Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: a systematic meta-review of meta-analyses

The Ubiquity of Cognitive Impairment in Human Illness: a Systematic Review of Meta-Analyses

OBJECTIVE

Cognitive dysfunction occurs in many neurological, psychiatric, and other health conditions. This review aimed to characterize the breadth and degree of cognitive morbidity associated with varied health conditions.

METHOD

We systematically reviewed Medline, EMBASE, and Cochrane databases for meta-analyses of cognitive dysfunction associated with any health condition. Meta-analyses were eligible if they reviewed studies that compared patients with health conditions to healthy controls on cognitive testing and provided effect sizes.

RESULTS

We found 91 meta-analyses for 94 health conditions. Among >800,297 participants, healthy controls out-performed clinical participants in every condition on cognitive testing. Mean effect sizes ranged from -2.02 to -0.00 across conditions and were ≤ -0.5 on average, denoting moderate to very severe dysfunction for 41% of them.

CONCLUSIONS

Cognitive dysfunction is ubiquitous in medicine. Both primary care and specialist physicians likely treat patients with cognitive dysfunction. Depending on its severity, cognitive dysfunction can affect treatment adherence, everyday functioning, quality of life, and the capacity to provide informed consent for treatment. These findings highlight the transdiagnostic nature of cognitive symptoms and the potential value of establishing collaborations between physicians and clinical neuropsychologists to integrate cognitive assessment into patient care. Even brief assessments can identify cognitive deficits that likely affect treatment adherence and functional outcomes.

Cannabis use disorder uniquely predicts educational impairment in college students over and above other mental health disorders

Objective: The impact of cannabis use disorder (CUD) on education functioning and GPA was examined within the context of co-occurring alcohol use disorder (AUD), major depressive disorder (MDD), and post-traumatic stress disorder (PTSD). Participants: Undergraduates (N = 210) who reported using cannabis within the past six months were recruited. Methods: Hierarchical multiple regression analyses were used to determine whether CUD symptom severity and presence of probable CUD diagnosis predicted educational impairment and current GPA, over and above other mental health conditions. Results: CUD symptom severity, but not probable CUD, significantly predicted greater educational impairment, over and above probable PTSD and MDD, which were also significant predictors. CUD symptom severity, but not probable CUD, significantly predicted lower GPA. Conclusion: In addition to other common mental health conditions, CUD may be an important area of assessment and intervention for university counseling centers to foster student academic success.

Cannabis Use and Anesthesia

Consistent evidence supporting the use of cannabinoids for management of acute pain is lacking. A small number of observational studies suggest cannabinoid use is associated with reduced opioid use but pain scores remain unchanged. The majority of randomized trials involving a variety of cannabinoid compounds have shown no benefit for acute pain. Chronic cannabis users may be at increased risk of experiencing elevated levels of acute pain and these individuals may require greater quantities of opioids compared to non-cannabis users. There is also evidence suggesting that chronic, high-dose cannabis users may be at increased risk of perioperative cardiovascular complications.

Childhood maltreatment and adult aggression: The moderating role of neurocognitive ability and substance use

BACKGROUND

Achieving positive intervention outcomes for aggressive behaviour in adulthood is challenging. This difficulty is enhanced by the complex presentations of those engaging in such behaviours and the impact this has on their engagement with interventions.

OBJECTIVE

This study assessed the cumulative impact of childhood maltreatment, substance use, and neurocognitive ability (working memory, cognitive flexibility, decision making, response inhibition, and cognitive control) on aggressive behaviour in adulthood.

PARTICIPANTS AND SETTING

Adult participants (N = 179; 69 % female) recruited from the community, and clinical and forensic services, aged 18 to 81 (M = 40.5, SD = 15.9).

METHODS

Participants completed an online Qualtrics survey and remote neurocognitive testing via Inquisit.

RESULTS

We implemented an a priori approach, assessing three-way interactions between childhood maltreatment, substance use, neurocognitive ability, and aggression. No three-way interactions were significant. We then utilised a data-driven modelling approach, using automatic linear forward stepwise modelling to identify the most important variables for predicting aggression. Four were significant: physical maltreatment (b = 0.053, p < .001), drug use risk level (b = 0.015, p < .001), poorer response inhibition (b = 0.001, p = .016), and the interaction between poorer response inhibition and physical maltreatment (b = 0.205, p = .017).

CONCLUSIONS

Physical maltreatment in childhood, drug use risk level, and response inhibition impact significantly on adult aggression, indicating a need for early intervention for children who have experienced maltreatment. Consideration should be given to how maltreatment in childhood may impact on ability to engage with interventions as an adult, particularly response inhibition difficulties that may hinder skill implementation.

Critical Review of Recently Published Studies Claiming Long-Term Neurocognitive Abnormalities in Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common claimed personal injury condition for which neuropsychologists are retained as forensic experts in litigation. Therefore, it is critical that experts have accurate information when testifying as to neurocognitive outcome from concussion. Systematic reviews and six meta-analyses from 1997 to 2011 regarding objective neurocognitive outcome from mTBI provide no evidence that concussed individuals do not return to baseline by weeks to months post-injury. In the current manuscript, a critical review was conducted of 21 research studies published since the last meta-analysis in 2011 that have claimed to demonstrate long-term (i.e., ≥12 months post-injury) neurocognitive abnormalities in adults with mTBI. Using seven proposed methodological criteria for research investigating neurocognitive outcome from mTBI, no studies were found to be scientifically adequate. In particular, more than 50% of the 21 studies reporting cognitive dysfunction did not appropriately diagnose mTBI, employ prospective research designs, use standard neuropsychological tests, include appropriate control groups, provide information on motive to feign or use PVTs, or exclude, or adequately consider the impact of, comorbid conditions known to impact neurocognitive scores. We additionally analyzed 15 studies published during the same period that documented no longer term mTBI-related cognitive abnormalities, and demonstrate that they were generally more methodologically robust than the studies purporting to document cognitive dysfunction. The original meta-analytic conclusions remain the most empirically-sound evidence informing our current understanding of favorable outcomes following mTBI.

Cannabis Use and Age-Related Changes in Cognitive Function From Early Adulthood to Late Midlife in 5162 Danish Men

INTRODUCTION

Cannabis is by far the most widely used and abused drug listed on the Drug Enforcement Administration's Schedule I, which includes drugs with a high potential for abuse. There is evidence of short-term negative effects of cannabis use on cognition, but only a limited number of studies have explored the association between cannabis use and age-related cognitive decline. The aim of the present study was to investigate the relationship between cannabis use and age-related cognitive decline from early adulthood to late midlife.

METHODS

The study population consisted of 5162 men who had participated in Danish follow-up studies on cognitive aging. These studies included scores on the military intelligence test Børge Prien's Prøve from both the conscription assessment (mean age = 20 years; p1 and p99: 18 and 26 years) and from the follow-up (mean age = 64 years; p1 and p99: 55 and 72 years) as well as extensive data on lifestyle and health from the follow-up questionnaires. The association between cannabis use and age-related cognitive decline was investigated in linear regression models.

RESULTS

Men with a history of cannabis use had less cognitive decline from early adulthood to late midlife compared to men without a history of cannabis use. Among cannabis users, neither age of initiation of cannabis use nor frequent use was significantly associated with a greater age-related cognitive decline.

DISCUSSION AND CONCLUSIONS

In a sample of more than 5000 men followed for a mean of 44 years, we found no significant harmful effects of cannabis use on age-related cognitive decline.

Surgery-Related Considerations in Treating People Who Use Cannabis: A Review

Importance

Cannabis use has experienced substantial growth. Many patients treated by otolaryngologists are using cannabis in various forms, often without the knowledge of the treating surgeon. These cannabinoid substances have various systemic effects, and it is critical for otolaryngologists to recognize how cannabis use may contribute to a patient's care.

Observations

Cannabis use has effects that contribute to every phase of a surgeon's care. Preoperative counseling for tapering use may prevent increased rates of adverse effects. Care with anesthesia must be observed due to increased rates of myocardial ischemia, higher tolerance to standard doses, and prolonged sedation. Although results of studies are mixed, there may be an association with cannabis use and postoperative pain, nausea, and vomiting. Postoperative wound healing may be improved through the use of topical cannabinoids. Significant drug-drug interactions exist with cannabis, most notably with several common anticoagulant medications. Care should be exercised when managing medications for people who use cannabis. While many people who use cannabis consume it infrequently, a substantial population has developed cannabis use disorder, which is associated with increased morbidity and mortality postoperatively. Screening for cannabis use disorder is important and can be done through short screening tools.

Conclusions and Relevance

Patients who use cannabis may require special attention regarding preoperative counseling and workup, intraoperative anesthesia, postoperative pain management, nausea, wound healing, and drug-drug interactions. As patient use continues to increase, otolaryngologists will find an increasing need to remain up to date on how cannabis use contributes to patient care.

Cannabis, cannabinoids and health: a review of evidence on risks and medical benefits

The legalization of cannabis for medical and recreational purposes has progressed internationally. Cannabis and cannabinoids are advocated for a plethora of medical indications. An increasing number of medical and nonmedical users regularly consume large doses of delta-9-Tetrahydrocannabinol (THC), the main active component of cannabis. Aim: to summarize the evidence on (1) risks of recreational cannabis use and (2) effectiveness and safety of medicinal cannabis. Findings on recreational use: Cannabis is mostly used to experience its acute rewarding effects. Regular use of high THC products can produce addiction (cannabis use disorder or CUD). Acute consumption of high THC doses (including unintentionally) can cause time-limited mental, gastrointestinal, and cardiovascular problems and motor vehicle accidents. Chronic patterns of cannabis use have been associated with multiple adverse outcomes that are of particular concern among adolescents and young adults, such as, disrupted learning, impaired cognitive performance, reduced educational attainment and an increased risk of CUD, psychosis/schizophrenia, mood and anxiety disorders and suicidal behaviors. There is debate about the extent to which cannabis use is a cause of these adverse outcomes. Physical health risks (e.g., respiratory and cardiovascular, prematurity and restricted fetal growth, hyperemesis syndrome among others) have also been linked with repeated consumption of cannabis with a high THC content. Findings on medical cannabis use: Herbal cannabis, medicines from extracted or synthetized cannabinoids-often used as adjuvants to standard medicines-may produce small to modest benefits. This is primarily the case in treating chronic pain, muscle spasticity, chemotherapy-induced nausea and vomiting, and refractory epilepsy (in the case of cannabidiol, CBD). The evidence is inconclusive on their value in treating mental disorders and other medical conditions. Safety: Cannabis-based medicine is generally well tolerated. There is a risk of mild to moderate adverse effects and CUD.

Year-Long Cannabis Use for Medical Symptoms and Brain Activation During Cognitive Processes

Importance

Cannabis is increasingly being used to treat medical symptoms, but the effects on brain function in those using cannabis for these symptoms are not known.

Objective

To test whether 1 year of cannabis use for medical symptoms after obtaining a medical cannabis card was associated with increased brain activation during working memory, reward, and inhibitory control tasks, areas of cognition affected by cannabis.

Design, Setting, and Participants

This cohort study was conducted from July 2017 to July 2020 among participants from the greater Boston area who were recruited as part of a clinical trial of individuals seeking medical cannabis cards for anxiety, depression, pain, or insomnia symptoms. Participants were aged between 18 and 65 years. Exclusion criteria were daily cannabis use and cannabis use disorder at baseline. Data analysis was conducted from August 2021 to April 2024.

Main Outcomes and Measures

Outcomes were whole brain functional activation during tasks involving working memory, reward, and inhibitory control at baseline and after 1 year of medical cannabis card ownership.

Results

Imaging was collected from participants before and 1 year after obtaining medical cannabis cards, with 57 participants at baseline (38 female [66.7%]; 6 [10.5%] Black and 45 [78.9%] White participants; 1 [1.8%] Hispanic participant; median [IQR] age, 34.0 [24.0-51.0] years) and 54 participants at 1 year (37 female [68.5%]; 4 [7.4%] Black and 48 [88.9%] White participants; 1 [1.9%] Hispanic participant, median [IQR] age, 36.5 [25.0-51.0] years). Imaging was also collected in 32 healthy control participants at baseline (22 female [68.8%]; 2 [6.2%] Black and 27 [84.4%] White participants; 3 [9.4%] Hispanic participants; median [IQR] age, 33.0 [24.8-38.2] years). In all groups and at both time points, functional imaging revealed canonical activations of the probed cognitive processes. No statistically significant difference in brain activation between the 2 time points (baseline and 1 year) in those with medical cannabis cards and no associations between changes in cannabis use frequency and brain activation after 1 year were found.

Conclusions and Relevance

In this cohort study of adults obtaining medical cannabis cards for medical symptoms, no significant association between brain activation in the areas of cognition of working memory, reward, and inhibitory control and 1 year of cannabis use was observed. The results warrant further studies that probe the association of cannabis at higher doses, with greater frequency, in younger age groups, and with larger, more diverse cohorts.

Recreational Cannabis Legalization: No Contribution to Rising Prescription Stimulants in the USA

INTRODUCTION

There have been substantial increases in the use of Schedule II stimulants in the United States. Schedule II stimulants are the gold standard treatment for attention-deficit hyperactivity disorder (ADHD), but also carry the risk of addiction. Since the neurocognitive deficits seen in ADHD resemble those of chronic cannabis use, and the rise in stimulant use is incompletely understood, this study sought to determine if recreational cannabis (RC) legalization increased distribution rates of Schedule II stimulants.

METHODS

The distribution of amphetamine, lisdexamfetamine, and methylphenidate were extracted from the ARCOS database of the Drug Enforcement Administration. The three-year population-corrected slopes of distribution before and after RC sales were evaluated.

RESULTS

Total stimulant distribution rates were significantly higher in states with RC sales after (p=0.049), but not before (p=0.221), program implementation compared to states without RC. Significant effects of time (p<0.001) and RC sales status (p=0.045) were observed, while time x RC sales status interaction effects were not significant (p=0.406).

DISCUSSION

RC legalization did not contribute to a more pronounced rise in Schedule II stimulant distribution in states. Future studies could explore the impact of illicit cannabis use on stimulant rates and the impact of cannabis sales on distribution rates of non-stimulant ADHD pharmacotherapies and ADHD diagnoses.

Occasional cannabis use is associated with higher premorbid functioning and IQ in youth at clinical high-risk (CHR) for psychosis: Parallel findings to psychosis cohorts

BACKGROUND

Neurocognitive deficits have been widely reported in clinical high-risk for psychosis (CHR) populations. Additionally, rates of cannabis use are high among CHR youth and are associated with greater symptom severity. Cannabis use has been sometimes shown to be associated with better neurocognition in more progressed psychosis cohorts, therefore in this study we aimed to determine whether a similar pattern was present in CHR.

METHODS

CHR participants ages 12-30 from the North American Prodromal Longitudinal Study (NAPLS-3) (N = 698) were grouped according to: "minimal to no cannabis use" (n = 406), "occasional use" (n = 127), or "frequent use" (n = 165). At baseline, cannabis use groups were compared on neurocognitive tests, clinical, and functional measures. Follow-up analyses were used to model relationships between cannabis use frequency, neurocognition, premorbid, and social functioning.

RESULTS

Occasional cannabis users performed significantly better than other use-groups on measures of IQ, with similar trend-level patterns observed across neurocognitive domains. Occasional cannabis users demonstrated better social, global, and premorbid functioning compared to the other use-groups and less severe symptoms compared to the frequent use group. Follow-up structural equation modeling/path analyses found significant positive associations between premorbid functioning, social functioning, and IQ, which in turn was associated with occasional cannabis use frequency.

DISCUSSION

Better premorbid functioning positively predicts both better social functioning and higher IQ which in turn is associated with a moderate cannabis use pattern in CHR, similar to reports in first-episode and chronic psychosis samples. Better premorbid functioning likely represents a protective factor in the CHR population and predicts a better functional outcome.

Cannabinoids and monoaminergic system: implications for learning and memory

Cannabinoids and the endocannabinoid system (ECS) have been intensively studied for their neuroregulatory roles in the central nervous system (CNS), especially in regulating learning and memory. However, many experimental and clinical studies obtained conflicting results indicating a complex network of interaction underlying the regulation of learning and memory by different cannabinoids and the ECS. The ECS influences neuronal synaptic communications, and therefore may exert different regulation via their different impact on other neurotransmitters. The monoaminergic system includes a variety of neurotransmitters, such as dopamine, norepinephrine, and serotonin, which play important roles in regulating mood, cognition, and reward. The interaction among cannabinoids, ECS and the monoaminergic system has drawn particular attention, especially their contributions to learning and memory. In this review, we summarized the current understanding of how cannabinoids, ECS and the monoaminergic system contribute to the process of learning and memory, and discussed the influences of monoaminergic neurotransmission by cannabinoids and ECS during this process.

Acute effects of cannabigerol on anxiety, stress, and mood: a double-blind, placebo-controlled, crossover, field trial

Cannabigerol (CBG) is a phytocannabinoid increasing in popularity, with preclinical research indicating it has anxiolytic and antidepressant effects. However, there are no published clinical trials to corroborate these findings in humans. The primary objective of this study was to examine acute effects of CBG on anxiety, stress, and mood. Secondary objectives were to examine whether CBG produces subjective drug effects or motor and cognitive impairments. A double-blind, placebo-controlled cross-over field trial was conducted with 34 healthy adult participants. Participants completed two sessions (with a one-week washout period) via Zoom. In each, they provided ratings of anxiety, stress, mood, and subjective drug effects prior to double-blind administration of 20 mg hemp-derived CBG or placebo tincture (T0). These ratings were collected again after participants ingested the product and completed an online survey (T1), the Trier Social Stress Test (T2), a verbal memory test and the DRUID impairment app (T3). Relative to placebo, there was a significant main effect of CBG on overall reductions in anxiety as well as reductions in stress at T1. CBG also enhanced verbal memory relative to placebo. There was no evidence of subjective drug effects or impairment. CBG may represent a novel option to reduce stress and anxiety in healthy adults.

Light Cannabis Use and the Adolescent Brain: An 8-years Longitudinal Assessment of Mental Health, Cognition, and Reward Processing

RATIONALE

For decades, cannabis has been the most widely used illicit substance in the world, particularly among youth. Research suggests that mental health problems associated with cannabis use may result from its effect on reward brain circuit, emotional processes, and cognition. However, findings are mostly derived from correlational studies and inconsistent, particularly in adolescents.

OBJECTIVES AND METHODS

Using data from the IMAGEN study, participants (non-users, persistent users, abstinent users) were classified according to their cannabis use at 19 and 22 years-old. All participants were cannabis-naïve at baseline (14 years-old). Psychopathological symptoms, cognitive performance, and brain activity while performing a Monetary Incentive Delay task were used as predictors of substance use and to analyze group differences over time.

RESULTS

Higher scores on conduct problems and lower on peer problems at 14 years-old (n = 318) predicted a greater likelihood of transitioning to cannabis use within 5 years. At 19 years of age, individuals who consistently engaged in low-frequency (i.e., light) cannabis use (n = 57) exhibited greater conduct problems and hyperactivity/inattention symptoms compared to non-users (n = 52) but did not differ in emotional symptoms, cognitive functioning, or brain activity during the MID task. At 22 years, those who used cannabis at both 19 and 22 years-old n = 17), but not individuals that had been abstinent for ≥ 1 month (n = 19), reported higher conduct problems than non-users (n = 17).

CONCLUSIONS

Impairments in reward-related brain activity and cognitive functioning do not appear to precede or succeed cannabis use (i.e., weekly, or monthly use). Cannabis-naïve adolescents with conduct problems and more socially engaged with their peers may be at a greater risk for lighter yet persistent cannabis use in the future.

Expectations of How Acute Cannabis Use Affects Gambling Experiences and Behaviors

Emerging research shows that many individuals commonly consume cannabis while gambling. However, individuals' expectations for how cannabis consumption will impact their gambling behavior remain unknown. Participants who gambled weekly (N = 472) were recruited from Amazon Mechanical Turk and completed assessments of gambling behaviors, cannabis consumption, and expectations about the influence of cannabis on gambling. Almost all participants (94%) screened positive for problem gambling. Over half of participants (55%) reported lifetime cannabis consumption, and almost all those participants (99%) reported gambling under the influence of cannabis (GUIC) in the past month. Most participants agreed with positive expectations of gambling; they expected that they would feel calmer when under the influence of cannabis (61.4%), that gambling would be more enjoyable (61.0%), and that their gambling skills would increase when GUIC (60.6%). At the same time, most participants also agreed with negative expectations of GUIC. They expected cannabis use would make them more careless (56.4%), more anxious (54.8%), and less able to concentrate (53.7%) while gambling. Negative cannabis expectancies were significantly associated with the severity of cannabis consumption. Both positive and negative cannabis expectancies were significantly associated with gambling problems and time spent gambling under the influence of cannabis. These findings indicate that expectations may influence the decision to consume cannabis and gamble simultaneously. This study contributes to the need for addressing cannabis expectations during treatment of gambling problems.

Impact of year-long cannabis use for medical symptoms on brain activation during cognitive processes

Importance

Cannabis is increasingly being used to treat medical symptoms, but the effects of cannabis use on brain function in those using cannabis for these symptoms is not known.

Objective

To test whether brain activation during working memory, reward, and inhibitory control tasks, areas of cognition impacted by cannabis, showed increases following one year of cannabis use for medical symptoms.

Design

This observational cohort study took place from July 2017 to July 2020 and is reported on in 2024.

Setting

Participants were from the greater Boston area.

Participants

Participants were recruited as part of a clinical trial based on seeking medical cannabis cards for anxiety, depression, pain, or sleep disorders, and were between 18 and 65 years. Exclusion criteria were daily cannabis use and cannabis use disorder at baseline.

Main Outcomes and Measures

Outcomes were whole brain functional activation during tasks involving working memory, reward and inhibitory control at baseline and after one year of cannabis use.

Results

Imaging was collected in participants before and one year after obtaining medical cannabis cards; 57 at baseline (38 female [66.7%]; mean [SD] age, 38.0 [14.6] years) at baseline, and 54 at one-year (37 female [68.5%]; mean [SD] age, 38.7 [14.3] years). Imaging was also collected in 32 healthy control participants (22 female [68.8%]; mean [SD] age, 33.8 [11.8] years) at baseline. In all groups and at both time points, functional imaging revealed canonical activations of the probed cognitive processes. No statistically significant difference in brain activation between the two timepoints (baseline and one-year) in those with medical cannabis cards and no association of changes in cannabis use frequency with brain activation were found.

Conclusions and Relevance

Findings suggest that adults do not show significant neural effects in the areas of cognition of working memory, reward, and inhibitory control after one year of cannabis use for medical symptoms. The results warrant further studies that probe effects of cannabis at higher doses, with greater frequency, in younger age groups, and with larger, more diverse cohorts.

Trial Registration

NCT03224468, https://clinicaltrials.gov/.

Investigating sex differences and age of onset in emotion regulation, executive functioning, and cannabis use in adolescents and young adults

BACKGROUND

Young adults have historically high levels of cannabis use at a time which coincides with emotional and cognitive development. Age of regular onset of cannabis use and sex at birth are hypothesized to influence the relationship between cannabis use and cognition. Here we investigated past 6-month cannabis use in relation to emotional and executive functioning. We further considered age of onset and sex in subgroup analyses.

METHOD

Young adults (N = 225; ages 16-22) completed a substance use interview and cognitive battery, including the Emotional Word-Emotional Face Stroop and NIH toolbox executive functioning tasks. Linear regressions examined relationships between past 6-month cannabis use episodes and performance. Subgroup analyses investigated whether age of onset or sex impacted relationships.

RESULTS

After correcting for multiple comparisons, greater past 6-month cannabis use episodes were related to poorer Emotional Stroop Congruent Accuracy (p = .0004, FDR-p = .002) and List Sorting Working Memory (p = .02, FDR-p = .10) performance. Younger age of regular use onset marginally related to lower Emotional Stroop Congruent Accuracy performance (p = .03, FDR-p = .13). There were no cannabis use by sex interactions on cognition.

CONCLUSIONS

Consistent with prior findings, results suggest small reductions in cannabis-related performance in processing speed during emotional Stroop and working memory tasks. Age of onset was modestly related to Stroop performance, but not sex. Longitudinal studies which detail patterns of cannabis and other substance use are needed to better assess brain-behavior relationships and other factors (e.g., age of onset of regular use, sex) which could influence cannabis-related impairments in cognitive functioning.

Cannabis Use Characteristics Associated with Self-Reported Cognitive Function in a Nationally Representative U.S. sample

BACKGROUND

With increases in cannabis use and potency, there is a need to improve our understanding of the impact of use on cognitive function. Previous research indicates long-term cannabis use may have a negative effect on executive function. Few studies have examined persistence of it in protracted abstinence, and there is limited evidence of predictors of worse cognitive function in current and former users. In this study, we aim to evaluate the associations between cannabis use status (current, former, and never use) and self-report cognition. Further, we investigate if cannabis use characteristics predict self-report cognitive function.

METHODS

Cross-sectional cannabis use data from the National Epidemiological Survey on Alcohol and Related Conditions-III (NESARC-III), a national survey (N = 36,309) conducted in the USA between 2012 and 2013 were used alongside the Executive Function Index scales. The data were analyzed by using Ordinary Least Squares regression.

RESULTS

Current (N = 3,681, Female = 37.7%) and former users (N = 7,448, Female = 45.4%) reported poorer cognition than never users (N = 24,956, Female = 56.6%). Self-reported cognition of former users was in-between that of current and never users. Several cannabis use characteristics were associated with self-reported cognition in current and former users.

CONCLUSION

While prospective studies are required to confirm, findings suggest cannabis use is linked to worse cognition. There may be some limited recovery of cognition in former users and some cannabis use characteristics predict impairment. These findings add to our understanding of the cognitive impact of cannabis use. As worse cognitive function may impact relapse, findings have implications for personalization of cannabis use disorder treatment.

The CB1 receptor interacts with cereblon and drives cereblon deficiency-associated memory shortfalls

Cereblon/CRBN is a substrate-recognition component of the Cullin4A-DDB1-Roc1 E3 ubiquitin ligase complex. Destabilizing mutations in the human CRBN gene cause a form of autosomal recessive non-syndromic intellectual disability (ARNSID) that is modelled by knocking-out the mouse Crbn gene. A reduction in excitatory neurotransmission has been proposed as an underlying mechanism of the disease. However, the precise factors eliciting this impairment remain mostly unknown. Here we report that CRBN molecules selectively located on glutamatergic neurons are necessary for proper memory function. Combining various in vivo approaches, we show that the cannabinoid CB1 receptor (CB1R), a key suppressor of synaptic transmission, is overactivated in CRBN deficiency-linked ARNSID mouse models, and that the memory deficits observed in these animals can be rescued by acute CB1R-selective pharmacological antagonism. Molecular studies demonstrated that CRBN interacts physically with CB1R and impairs the CB1R-Gi/o-cAMP-PKA pathway in a ubiquitin ligase-independent manner. Taken together, these findings unveil that CB1R overactivation is a driving mechanism of CRBN deficiency-linked ARNSID and anticipate that the antagonism of CB1R could constitute a new therapy for this orphan disease.

The prevalence of cannabis use disorder in attention-deficit hyperactivity disorder: A clinical epidemiological meta-analysis

Studies have shown that individuals with attention-deficit hyperactivity disorder (ADHD) pose an increased risk for developing substance use disorders. Increased cannabis product accessibility and recent legislative changes have led to increased cannabis consumption, thereby increasing the risk of cannabis use disorder (CUD). The present meta-analysis explored the lifetime and current prevalence of CUD in ADHD. A systematic review was conducted using the following databases: PubMed, PsycINFO and Web of Science. A total of 14 articles were included and used to estimate the aggregate lifetime and current prevalence of CUD in ADHD alongside risk ratios comparing increased risk of CUD in ADHD versus control samples. Mixed and random-effects models indicated that lifetime and current prevalence rates of CUD in ADHD populations were 26.9% and 19.2%, respectively (although prediction intervals ranged from 12.4% to 48.8% and 5.5%-39.1%, respectively). Analysis of the risk ratios indicated that those with ADHD were at 2.85- and 2.91-times greater risk of a lifetime or current diagnosis of CUD, respectively, than those in the general population. Our findings support the need for additional research on the prevalence of CUD in those with ADHD, as well as the inclusion of CUD screening in the treatment of ADHD.

Substance Use and Educational Impacts in Youth With and Without Chronic Illness

INTRODUCTION

Alcohol, cannabis, and nicotine are commonly used psychoactive substances that affect adolescent neurocognition. Little is known about the educational impacts of their use on measures of educational performance, participation and problems, especially among youth with a chronic illness who may use these substances to alleviate stress and symptoms.

METHODS

Adolescents receiving general or subspecialty care were administered an electronic survey from 2016 to 2018. Data were analyzed in 2023. Using modified Poisson models, cross-sectional associations between past 12-month usage of alcohol, cannabis, and/or nicotine and educational impacts were estimated.

RESULTS

Among 958 adolescents (mean age 16.0 years (SD 1.3), 564 (58.9%) female gender, 445 (46.5%) in subspecialty care), 294 (30.7%), 220 (23.0%), and 126 (13.2%) reported past 12-month use of alcohol, cannabis, and nicotine respectively, while 407 (42.5%) reported ≥1 educational impact, including recent lower grades 210 (21.9%), past 3-month truancy from school 164 (17.1%) or activities 170 (17.7%), and detention 82 (8.6%). Use of cannabis, but not other substances, was associated with negative educational impacts: lower grades (mostly C's/D's/F's), adjusted prevalence ratios [APR, (95% CI)] 1.54 (1.13-2.11); past 3-month truancy from school [2.16 (1.52-3.07)]; detention [2.29 (1.33-3.94)]. The association between cannabis use and any negative educational impact was stronger among adolescents with a chronic illness (p<0.001).

CONCLUSIONS

Among adolescents, cannabis use was associated with a heightened risk of negative educational impacts, even after controlling for alcohol and nicotine use. Adolescents with chronic illness were especially likely to experience negative educational impacts. Findings underscore need for preventive interventions and messaging to reduce risks.

Neurocognitive Impact of Exposure to Cannabis Concentrates and Cannabinoids Including Vaping in Children and Adolescents: A Systematic Review

During adolescence, significant changes unfold in the brain's maturation process. The density of white matter increases, accompanied by the pruning back of gray matter. This critical and vulnerable period becomes especially noteworthy in the context of drug use, as adolescents are extensively exposed to substances such as tobacco, alcohol, and cannabis. The concern is heightened now that cannabis has been legalized for recreational use in many places, leading to increased exposure levels. Additionally, knowledge about the impact of cannabis on neurocognitive development during this stage is limited. This knowledge gap compounds the issue, making it even more concerning. Therefore, a systematic review was carried out based on the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, using medical databases such as PubMed, PubMed Central (PMC), Medline, Cochrane Library, Internet Archive Scholar, and Embase-Elsevier for relevant medical literature. The identified articles were reviewed, eligibility criteria were applied, and 19 research articles were identified. The final papers explored the correlation between children's and adolescents' exposure to cannabis-containing compounds and subsequent changes in the central nervous system (CNS). Findings revealed a considerable impact, ranging from transient alterations in mood to permanent cognitive function and sensory processing changes, affecting the deterioration of the quality of life of these individuals in adulthood. Presently, most studies were conducted on animals, and the few studies on humans have considerable limitations, such as the type of study, age of the population, and small samples, among others. For this reason, it is essential for the scientific community and public health organizations, in general, to conduct more studies that demonstrate the true neurobiological impact of this drug and its accessibility to young people and, based on the results, consider its legalization or propose regulations for its use and commercialization.

Accuracy and replicability of identifying eyelid tremor as an indicator of recent cannabis smoking

INTRODUCTION

Cannabis intoxication may increase the risk of motor vehicle crashes. However, reliable methods of assessing cannabis intoxication are limited. The presence of eyelid tremors is among the signs of cannabis use identified under the Drug Evaluation and Classification Program of the International Association of Chiefs of Police. Our objectives were to assess the accuracy and replicability of identifying eyelid tremor as an indicator of recent cannabis smoking using a blinded, controlled study design.

METHODS

Adult subjects (N = 103) were recruited into three groups based on their cannabis use history: daily, occasional, and no current cannabis use. Participants' closed eyelids were video recorded for 30 seconds by infrared videography goggles before and at a mean ± standard deviation time of 71.4 ± 4.6 minutes after the onset of a 15-minute interval of ad libitum cannabis flower smoking or vaping. Three observers with expertise in neuro-ophthalmology and medical toxicology were trained on exemplar videos of eyelids to reach a consensus on how to grade eyelid tremor. Without knowledge of subjects' cannabis use history or time point (pre- or post-smoking), observers reviewed each video for eyelid tremor graded as absent, slight, moderate, or severe. During subsequent data analysis, this score was further dichotomized as a consensus score of absent (absent/slight) or present (moderate/severe).

RESULTS

Kappa and intraclass correlation coefficient statistics demonstrated moderate agreement among the coders, which ranged from 0.44-0.45 and 0.58-0.61, respectively. There was no significant association between recent cannabis use and the observers' consensus assessment that eyelid tremor was present, and cannabis users were less likely to have tremors (odds ratio: 0.75; 95 percent confidence interval: 0.25, 2.40). The assessment of eyelid tremor as an indicator of recent cannabis smoking had a sensitivity of 0.86, specificity of 0.18, and accuracy of 0.64.

DISCUSSION

Eyelid tremor has fair sensitivity but poor specificity and accuracy for identification of recent cannabis use. Inter-rater reliability for assessment of eyelid tremor was moderate for the presence and degree of tremor. The weak association between recent cannabis use and eyelid tremor does not support its utility in identifying recent cannabis use.

LIMITATIONS

Videos were recorded at only one time point after cannabis use. Adherence to abstinence could not be strictly supervised. Due to regulatory restrictions, we were unable to control the cannabis product used or administer a fixed Δ9-tetrahydrocannabinol dose. Participants were predominately non-Hispanic and White.

CONCLUSIONS

In a cohort of participants with a range of cannabis use histories, acute cannabis smoking was not associated with the presence of eyelid tremor, regardless of cannabis use history, at 70 minutes post-smoking. Additional research is needed to identify the presence of eyelid tremor accurately, determine the relationship between cannabis dose and timeline in relation to last cannabis use to eyelid tremor, and determine how it should be, if at all, utilized for cannabis Drug Recognition Evaluator examinations.

Spanish versions and validation of a series of rating scales and visual analogue scales to assess the subjective effects of cannabis

Cannabis is being legalized for medical and recreational purposes all around the world. However, the understanding of the psychological effects of cannabis is still limited, and it has been previously linked to mental disorders such as schizophrenia. Lately, new scales have been created and adapted to measure its psychological effects. The aim of this study is to create Spanish versions of some of these scales and test their psychometric characteristics. One hundred sixteen participants were recruited from Cannabis Social Clubs (CSC) in Barcelona, Spain. Participants under the effects of their own cannabis completed the Cannabis Experience Questionnaire-modified version (CEQ-mv), Addiction Research Centre Inventory-18 (ARCI-18), Psychotomimetic States Inventory (PSI) and Visual Analogue Scales (VAS). Questionnaires were completed in the CSC, providing a naturalistic setting for the study. Exploratory factor analysis and internal consistency were analyzed. PSI was reduced from a 6-factor to a 4-factor model with adequate to low reliability, ARCI-18 was reduced from a 3-factor to a 2-factor model with good reliability, and VAS were reduced from a 4-factor to a 3-factor model, also with good reliability. These questionnaires showed adequate reliability and can be used in future studies to test the subjective effects of cannabis in clinical and naturalistic settings.

Nicotinic Acetylcholine Receptor Dysfunction in Addiction and in Some Neurodegenerative and Neuropsychiatric Diseases

The cholinergic system plays an essential role in brain development, physiology, and pathophysiology. Herein, we review how specific alterations in this system, through genetic mutations or abnormal receptor function, can lead to aberrant neural circuitry that triggers disease. The review focuses on the nicotinic acetylcholine receptor (nAChR) and its role in addiction and in neurodegenerative and neuropsychiatric diseases and epilepsy. Cholinergic dysfunction is associated with inflammatory processes mainly through the involvement of α7 nAChRs expressed in brain and in peripheral immune cells. Evidence suggests that these neuroinflammatory processes trigger and aggravate pathological states. We discuss the preclinical evidence demonstrating the therapeutic potential of nAChR ligands in Alzheimer disease, Parkinson disease, schizophrenia spectrum disorders, and in autosomal dominant sleep-related hypermotor epilepsy. PubMed and Google Scholar bibliographic databases were searched with the keywords indicated below.

Cognitive test performance in chronic cannabis flower users, concentrate users, and non-users

Extremely high-potency cannabis concentrates are becoming increasingly available and popular among consumers. While prior research indicates these products are perceived to have greater detrimental effects relative to cannabis flower, few studies have examined their relative objective effects, and no existing studies have compared the cognitive test performance of sober flower users, concentrate users, and non-users. A total of 198 healthy adults (98 non-users, 46 exclusive flower users, and 54 concentrate users) were administered a battery of tests of memory, psychomotor speed, attention, and executive functioning under sober laboratory-controlled conditions. Significant group differences were detected on tests of verbal free recall and episodic prospective memory, with both the flower users and concentrate users demonstrating significantly worse performance than non-users. Concentrate (but not flower) users performed worse than non-users on a measure of source memory, but contrary to our hypothesis, there were no significant differences between flower and concentrate users on any of the cognitive tests. Results indicate that, under sober conditions, individuals who regularly use concentrates are no more cognitively impacted than those who exclusively use flower. These null findings may reflect the tendency for concentrate users to self-titrate and use significantly lower quantities of concentrates than flower.

Avatar Intervention for Cannabis Use Disorder in Individuals with Severe Mental Disorders: A Pilot Study

Cannabis use disorder (CUD) is a complex issue, even more so when it is comorbid with a severe mental disorder (SMD). Available interventions are at best slightly effective, and their effects are not maintained over time. Therefore, the integration of virtual reality (VR) may increase efficacy; however, it has not yet been investigated in the treatment of CUD. A novel approach, avatar intervention for CUD, uses existing therapeutic techniques from other recommended therapies (e.g., cognitive behavioral methods, motivational interviewing) and allows participants to practice them in real-time. During immersive sessions, participants are invited to interact with an avatar representing a significant person related to their drug use. This pilot clinical trial aimed to evaluate the short-term efficacity of avatar intervention for CUD on 19 participants with a dual diagnosis of SMD and CUD. Results showed a significant moderate reduction in the quantity of cannabis use (Cohen's d = 0.611, p = 0.004), which was confirmed via urinary quantification of cannabis use. Overall, this unique intervention shows promising results. Longer-term results, as well as comparison with classical interventions in a larger sample, are warranted through a future single-blind randomized controlled trial.

Emerging Adult Perceptions of Cannabis Consumption Post-Legalization: Considering Age and Sex Differences

PURPOSE

Increased access to legalized non-medical cannabis has led to growing concern over the potential adverse health impacts of cannabis consumption among youth and emerging adults. This study explored emerging adult perceptions of cannabis consumption and if perceptions changed based on the age and sex of the cannabis consumer.

METHODS

Canadian emerging adults between the ages of 18 and 25 years (N = 1,424, Mean = 21.23) were randomly assigned to one of six vignettes that varied by age (14 years, 21 years, and 28 years) or sex (male, female) of the cannabis consumer. Participants were asked to rate seven single-item measures on perceived dangerousness, problematic consumption, negative impacts, and level of disapproval related to the vignette character's almost daily cannabis consumption.

RESULTS

The results of seven 2 × 3 factorial analyses of variance revealed a main effect of age on six of seven items, no main effects of sex, and no interactions. Except for social life, participants noted significant differences in harms of cannabis consumption by 14-year-olds, compared to 21-year-olds and 28-year-olds. There were no significant differences in overall perceived dangerousness, problematic consumption, or impact on mental or cognitive health between 21-year-olds and 28-year-olds. Participants perceived cannabis consumption by a 21-year-old to be more harmful to brain development and reported greater disapproval than consumption by a 28-year-old.

DISCUSSION

Emerging adults may appreciate the impacts of cannabis consumption within their age cohort on brain development and perceive greater risks for youth. Further education should focus on the potential cognitive and mental health impacts of cannabis in emerging adults.

Role of Neuronal Nicotinic Acetylcholine Receptors in Cannabinoid Dependence

Cannabis is among the most widely consumed psychoactive drugs around the world and cannabis use disorder (CUD) has no current approved pharmacological treatment. Nicotine and cannabis are commonly co-used which suggests there to be overlapping neurobiological actions supported primarily by the co-distribution of both receptor systems in the brain. There appears to be strong rationale to explore the role that nicotinic receptors play in cannabinoid dependence. Preclinical studies suggest that the ɑ7 nAChR subtype may play a role in modulating the reinforcing and discriminative stimulus effects of cannabinoids, while the ɑ4β2 * nAChR subtype may be involved in modulating the motor and sedative effects of cannabinoids. Preclinical and human genetic studies point towards a potential role of the ɑ5, ɑ3, and β4 nAChR subunits in CUD, while human GWAS studies strongly implicate the ɑ2 subunit as playing a role in CUD susceptibility. Clinical studies suggest that current smoking cessation agents, such as varenicline and bupropion, may also be beneficial in treating CUD, although more controlled studies are necessary. Additional behavioral, molecular, and mechanistic studies investigating the role of nAChR in the modulation of the pharmacological effects of cannabinoids are needed.

ASRA Pain Medicine consensus guidelines on the management of the perioperative patient on cannabis and cannabinoids

BACKGROUND

The past two decades have seen an increase in cannabis use due to both regulatory changes and an interest in potential therapeutic effects of the substance, yet many aspects of the substance and their health implications remain controversial or unclear.

METHODS

In November 2020, the American Society of Regional Anesthesia and Pain Medicine charged the Cannabis Working Group to develop guidelines for the perioperative use of cannabis. The Perioperative Use of Cannabis and Cannabinoids Guidelines Committee was charged with drafting responses to the nine key questions using a modified Delphi method with the overall goal of producing a document focused on the safe management of surgical patients using cannabinoids. A consensus recommendation required ≥75% agreement.

RESULTS

Nine questions were selected, with 100% consensus achieved on third-round voting. Topics addressed included perioperative screening, postponement of elective surgery, concomitant use of opioid and cannabis perioperatively, implications for parturients, adjustment in anesthetic and analgesics intraoperatively, postoperative monitoring, cannabis use disorder, and postoperative concerns. Surgical patients using cannabinoids are at potential increased risk for negative perioperative outcomes.

CONCLUSIONS

Specific clinical recommendations for perioperative management of cannabis and cannabinoids were successfully created.

High on Hookah: Smoking Marijuana from a Hookah among Adults in the United States, Population Assessment of Tobacco and Health Study, 2015-2019

Background: This study aimed to examine the trend and factors associated with smoking marijuana from a hookah device among US adults. Methods: Data were drawn from the Population Assessment of Tobacco and Health (PATH) Study, an ongoing nationally representative, longitudinal cohort study of the US population. Adult respondents who self-reported ever smoking marijuana from a hookah at Wave 5 (2018-19, N = 34,279 US adults) were included in the multivariable analysis. Trend analysis also was conducted using National Cancer Institute JoinPoint software from 2015 to 2019. Results: In 2018-19, an estimated 23.6 million (9.7%) US adults reported ever smoking marijuana from a hookah. Trend analysis showed the increasing prevalence of using marijuana from a hookah device from Wave 3 (8.9%) to Wave 5 (9.7%; time trend p = .007). Adults aged 25-44 years old (vs. 18-24; 13%, vs. 9%), whites (vs. Black; 11% vs. 9%), and lesbian, gay, or bisexual (LGB vs. straight; 17% vs. 9%) were more likely to report ever smoking marijuana from a hookah (ps < .05). Former and current users (vs. never users) of e-cigarettes (19% and 25% vs. 5%), cigarettes (11% and 21% vs. 2%), cigars (17% and 27% vs. 3%), and pipes (21% and 33% vs. 7%) and past 30-day blunt users (vs. non-users; 39% vs. 9%) were more likely to ever smoke marijuana from a hookah (ps < .05). Pregnant women (vs. non-pregnant; 12.8% vs. 8.6%; p = 0.03) were more likely to smoke marijuana from a hookah. Conclusions: Smoking marijuana from a hookah device is prevalent among young adults in the US, especially among vulnerable populations, and has increased significantly from 2015-2019.

Effects of cannabinoids on resting state functional brain connectivity: A systematic review

Cannabis products are widely used for medical and non-medical reasons worldwide and vary in content of cannabinoids such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Resting state functional connectivity offers a powerful tool to investigate the effects of cannabinoids on the human brain. We systematically reviewed functional neuroimaging evidence of connectivity during acute cannabinoid administration. A pre-registered (PROSPERO ID: CRD42020184264) systematic review of 13 studies comprising 318 participants (mean age of 25 years) was conducted and reported using the PRISMA checklist. During THC and THCv exposure vs placebo reduced connectivity with the NAcc was widely reported. Limited evidence shows that such effects are offset by co-administration of CBD. NAcc-frontal region connectivity was associated with intoxication levels. Cannabis intoxication vs placebo was associated with lower striatal-ACC connectivity. CBD and CBDv vs placebo were associated with both higher and lower connectivity between striatal-prefrontal/other regions. Overall, cannabis and cannabinoids change functional connectivity in the human brain during resting state as a function of the type of cannabinoid examined.

Relationship perceptions and conflict behavior among cannabis users

BACKGROUND

Cannabis use is increasingly common, yet few studies have examined its associations with couple functioning. To address this gap, we used actor-partner interdependence modeling to examine the associations between cannabis use, relationship perceptions, and observed conflict behavior in a community-based sample of cannabis users and their partners.

METHODS

Cannabis users (N = 232; 96 males; 122 females; 14 undisclosed biological sex) and their partners completed self-reports of cannabis frequency and global relationship satisfaction and commitment. At a laboratory visit, couples engaged in a 10 min conflict discussion and a 5 min discussion of areas of agreement, and reported on their post-conflict perceptions. Each partner's parasympathetic activity was assessed during the conflict task, and trained raters coded conflict and recovery behavior RESULTS: More frequent actor cannabis use was associated with more negative engagement and avoidance behavior during conflict, less parasympathetic withdrawal during conflict, and less effective behavioral recovery immediately after conflict. More frequent cannabis use was also associated with greater satisfaction with conflict resolution following the conflict discussion, but was not associated with perceived overall relationship satisfaction or commitment. Cannabis effects were independent of alcohol use CONCLUSIONS: Among cannabis users, there are discrepancies between perceived and objective measures of relationship functioning, such that cannabis users viewed their relationships as better functioning compared to independent raters' reports. These findings highlight the need for a nuanced understanding of the associations between cannabis and relationship functioning, which appear to be distinct from alcohol, as well as an organizing theoretical framework to stimulate future research.

The Potential Paradoxical Neurocognitive Effects of Cannabis Use in Patients with Psychotic Disorders: A Critical Meta-Review of Meta-Analytical Evidence

Background: The association between cannabis and cognitive functions has been thoroughly studied in psychotic disorders, but conflictual/paradoxical results have emerged. This critical meta-review examined the magnitude of effects of cannabis on neurocognitive functions in patients with psychotic disorders provided by meta-analyses and evaluated the quality of evidence. Methods: A systematic search of meta-analyses was performed in PubMed, PsycINFO, Web of Science, and Google Scholar. Results: The search retrieved six meta-analyses. Quality of evidence varied from very low to moderate quality. No neurocognitive difference was observed between cannabis users and nonusers in first episode of psychosis samples. Limited evidence showed no significant difference in language, psychomotor functioning, and verbal/visual learning/memory, apart from improvements in verbal and visual memory (recognition). Findings showed better neurocognitive performances in cannabis-using patients for planning/reasoning and working memory. There were tendencies toward significance for processing speed and attention. Most effect sizes showed small to moderate degrees of outperformances in cannabis users. Individuals with lifetime use appeared to show better neurocognitive functions. Conclusion: Evidence indicated nonuniform effects of cannabis use across cognitive domains, with some areas suggesting better cognitive performances in cannabis users, entitled the paradoxical effect of the dually diagnosed. Clinical significance of these findings should be interpreted cautiously.