Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition. Arkell T.R., Lintzeris N., Kevin R.C., Ramaekers J.G., Vandrey R., Irwin C., Haber P.S., McGregor I.S. Psychopharmacology (Berlin), 2019 DOI : 10.1007/s00213-019-05246-8 PMID : 31044290 Abstract BACKGROUND : The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can impair driving performance. Cannabidiol (CBD), a non-intoxicating cannabis component, is thought to mitigate certain adverse effects of THC. It is possible then that cannabis containing equivalent CBD and THC will differentially affect driving and cognition relative to THC-dominant cannabis. AIMS : The present study investigated and compared the effects of THC-dominant and [...]
Lire la suiteDoes cannabidiol protect against adverse psychological effects of THC ? Raymond J. M. Niesink and Margriet W. van Laar Frontiers in Psychiatry, 2013, 4, 130 doi : 10.3389/fpsyt.2013.00130. Abstract The recreational use of cannabis can have persistent adverse effects on mental health. Delta 9-tetrahydro-cannabinol (THC) is the main psychoactive constituent of cannabis, and most, if not all, of the effects associated with the use of cannabis are caused by THC. Recent studies have suggested a possible protective effect of another cannabinoid, cannabidiol (CBD). A literature search was performed in the bibliographic databases PubMed, PsycINFO, andWeb of Science using the keyword “cannabidiol.” After removing duplicate entries, [...]
Lire la suiteDebate over recreational cannabis use legalisation in Canada Paul Webster The Lancet, 2018, 391, 725-726 www.thelancet.com February 24, 2018 The Trudeau Government presents this proposed law as a boon for public health and safety, but debate rages over cannabis-harm reduction in youths. Paul Webster reports from Toronto. As Canada prepares to legalise recreational cannabis use next summer, the government faces increasingly tough questions about a widely praised national drug control experiment being closely watched internationally. “We’re approaching it purely from a public health and safety standpoint”, Prime Minister Justin Trudeau explained in a televised gathering in Toronto last autumn. “The questions around revenue and taxation are [...]
Lire la suiteThe neuropsychopharmacology of cannabis : A review of human imaging studies Michael A.P. Bloomfield, Chandni Hindocha, Sebastian F. Green, Matthew B.Wall, Rachel Lees, Katherine Petrilli, Harry Costello, M. Olabisi Ogunbiyi, Matthijs G. Bossong, Tom P. Freeman Pharmacology & Therapeutics, 2019, 195, 132-161 doi : 10.1016/j.pharmthera.2018.10.006 a b s t r a c t The laws governing cannabis are evolving worldwide and associated with changing patterns of use. The main psychoactive drug in cannabis is Δ9-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, [...]
Lire la suiteLong-Term Stress and Concomitant Marijuana Smoke Exposure Affect Physiology, Behavior and Adult Hippocampal Neurogenesis Kitti Rusznák, Kata Csekö, Zsófia Varga, Dávid Csabai, Ágnes Bóna, Mátyás Mayer, Zsolt Kozma, Zsuzsanna Helyes and Boldizsár Czéh Frontiers in Pharmacology, 2018, 9, 786 doi: 10.3389/fphar.2018.00786. eCollection 2018 www.frontiersin.org Abstract Marijuana is a widely used recreational drug with increasing legalization worldwide for medical purposes. Most experimental studies use either synthetic or plant-derived cannabinoids to investigate the effect of cannabinoids on anxiety and cognitive functions. The aim of this study was to mimic real life situations where young people smoke cannabis regularly to relax from everyday stress. Therefore, we exposed young adult [...]
Lire la suiteRegular cannabis use is associated with altered activation of central executive and default mode networks even after prolonged abstinence in adolescent users : Results from a complementary meta-analysis Grace Blest-Hopley, Vincent Giampietro and Sagnik Bhattacharyya Neuroscience & Biobehavioral Reviews, 2019, 96, 45–55. doi: 10.1016/j.neubiorev.2018.10.026: 10.1016/j.neubiorev.2018.10.026 PMCID: PMC6331661 PMID: 30395923 Abstract Whether the effects of cannabis use on brain function persist or recover following abstinence remains unclear. Therefore, using meta-analytic techniques, we examined whether functional alterations measured using fMRI persist in cannabis users abstinent for over 25 days (or 600 h) as evidence suggests that the effects on cognitive performance no longer persist beyond this period. Systematic literature search [...]
Lire la suiteDelta-9-tetrahydrocannabinol increases striatal glutamate levels in healthy individuals: implications for psychosis. Colizzi M., Weltens N., McGuire P., Lythgoe D., Williams S., Van Oudenhove L., Bhattacharyya S. Molecular Psychiatry, 2019 doi : 10.1038/s41380-019-0374-8. PMID : 30770892 Abstract The neurobiological mechanisms underlying the association between cannabis use and acute or long-lasting psychosis are not completely understood. While some evidence suggests altered striatal dopamine may underlie the association, direct evidence that cannabis use affects either acute or chronic striatal dopamine is inconclusive. In contrast, pre-clinical research suggests that cannabis may affect dopamine via modulation of glutamate signaling. A double-blind, randomized, placebo-controlled, crossover design was used to investigate whether [...]
Lire la suiteThe effects of Δ9-tetrahydrocannabinol on the dopamine system Michael A P Bloomfield, Abhishekh H Ashok, Nora D Volkow, and Oliver D Howes Nature, 2016, 539, 7629, 369–377. doi : 10.1038/nature20153. Preface Δ9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, is a pressing concern to global mental health. Patterns of use are changing drastically due to legalisation, availability of synthetic analogues (‘spice’), cannavaping and aggrandizements in the purported therapeutic effects of cannabis. Many of THC’s reinforcing effects are mediated by the dopamine system. Due to complex cannabinoid-dopamine interactions there is conflicting evidence from human and animal research fields. Acute THC causes increased dopamine release and neuron [...]
Lire la suiteDescriptive Psychopathology of the Acute Effects of Intravenous Delta-9-Tetrahydrocannabinol Administration in Humans Marco Colizzi, NathalieWeltens, Philip McGuire, Lukas Van Oudenhove and Sagnik Bhattacharyya Brain Sciences, 2019, 9, 93 doi : 10.3390/brainsci9040093 Abstract : Background : Cannabis use can increase the risk of psychosis, and the acute administration of its key psychoactive ingredient, delta-9-tetrahydrocannabinol (D9-THC), can induce transient psychotomimetic symptoms. Methods : A double-blind, randomized, placebo-controlled crossover design was used to investigate the symptomatic effects of acute intravenous administration of D9-THC (1.19 mg/2 mL) in 16 healthy participants (seven males) with modest previous cannabis exposure. Results : In the 20 min following acute D9-THC administration, symptomatic effects of [...]
Lire la suiteDoes Cannabis Composition Matter? Differential Effects of Delta-9-tetrahydrocannabinol and Cannabidiol on Human Cognition Marco Colizzi & Sagnik Bhattacharyya Current Addiction Reports, 2017, 4, 62–74 DOI 10.1007/s40429-017-0142-2 Abstract Purpose of Review : The lack of clarity about the effect of cannabis use on cognition may be attributable to the considerable heterogeneity among studies in terms of cannabis composition. This article selectively reviews studies examining the distinctive effects of cannabinoids on human cognition, particularly those of delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). Recent Findings : Research indicates that Δ9-THC administration acutely impairs cognition, particularly memory and emotional processing. Limited evidence suggests that CBD administration might improve cognition in cannabis [...]
Lire la suite