Effects Of Chronic Cannabis Use Research Articles

The Impact of Chronic Cannabis Use on Esophageal Motility in Patients Referred for Esophageal Manometry.

Tetrahydrocannabinol, the main psychoactive compound in cannabis, binds with high affinity to the cannabinoid 1 receptor. Small randomized controlled studies using conventional manometry have shown that the cannabinoid 1 receptor can modulate esophageal function, namely transient lower esophageal sphincter relaxation frequency and lower esophageal sphincter tone. The effect of cannabinoids on esophageal motility in patients referred for esophageal manometry has not been fully elucidated using high-resolution esophageal manometry (HREM). We aimed to characterize the clinical effect of chronic cannabis use on esophageal motility utilizing HREM. Patients who underwent HREM from 2009 to 2019 were identified at 4 academic medical centers. The study group consisted of patients with a noted history of chronic cannabis use, a diagnosis of cannabis-related disorder, or a positive urine toxicology screen. Age and gender-matched patients with no history of cannabis use were selected to form the control group. Data on HREM metrics based on the Chicago classification V3, and the prevalence of esophageal motility disorders were compared. Confounding effects of BMI and medications on esophageal motility were adjusted for. Chronic cannabis use was found to be an independent negative predictor of weak swallows (β=-8.02, P =0.0109), but not a predictor of failed swallows ( P =0.6890). The prevalence of ineffective esophageal motility was significantly lower in chronic cannabis users compared with nonusers (OR=0.44, 95% CI 0.19-0.93, P =0.0384). There was no significant difference in the prevalence of other esophageal motility disorders between the 2 cohorts. In patients with dysphagia as their primary indication for HREM, chronic cannabis use was found to be independently associated with increased median integrated relaxation pressure (β=6.638, P =0.0153) and increased mean lower esophageal sphincter resting pressure (β=10.38, P =0.0084). Chronic cannabis use is associated with decreased weak swallows and reduced prevalence of ineffective esophageal motility in patients referred for esophageal manometry. In patients referred for dysphagia, chronic cannabis use is associated with increased integrated relaxation pressure and lower esophageal sphincter resting pressure, though not to levels above the normal range.

Riesgos inducidos por la mariguana recreativa vs. la utilidad de los cannabinoides en el COVID-19

Introduction: the SARS-CoV-2 virus pandemic has caused a crisis in the health sector due to the lack of medical and pharmacological resources to treat the COVID-19 disease. Recent findings have shown that some compounds isolated from cannabis can reduce the entry of the SARS-CoV-2 virus into host cells, and prevent the proinflammatory cytokine storm, which is why they are considered drugs with potential for the treatment of COVID-19. On the other hand, frequent or chronic recreational use of cannabis may facilitate SARS-CoV-2 infection by depressing the immune system but also promote proinflammatory cytokine storm, worsening the disease. Objective: to discuss the proposed mechanisms of action of cannabinoids in the treatment of COVID-19 and the difference between the immunological effects produced by the chronic recreational use of marijuana and the pharmacological use of the isolated and purified compounds of cannabis for the treatment of this disease. Method: the most recent scientific articles published in PubMed were browsed, in which the effects of cannabinoids in relation to the SARS-CoV-2 virus were studied, as well as articles about the effects of chronic cannabis use on the immune system. Discussion and conclusions: high and frequent use of marijuana could worsen the disease caused by SARS-CoV-2, while the use of isolated and purified compounds can attenuate COVID-19 disease.

Impact of cannabis use on Schizo-affective disorder

IntroductionSchizoaffective disorder (SAD) is a nosographic entity characterized by an association of schizophrenic symptoms with thymic episodes. Addictive substance abuse behaviours precede or appear concomitantly with thymic and/or schizophrenic symptoms for the majority of patients.ObjectivesThe objective of our work was to specify the sociodemographic ,clinical and therapeutic characteristics of this population and to compare them to a group of schizophrenic patients who do not use cannabis.MethodsThis is a retrospective descriptive study of patients with Schizoaffective Disorder (SAD) meeting the criteria of the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, 5th Version (DSM-5), hospitalized between January 2015 and December 2021 in the psychiatry department of the EPS Tahar Sfar Mahdia.ResultsOur sample was composed of two groups: A first group formed by patients with a positive toxicological assessment to tetra-hydro-cannabinol (n=14) and a second group witha negative toxicological assessment (n=36). In SAD subjects using cannabis, the average age at first hospitalization was younger (27.5 years) than in the other groups, hospitalization was earlier (27.27 vs 33.58; p=0.04), the duration in number of days of hospitalization was greater (29.33 vs. 24.67; p=0.02) and they had required during their hospital stay a higher dosage of antipsychotics in equivalent doses of chlorpromazine (723 vs 603; p=0.04). There was a significant difference (p ≤ 0.04) in the psychometric scales (BPRS, SAPS and SANS) in favour of patients who did not use cannabis.ConclusionsThe deleterious psychic effects of chronic cannabis use have long been suspected for a long time. Patients followed for SAD present more frequently than the reference population addictive behaviours towards cannabis which is associated with many negative events affecting clinical symptomatology, evolution, prognosis and therapeutic response.Disclosure of InterestNone Declared

CANNABIS USE AND RISK OF FALLING IN OLDER ADULTS

Abstract The prevalence of cannabis use has significantly increased among US adults ≥ 50 years. However, the effect of chronic cannabis use on fall risk in older adults is unclear. A series of investigations were conducted to examine the intersection between cannabis use and fall risk in older adults. The findings indicated that: 1) Older (≥ 50 years) chronic cannabis users have a higher fall risk and walking impairments, 2) cannabis users might have a discrepancy between perceptual and physiological fall risk, and 3) chronic use of Δ-9-tetrahydrocannabinol (THC) might have negative influences on inhibitory control and brain activity. Future mechanistic (e.g., neuroimaging) investigations of the short- and long-term effects a variety of cannabis products (e.g., THC/CBD ratios, routes of administration) on cognitive/motor function, and fall incidence in older adults are suggested.

Chronic cannabis use affects cerebellum dependent visuomotor adaptation

BackgroundCannabis is one of the most commonly used substances in the world. However, its effects on human cognition are not yet fully understood. Although the cerebellum has the highest density of cannabinoid receptor type 1 (CB1R) in the human brain, literature on how cannabis use affects cerebellar-dependent learning is sparse. This study examined the effect of chronic cannabis use on sensorimotor adaptation, a cerebellar-mediated task, which has been suggested to depend on endocannabinoid signaling. MethodsChronic cannabis users (n = 27) with no psychiatric comorbidities and healthy, cannabis-naïve controls (n = 25) were evaluated using a visuomotor rotation task. Cannabis users were re-tested after 1 month of abstinence (n = 13) to assess whether initial differences in performance would persist after cessation of use. ResultsCannabis users showed lower adaptation rates compared to controls at the first time point. However, this difference in performance did not persist when participants were retested after one month of abstinence (n = 13). Healthy controls showed attenuated implicit learning in the late phase of the adaptation during re-exposure, which was not present in cannabis users. This explains the lack of between group differences in the second time point and suggests a potential alteration of synaptic plasticity required for cerebellar learning in cannabis users. ConclusionsOverall, our results suggest that chronic cannabis users show alterations in sensorimotor adaptation, likely due to a saturation of the endocannabinoid system after chronic cannabis use.

TRPV1: A Common Denominator Mediating Antinociceptive and Antiemetic Effects of Cannabinoids.

The most common medicinal claims for cannabis are relief from chronic pain, stimulation of appetite, and as an antiemetic. However, the mechanisms by which cannabis reduces pain and prevents nausea and vomiting are not fully understood. Among more than 450 constituents in cannabis, the most abundant cannabinoids are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabinoids either directly or indirectly modulate ion channel function. Transient receptor potential vanilloid 1 (TRPV1) is an ion channel responsible for mediating several modalities of pain, and it is expressed in both the peripheral and the central pain pathways. Activation of TRPV1 in sensory neurons mediates nociception in the ascending pain pathway, while activation of TRPV1 in the central descending pain pathway, which involves the rostral ventral medulla (RVM) and the periaqueductal gray (PAG), mediates antinociception. TRPV1 channels are thought to be implicated in neuropathic/spontaneous pain perception in the setting of impaired descending antinociceptive control. Activation of TRPV1 also can cause the release of calcitonin gene-related peptide (CGRP) and other neuropeptides/neurotransmitters from the peripheral and central nerve terminals, including the vagal nerve terminal innervating the gut that forms central synapses at the nucleus tractus solitarius (NTS). One of the adverse effects of chronic cannabis use is the paradoxical cannabis-induced hyperemesis syndrome (HES), which is becoming more common, perhaps due to the wider availability of cannabis-containing products and the chronic use of products containing higher levels of cannabinoids. Although, the mechanism of HES is unknown, the effective treatment options include hot-water hydrotherapy and the topical application of capsaicin, both activate TRPV1 channels and may involve the vagal-NTS and area postrema (AP) nausea and vomiting pathway. In this review, we will delineate the activation of TRPV1 by cannabinoids and their role in the antinociceptive/nociceptive and antiemetic/emetic effects involving the peripheral, spinal, and supraspinal structures.

Chronic use of cannabis might impair sensory error processing in the cerebellum through endocannabinoid dysregulation

Chronic use of cannabis leads to both motor deficits and the downregulation of CB1 receptors (CB1R) in the cerebellum. In turn, cerebellar damage is often related to impairments in motor learning and control. Further, a recent motor learning task that measures cerebellar-dependent adaptation has been shown to distinguish well between healthy subjects and chronic cannabis users. Thus, the deteriorating effects of chronic cannabis use in motor performance point to cerebellar adaptation as a key process to explain such deficits. We review the literature relating chronic cannabis use, the endocannabinoid system in the cerebellum, and different forms of cerebellar-dependent motor learning, to suggest that CB1R downregulation leads to a generalized underestimation and misprocessing of the sensory errors driving synaptic updates in the cerebellar cortex. Further, we test our hypothesis with a computational model performing a motor adaptation task and reproduce the behavioral effect of decreased implicit adaptation that appears to be a sign of chronic cannabis use. Finally, we discuss the potential of our hypothesis to explain similar phenomena related to motor impairments following chronic alcohol dependency.

Female Sex as a Protective Factor in the Effects of Chronic Cannabis Use on Verbal Learning and Memory

AbstractObjective:The variability of findings in studies examining the effects of chronic cannabis use on neuropsychological functioning highlights the importance of examining contributing factors. Few studies examine the role of sex in the relationship between cannabis and neuropsychological functioning, despite known neurobiological structural differences between males and females. This study examined whether males and females experience differential cognitive effects of chronic cannabis use.Method:Chronic cannabis users (3+ days per week for >12 months, n = 110, 72% male) and non-users (n = 71, 39% male) completed a neuropsychological test battery. Two multivariate analyses of covariance (MANCOVAs) examined for sex differences in performance within users and non-users on neuropsychological tests, controlling for potential confounding variables. Bonferroni corrections were applied to adjust for multiple comparisons.Results:Male and female cannabis users did not differ in cannabis use variables. Female cannabis users performed better than males on multiple subtests of the California Verbal Learning Test-II (CVLT-II), a verbal learning and memory test. Male cannabis users performed better than female users on Trial 1 of the CVLT-II (p = .002), and Trail Making Test B (p = .001), which measure attention and cognitive flexibility, respectively. Non-user males and females performed comparably, with the exception of Trail Making Test B (p = .001).Conclusions:Results suggest that chronic cannabis use differentially impacts males and females, with females exhibiting better verbal learning and memory despite males demonstrating better attention and cognitive flexibility. Further research is needed to understand the potential protective mechanism of female sex on learning and memory effects of cannabis use.

Investigating the Residual Effects of Chronic Cannabis Use and Abstinence on Verbal and Visuospatial Learning.

Rationale: Regular cannabis users have been shown to differ from non-using controls in learning performance. It is unclear if these differences are specific to distinct domains of learning (verbal, visuospatial), exacerbate with extent of cannabis exposure and dissipate with sustained abstinence.Objective: This study examines different domains of learning (verbal, visuospatial) in current and abstaining cannabis users, and the role of chronicity of use.Methods: In a cross-sectional design, we examined 127 psychiatrically healthy participants (65 female) with mean aged of 34 years. Of these, 69 individuals were current regular cannabis users (mean 15 years use), 12 were former cannabis users abstinent for ~2.5 yrs (after a mean of 16 years use), and 46 were non-cannabis using controls. Groups were compared on verbal learning performance assessed via the California Verbal Learning Test (CVLT-II) and for visuospatial learning measured with the Brown Location Test (BLT). We explored the association between CVLT/BLT performance and cannabis use levels in current and former users.Results: Current cannabis use compared to non-use was associated with worse performance on select aspects of verbal learning (Long Delay Cued Recall) and of visuospatial learning (Retroactive Interference and LD Rotated Recall). Prolonged abstinence was associated with altered verbal learning but intact visuospatial learning. There were non-significant correlations between distinct cannabis use measures, age and learning in both current and former users.Conclusions: Our findings suggest cannabis use status (current use, former use) affects different domains of learning (verbal and visuospatial) in a distinct fashion. These findings might be accounted for in the design of cognitive interventions aimed to support abstinence in cannabis users.

Cannabis Affects Cerebellar Volume and Sleep Differently in Men and Women.

Background: There are known sex differences in behavioral and clinical outcomes associated with drugs of abuse, including cannabis. However, little is known about how chronic cannabis use and sex interact to affect brain structure, particularly in regions with high cannabinoid receptor expression, such as the cerebellum, amygdala, and hippocampus. Based on behavioral data suggesting that females may be particularly vulnerable to the effects of chronic cannabis use, we hypothesized lower volumes in these regions in female cannabis users. We also hypothesized poorer sleep quality among female cannabis users, given recent findings highlighting the importance of sleep for many outcomes related to cannabis use disorder.Methods: Using data from the Human Connectome Project, we examined 170 chronic cannabis users (>100 lifetime uses and/or a lifetime diagnosis of cannabis dependence) and 170 controls that we attempted to match on age, sex, BMI, race, tobacco use, and alcohol use. We performed group-by-sex ANOVAs, testing for an interaction in subcortical volumes, and in self-reported sleep quality (Pittsburgh Sleep Questionnaire Inventory).Results: After controlling for total intracranial volume and past/current tobacco usage, we found that cannabis users relative to controls had smaller cerebellum volume and poorer sleep quality, and these effects were driven by the female cannabis users (i.e., a group-by-sex interaction). Among cannabis users, there was an age of first use-by-sex interaction in sleep quality, such that females with earlier age of first cannabis use tended to have more self-reported sleep issues, whereas this trend was not present among male cannabis users. The amygdala volume was smaller in cannabis users than in non-users but the group by sex interaction was not significant.Conclusions: These data corroborate prior findings that females may be more sensitive to the neural and behavioral effects of chronic cannabis use than males. Further work is needed to determine if reduced cerebellar and amygdala volumes contribute to sleep impairments in cannabis users.

068 Morning Cardiovascular Function in Chronic Cannabis Users and Healthy Controls

Abstract Introduction In the US cannabis is recreationally legal in 15 states and medically legal in 34 states. Preclinical studies suggest beneficial effects of cannabis on the cardiovascular system (e.g., vasorelaxation). Yet, acute cases of hospitalization after cannabis consumption indicate potential adverse cardiac effects. Vascular endothelial function is a marker of cardiovascular disease and is measured as a change in resting brachial artery diameter (flow-mediated dilation, FMD) during reactive hyperemia. Both resting diameter (positively) and FMD response (negatively) are associated with cardiovascular risk. Resting diameter likely depends on long-term structural changes, and FMD response mostly depends on nitric oxide. Reactive hyperemia is more complex and depends on numerous variables, including adenosine and prostaglandins. FMD is attenuated in the morning when the frequency of adverse cardiovascular events peaks. To begin to understand the effects of chronic cannabis use on the cardiovascular system, in this pilot study, we compared morning measurements of vascular endothelial function, blood pressure, and heart rate between chronic cannabis users and controls while controlling for prior nighttime sleep opportunities. Methods Participants, cannabis non-users (n=5) and users (n=4), 44% female, age 25.4 ± 3.6 years - no demographic differences between groups, kept a consistent 2-week sleep schedule at home followed by an 8h sleep opportunity at their habitual time in the laboratory. Upon-wakening, we measured resting blood pressure, heart rate, baseline diameter, hyperemic response, and FMD. Statistical differences between groups were calculated using a two-tailed t-test. Results Systolic and diastolic blood pressures (p=0.13 and 0.26 respectively), heart rate (p=0.97), and FMD response (p=0.99) did not differ between groups. However, chronic cannabis users had a significantly higher baseline brachial artery diameter (mean difference: 1.04 mm ± 0.26, p=0.005), and lower hyperemic response (mean difference: -7944 iu/s ± 2538, p=0.02) compared to non-users. Conclusion These preliminary findings suggest that chronic cannabis consumption may be associated with adverse structural and functional changes in the vasculature of otherwise healthy young adults. Based on these initial observations, cannabis may act on the cardiovascular system via non-nitric oxide mechanisms. However, it is necessary to increase our sample size to test the robustness of these findings. Support (if any) KL2TR002370, AASM

Heart Rate Variability is Altered in College‐Aged Chronic Cannabis Users versus Non‐Users

Cannabis is an increasingly popular recreational drug among college students. Prior investigations have shown that acute cannabis use alters heart rate variability via increased sympathetic activation. However, the effects of chronic cannabis use on heart rate variability (HRV) have not been reported. PURPOSE We tested the hypothesis that HRV would be lower in chronic cannabis users (THC) compared to non-users (CON). METHODS Eleven cannabis users (age: 21±2 y, 2 females) and six controls (age: 20±2 y; 4 females) completed one study visit. Participants in the THC group self-reported using cannabis at least once per week for the past year or more. Participants in the CON reported to not use for 6 months prior to enrollment. Participants were instructed to abstain from alcohol for 24 h and cannabis for 72 h prior to the study visit. After 10 minutes of supine rest, heart rate (5-lead electrocardiogram) was continuously recorded at 1 kHz for 5 minutes of supine rest while participants breathed spontaneously. HRV was assessed using linear analysis via Fast Fourier transformation and non-linear analysis via Poincare plots. The root mean square of successive differences (RMSSD), percent of R-R intervals that differ by more than 50 ms (pRR50), and the standard deviation of R-R intervals (SDRR) were calculated to assess HRV in the time-domain. Fast Fourier transformation was used to assess HRV in the frequency domain (low-frequency (LF) and high-frequency (HF) power). Non-linear HRV analysis was performed using Poincare plots to calculate standard deviation 1 (SD1) and 2 (SD2). We used one-tailed unpaired t-tests to determine if the main outcome variables were different between groups. Values are reported as mean ± SD. RESULTS RRI was lower in THC (THC: 917±109 vs. CON: 1018±141 ms; P=0.06). RMSSD was lower in THC (THC: 57±21 vs. CON: 74±24 ms; P=0.07). There was no difference between groups for pRR50 (THC: 36±20 vs. CON: 47±21 %; P=0.12) or SDRR (THC: 68±16 vs. CON: 78±24 ms; P=0.15). LF power was not different between groups (THC: 1105±850 vs. CON: 1321±852 ms2; P=0.31), but HF power was lower in THC (THC: 1353±925 vs. CON: 2256±1195 ms2; P=0.05). SD1 was lower in THC (THC: 40±15 vs. CON: 53±17 ms; P=0.07). SD2 was not different between groups (THC: 86±19 vs. CON: 96±33 ms; P=0.23). CONCLUSION These preliminary data indicate that college-aged adults who regularly use cannabis have lower heart rate variability than their non-cannabis user counterparts. Based on linear and non-linear analyses, it appears that cannabis users have altered cardiac vagal activity at rest. However, more research is warranted to determine if cannabis use alters autonomic function and reactivity.

Disentangling the Effects of Chronic Cannabis on Cognition in Bipolar Disorder

Although well-studied in schizophrenia, little is known about how cannabis use affects cognitive function in bipolar disorder (BD). Chronic, heavy cannabis use is highly prevalent among people with BD. Although associated with poor health outcomes, many people with BD report using cannabis to ameliorate their symptoms. Research also suggests possible pathophysiological interactions between the endocannabinoid and dopaminergic systems that contribute to effects on cognition. We sought to delineate the effects of chronic cannabis use on cognitive functions relevant to BD and cannabis.

Effects of Chronic Cannabis Use on the Neural Dynamics Underlying Attentional Reorientation

Cannabis is the most widely used illicit drug in the United States and is often associated with changes in attention function, which may ultimately impact numerous other cognitive faculties (e.g., memory, executive function). Importantly, despite the increasing rates of cannabis use and widespread legalization in the United States, the neural mechanisms underlying attentional dysfunction in chronic users are poorly understood.

Effect of chronic marijuana use on cognition: A crosssectional study in urban Bengaluru

Background and Aim Cannabis or Marijuana is a psychoactive drug. It is one of the commonest recreational drug and the most common illegal drug across the globe. Aim of this study is to assess the cognitive effects of chronic cannabis use using the standardized Montreal Cognitive Assessment MoCA Test and contrast the sociodemographic profile between users and non-users.Materials and methods This was a cross-sectional study conducted in Urban Bengaluru India between July and September 2016. Male and female students aged between 18 and 25 years were included and grouped into Chronic cannabis user or a Control. The MoCA Test was then administered in the subjectrsquos preferred language and assessed based on the defined MoCA administration and grading standards.Results A total of 62 individuals were recruited. 31 individuals were grouped as cases and a matching 31 individualsrsquo controls. Each group comprised on 29 males and 2 females. There was a significant difference between the total score of the MoCA test in the chronic marijuana user group Median 25 when compared to the control group Median 28 U 181 p lt 0.001. Among the different categories of the MoCA tool there was a significant difference between the userrsquos group and the control group in the categories of Visuospatial function Attention and Language.Conclusion Chronic cannabis users were found to have cognitive impairment than those who have never used cannabis.

Altered fronto-occipital connectivity during visual selective attention in regular cannabis users

Cognitive processing impairments have been associated with acute cannabis use, but there is mixed evidence regarding the cognitive effects of chronic cannabis use. Several neuroimaging studies have noted selective-attention processing differences in those who chronically use cannabis, but the neural dynamics governing the altered processing is unclear. Twenty-four adults reporting at least weekly cannabis use in the past 6months on the Cannabis Use Disorder Identification Test - Revised were compared to 24 demographically matched controls who reported no prior cannabis use. All participants completed a visual selective attention processing task while undergoing magnetoencephalography. Time-frequency windows of interest were identified using a data-driven method, and spectrally specific neural activity was imaged using a beamforming approach. All participants performed within normal range on the cognitive task. Regular cannabis users displayed an aberrant cognitive interference effect in the theta (4-8Hz) frequency range shortly after stimulus onset (i.e., 0-250ms) in the right occipital cortex. Cannabis users also exhibited altered functional connectivity between the right prefrontal cortex and right occipital cortices in comparison to controls. Individuals with a history of regular cannabis use exhibited abnormal theta interference activity in the occipital cortices, as well as altered prefrontal-occipital functional connectivity in the theta range during a visual selective attention task. Such differences may reflect compensatory processing, as these participants performed within normal range on the task. Understanding the neural dynamics in chronic, regular cannabis users may provide insight on how long-term and/or frequent use may affect neural networks underlying cognitive processes.

Brain structural changes in cannabis dependence: association with MAGL

Cannabis use is rising, yet there is poor understanding of biological processes that might link chronic cannabis use to brain structural abnormalities. To lend insight into this topic, we examined white matter microstructural integrity and gray matter cortical thickness/density differences between 89 individuals with cannabis dependence (CD) and 89 matched controls (64 males, 25 females in each group) from the Human Connectome Project. We tested whether cortical patterns for expression of genes relevant for cannabinoid signaling (from Allen Human Brain Atlas postmortem tissue) were associated with spatial patterns of cortical thickness/density differences in CD. CD had lower fractional anisotropy than controls in white matter bundles innervating posterior cingulate and parietal cortex, basal ganglia, and temporal cortex. The CD group also had significantly less gray matter thickness and density in precuneus, relative to controls. Sibling-pair analysis found support for causal and graded liability effects of cannabis on precuneus structure. Spatial patterns of gray matter differences in CD were significantly associated with regional differences in monoacylglycerol lipase (MAGL) expression in postmortem brain tissue, such that regions with higher MAGL expression (but not fatty-acid amide hydrolase or FAAH) were more vulnerable to cortical thinning. In sum, chronic cannabis use is associated with structural differences in white and gray matter, which was most prominent in precuneus and associated white matter tracts. Regions with high MAGL expression, and therefore with potentially physiologically restricted endogenous cannabinoid signaling, may be more vulnerable to the effects of chronic cannabis use on cortical thickness.

Reward, Control & Decision-Making in Cannabis Use Disorder: Insights from Functional MRI.

The recreational consumption of cannabis has increased significantly across the world with an estimated 180 million people currently using. In the United States, 4.1 million are currently diagnosed with cannabis use disorder. Cannabis dependence and abuse was combined into a single entity as a behavioral disorder with a problematic pattern of cannabis use and termed cannabis use disorder by the Diagnostic and Statistical Manual of Mental Disorders. Chronic use of cannabis has been linked with region-specific effects across the brain mediating reward processing, cognitive control and decision-making that are central to understanding addictive behaviors. This review presents a snapshot of the current literature assessing the effects of chronic cannabis use on human brain function via functional MRI. Studies employing various paradigms and contrasting cognitive activation amongst cannabis users and non-users were incorporated. The effects of trans-del-ta-9-tetrahydrocannabinol (Δ9-THC) in marijuana and other preparations of cannabis are mediated by the endocannabinoid system, which is also briefly introduced.Much variation exists in the current literature regarding the functional changes associated with chronic cannabis use. One possible explanation for this variation is the heterogeneity in study designs, with little implementation of standardized diagnostic criteria when selecting chronic users, distinct time points of participant assessment, differing cognitive paradigms and imaging protocols. As such, there is an urgent requirement for future investigations that further characterize functional changes associated with chronic cannabis use.

Cream of the Crop: Clinical Representativeness of Eligible and Ineligible Cannabis Users in Research

ABSTRACTBackground: Experts have recommended criteria (Gonzalez et al., 2002) for recruiting pure chronic cannabis users (i.e., those without polysubstance use or psychiatric illness) when evaluating cannabis' non-acute effects on cognition. Objectives: We sought to demonstrate the implications of using such criteria by examining characteristics of respondents who completed an eligibility screening for a parent study evaluating the cognitive effects of chronic cannabis use. Methods: Over a 3-year, 8-month period, 612 respondents from the community completed an eligibility screening based on recommendations in the cannabis literature. Using independent samples t-tests and chi-square tests, we examined whether qualified/eligible respondents (n = 219) differed from non-qualified/ineligible respondents (n = 393). Results: Compared to ineligible cannabis users, eligible cannabis-using respondents were significantly younger, used cannabis more frequently, used alcohol less frequently, and were less likely to have a history of other drug use, a psychiatric diagnosis, or to have used psychiatric medication. Conclusions/Importance: Our findings indicate that eligible/pure cannabis users are not representative of typical cannabis users in the general community (i.e., ineligible users with polysubstance use and/or psychiatric diagnoses) who ultimately comprised the majority of our cannabis-using sample (65.2%). Thus, typical cannabis users may be more accurately characterized as polysubstance users, posing a number of challenges related to the generalizability of findings from studies utilizing pure samples of cannabis users. Recruiting samples of typical cannabis users will improve external validity in research. Furthermore, reporting comprehensive characteristics of such samples will enable consumers to gauge the applicability of study findings to populations of interest.

The Road towards the Responsible and Safe Legalization of Cannabis Use in Portugal

Recently, the world has seen examples of the legalization of cannabis for recreational purposes. Due to the diversity ofexperiences in progress, it is urgent to analyze the impacts of this legalization, from a public health perspective. Therefore, this article aimsto review the accumulated knowledge in the states and countries where the use of cannabis is legal and to ponder over the relevance ofstarting a similar path towards legalization in Portugal, thus supporting political decisions to be properly informed and evidence-based. An extensive literature review was performed using databases and scientific journals, such as PubMed, as wellas the search of institutional documentation, including the EMCDDA and SICAD. The gathered information provided insights and enabled assessment of (1) the acute and chronic effects of cannabis use onhealth, (2) the Portuguese situation related to cannabis and (3) the processes and lessons learned after the legalization of cannabis inother countries or states. Given the above, and according to the data presented, the authors argue for a safe and responsible strategytowards the legalization of cannabis use in Portugal. In accordance, a set of concrete proposals are presented. From a public health perspective, it is assumed that the interest of this proposal is to reduce the problematic use of cannabis,to effectively fight against illicit drug trafficking and drug-related crime, as well as health promotion and prevention of addictions andother adverse health impacts. This article reveals that the effects of legalization might, contrary to general beliefs, generate positiveresults with respect to these aims, given that there will be greater control on the market, price, quality, and information - to name a few - ifimplementation occurs with proper consideration and definition. The debate on the responsible and safe legalization of cannabis use in Portugal should be open and promoted, based on apublic health perspective.