Structural and Functional Imaging Studies in Chronic Cannabis Users: A Systematic Review of Adolescent and Adult Findings

PLoS ONE, Journal Year: 2013, Volume and Issue: 8(2), P. e55821 - e55821

Published: Feb. 4, 2013

The growing concern about cannabis use, the most commonly used illicit drug worldwide, has led to a significant increase in number of human studies using neuroimaging techniques determine effect on brain structure and function. We conducted systematic review assess evidence impact chronic use function adults adolescents.Papers published until August 2012 were included from EMBASE, Medline, PubMed LILACS databases following comprehensive search strategy pre-determined set criteria for article selection. Only involving users with matched control group considered.One hundred forty-two identified, which 43 met established criteria. Eight adolescent population. Neuroimaging provide morphological alterations both population groups, particularly medial temporal frontal cortices, as well cerebellum. These effects may be related amount exposure. Functional suggest different patterns resting global activity during performance several cognitive tasks adolescents adults, indicate compensatory response exposure.However, results pointed out methodological limitations work date considerable heterogeneity findings.Chronic alter adult Further should consider convergent methodology, prospective large samples adulthood subjects, data-sharing initiatives.

Language: Английский

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Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations

American Journal of Public Health, Journal Year: 2017, Volume and Issue: 107(8), P. e1 - e12

Published: June 23, 2017

Cannabis use is common in North America, especially among young people, and associated with a risk of various acute chronic adverse health outcomes. control regimes are evolving, for example toward national legalization policy Canada, the aim to improve public health, thus require evidence-based interventions. As cannabis-related outcomes may be influenced by behaviors that modifiable user, Lower-Risk Use Guidelines (LRCUG)-akin similar guidelines other fields-offer valuable, targeted prevention tool outcomes.To systematically review, update, quality-grade evidence on behavioral factors determining from cannabis translate this into revised LRCUG as intervention based an expert consensus process.We used pertinent medical search terms structured strategies, MEDLINE, EMBASE, PsycINFO, Cochrane Library databases, reference lists primarily systematic reviews meta-analyses, additional use.We included studies if they focused potentially behavior-based risks or harms use, excluded was assessed therapeutic purposes.We screened titles abstracts all identified strategy full texts eligible inclusion; 2 authors independently extracted data review. We created Preferred Reporting Items Systematic Reviews Meta-Analyses flow-charts each topical searches. Subsequently, we summarized factor topic, quality-graded it following standard (Grading Recommendations Assessment, Development, Evaluation; GRADE) criteria, translated recommendations author collective basis iterative process.For most recommendations, there at least "substantial" (i.e., good-quality) evidence. developed 10 major lower-risk use: (1) effective way avoid use-related abstinence, (2) early age initiation definitively before 16 years), (3) choose low-potency tetrahydrocannabinol (THC) balanced THC-to-cannabidiol (CBD)-ratio products, (4) abstain using synthetic cannabinoids, (5) combusted inhalation give preference nonsmoking methods, (6) deep risky practices, (7) high-frequency (e.g., daily near-daily) (8) cannabis-impaired driving, (9) populations higher problems should altogether, (10) combining previously mentioned use).Evidence indicates substantial extent reduced informed choices users. The serve population-level education inform such user improved However, ought communicated supported key regulation measures product labeling, content regulation) effective. All these concretely possible under emerging regimes, actively implemented regulatory authorities. impact reducing evaluated. Public implications. including uncertain impacts health. Evidence-based offer valuable reduce (especially young) users contexts, hence contribute

Language: Английский

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Long-Term Effects of Cannabis on Brain Structure

Neuropsychopharmacology, Journal Year: 2014, Volume and Issue: 39(9), P. 2041 - 2048

Published: March 17, 2014

The dose-dependent toxicity of the main psychoactive component cannabis in brain regions rich cannabinoid CB1 receptors is well known animal studies. However, research humans does not show common findings across studies regarding that are affected after long-term exposure to cannabis. In present study, we investigate (using Voxel-based Morphometry) gray matter changes a group regular smokers comparison with occasional matched by years use. We provide evidence use associated volume reduction medial temporal cortex, pole, parahippocampal gyrus, insula, and orbitofrontal cortex; these functionally motivational, emotional, affective processing. Furthermore, correlate frequency 3 months before inclusion study. age onset drug also influences magnitude changes. Significant could result either from heavy consumption unrelated or instead recreational initiated at an adolescent age. contrast, larger detected cerebellum without any correlation monthly may be related developmental (ontogenic) processes occur adolescence.

Language: Английский

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Effect of long-term cannabis use on axonal fibre connectivity

Brain, Journal Year: 2012, Volume and Issue: 135(7), P. 2245 - 2255

Published: June 4, 2012

Cannabis use typically begins during adolescence and early adulthood, a period when cannabinoid receptors are still abundant in white matter pathways across the brain. However, few studies to date have explored impact of regular cannabis on structure, with no previous examining its axonal connectivity. The aim this study was examine fibre brain for evidence microstructural alterations associated long-term test whether age is severity any change. To end, diffusion-weighted magnetic resonance imaging connectivity mapping techniques were performed 59 users longstanding histories heavy 33 matched controls. Axonal found be impaired right fimbria hippocampus (fornix), splenium corpus callosum commissural fibres. Radial axial diffusivity these at which commenced. Our findings indicate hazardous developing Delaying may minimize impairment.

Language: Английский

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GABAergic mechanisms of hippocampal hyperactivity in schizophrenia

Schizophrenia Research, Journal Year: 2014, Volume and Issue: 167(1-3), P. 4 - 11

Published: Oct. 18, 2014

Language: Английский

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Cannabis Use Is Quantitatively Associated with Nucleus Accumbens and Amygdala Abnormalities in Young Adult Recreational Users

Journal of Neuroscience, Journal Year: 2014, Volume and Issue: 34(16), P. 5529 - 5538

Published: April 16, 2014

Marijuana is the most commonly used illicit drug in United States, but little known about its effects on human brain, particularly reward/aversion regions implicated addiction, such as nucleus accumbens and amygdala. Animal studies show structural changes brain after exposure to Δ9-tetrahydrocannabinol, less cannabis use morphometry these humans. We collected high-resolution MRI scans young adult recreational marijuana users nonusing controls conducted three independent analyses of structures: (1) gray matter density using voxel-based morphometry, (2) volume (total regional volumes), (3) shape (surface morphometry). Gray revealed greater than control participants left extending subcallosal cortex, hypothalamus, sublenticular extended amygdala, even controlling for age, sex, alcohol use, cigarette smoking. Trend-level were observed a increase only. Significant differences detected right The showed salient exposure-dependent alterations across all measures an altered multimodal relationship group. These data suggest that exposure, users, associated with neural matrix core reward structures consistent animal dendritic arborization.

Language: Английский

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Long-term effects of marijuana use on the brain

Proceedings of the National Academy of Sciences, Journal Year: 2014, Volume and Issue: 111(47), P. 16913 - 16918

Published: Nov. 10, 2014

Questions surrounding the effects of chronic marijuana use on brain structure continue to increase. To date, however, findings remain inconclusive. In this comprehensive study that aimed characterize alterations associated with use, we measured gray matter (GM) volume via structural MRI across whole by using voxel-based morphology, synchrony among abnormal GM regions during resting state functional connectivity MRI, and white integrity (i.e., connectivity) between diffusion tensor imaging in 48 users 62 age- sex-matched nonusing controls. The results showed compared controls, had significantly less bilateral orbitofrontal gyri volume, higher cortex (OFC) network, tracts innervate OFC (forceps minor) as fractional anisotropy (FA). Increased was earlier age onset. Lastly, a quadratic trend observed suggesting FA forceps minor tract initially increased following regular but decreased protracted use. This pattern may indicate differential initial reflect complex neuroadaptive processes response Despite onset effects, longitudinal studies are needed determine causality these effects.

Language: Английский

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Effects of Cannabis on the Adolescent Brain

Current Pharmaceutical Design, Journal Year: 2014, Volume and Issue: 20(13), P. 2186 - 2193

Published: May 10, 2014

This article reviews neuroimaging, neurocognitive, and preclinical findings on the effects of cannabis adolescent brain. Marijuana is second most widely used intoxicant in adolescence, teens who engage heavy marijuana use often show disadvantages neurocognitive performance, macrostructural microstructural brain development, alterations functioning. It remains unclear whether such reflect pre-existing differences that lead to increased substances further changes architecture behavioral outcomes. Future work should focus prospective investigations help disentangle dose-dependent from effects, better understand interactive relationships with other commonly abused (e.g., alcohol) role regular neurodevelopmental trajectories.

Language: Английский

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Positive and Negative Effects of Cannabis and Cannabinoids on Health

Clinical Pharmacology & Therapeutics, Journal Year: 2019, Volume and Issue: 105(5), P. 1139 - 1147

Published: Jan. 31, 2019

Cannabis is the most popular illicit drug in Western world. Repeated cannabis use has been associated with short‐ and long‐term side effects, including respiratory cardiovascular disorders, cognitive alterations, psychosis, schizophrenia, mood disorders. However, casual relations between these adverse effects are missing. On other hand, recent research proposed promising therapeutic potential of cannabinoid‐based drugs for a wide range medical conditions, neurological psychiatric The current article presents contemporary review on safety, drugs. Given growing popularity both recreational purposes their harmful there need further investigation this field.

Language: Английский

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The neuropsychopharmacology of cannabis: A review of human imaging studies

Pharmacology & Therapeutics, Journal Year: 2018, Volume and Issue: 195, P. 132 - 161

Published: Oct. 20, 2018

The laws governing cannabis are evolving worldwide and associated with changing patterns of use. main psychoactive drug in is Δ9-tetrahydrocannabinol (THC), a partial agonist at the endocannabinoid CB1 receptor. Acutely, THC produce range effects on several neurocognitive pharmacological systems. These include executive, emotional, reward memory processing via direct interactions system indirect glutamatergic, GABAergic dopaminergic Cannabidiol, non-intoxicating cannabinoid found some forms cannabis, may offset these acute effects. Heavy repeated use, particularly during adolescence, has been adverse systems, which increase risk mental illnesses including addiction psychosis. Here, we provide comprehensive state art review chronic neuropsychopharmacology by synthesizing available neuroimaging research humans. We describe exposure development, implications for understanding psychosis use disorder, methodological considerations. Greater precise mechanisms underlying also give rise to new treatment targets.

Language: Английский

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