The 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 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 suiteSchizotypy and psychosis-like experiences from recreational cannabis in a non-clinical sample Emma Barkus, Shon Lewis Psychological Medicine, 2008, 38, 1267-1276. doi:10.1017/S0033291707002619 Research On Line, University of Wollongong, 2008 Copyright Cambridge University Press. Abstract Background : The relationship between cannabis use and psychosis is still a matter for debate. Accounting for the individual differences in subjective experiences to recreational cannabis use in the general population may hold some clues to the aetiological relationship between cannabis and psychotic symptoms. We hypothesized that schizotypy would account for the individual differences in subjective experiences after cannabis use but not in patterns of use. Method : In a sample of 532 young people [...]
Lire la suiteCannabis-induced psychosis-like experiences are associated with high schizotypy BARKUS E.J., STIRLING J., HOPKINS R.S., LEWIS S. Psychopathology, 2006, 39, 4, 175-178 PMID : 16636640 DOI : 10.1159/000092678 Abstract OBJECTIVE: Recent studies have suggested that cannabis use is a risk factor for developing schizophrenia. We tested the hypothesis that cannabis use increases the likelihood of psychosis-like experiences in non-clinical participants who scored highly on a measure of schizotypy. METHOD: The psychological effects of cannabis were assessed in 137 healthy individuals (76% female, mean age 22 years) using a newly developed questionnaire concerned with subjective experiences of the drug: the Cannabis Experiences Questionnaire. The questionnaire has three subscales: Pleasurable [...]
Lire la suiteAcute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: A randomised, double-blind, placebo-controlled study in cannabis users Chandni Hindocha, Tom P. Freeman, Grainne Schafer, Chelsea Gardener, Ravi K. Das, Celia J.A. Morgan and H. Valerie Curran Eur Neuropsychopharmacology, 2015, 25, 3, 325–334. doi:10.1016/j.euroneuro.2014.11.014 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4398332/?report=printable Abstract Acute administration of the primary psychoactive constituent of cannabis, Δ-9-tetrahydrocannabinol (THC), impairs human facial affect recognition, implicating the endocannabinoid system in emotional processing. Another main constituent of cannabis, cannabidiol (CBD), has seemingly opposite functional effects on the brain. This study aimed to determine the effects of THC and CBD, both alone and in combination on emotional facial affect [...]
Lire la suiteClinical and Preclinical Evidence for Functional Interactions of Cannabidiol and Δ9-Tetrahydrocannabinol Douglas L. Boggs, Jacques D. Nguyen, Daralyn Morgenson, Michael A. Taffe and and Mohini Ranganathan Neuropsychopharmacology, 2018, 43, 142-154 Doi : 10.1038/npp.2017.209; published online 18 October 2017 Abstract The plant Cannabis sativa, commonly called cannabis or marijuana, has been used for its psychotropic and mind-altering side effects for millennia. There has been growing attention in recent years on its potential therapeutic efficacy as municipalities and legislative bodies in the United States, Canada, and other countries grapple with enacting policy to facilitate the use of cannabis or its constituents for medical purposes. There are >550 [...]
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