in the world. While the impact of adolescent cannabis use on the development of psychosis has been investigated in depth, little is known about the impact of cannabis use on mood and suicidality in young adulthood.  To provide a summary estimate of the extent to which cannabis use during adolescence is associated with the risk of developing subsequent major depression, anxiety, and suicidal behavior.  Medline, Embase, CINAHL, PsycInfo, and Proquest Dissertations and Theses were searched from inception to January 2017. Study Selection Longitudinal and prospective studies, assessing cannabis use in adolescents younger than 18 years (at least 1 assessment point) and then ascertaining development of depression in young adulthood (age 18 to 32 years) were selected, and odds ratios (OR) adjusted for the presence of baseline depression and/or anxiety and/or suicidality were extracted.  Study quality was assessed using the Research Triangle Institute item bank on risk of bias and precision of observational studies. Two reviewers conducted all review stages independently. Selected data were pooled using random effects meta analysis.  The studies assessing cannabis use and depression at different points from adolescence to young adulthood and reporting the corresponding OR were included. In the studies selected, depression was diagnosed according to the third or fourth editions of Diagnostic and Statistical Manual of Mental Disorders or by using scales with predetermined cutoff points.  After screening 3142 articles, 269 articles were selected for full text review, 35 were selected for further review, and 11 studies comprising 23 317 individuals were included in the quantitative analysis. The OR of developing depression for cannabis users in young adulthood compared with nonusers was 1.37 (95% CI, 1.16 1.62; I2 0% The pooled OR for anxiety was not statistically significant: 1.18 (95% CI, 0.84 1.67; I2 42% The pooled OR for suicidal ideation was 1.50 (95% CI, 1.11 2.03; I2 0% and for suicidal attempt was 3.46 (95% CI, 1.53 7.84, I2 61.3% Conclusions and Relevance Although individual level risk remains moderate to low and results from this study should be confirmed in future adequately powered prospective studies, the high prevalence of adolescents consuming cannabis generates a large number of young people who could develop depression and suicidality attributable to cannabis. This is an important public health problem and concern, which should be properly addressed by health care policy.

title: New trends in cannabis potency in USA and Europe during the last decade (2008 2017)
abstract: Through the potency monitoring program at the University of Mississippi supported by National Institute on Drug Abuse (NIDA) a total of 18108 samples of cannabis preparations have been analyzed over the last decade, using a validated GC/FID method. The samples are classified as sinsemilla, marijuana, ditchweed, hashish, and hash oil (now referred to as cannabis concentrate) The number of samples received over the last 5 years has decreased dramatically due to the legalization of marijuana either for medical or for recreational purposes in many US states. The results showed that the mean D9 THC concentration has increased dramatically over the last 10 years, from 8.9% in 2008 to 17.1% in 2017. The mean D9 THC:CBD ratio also rose substantially from 23 in 2008 to 104 in 2017. There was also marked increase in the proportion of hash oil samples (concentrates) seized (0.5 4.7% and their mean D9 THC concentration (6.7 55.7% from 2008 to 2017. Other potency monitoring programs are also present in several European countries such as The Netherlands, United Kingdom, France, and Italy. These programs have also documented increases in D9 THC concentrations and D9 THC:CBD ratios in cannabis. These trends in the last decade suggest that cannabis is becoming an increasingly harmful product in the USA and Europe.

title: The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research
abstract: Recent years have seen a rapid rise in the medical and recreational use of cannabis: a broad term that can be used to describe the various products and chemical compounds (e.g. marijuana, cannabinoids) derived from different species of the cannabis plant. Despite increased cannabis use and a changing state level policy landscape, conclusive evidence regarding the shortand long term health effects both harms and benefits of cannabis use remains elusive.

title: Public health implications of legalising the production and sale of cannabis for medicinal and recreational use
abstract: We assess the current and describe possible future public health impacts of the legalisation of cannabis production, sale, and use in the Americas. First, we describe global patterns of cannabis use and their most probable adverse health effects. Second, we summarise evidence regarding the effectiveness of cannabinoids for medicinal use and describe approaches that have been used to regulate the use of medicinal cannabis and how these approaches might have affected medicinal and recreational use and harms (eg, road crashes) Third, we describe how jurisdictions that have legalised recreational use have regulated production and sale of cannabis. Fourth, we evaluate the effects of cannabis legalisation on cannabis use and harms and on the use of alcohol, tobacco, and other drugs. Fifth, we use alcohol and tobacco policy examples to identify possible long term public health effects of cannabis legalisation. Finally, we outline policy approaches that could minimise harms to public health arising from the legalisation of a commercial cannabis industry.

title: Increasing potency and price of cannabis in Europe, 2006 16
abstract: To quantify changes in (i) potency (concentration of D9 tetrahydrocannabinol; %THC) (ii) price (euros/g of cannabis) and (iii) value (mg THC/euro) of cannabis resin and herbal cannabis in Europe.  Repeated cross sectional study.  Data collected from 28 European Union (EU) member states, Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction.  Outcome variables were potency, price and value for cannabis resin and herbal cannabis in Europe, 2006 16. Inflation was estimated using the Harmonised Indices of Consumer Prices. Mixed effects linear regression models were used to estimate linear and quadratic time trends, with a random intercept and slope fitted to account for variation across countries.  Resin potency increased from a mean [95% confidence interval (CI) of 8.14% THC (6.89, 9.49) in 2006 to 17.22 (15.23, 19.25) in 2016. Resin price increased from 8.21 euros/g (7.54, 8.97) to 12.27 (10.62, 14.16) Resin increased in value, from 11.00 mg THC per euro (8.60, 13.62) to 16.39 (13.68, 19.05) Quadratic time trends for resin potency and value indicated minimal change from 2006 to 2011, followed by marked increases from 2011 to 2016. Herbal cannabis potency increased from 5.00% THC (3.91, 6.23) to 10.22 (9.01, 11.47) Herbal price increased from 7.36 euros/g (6.22, 8.53) to 12.22 (10.59, 14.03) The value of herbal cannabis did not change from 12.65 mg of THC per euro (10.18, 15.34) to 12.72 (10.73, 14.73) All price trends persisted after adjusting for inflation.  European cannabis resin and herbal cannabis increased in potency and price from 2006 to 2016. Cannabis resin (but not herbal cannabis) increased in the quantity of D9 tetrahydrocannabinol per euro spent. Marked increases in resin potency and value from 2011 to 2016 are consistent with the emergence of new resin production techniques in European and neighbouring drug markets.

title: The Case for the Entourage Effect and Conventional Breeding of Clinical Cannabis: No "Strain," No Gain
abstract: The topic of Cannabis curries controversy in every sphere of influence, whether politics, pharmacology, applied therapeutics or even botanical taxonomy. Debate as to the speciation of Cannabis, or a lack thereof, has swirled for more than 250 years. Because all Cannabis types are eminently capable of cross breeding to produce fertile progeny, it is unlikely that any clear winner will emerge between the "lumpers" vs. "splitters" in this taxonomical debate. This is compounded by the profusion of Cannabis varieties available through the black market and even the developing legal market. While labeled "strains" in common parlance, this term is acceptable with respect to bacteria and viruses, but not among Plantae. Given that such factors as plant height and leaflet width do not distinguish one Cannabis plant from another and similar difficulties in defining terms in Cannabis, the only reasonable solution is to characterize them by their biochemical/pharmacological characteristics. Thus, it is best to refer to Cannabis types as chemical varieties, or "chemovars." The current wave of excitement in Cannabis commerce has translated into a flurry of research on alternative sources, particularly yeasts, and complex systems for laboratory production have emerged, but these presuppose that single compounds are a desirable goal. Rather, the case for Cannabis synergy via the "entourage effect" is currently sufficiently strong as to suggest that one molecule is unlikely to match the therapeutic and even industrial potential of Cannabis itself as a phytochemical factory. The astounding plasticity of the Cannabis genome additionally obviates the need for genetic modification techniques.

title: The neuropsychopharmacology of cannabis: A review of human imaging studies
abstract: The laws governing cannabis are evolving worldwide and associated with changing patterns of use. The main psychoactive drug in cannabis is &Dgr;9 tetrahydrocannabinol (THC) a partial agonist at the endocannabinoid CB1 receptor. Acutely, cannabis and THC produce a range of effects on several neurocognitive and pharmacological systems. These include effects on executive, emotional, reward and memory processing via direct interactions with the endocannabinoid system and indirect effects on the glutamatergic, GABAergic and dopaminergic systems. Cannabidiol, a non intoxicating cannabinoid found in some forms of cannabis, may offset some of these acute effects. Heavy repeated cannabis use, particularly during adolescence, has been associated with adverse effects on these systems, which increase the risk of mental illnesses including addiction and psychosis. Here, we provide a comprehensive state of the art review on the acute and chronic neuropsychopharmacology of cannabis by synthesizing the available neuroimaging research in humans. We describe the effects of drug exposure during development, implications for understanding psychosis and cannabis use disorder, and methodological considerations. Greater understanding of the precise mechanisms underlying the effects of cannabis may also give rise to new treatment targets.

title: Association between medical cannabis laws and opioid overdose mortality has reversed over time
abstract: Medical cannabis has been touted as a solution to the US opioid overdose crisis since Bachhuber et al. [M. A. Bachhuber, B. Saloner, C. O. Cunningham, C. L. Barry, JAMA Intern. Med. 174, 1668 1673] found that from 1999 to 2010 states with medical cannabis laws experienced slower increases in opioid analgesic overdose mortality. That research received substantial attention in the scientific literature and popular press and served as a talking point for the cannabis industry and its advocates, despite caveats from the authors and others to exercise caution when using ecological correlations to draw causal, individual level conclusions. In this study, we used the same methods to extend Bachhuber et al.'s analysis through 2017. Not only did findings from the original analysis not hold over the longer period, but the association between state medical cannabis laws and opioid overdose mortality reversed direction from 21% to +23% and remained positive after accounting for recreational cannabis laws. We also uncovered no evidence that either broader (recreational) or more restrictive (low tetrahydrocannabinol) cannabis laws were associated with changes in opioid overdose mortality. We find it unlikely that medical cannabis used by about 2.5% of the US population has exerted large conflicting effects on opioid overdose mortality. A more plausible interpretation is that this association is spurious. Moreover, if such relationships do exist, they cannot be rigorously discerned with aggregate data. Research into therapeutic potential of cannabis should continue, but the claim that enacting medical cannabis laws will reduce opioid overdose death should be met with skepticism.

title: Terpenes in Cannabis sativa From plant genome to humans.
abstract: Cannabis sativa (cannabis) produces a resin that is valued for its psychoactive and medicinal properties. Despite being the foundation of a multi billion dollar global industry, scientific knowledge and research on cannabis is lagging behind compared to other high value crops. This is largely due to legal restrictions that have prevented many researchers from studying cannabis, its products, and their effects in humans. Cannabis resin contains hundreds of different terpene and cannabinoid metabolites. Many of these metabolites have not been conclusively identified. Our understanding of the genomic and biosynthetic systems of these metabolites in cannabis, and the factors that affect their variability, is rudimentary. As a consequence, there is concern about lack of consistency with regard to the terpene and cannabinoid composition of different cannabis 'strains' Likewise, claims of some of the medicinal properties attributed to cannabis metabolites would benefit from thorough scientific validation.