Lifetime Cannabis Use Research Articles

Association of Neuromelanin-Sensitive MRI Signal With Lifetime Substance Use in Young Women.

Midbrain dopamine function plays a key role in translational models of substance use disorders. Whether midbrain dopamine function is associated with substance use frequency and severity or reward function in 20-24 year-olds remains a critical gap in knowledge. The authors collected neuromelanin-sensitive magnetic resonance imaging (NM-MRI), a validated index of lifetime dopamine function in the substantia nigra/ventral tegmentum area (SN-VTA) complex, to characterize altered dopamine function. Midbrain NM-MRI contrast-to-noise ratio (CNR) was acquired in 135 20-24 year-olds (105 women and 30 men). A composite measure of cumulative substance use was derived from factor analysis of lifetime alcohol intoxications, lifetime cannabis use, use of nicotine in heaviest month, number of classes of drugs used, and ever meeting DSM-5 criteria for a SUD. Trait reward function was assessed by self-report. Cumulative substance use was significantly positively associated with NM-MRI CNR in a large area of the bilateral SN-VTA complex, an effect which was driven by women (who comprised most of the sample) and by voxels with greater NM-MRI CNR, including the ventral tegmentum area. NM-MRI CNR was not associated with individual differences in trait reward function. History of substance use is associated with greater NM signal in NM-rich areas of the midbrain, especially in women. Future longitudinal studies with repeated NM-MRI assessments, especially in younger cohorts and while including more men, are warranted to evaluate whether aberrant dopamine function predates, follows, or is modulated by substance use.

National cross-sectional survey of US adults to assess the reliability of current and lifetime cannabis smoking

ObjectiveThe objective is to examine the test–retest reliability and internal reliability of six self-report questions assessing both current (past 30 days) and lifetime cannabis smoking in an internet survey in...

Ethnic differences in the patterns, sources, and reasons for cannabis use among cancer patients at an NCI-Designated Cancer Center.

This study aims to describe patterns, sources, and reasons for cannabis use among cancer patients by ethnic group. Data are from a cross-sectional study of 416 surveys collected via RedCap anonymously from adult cancer patients seen at a National Cancer Institute-designated comprehensive cancer center within the last 5 years. A harmonized survey was created with 11 other National Cancer Institute centers to assess cannabis use patterns, sources, and reasons for use. Sociodemographics and cancer details were also collected via self-report. Descriptive statistics by ethnic group were compared using χ2 and Fisher exact tests. Among the sample (age mean = 50.4 [15.7] years; 53% male; 8.3% lesbian, gay, bisexual, transgender, queer; 46.7% Hispanic and Latinx individuals), 69.6% reported lifetime use of cannabis, 33.7% began cannabis use after cancer diagnosis, 48.1% of those consuming cannabis did not have a prescription for cannabis, and 29.4% of cannabis users consumed daily. The frequency of cannabis use (P = .04) and reasons for cannabis use (P = .02) varied by ethnic group. Sleep and pain were the most prevalent reasons for use among the Hispanics and Latinx populations; pain, mental health management, and neuropathy were the most prevalent reasons for cannabis use among non-Hispanic White individuals. Patterns and reasons for cannabis use differed among cancer patients by ethnic group in this exploratory cross-sectional study aimed to provide data for more rigorous study. Understanding these distinctions are pivotal in conducting more rigorous studies that address the unique needs of diverse populations utilizing cannabis for managing cancer-related symptoms.

Daily cannabis use and cognitive impairment in community residents aged 50 and over

ABSTRACT Background Cannabis use is associated with cognitive dysfunction in younger adults, but little is known about its role as a risk factor for dementia. This study aimed to explore the association between daily cannabis use and cognitive impairment in a cohort study of middle-aged and older people at risk of dementia. Methods Sample drawn from a cross-sectional study involving 15,582 people aged 50 and over from PROTECT study. Lifetime heavy cannabis use was defined by daily use. Results A total of 4203 (27%) participants reported lifetime cannabis use, of whom 4097 responses to frequency of use were obtained. Among them, 259 participants reported lifetime daily, and 3838 reported less than daily use. Those with lifetime daily cannabis use were more likely than those without to be unmarried, of lower educational attainment, and current or past tobacco smokers. They were more likely to show moderate or moderate-to-severe anxiety and depression. Baseline lifetime daily cannabis use was also associated with improved verbal reasoning but not with change in other cognitive scores. Conclusions Given improved verbal reasoning in people with daily lifetime cannabis use, the relationship between quantity and frequency of cannabis use and cognitive impairment in later life warrants further examination.

S19 - Neural Reward Reactivity to Delta-9-Tetrahydrocannabinol (THC) Among Young Adults as a Function of Lifetime Cannabis Use Frequency

S19 - Neural Reward Reactivity to Delta-9-Tetrahydrocannabinol (THC) Among Young Adults as a Function of Lifetime Cannabis Use Frequency

W23 - Effect of Acute THC, Sex, and Lifetime Cannabis Use on Neural Reward Activation

W23 - Effect of Acute THC, Sex, and Lifetime Cannabis Use on Neural Reward Activation

App-Based Addiction Prevention at German Vocational Schools: Implementation and Reach for a Cluster-Randomized Controlled Trial

This article examines the implementation, participation rates, and potential determinants of participation in the digital addiction prevention program “ready4life.” A two-arm cluster-randomized trial recruited German vocational students via class-based strategies. Intervention group received 16 weeks of in-app coaching; the control group received health behavior information, with coaching offered after 12 months. Potential determinants of participation were analyzed based on class and individual characteristics. Out of 525 contacted schools, 35 participated, enrolling 376 classes. Implementation during the pandemic required flexible adjustments, with 49.7% of introductions conducted in person, 43.1% digitally via online streaming, and 7.2% received a video link via email. Despite challenges, 72.3% of the vocational students downloaded the app, and 46.7% gave informed consent. Participation rates were highest among (associate) professionals, vocational grammar school classes, classes introduced by females, younger individuals, members of the project team, and classes introduced face-to-face. Female gender, lower social competencies, lifetime cannabis use, higher problematic internet use, and higher perceived stress were associated with higher individual participation. The study highlights the importance of proactive outreach and personalized interventions for addiction prevention programs in vocational schools. While reached students aligned with the aims of the app, tailored recruitment strategies could enhance engagement among under-represented groups. The trial was registered in the German Clinical Trials Register (DRKS): DRKS00022328; registration date 09.10.2020.

Prevalence of Cannabis Use Disorder: A Meta-Analysis of Population Surveys.

Epidemiologic surveys aim to estimate the population prevalence of cannabis use and cannabis use disorder. Prevalences estimates are important for understanding trends, such as the impact of policy change. Existing epidemiologic surveys have produced discrepant and potentially unreliable estimates. The current meta-analysis (PROSPERO CRD42022364818) aims to identify potential sources of unreliability in prevalence estimates of cannabis use and use disorder among the general population (aged 12+). There was no specific hypothesis about overall prevalence estimate, but we expected significant variability (i.e., heterogeneity) in estimates based on factors such as country, year of data collection, and specific methodological factors (e.g., diagnostic instrument). Systematic searches identified manuscripts and reports documenting nationally representative lifetime or past-year cannabis use disorder prevalence estimates. Meta-analysis was used to synthesize prevalence estimates, evaluate heterogeneity, and test moderators. There were 39 manuscripts/reports included in analyses which resulted in 259 unique prevalence estimates spanning 1980-2013 and an aggregated sample size of 973,281 individuals. Past-year and lifetime prevalence estimates for cannabis use were 12.83% (95% CI: 11.15%, 14.71%) and 38.31% (95% CI: 35.92%, 40.76%) and those for cannabis use disorder were 2.59% (95% CI:2.30%, 2.90%) and 6.77% (95% CI: 4.89%, 9.30%), respectively. There was significant heterogeneity in estimates, which was partially explained by factors such as country, year of data collection, and methodological characteristics. The significant heterogeneity in prevalence estimates as a function of methodological characteristics raises concerns about the generalizability of estimates. Recommendations for enhancing validity and reliability of these estimates are offered.

Randomized Laboratory Study of Single-Dose Cannabis, Dronabinol, and Placebo in Patients With Schizophrenia and Cannabis Use Disorder.

Up to 43% of people with schizophrenia have a lifetime cannabis use disorder (CUD). Tetrahydrocannabinol (THC) has been shown to exacerbate psychosis in a dose-dependent manner, but little research has assessed its effects on schizophrenia and co-occurring CUD (SCZ-CUD). In this double-dummy, placebo-controlled trial (total n = 130), we hypothesized that a modest dose of THC would worsen cognitive function but not psychosis. Effects of single-dose oral THC (15mg dronabinol) or smoked 3.5% THC cigarettes vs placebo in SCZ-CUD or CUD-only on positive and negative symptoms of schizophrenia (only for SCZ-CUD), cognition, and drug experiences assessed several hours after drug administration. SCZ-only and healthy control participants were also assessed. Drug liking was higher in THC groups vs placebo. Neither smoked THC nor oral dronabinol predicted positive or negative symptom subscale scores 2 and 5h, respectively, after drug exposure in SCZ-CUD participants. The oral dronabinol SCZ-CUD group, but not smoked THC SCZ-CUD group, performed worse than placebo on verbal learning (B = -9.89; 95% CI: -16.06, -3.18; P = .004) and attention (B = -0.61; 95% CI: -1.00, -0.23; P = .002). Every 10-point increment in serum THC + THCC ng/ml was associated with increased negative symptoms (0.40 points; 95% CI: 0.15, 0.65; P = .001; subscale ranges 7-49) and trends were observed for worse positive symptoms and performance in verbal learning, delayed recall, and working memory. In people with SCZ-CUD, a modest single dose of oral THC was associated with worse cognitive functioning without symptom exacerbation several hours after administration, and a THC dose-response effect was seen for negative symptoms.

Genome-wide association studies of lifetime and frequency cannabis use in 131,895 individuals.

Cannabis is one of the most widely used drugs globally. Decriminalization of cannabis is further increasing cannabis consumption. We performed genome-wide association studies (GWASs) of lifetime (N=131,895) and frequency (N=73,374) of cannabis use. Lifetime cannabis use GWAS identified two loci, one near CADM2 (rs11922956, p=2.40E-11) and another near GRM3 (rs12673181, p=6.90E-09). Frequency of use GWAS identified one locus near CADM2 (rs4856591, p=8.10E-09; r2 =0.76 with rs11922956). Both traits were heritable and genetically correlated with previous GWASs of lifetime use and cannabis use disorder (CUD), as well as other substance use and cognitive traits. Polygenic scores (PGSs) for lifetime and frequency of cannabis use associated cannabis use phenotypes in AllofUs participants. Phenome-wide association study of lifetime cannabis use PGS in a hospital cohort replicated associations with substance use and mood disorders, and uncovered associations with celiac and infectious diseases. This work demonstrates the value of GWASs of CUD transition risk factors.

Heavy Lifetime Cannabis Use and Mortality by Sex

The association between mortality and cannabis use remains unclear. To examine sex-stratified associations of cumulative lifetime cannabis use with all-cause, cardiovascular disease (CVD), and cancer mortality in the UK Biobank population. This cohort study used data from volunteers in the UK Biobank population. Participant monitoring for mortality in the UK Biobank study commenced from the point of their inclusion between 2006 and 2010 and continued until December 19, 2020. Data regarding the causes of death were sourced from the National Health Service Information Centre. Data were analyzed from inception of study inclusion to December 2020. Cannabis use status was assessed by questionnaire and categorized as heavy, moderate, low, and never. The main outcomes were all-cause, CVD, and cancer mortality. Sex-stratified associations of cumulative lifetime cannabis use with mortality were estimated using Cox proportional hazards regression with adjustment for demographic and clinical variables. Among 121 895 participants (54.51% females with mean [SD] age of 55.15 [7.64] years; 45.49% males with mean [SD] age of 56.46 [7.79] years) during an overall median of 11.80 years (IQR, 10.53-13.22 years) of follow-up, 2375 total deaths occurred, including 1411 deaths from CVD and 440 from cancer. In males, after full adjustment, the hazard ratios (HRs) were 1.28 (95% CI, 0.90-1.81) for all-cause mortality, 0.98 (95% CI, 0.43-2.25) for CVD mortality, and 1.09 (95% CI, 0.71-1.67) for cancer mortality among heavy cannabis users compared with never users. In females, after full adjustment, the HRs were 1.49 (95% CI, 0.92-2.40) for all-cause mortality, 2.67 (95% CI, 1.19-4.32) for CVD mortality, and 1.61 (95% CI, 0.91-2.83) for cancer mortality among heavy cannabis users compared with never users. In female current tobacco users, after full adjustment, heavy cannabis use was associated with all-cause mortality (HR, 2.25; 95% CI, 1.12-4.53), CVD mortality (HR, 2.56; 95% CI, 1.43-15.36), and cancer mortality (HR, 3.52; 95% CI, 1.50-8.33) and among never tobacco users was associated with CVD mortality (HR, 2.98; 95% CI, 1.67-6.61). In male current tobacco users, heavy cannabis use was associated with cancer mortality (HR, 2.44; 95% CI, 1.14-5.23). In this study, a positive association between CVD mortality and heavy lifetime cannabis use was observed among females. Longitudinal studies are needed in general populations to investigate the potential effects of cannabis on mortality.

The impact of cannabis use on erectile dysfunction and sex hormones: a Mendelian randomization analysis.

Previous study has highlighted an association between cannabis use (CU) and an increased risk of erectile dysfunction (ED), potentially due to indirect effects on sex hormonal balance. However, the evidence remains controversial, and the causal relationship is unclear. This study utilized genome-wide association study (GWAS) data to investigate the causal relationships between cannabis use disorder (CUD), lifetime cannabis use (LCU), and ED, as well as levels of sex hormones including estradiol (E2), bioavailable testosterone (BT), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) through Mendelian randomization (MR) analysis. The primary method of analysis was the inverse variance weighted (IVW) method. Data from the FinnGen and UK Biobank were used for replication and meta-analysis. The results indicated no causal relationship between genetically predicted CUD (OR = 0.97, 95% CI 0.87-1.10, P = 0.66) and LCU (OR = 1.13, 95% CI 0.84-1.50, P = 0.42) with the risk of ED. The meta-analysis provided consistent evidence (P > 0.05). No causal relationships were found between CUD and LCU with E2(CUD: β = 0.00, 95% CI 0.00-0.01, P = 0.37; LCU: β = 0.00, 95% CI -0.02-0.01, P = 0.62), BT (CUD: β = 0.00, 95% CI -0.03-0.02, P = 0.90; LCU: β = 0.02, 95% CI -0.04-0.09, P = 0.46), FSH (CUD: β = 0.01, 95% CI -0.18-0.20, P = 0.92; LCU: β = 0.01, 95% CI -0.44-0.47, P = 0.95), and LH (CUD: β = 0.01, 95% CI -0.18-0.21, P = 0.90; LCU: β = 0.13, 95% CI -0.22-0.49, P = 0.46). Sensitivity analyses detected no evidence of horizontal pleiotropy or heterogeneity, ensuring the robustness of the results. In conclusion, this MR analysis did not provide evidence supporting a causal relationship between CU and ED or sex hormone levels.

A randomized trial of topical cannabis balms for the treatment of aromatase inhibitor–associated musculoskeletal syndrome (AIMSS).

e24129 Background: Aromatase inhibitors (AIs) are commonly used for postmenopausal women with hormone receptor positive breast cancer. Nearly 2 of 3 women on AIs complain of AIMSS leading to poor adherence. Preclinical and clinical pilot data suggest topical cannabinoids can reduce inflammation in arthritis. Methods: We conducted a randomized controlled trial assessing the feasibility and acceptability of two different topical medical cannabis balms for AIMSS. Women with stage 1-3 breast cancer with AIMSS [scoring 4 or higher on at least one of the four screening Modified Score for the Assessment and Quantification of Chronic Rheumatoid Affectations of the Hands (M-SACRAH) questions] were eligible. Patients with skin lesions, use of any cannabis in prior 4 weeks, acupuncture, or plans to increase doses of other analgesics were excluded. Women were randomized 1:1 to cannabidiol (CBD) (2210mg CBD/ < 0.3% THC) vs delta-9-tetrahydrocannabinol (THC) (375mg THC/ < 20mg CBD) predominant balm. Participants enrolled in the Minnesota Medical Cannabis Program and were dispensed balms at state-registered dispensaries. 125cc of balm was applied 3 times daily to hands for 2 weeks. M-SACRAH, brief pain inventory (BPI), and NCI Patient Reported Outcomes Common Terminology Criteria for Adverse Events (PRO-CTCAE) measures were captured weekly. Results: 20 women were enrolled from one academic and one community oncology practice in Minnesota over a 10-month period. Reasons patients with AIMSS did not enroll included patient/clinician not interested, AIMSS not meeting M-SACRAH severity, and patient already using cannabis. Adherence to study protocol through week 2 was 85%. Mean age was 54 years, 85% White/15% Asian, 45% received adjuvant chemotherapy, and 50% reported no lifetime cannabis use. Participants reported improvement in M-SACRAH, BPI, and PRO-CTCAE pain scores from baseline to week 2 (Table 1). No skin toxicity was reported by patients. One patient discontinued balm due to greasy texture. Conclusions: Conducting a randomized trial of topical cannabis using state approved dispensaries is feasible. Both THC and CBD predominant topical balms are well tolerated and appear to reduce AIMSS severity in this pilot study of breast cancer survivors. Further confirmatory studies are warranted. Clinical trial information: NCT05935891 . [Table: see text]

Incident psychotic experiences following self-reported use of high-potency cannabis: Results from a longitudinal cohort study.

High-potency cannabis has been associated with increased risk of psychosis, but a lack of prospective data hinders understanding of causality in this relationship. This study aimed to combine prospective report of cannabis use with retrospective report of potency to infer the potency of cannabis used in adolescence and explore whether use of cannabis, and the use of high-potency cannabis, in adolescence is associated with incident psychotic experiences. Population-based birth cohort study. United Kingdom. n = 5570 participants who reported on any cannabis use (yes/no) age 16 and 18 years, and n = 1560 participants from this group who also retrospectively reported on cannabis potency. In questionnaires at ages 16 and 18, individuals self-reported lifetime cannabis use, and at age 24, participants reported the type of cannabis they most commonly used in the whole time since first using cannabis. Psychotic experiences were assessed at age 24 years using the semi-structured Psychosis-Like Symptom Interview, with incident defined as new-onset occurring between ages 19 and 24 years. Use of high-potency cannabis at age 16 or 18 was associated with twice the likelihood of experiencing incident psychotic experiences from age 19-24 (Odds Ratio 2.15, 95% Confidence Intervals 1.13-4.06). There was less evidence for an effect of any cannabis use on incident psychotic experiences (Odds Ratio 1.45, 95% Confidence Intervals 0.94-2.12). Use of high-potency cannabis appears to be associated with increased likelihood of psychotic experiences.

Characteristics of women concordant and discordant for urine drug screens for cannabis exposure and self-reported cannabis use during pregnancy

BackgroundIncreasing cannabis use among pregnant people and equivocal evidence linking prenatal cannabis exposure to adverse outcomes in offspring highlights the need to understand its potential impact on pregnancy and child outcomes. Assessing cannabis use during pregnancy remains a major challenge with potential influences of stigma on self-report as well as detection limitations of easily collected biological matrices. ObjectiveThis descriptive study examined the concordance between self-reported (SR) cannabis use and urine drug screen (UDS) detection of cannabis exposure during the first trimester of pregnancy and characterized concordant and discordant groups for sociodemographic factors, modes of use, secondhand exposure to cannabis and tobacco, and alcohol use and cotinine positivity. Study designThe Cannabis Use During Development and Early Life (CUDDEL) Study is an ongoing longitudinal study that recruits pregnant individuals presenting for obstetric care, who report lifetime cannabis use as well as using (n = 289) or not using cannabis (n = 169) during pregnancy. During the first trimester pregnancy visit, SR of cannabis use and a UDS for cannabis, other illicit drugs and nicotine are acquired from eligible participants, of whom 333 as of 05/01/2023 had both. ResultsUsing available CUDDEL Study data on both SR and UDS (n = 333; age 26.6 ± 4.7; 88.6% Black; 45.4% below federal poverty threshold; 56.5% with paid employment; 89% with high school education; 22% first pregnancy; 12.3 ± 3.6 weeks gestation), we classified pregnant individuals with SR and UDS data into 4 groups based on concordance (k = 0.49 [95% C.I. 0.40–0.58]) between SR cannabis use and UDS cannabis detection during the first trimester: 1) SR+/UDS+ (n = 107); 2) SR-/UDS- (n = 142); 3) SR+/UDS- (n = 44); 4) SR-/UDS+ (n = 40). Those who were SR+/UDS- reported less frequent cannabis use and fewer hours under the influence of cannabis during their pregnancy. Those who were SR-/UDS+ were more likely to have joined the study at a lower gestational age with 62.5% reporting cannabis use during their pregnancy prior to being aware that they were pregnant. Of the 40 SR-/UDS+ women, 14 (i.e., 35%) reported past month secondhand exposure, or blunt usage. In the subset of individuals with SR and UDS available at trimester 2 (N = 160) and 3 (N = 140), concordant groups were mostly stable and > 50% of those in the discordant groups became concordant by the second trimester. Classifying individuals as exposed or not exposed who were SR+ and/or UDS+ resulted in minor changes in group status based on self-report at screening. ConclusionOverall, there was moderate concordance between SR and UDS for cannabis use/exposure during pregnancy. Instances of SR+/UDS- discordancy may partially be attributable to lower levels of use that are not detected on UDS. SR-/UDS+ discordancy may arise from recent use prior to knowledge of pregnancy, extreme secondhand exposure, deception, and challenges with completing questionnaires. Acquiring both self-report and biological detection of cannabis use/exposure allows for the examination of convergent evidence. Classifying those who are SR+ and/or UDS+ as individuals who used cannabis during their first trimester after being aware of their pregnancy resulted in only a minor change in exposure status; thus, relying on self-report screening, at least in this population and within this sociocultural context likely provides an adequate approximation of cannabis use during pregnancy.

Genetic influences and causal pathways shared between cannabis use disorder and other substance use traits

Cannabis use disorder (CanUD) has increased with the legalization of the use of cannabis. Around 20% of individuals using cannabis develop CanUD, and the number of users has grown with increasing ease of access. CanUD and other substance use disorders (SUDs) are associated phenotypically and genetically. We leveraged new CanUD genomics data to undertake genetically-informed analyses with unprecedented power, to investigate the genetic architecture and causal relationships between CanUD and lifetime cannabis use with risk for developing SUDs and substance use traits. Analyses included calculating local and global genetic correlations, genomic structural equation modeling (genomicSEM), and Mendelian Randomization (MR). Results from the genetic correlation and genomicSEM analyses demonstrated that CanUD and cannabis use differ in their relationships with SUDs and substance use traits. We found significant causal effects of CanUD influencing all the analyzed traits: opioid use disorder (OUD) (Inverse variant weighted, IVW β = 0.925 ± 0.082), problematic alcohol use (PAU) (IVW β = 0.443 ± 0.030), drinks per week (DPW) (IVW β = 0.182 ± 0.025), Fagerström Test for Nicotine Dependence (FTND) (IVW β = 0.183 ± 0.052), cigarettes per day (IVW β = 0.150 ± 0.045), current versus former smokers (IVW β = 0.178 ± 0.052), and smoking initiation (IVW β = 0.405 ± 0.042). We also found evidence of bidirectionality showing that OUD, PAU, smoking initiation, smoking cessation, and DPW all increase risk of developing CanUD. For cannabis use, bidirectional relationships were inferred with PAU, smoking initiation, and DPW; cannabis use was also associated with a higher risk of developing OUD (IVW β = 0.785 ± 0.266). GenomicSEM confirmed that CanUD and cannabis use load onto different genetic factors. We conclude that CanUD and cannabis use can increase the risk of developing other SUDs. This has substantial public health implications; the move towards legalization of cannabis use may be expected to increase other kinds of problematic substance use. These harmful outcomes are in addition to the medical harms associated directly with CanUD.

The association between cannabis use and neuroimaging measures in older adults: findings from the UK biobank.

Cannabis use has increased in recent years. However, the long-term implications of cannabis use on brain health remain unknown. We explored the associations of cannabis use with volumetric brain magnetic resonance imaging (MRI) measures in dementia-free older adults. This cross-sectional and longitudinal study included dementia-free participants of the UK Biobank aged ≥60years. Linear regression models were used to evaluate the association of cannabis use and patterns of use with volumetric brain MRI measures. The association between cannabis use and change in brain MRI measures over time was also tested. All models were adjusted for potential confounders. The sample included 19,932 participants (mean age 68 ± 5years, 48% men), 3,800 (19%) reported lifetime use of cannabis. Cannabis use was associated with smaller total, white, grey and peripheral cortical grey matter volumes (B= -6,690 ± 1,157; P< 0.001, B= -4,396 ± 766; P< 0.001, B= -2,140 ± 690; P= 0.002 and B= -2,451 ± 606; P< 0.001, respectively). Among cannabis users, longer duration of use was associated with smaller total brain, grey and cortical grey matter volumes (B= -7,878 ± 2,396; P= 0.001, B= -5,411 ± 1,430; P< 0.001, B = -5,396 ± 1,254; P< 0.001, respectively), and with increased white matter hyperintensity volume (B= 0.09 ± 0.03; P= 0.008). Additionally, current vs. former users (B= -10,432 ± 4,395; P= 0.020) and frequent versus non-frequent users (B= -2,274 ± 1,125; P= 0.043) had smaller grey and cortical grey matter volumes, respectively. No significant associations were observed between cannabis use and change in brain MRI measures. Our findings suggest that cannabis use, particularly longer duration and frequent use, may be related to smaller grey and white matter volumes in older ages, but not to late-life changes in these measures over time.

Endocannabinoid system alterations in schizophrenia: association with cannabis use and antipsychotic medication.

Determining peripheral modulation of the endocannabinoid system (ECS) may be important for differentiating individuals with schizophrenia. Such differentiation can also be extended to subgroups of individuals, those who use cannabis and antipsychotic medications, particularly those who are treatment resistant. Patients and controls were recruited from the outpatient clinic of the Psychosis Group of the University of São Paulo, Brazil. A final sample of 93 individuals was divided into 3 groups: patients with schizophrenia using clozapine (treatment-resistant) (n = 29), patients with schizophrenia using another antipsychotic (n = 31), and controls (n = 33). By measuring the proteins and metabolites involved in the ECS pathways in the peripheral blood, AEA (anandamide), 2-AG (2-arachidonoyl ethanolamine), and CB2 receptor (peripheral) were quantified. Individuals reporting lifetime cannabis use had lower 2-AG plasma levels (p = 0.011). Regarding the CB2 receptor, the values of patients with schizophrenia and controls were similar, but those of patients using antipsychotics other than clozapine differed (p = 0.022). In generalized linear models to control for confounders, the use of cannabis remained the only factor that significantly influenced 2-AG levels. The relationship for non-clozapine antipsychotics as the only factor related to CB2 changes was marginally significant. We found for the first time that cannabis use and non-clozapine antipsychotic medication are potentially involved in the modulation of the ECS, specifically influencing 2-AG endocannabinoid and CB2 receptor levels. More studies regarding the ECS are needed since it has been increasingly related to the physiopathology of schizophrenia.

Predictors of lifetime cannabis use among undergraduate students and changes during COVID‐19

AbstractIn this study, we examined predictors of traditional‐aged undergraduate students’ (n = 115) lifetime cannabis use during COVID‐19. Participants who had lower scores of self‐regulation, higher levels of emotional dysregulation strategies, and a higher number of ACEs had more lifetime cannabis use. Additionally, participants’ methods of cannabis use changed during the pandemic as they primarily ingested more cannabis products (i.e., edibles) compared with before the pandemic began. Finally, the number of participants using cannabis in group settings during the pandemic was lower compared with before the pandemic began. Implications for counselors and counselor education programs are provided.

Reduced Diffusivity along Perivascular Spaces on MR Imaging Associated with Younger Age of First Use and Cognitive Impairment in Recreational Marijuana Users.

The impairment of the glymphatic system, a perivascular network crucial for brain waste clearance, has been linked to cognitive impairment, potentially attributed to the accumulation of brain waste. Although marijuana use has been associated with poorer cognitive performance, particularly in adolescents, its influence on the glymphatic system remains unexplored. This study evaluated the influence of the age of first marijuana use and the total number of lifetime uses on the glymphatic system, measured using the index of DTI along the perivascular space (DTI-ALPS). Furthermore, we explored the correlation between glymphatic clearance and cognitive performance among marijuana users. In this study, 125 individuals who reported using marijuana at least once in their lifetime (43 men; mean age, 28.60 [SD, 3.84] years) and 125 individuals with zero lifetime cannabis use (nonusers; 44 men; mean age, 28.82 [SD, 3.56] years) were assessed. ALPS indices of all study participants were calculated using 3T diffusion MR imaging data (b = 1000 s/mm2). After we adjusted for age, sex, education years, Pittsburgh Sleep Quality Index, alcohol use, tobacco use, and intracranial volume, our analysis using a univariate General Linear Model revealed no significant difference in the ALPS index among nonusers and marijuana users with different ages of first use or various frequencies of lifetime usage. However, in marijuana users, multiple linear regression analyses showed associations between a lower ALPS index and earlier age of first marijuana use (standardized β, -0.20; P = .041), lower accuracy in the working memory 0-back task (standardized β, 0.20; P = .042), and fewer correct responses in the Fluid Intelligence Test (standardized β, 0.19; P = .045). This study shows the potential use of DTI-ALPS as a noninvasive indirect indicator of the glymphatic clearance in young adults. Our findings show novel adverse effects of younger age at first use of marijuana on the glymphatic system function, which is associated with impaired working memory and fluid intelligence. Gaining insight into the alterations in glymphatic function following marijuana use could initiate novel strategies to reduce the risk of cognitive impairment.