Impulsivity, attention, memory, and decision-making among adolescent marijuana users

Association of Marijuana Use With Psychological Distress Among Adults in United States

PurposeDetermine the association of marijuana use with serious psychological distress (SPD) among adults aged 18 years or older using a large, nationally representative sample of US households.DesignCross-sectional analysis.SettingData from the National Survey on Drug Use and Health, 2021.Subjects47,247 respondents representing 253.7 million adults (age>18 years) in the US.MeasuresMarijuana use was categorized as (1) None, (2) within the past month, (3) within 1 year, and (4) more than a year ago from the interview time. SPD was measured with the Kessler-6 distress scale.AnalysisBivariable and multivariable logistic regression analyses accounting for complex survey designs were conducted.ResultsAmong adults in the US, 50.9% never used marijuana, 13.7%, 6.0%, and 29.4% reported marijuana use in the past month, in the past year, and more than a year ago, respectively. Individuals using marijuana within the past month, within a year, and more than a year ago reported higher past month SPD (15.3%, 13.5%, and 6.8%, respectively) than never-users (4.9%). Adjusted logistic regression analysis revealed that marijuana use in the past month, past year (1-12 months), and over a year ago is associated with higher SPD (AOR [95% CI] = 2.06 [1.72, 2.45]; 1.82 [1.50, 2.21]; 1.53 [1.26, 1.87], respectively) compared to no marijuana use.ConclusionAdults who used marijuana more recently were more likely to report SPD.

A robust brain network for sustained attention from adolescence to adulthood that predicts later substance use

Substance use, including cigarettes and cannabis, is associated with poorer sustained attention in late adolescence and early adulthood. Previous studies were predominantly cross-sectional or under-powered and could not indicate if impairment in sustained attention was a predictor of substance use or a marker of the inclination to engage in such behavior. This study explored the relationship between sustained attention and substance use across a longitudinal span from ages 14 to 23 in over 1000 participants. Behaviors and brain connectivity associated with diminished sustained attention at age 14 predicted subsequent increases in cannabis and cigarette smoking, establishing sustained attention as a robust biomarker for vulnerability to substance use. Individual differences in network strength relevant to sustained attention were preserved across developmental stages and sustained attention networks generalized to participants in an external dataset. In summary, brain networks of sustained attention are robust, consistent, and able to predict aspects of later substance use.

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.

A robust brain network for sustained attention from adolescence to adulthood that predicts later substance use

Substance use, including cigarettes and cannabis, is associated with poorer sustained attention in late adolescence and early adulthood. Previous studies were predominantly cross-sectional or under-powered and could not indicate if impairment in sustained attention was a predictor of substance-use or a marker of the inclination to engage in such behaviour. This study explored the relationship between sustained attention and substance use across a longitudinal span from ages 14 to 23 in over 1,000 participants. Behaviours and brain connectivity associated with diminished sustained attention at age 14 predicted subsequent increases in cannabis and cigarette smoking, establishing sustained attention as a robust biomarker for vulnerability to substance use. Individual differences in network strength relevant to sustained attention were preserved across developmental stages and sustained attention networks generalized to participants in an external dataset. In summary, brain networks of sustained attention are robust, consistent, and able to predict aspects of later substance use.

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/.

Patterns of Polysubstance Use in Young Black and Latinx Sexual Minority Men and Transgender Women and Its Association with Sexual Partnership Factors: The PUSH Study

Background: Adult studies have demonstrated that polysubstance use increases HIV acquisition risk through increased sexual behaviors, however, few studies have examined polysubstance in young Black and Latinx sexual minority men (SMM) and transgender women (TW). Methods: We used cross-sectional data from 466 young Black and Latinx SMM and TW living in four high HIV-burden US cities enrolled in the PUSH Study, a status-neutral randomized control trial to increase HIV prevention and treatment adherence. We examined data for patterns of polysubstance use comparing age differences of use and explored associations between substance use and sexual partnership factors - inconsistent condom use, pressure to have condomless anal sex, and older partner, using bivariate and multivariate analyses. Results: Most participants described prior substance use with alcohol and cannabis being most common (76% each) and 23% described other illicit drug use, including stimulants, cocaine, hallucinogens, sedatives, opioids, and inhalants. Polysubstance use was common with nearly half (47%) of participants reporting alcohol and cannabis use, 20% reporting alcohol, cannabis, and one other illicit drug use, and 19% reporting alcohol or cannabis use plus one other illicit drug use. Polysubstance use was associated with greater adjusted odds of pressure to have condomless anal sex, older partner (>5 years older), and inconsistent condom use. Conclusions: Associations of polysubstance use with sexual practices and sexual partnerships that are known predictors of HIV acquisition or transmission among Black and Latinx SMM and TW underscore the need for combination interventions that include substance use treatment alongside antiretroviral-based and partner-based HIV prevention and treatment interventions.Trial Registration: ClinicalTrials.gov Identifier: NCT03194477.

Relationships Between Prenatal Cocaine Exposure, Cannabis-Use Onset and Emotional and Related Characteristics in Young/Emerging Adults

Background: Exposure to substances in utero may have significant early-life consequences. Less is known about the effects in emerging adulthood, particularly regarding patterns of substance use and related characteristics.Objectives: In this study, we recruited emerging adults, followed since birth, who had been prenatally exposed, or not, to cocaine. Individuals reported on their cannabis, alcohol, and tobacco use, and measures of impulsivity, anhedonia, emotional regulation, and mental health were obtained. Comparisons were made between emerging adults with prenatal cocaine exposure and those without. Correlations were performed between psychological measures and substance use, and regression analyses were conducted to determine potential pathways by which such measures may relate to prenatal exposure or substance use.Results: Individuals with prenatal cocaine exposure (vs. those without) used cannabis at younger ages, reported greater cannabis-use severity, and demonstrated higher impulsivity, state anxiety, and alexithymia. Earlier age of onset of cannabis use was associated with higher impulsivity, state anxiety, alexithymia, and social and physical anhedonia. Cannabis-use age-of-onset mediated the relationship between prenatal cocaine-exposure status and state anxiety and between prenatal cocaine-exposure status and cannabis-use severity in emerging adulthood but not relationships between prenatal cocaine-exposure status and impulsivity or alexithymia in emerging adulthood. Findings suggest that adults with prenatal cocaine exposure may use cannabis at younger ages, which may relate to increased anxiety and more severe use.Conclusions: These findings suggest both mechanisms and possible intervention targets to improve mental health in emerging adults with prenatal cocaine exposure.

Impact of Adolescent Cannabis Use on Neurocognitive and Brain Development

Research examining associations between frequent cannabis use in adolescence and brain-behavior outcomes has increased substantially over the past 2 decades. This review attempts to synthesize the state of evidence in this area of research while acknowledging challenges in interpretation. Although there is converging evidence that ongoing, frequent cannabis use in adolescence is associated with small reductions in cognitive functioning, there is still significant debate regarding the persistence of reductions after a period of abstinence. Similarly, there is controversy regarding the replicability of structural and functional neuroimaging findings related to frequent cannabis use in adolescence. Larger studies with informative designs are needed.

Impact of a brief distress intolerance intervention on acute stress modulation of response inhibition neurophysiology in cannabis use disorder

BACKGROUND

The prevalence of cannabis use in the US has increased within the past two decades. Moreover, cannabis use disorder (CUD) is associated with significant disability, but the underlying neural mechanisms of CUD are unclear. Distress intolerance (DI), a psychological risk factor for CUD, may confer risk in part via impaired inhibitory control (IC) capacity during acute stress. DI and cannabis use problems have been associated with altered N2 amplitude, an IC-related event-related potential, in prior cross-sectional studies, but whether altered N2 is a state marker of CUD severity, a pathoplastic factor responsive to intervention and predictive of CUD symptom change over time, or an enduring trait-like vulnerability is unclear. In this secondary analysis, we tested the impact of a DI-targeted intervention on acute stress-related modulation of the N2 and whether pre-intervention N2 predicted CUD symptom change through follow-up.

METHOD

Sixty participants were randomly assigned to a DI-targeted or control intervention. Participants completed an IC task before and after a stress induction at pre- and post-intervention lab visits while EEG activity was recorded.

RESULTS

The DI intervention did not alter the N2 compared to a control intervention. Pre-intervention post-stress IC-related N2 was associated with worse CUD severity but did not predict changeover time.

CONCLUSION

Findings are consistent with blunted N2 after acute stress acting as a stable marker of CUD severity rather than a pathoplastic factor predictive of CUD trajectory. Future research should investigate whether stress-related blunting of N2 is a consequence of severe CUD or a pre-existing vulnerability.

FABP5 is important for cognitive function and is an important regulator of the physiological effects and pharmacokinetics of acute Δ9 tetrahydrocannabinol inhalation in mice

Fatty acid binding protein 5 (FABP5) interacts with the endocannabinoid system in the brain via intracellular transport of anandamide, as well as Δ9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis. Previous work has established the behavioral effects of genetic deletion of FABP5, but not in the presence of THC. The present study sought to further elucidate the role of FABP5 on the pharmacokinetic and behavioral response to THC through global deletion. Adult FABP5+/+ and FABP5-/- mice were tested for behavioral response to THC using Open Field (OF), Novel Object Recognition (NOR), T-Maze, Morris Water Maze (MWM), and Elevated Plus Maze (EPM). An additional cohort of mice was used to harvest blood, brains, and liver samples to measure THC and metabolites after acute administration of THC. Behavioral tests showed that some cognitive deficits from FABP5 deletion, particularly in MWM, were blocked by THC administration, while this was not observed in other measures of memory and anxiety (such as T-Maze and EPM). Measurement of THC and metabolites in blood serum and brain tissue through UPLC-MS/MS analysis showed that the pharmacokinetics of THC was altered by FABP5. The present study shows further evidence of the importance of FABP5 in cognitive function. Additionally, results showed that FABP5 is an important regulator of the physiological effects and pharmacokinetics of THC.

Regular recreational Cannabis users exhibit altered neural oscillatory dynamics during attention reorientation

BACKGROUND

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

METHODS

We used magnetoencephalography (MEG) and a modified Posner cueing task in 21 regular cannabis users and 32 demographically matched non-user controls. MEG data were imaged in the time-frequency domain using a beamformer and peak voxel time series were extracted to quantify the oscillatory dynamics underlying use-related aberrations in attentional reorienting, as well as the impact on spontaneous neural activity immediately preceding stimulus onset.

RESULTS

Behavioral performance on the task (e.g. reaction time) was similar between regular cannabis users and non-user controls. However, the neural data indicated robust theta-band synchronizations across a distributed network during attentional reorienting, with activity in the bilateral inferior frontal gyri being markedly stronger in users relative to controls (p's < 0.036). Additionally, we observed significantly reduced spontaneous theta activity across this distributed network during the pre-stimulus baseline in cannabis users relative to controls (p's < 0.020).

CONCLUSIONS

Despite similar performance on the task, we observed specific alterations in the neural dynamics serving attentional reorienting in regular cannabis users compared to controls. These data suggest that regular cannabis users may employ compensatory processing in the prefrontal cortices to efficiently reorient their attention relative to non-user controls.

Prenatal Exposure to Δ9-Tetrahydrocannabinol Affects Hippocampus-Related Cognitive Functions in the Adolescent Rat Offspring: Focus on Specific Markers of Neuroplasticity

Previous evidence suggests that prenatal exposure to THC (pTHC) derails the neurodevelopmental trajectories towards a vulnerable phenotype for impaired emotional regulation and limbic memory. Here we aimed to investigate pTHC effect on hippocampus-related cognitive functions and markers of neuroplasticity in adolescent male offspring. Wistar rats were exposed to THC (2 mg/kg) from gestational day 5 to 20 and tested for spatial memory, object recognition memory and reversal learning in the reinforce-motivated Can test and in the aversion-driven Barnes maze test; locomotor activity and exploration, anxiety-like behaviour, and response to natural reward were assessed in the open field, elevated plus maze, and sucrose preference tests, respectively. The gene expression levels of NMDA NR1-2A subunits, mGluR5, and their respective scaffold proteins PSD95 and Homer1, as well as CB1R and the neuromodulatory protein HINT1, were measured in the hippocampus. pTHC offspring exhibited deficits in spatial and object recognition memory and reversal learning, increased locomotor activity, increased NR1-, decreased NR2A- and PSD95-, increased mGluR5- and Homer1-, and augmented CB1R- and HINT1-hippocampal mRNA levels. Our data shows that pTHC is associated with specific impairment in spatial cognitive processing and effectors of hippocampal neuroplasticity and suggests novel targets for future pharmacological challenges.

The Relationship Between Cannabis, Cognition, and Schizophrenia: It's Complicated

The consequences of cannabis use, especially in the context of schizophrenia, have gained increased importance with the legalization of cannabis in North America and across the globe. Cannabis use has multifaceted impacts on cognition in schizophrenia patients and healthy subjects. Healthy subjects, particularly those who initiated cannabis use at earlier ages and used high-potency cannabis for longer durations, exhibited poorer cognition mainly in working memory and attention. Cannabis use in schizophrenia has been associated with symptom exacerbation, longer and more frequent psychotic episodes, and poorer treatment outcomes. However, cannabis-using patients have better overall cognitive performance compared to patients who were not cannabis users. Interestingly, these effects were only apparent in lifetime cannabis users, but not in current (or within last 6 months) users. Moreover, higher frequency and earlier age of cannabis use initiation (i.e., before 17 years of age) were associated with better cognitive performance, although they had an earlier illness onset. Three possible hypotheses seem to come forward to explain this paradox. First, some components of cannabis may have antipsychotic or cognitive-enhancing properties. Secondly, chronic cannabis use may alter endocannabinoid signaling in the brain which could be a protective factor for developing psychosis or cognitive impairments. A third explanation could be their representation of a phenotypically distinct patient group with more intact cognitive functioning and less neurodevelopmental pathology. Multiple factors need to be considered to understand the complex relationship between cannabis, cognitive function, and schizophrenia. In short, age at initiation, duration and rate of cannabis use, abstinence duration, co-use of substances and alcohol, prescribed medications, relative cannabinoid composition and potency of cannabis, presence of genetic and environmental vulnerability factors are prominent contributors to the variability in outcomes. Animal studies support the disruptive effects of Δ9-tetrahydrocannabinol (THC) administration during adolescence on attention and memory performance. They provide insights about interaction of cannabinoid receptors with other neurotransmitter systems, such as GABA and glutamate, and other regulatory molecules, such as PSD95 and synaptophysin. Cannabidiol (CBD), on the other hand, can improve cognitive deficits seen in neurodevelopmental and chemically-induced animal models of schizophrenia. Future studies focusing on bridging the translational gaps between human and animal studies, through the use of translationally relevant methods of exposure (e.g., vaping), consistent behavioral assessments, and congruent circuit interrogations (e.g., imaging) will help to further clarify this complex picture.

Impact of Adolescent Cannabis Use on Neurocognitive and Brain Development

Research examining associations between frequent cannabis use in adolescence and brain-behavior outcomes has increased substantially over the past 2 decades. This review attempts to synthesize the state of evidence in this area of research while acknowledging challenges in interpretation. Although there is converging evidence that ongoing, frequent cannabis use in adolescence is associated with small reductions in cognitive functioning, there is still significant debate regarding the persistence of reductions after a period of abstinence. Similarly, there is controversy regarding the replicability of structural and functional neuroimaging findings related to frequent cannabis use in adolescence. Larger studies with informative designs are needed.

A Meta-Analysis of fMRI Studies of Youth Cannabis Use: Alterations in Executive Control, Social Cognition/Emotion Processing, and Reward Processing in Cannabis Using Youth

Background: Adolescent cannabis use (CU) is associated with adverse health outcomes and may be increasing in response to changing cannabis laws. Recent imaging studies have identified differences in brain activity between adult CU and controls that are more prominent in early onset users. Whether these differences are present in adolescent CU and relate to age/developmental stage, sex, or cannabis exposure is unknown. Methods: A systematic review and subsequent effect-size seed-based d mapping (SDM) meta-analysis were conducted to examine differences in blood-oxygen-level-dependent (BOLD) response during fMRI studies between CU and non-using typically developing (TD) youth. Supplemental analyses investigated differences in BOLD signal in CU and TD youth as a function of sex, psychiatric comorbidity, and the dose and severity of cannabis exposure. Results: From 1371 citations, 45 fMRI studies were identified for inclusion in the SDM meta-analysis. These studies compared BOLD response contrasts in 1216 CU and 1486 non-using TD participants. In primary meta-analyses stratified by cognitive paradigms, CU (compared to TD) youth showed greater activation in the rostral medial prefrontal cortex (rmPFC) and decreased activation in the dorsal mPFC (dmPFC) and dorsal anterior cingulate cortex (dACC) during executive control and social cognition/emotion processing, respectively. In meta-regression analyses and subgroup meta-analyses, sex, cannabis use disorder (CUD) severity, and psychiatric comorbidity were correlated with brain activation differences between CU and TD youth in mPFC and insular cortical regions. Activation differences in the caudate, thalamus, insula, dmPFC/dACC, and precentral and postcentral gyri varied as a function of the length of abstinence. Conclusions: Using an SDM meta-analytic approach, this report identified differences in neuronal response between CU and TD youth during executive control, emotion processing, and reward processing in cortical and subcortical brain regions that varied as a function of sex, CUD severity, psychiatric comorbidity, and length of abstinence. Whether aberrant brain function in CU youth is attributable to common predispositional factors, cannabis-induced neuroadaptive changes, or both warrants further investigation.

Dynamic Changes in the Endocannabinoid System during the Aging Process: Focus on the Middle-Age Crisis

Endocannabinoid (eCB) signaling is markedly decreased in the hippocampus (Hip) of aged mice, and the genetic deletion of the cannabinoid receptor type 1 (CB1) leads to an early onset of cognitive decline and age-related histological changes in the brain. Thus, it is hypothesized that cognitive aging is modulated by eCB signaling through CB1. In the present study, we detailed the changes in the eCB system during the aging process using different complementary techniques in mouse brains of five different age groups, ranging from adolescence to old age. Our findings indicate that the eCB system is most strongly affected in middle-aged mice (between 9 and 12 months of age) in a brain region-specific manner. We show that 2-arachidonoylglycerol (2-AG) was prominently decreased in the Hip and moderately in caudate putamen (CPu), whereas anandamide (AEA) was decreased in both CPu and medial prefrontal cortex along with cingulate cortex (mPFC+Cg), starting from 6 months until 12 months. Consistent with the changes in 2-AG, the 2-AG synthesizing enzyme diacylglycerol lipase α (DAGLα) was also prominently decreased across the sub-regions of the Hip. Interestingly, we found a transient increase in CB1 immunoreactivity across the sub-regions of the Hip at 9 months, a plausible compensation for reduced 2-AG, which ultimately decreased strongly at 12 months. Furthermore, quantitative autoradiography of CB1 revealed that [3H]CP55940 binding markedly increased in the Hip at 9 months. However, unlike the protein levels, CB1 binding density did not drop strongly at 12 months and at old age. Furthermore, [3H]CP55940 binding was significantly increased in the lateral entorhinal cortex (LEnt), starting from the middle age until the old age. Altogether, our findings clearly indicate a middle-age crisis in the eCB system, which could be a potential time window for therapeutic interventions to abrogate the course of cognitive aging.

Users of cannabis-only are less likely to accept brief interventions than other substance use profiles in a sample of people living with HIV/AIDS

BACKGROUND AND OBJECTIVES

Research has shown that people living with HIV/AIDS (PLWHA) engage in increased rates of substance use, which has a number of potential negative health outcomes. Increased legalization of cannabis is likely to further increase the availability and use of cannabis in this population. Efforts have been made to integrate screening and intervention resources as part of an individual's routine healthcare visits. Though brief approaches such as Screening and Brief Intervention (SBIRT) have shown promise in addressing alcohol use, results are mixed in addressing cannabis use. The present study investigated how individuals reporting cannabis use responded to an invitation to engage in a brief negotiated intervention (BNI).

METHODS

PLWHA participated in a self-administered tablet computer-based version of SBIRT. Patients screened as having at-risk, high-risk, or dependent substance use (N = 331) were eligible to receive the BNI. Of these patients, 101 reported cannabis-only use, with or without alcohol.

RESULTS

Binary logistic regressions controlling for Alcohol Use Disorders Identification Test and Drug Abuse Screening Test score and demographics, found that cannabis-only use was significantly related to declining the BNI.

DISCUSSION AND CONCLUSIONS

Cannabis-only engagement predicts lower BNI acceptance rates than other substance use profiles; inappropriate screening tools may be one reason for this discrepancy. Implications and directions for future research are discussed.

SCIENTIFIC SIGNIFICANCE

Findings are relevant in modifying SBIRT for cannabis use. To our knowledge, this is the first work to evaluate acceptance of brief interventions for cannabis as compared to other substances and brief intervention acceptance in a sample of PLWHA.

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

BACKGROUND

Cannabis is among the most consumed psychoactive substances world-wide. Considering changing policy trends regarding the substance, it is crucial to understand more clearly its potential acute and residual adverse effects from a public health viewpoint. Cognitive function is one of the targeted areas with conflicting findings. This meta-review measured the magnitude of acute and residual effects of cannabis on cognition in adolescents and adults provided by meta-analyses and evaluated quality of evidence.

METHODS

A systematic search was performed in PubMed, PsycINFO, Web of Science and Google Scholar. Meta-analyses were included if they quantitatively examined the performances of users from the general population on cognitive tasks.

RESULTS

The search retrieved 10 eligible meta-analyses (71 effects sizes, n = 43 761) with evidence ranging from low to moderate quality, which were categorized into domains of cognitive functions: executive functions (k = 7), learning and memory (k = 5), attention (k = 4), processing speed (k = 5), perceptual motor function (k = 2) and language (k = 2). Verbal learning and memory displayed the most robust evidence and were most impaired by acute cannabis intoxication that persisted after intoxication passed. Small-to-moderate acute and residual   adverse effects were reported for executive functioning. Cannabis use led to small deficits in inhibitory processes and flexibility, whereas small-to-moderate deficits were reported for working memory and decision-making. Evidence regarding processing speed and attention has shown that cannabis administration induced small-to-moderate adverse effects and residual neurocognitive deficits were observed in heavy cannabis-using youths. Results showed no significant difference between cannabis users and non-users on language, and small-to-moderate effects for simple motor skills.

CONCLUSION

Meta-analytical data on the acute effects of cannabis use on neurocognitive function have shown that cannabis intoxication leads to small to moderate deficits in several cognitive domains. These acute impairments accord with documented residual effects, suggesting that the detrimental effects of cannabis persist beyond acute intake.

Cannabis Use and Parenting Practices among Young People: The Impact of Parenting Styles, Parental Cannabis-Specific Rules, and Parental Cannabis Use

Cannabis is the most commonly used illicit drug. Its use typically starts in adolescence, and parents play a key role in young people’s cannabis use. Our study aimed to examine and compare the effects of parenting styles, parental cannabis-specific rules, and parental cannabis use on young people’s cannabis use. The research sample consisted of 839 students from various secondary education programs in Slovenia, aged 14 to 21. Associations between the young people’s lifetime cannabis use and their experience of parenting practices were assessed using logistic regression, with demographic, socioeconomic, educational, health, and risk behaviors controlled in a multivariate model. Maternal authoritative parenting (in comparison with permissive parenting), strict maternal, cannabis-specific rules, and parental cannabis non-use statistically significantly reduced the likelihood of young people’s cannabis use. Its strongest predictor was parental cannabis use, followed by the mother’s specific cannabis-use rules and maternal parenting style. The findings of our study can contribute to the development of public health policies to more effectively prevent cannabis use among adolescents and emerging adults, including by designing prevention programs aimed at strengthening parents’ general and cannabis-specific practices and competences.

Effort-based decision making and self-reported apathy in frequent cannabis users and healthy controls: A replication and extension

INTRODUCTION

Amotivational syndrome is a term used to refer to lack of motivation and passive personality related to chronic cannabis use. Given mixed findings, the current study aimed to replicate and extend previous research on frequent cannabis use, motivated behavior, and self-reported apathy.

METHOD

Cannabis users (on average, ≥3 days/week of cannabis use over the past year), and healthy controls (≤1 day/month of cannabis use over the past year) completed the Apathy Evaluation Scale (AES), and the Effort Expenditure for Rewards Task (EEfRT). Repeated measures analysis of covariance was used to 1) examine the effects of group, reward magnitude, probability, and their interaction on hard task selections on the EEfRT, and 2) examine between-group differences on the AES, controlling for alcohol use and depressive symptoms.

RESULTS

There were significant main effects of reward magnitude, probability, and an interaction between reward magnitude and probability on hard task selection (p's < 0.05). Specifically, as reward magnitude and probability of winning the reward increased, participants were more likely to select hard tasks on the EEfRT. Relative to healthy controls, cannabis users were significantly more likely to select hard tasks on the EEfRT (F(1,56) = 6.49, p = 0.014, η_p² = 0.10). When controlling for alcohol use and depressive symptoms, no significant group differences in self-reported apathy were present (p = 0.46).

CONCLUSIONS

Cannabis users exhibit a greater likelihood of exerting more effort for reward, suggesting enhanced motivation relative to healthy controls. Thus, the current results do not support amotivational syndrome in adult frequent cannabis users. Despite some harms of long-term cannabis use, amotivation may not be among them.

Examination of gamma-aminobutyric acid and glutamate-glutamine levels in association with impulsive behavior in adolescent marijuana users

BACKGROUND

Adolescent marijuana (MJ) use has been associated with alterations in brain structure and function as well as behavior. Examination of neurochemical correlates such as GABA (gamma-aminobutyric acid) and Glx (glutamate + glutamine) in MJ users remains limited. Impulsivity, identified as a risk factor and consequence of MJ use, has been associated with GABA and Glx levels in healthy and clinical populations. However, this relationship has not been investigated in MJ users. In this study, we examined levels of GABA and Glx in the anterior cingulate cortex (ACC) and its relationship with impulsive behavior in MJ-using adolescents and healthy controls.

METHODS

Healthy control subjects (HC; N = 21) and MJ-using adolescents (N = 18) completed a metabolite-edited ¹H MRS exam to measure ACC GABA and Glx levels, a structured clinical interview to assess MJ use, and the Barratt Impulsivity Scale (BIS-11) to evaluate impulsive behavior.

RESULTS

Adolescent MJ users had significantly lower tissue-corrected GABA (with macromolecules; GABA+) levels (p = 0.029) compared to HC's. No significant between-group differences were observed in ACC Glx levels. Assessment of impulsive behavior demonstrated no significant between-group differences in motor, non-planning, attention, and total impulsivity scores. Additionally, impulsivity measures and tissue-corrected GABA+ or Glx levels were not significantly correlated in either group.

CONCLUSION

Lower GABA levels in MJ users may indicate alterations in excitatory-inhibitory mechanisms critical for neurodevelopment. Although no significant relationships were observed between impulsive measures and GABA or Glx levels in both groups, further investigations are needed examining the relationship between neurochemical correlates, behavior, and adolescent MJ use.

Examining Inhibitory Affective Processing Within the Rostral Anterior Cingulate Cortex Among Abstinent Cannabis-Using Adolescents and Young Adults

Cannabis use has been associated with deficits in self-regulation, including inhibitory control. Cannabis users have previously exhibited both structural and functional deficits in the rostral anterior cingulate cortex (rACC), a region involved in self-regulation of emotional response and inhibitory control. The present study aimed to examine whether abstinent cannabis users demonstrated abnormal functional activation and connectivity of the bilateral rACC during an emotional inhibitory processing task, and whether gender moderated these relationships. Cannabis-using (N = 34) and non-using (N = 32) participants ages 16-25 underwent at least 2-weeks of monitored substance use abstinence (excluding tobacco) and fMRI scanning while completing a Go/No-go task using fearful and calm emotional faces as non-targets. Multiple linear regression and ANCOVA were used to determine if cannabis group status was related to rACC activation and context-dependent functional connectivity, and whether gender moderated these relationships. Results showed decreased bilateral rACC activation in cannabis users during fearful response inhibition, although groups did not show any context-dependent connectivity differences between the left or right rACC during calm or fearful inhibition. Gender findings revealed that cannabis-using females compared to males did show aberrant connectivity between the right rACC and right cerebellum. These results are consistent with literature demonstrating aberrant structural and functional rACC findings and suggest that chronic cannabis use may disrupt typical rACC development-even after abstinence-potentially conferring risk for later development of mood disorders. Marginal gender-specific connectivity findings bolster continued findings regarding female vulnerability to effects of cannabis on cognition and affect. Findings should be assessed in longitudinal studies to determine causality and timing effects.

Effects of Δ9-Tetrahydrocannibinol (THC) on Obesity at Different Stages of Life: A Literature Review

The Cannabis sativa plant has historically been used for both recreational and medical purposes. With the recent surge in recreational use of cannabis among adolescents and adults in particular, there is an increased obligation to determine the short- and long-term effects that consuming this plant may have on several aspects of the human psyche and body. The goal of this article was to examine the negative effects of obesity, and how the use of Δ9-tetrahydrocannibinol (THC) or cannabidiol (CBD) can impact rates of this global pandemic at different timepoints of life. Conflicting studies have been reported between adult and adolescents, as there are reports of THC use leading to increased weight due to elevated appetite and consumption of food, while others observed a decrease in overall body weight due to the regulation of omega-6/omega-3 endocannabinoid precursors and a decrease in energy expenditure. Studies supported a positive correlation between prenatal cannabis use and obesity rates in the children as they matured. The data did not indicate a direct connection between prenatal THC levels in cannabis and obesity rates, but that this development may occur due to prenatal THC consumption leading to low birthweight, and subsequent obesity. There are few studies using animal models that directly measure the effects that prenatal THC administration on obesity risks among offspring. Thus, this is a critical area for future studies using a developmental framework to examine potential changes in risk across development.

Disrupted Resting State Attentional Network Connectivity in Adolescent and Young Adult Cannabis Users following Two-Weeks of Monitored Abstinence

Background. Numerous neuropsychological studies have shown that cannabis use during adolescence and young adulthood led to deficits in sustained and selective attention. However, few studies have examined functional connectivity in attentional networks among young cannabis users, nor have characterized relationships with cannabis use patterns following abstinence. Methods. Differences in resting state functional connectivity (RSFC) within the dorsal (DAN) and ventral (VAN) attention networks were examined in 36 adolescent and young adult cannabis users and 39 non-substance using controls following two weeks of monitored abstinence. Observed connectivity differences were then correlated with past-year and lifetime cannabis use, length of abstinence, age of regular use onset, and Cannabis Use Disorder symptoms (CUD). Results. After controlling for alcohol and nicotine use, cannabis users had lower RSFC within the DAN network, specifically between right inferior parietal sulcus and right anterior insula, as well as white matter, relative to controls. This region was associated with more severe cannabis use measures, including increased lifetime cannabis use, shorter length of abstinence, and more severe CUD symptoms. Conclusions. Findings demonstrate that regular cannabis use by adolescents and young adults is associated with subtle differences in resting state connectivity within the DAN, even after two weeks of monitored abstinence. Notably, more severe cannabis use markers (greater lifetime use, CUD symptoms, and shorter abstinence) were linked with this reduced connectivity. Thus, findings support public policy aimed at reducing and delaying cannabis use and treatments to assist with sustained abstinence. Future longitudinal studies are needed to investigate causation.

Risky decision-making as an antecedent or consequence of adolescent cannabis use: findings from a 2-year longitudinal study

BACKGROUND AND AIMS

Although poor decision-making (DM) has been correlated with problematic cannabis use (CU), cross-sectional designs make it difficult to determine whether poor DM represents an antecedent and/or consequence of CU. The current study measured bidirectional associations between CU and DM among adolescents over 2 years and compared these findings to those observed with episodic memory, which is consistently reported as a consequence of CU. We also measured the role of DM as a risk factor for cannabis use disorder (CUD) onset.

DESIGN

Two-year longitudinal study with five bi-annual assessments.

PARTICIPANTS

Participants were 401 adolescents aged 14-17 years at baseline.

SETTING

Miami, Florida, USA.

MEASUREMENTS

CU frequency and CUDs were assessed at each time-point through the Drug Use History Questionnaire and Structured Clinical Interview for DSM-IV, respectively. Neurocognition was assessed at odd time-points throughout the Iowa Gambling Task, Game of Dice Task and Cups Task [decision-making (DM)] and the Wechsler Memory Scale IV and California Verbal Learning Test II (episodic memory). We used latent growth curve modeling to examine bidirectional influences between CU and neurocognition over time. We applied discrete time survival analyses to determine whether baseline DM predicted CUD onset.

FINDINGS

Greater lifetime CU frequency was associated with poorer episodic memory at baseline (bs = -14.84, -16.44, Ps = 0.038, 0.021). Greater CU escalation predicted lesser gains in immediate episodic memory (b = -0.05, P = 0.020). Baseline DM did not predict CU escalation (b = 0.07, P = 0.421), nor did escalation in CU predict changes in DM (b = 0.02, P = 0.352). Baseline DM also did not predict CUD onset (adjusted OR = 1.01, 95% confidence interval = 0.98-1.06).

CONCLUSIONS

This study replicates findings that poorer episodic memory in adolescents appears to be a consequence of cannabis use, even among adolescents at earlier stages of use. Poor decision-making does not appear to be either a consequence of or a risk factor for escalating cannabis use or onset of cannabis use disorder among adolescents.

Alterations in rat prefrontal cortex kynurenic acid levels are involved in the enduring cognitive dysfunctions induced by tetrahydrocannabinol exposure during the adolescence

INTRODUCTION

Cannabis abuse during adolescence is a risk factor for cognitive impairments in psychiatric disorders later in life. To date, the possible causal relationship between cannabinoids, kynurenic acid (KYNA; i.e., a neuroactive metabolite of tryptophan degradation) and cognition has not been investigated in adolescence. Early exposure to delta 9-tetrahydrocannabinol (THC; i.e., the main psychotropic component of cannabis) causes enduring cognitive deficits, which critically involve impaired glutamatergic function in the prefrontal cortex (PFC). In addition, prenatal cannabis exposure results in enduring increases in PFC KYNA levels. Based on these findings, the effects of chronic THC exposure in rats, during another critical period of neurodevelopment particularly sensitive to perturbation by exogenous stimuli, such as adolescence, have been investigated.

METHODS

Male Wistar rats were chronically treated with vehicle or ascending intraperitoneal (i.p.) doses of THC starting on postnatal day (PND) 35 until PND 45. In adulthood (PND 75), cognitive assessment (Y-maze) and extracellular KYNA/glutamate levels were measured in the PFC by in vivo microdialysis, before and after a challenge with KYN (5 mg/kg i.p., the biological precursor of KYNA). By using the selective, brain-penetrable KAT II inhibitor PF-04859989, we then examined whether blockade of KYNA neosynthesis prevents the cognitive impairment.

RESULTS

Compared to vehicle-treated controls, extracellular basal KYNA levels were higher in the PFC of adult rats chronically exposed to THC in adolescence (p < 0.01). No changes were observed in extracellular glutamate levels. Following a challenge with KYN, extracellular KYNA levels similarly increased in both groups (i.e., vehicle- and THC-treated; p < 0.001 and p < 0.01, respectively). Chronic adolescent THC exposure negatively affected short-term memory (reduced spontaneous alternation), in adult animals (p < 0.001), while PF-04859989 (30 mg/kg i.p.) restored the cognitive impairment (p < 0.05).

DISCUSSION

We propose that the observed alterations in PFC KYNA signaling might be involved in the cognitive dysfunction induced by the exposure to THC during the adolescence. In the translational realm, these experiments raise the prospect of prevention of KYNA neosynthesis as a possible novel approach to counteract some of the detrimental long-term effects of adolescence cannabis use.

Initiation of Moderately Frequent Cannabis use in Adolescence and Young Adulthood is Associated with Declines in Verbal Learning and Memory: A Longitudinal Comparison of Pre- versus Post-Initiation Cognitive Performance

OBJECTIVE

Cannabis use is associated with relative cognitive weaknesses as observed by cross-sectional as well as longitudinal research. Longitudinal studies, controlling for relevant confounds, are necessary to differentiate premorbid from post-initiation contributions to these effects.

METHODS

We followed a sample of adolescents and young adults across ten years. Participants provided neurocognitive data and substance use information at two-year intervals. Participants who initiated cannabis and/or alcohol use were identified (n = 86) and split into alcohol-only initiators (n = 39) and infrequent (n = 29) and moderately frequent (n = 18) cannabis initiators. Participants completed the Rey Auditory Verbal Learning Task (RAVLT) and the Iowa Gambling Task (IGT). Group differences before and after substance use initiation and the extent to which alcohol, nicotine, and cannabis use frequencies contributed to cognitive functions over time were examined.

RESULTS

After controlling for parental education, RAVLT new learning was worse in moderately frequent cannabis users prior to use initiation. RAVLT total learning and delayed recall showed significant declines from pre- to post-initiation in moderately frequent cannabis users. Regression analyses confirmed that frequencies of cannabis, but not alcohol, use contributed to post-initiation variations. Nicotine use showed an independent negative association with delayed memory. Findings for the IGT were not significant.

CONCLUSIONS

Verbal learning and memory may be disrupted following the initiation of moderately frequent cannabis use while decreased new learning may represent a premorbid liability. Our use of a control group of alcohol-only users adds interpretive clarity to the findings and suggests that future studies should carefully control for comorbid substance use.

Daily cannabis use in adolescents who smoke tobacco is associated with altered late-stage feedback processing: A high-density electrical mapping study

Impairments in feedback processing, often associated with risk-taking behavior, may have implications for development of substance abuse in adolescents. The most commonly used substances by adolescents include tobacco and cannabis, with some individuals using both substances, potentially heightening risk. Our objective was to examine feedback processing and impulsivity in adolescents who smoke cigarettes and use cannabis daily (N = 21), comparing them with adolescents who smoke cigarettes daily and use cannabis occasionally (N = 18) and non-smoking (N = 27) adolescents. To do this, the Balloon Analog Risk Task (BART) with concurrent EEG was used to measure risk-related feedback processing, and impulsivity was measured using the Barratt's impulsiveness scale (BIS-11). It was found that adolescent daily tobacco/cannabis smoking was associated with higher BIS-11 scores, shortened feedback-related-negativity (FRN) latencies and reduced P300 amplitudes. In addition, FRN latencies during win conditions were inversely associated with tobacco-use severity, indicated by scores on the Fagerstrom Test for Nicotine Dependence (FTND), and with BIS-11 scores. Adolescents with concurrent tobacco and cannabis use show altered feedback processing and higher impulsivity. Future work should disentangle whether the effect reflects risk, consequences of use or both.

Decision Making and Impulsivity in Young Adult Cannabis Users

Aims: Chronic cannabis users show impairments on laboratory measures of decision making which reflect risk factors for initiation and continued use of cannabis. However, the differential sensitivity of these tasks to cannabis use has not been established. Moreover, studies to date have often lacked assessment of psychiatric histories and use of other illicit substances, both of which may influence decision making outcomes. The current study aimed to address these limitations by (1) including multiple types of decision making tasks, (2) implementing the Probabilistic Reversal Learning Task, a measure of decision making under uncertainty, for the first time in cannabis users, (3) including young adult cannabis users with no other psychiatric disorders, and (4) conducting urinalysis to exclude users of other illicit drugs.

Methods: Thirty-three current cannabis users without comorbid psychiatric disorders and 35 cannabis non-users completed behavioral measures of decision-making (Iowa Gambling Task), reward discounting (Delay Discounting Task), choice-outcome learning (the Probabilistic Reversal Learning Task) and a questionnaire assessment of impulsivity (Barratt Impulsiveness Scale).

Results: Relative to non-users, cannabis users demonstrated greater preference for immediate vs. delayed rewards on the Delay Discounting Task, made fewer advantageous decisions on the Iowa Gambling Task, and endorsed greater impulsivity on the Barratt Impulsiveness Scale scales. Cannabis users and non-users showed comparable performance on the Probabilistic Reversal Learning Task. Frequency of past-month cannabis use and total years of use did not predict decision making or impulsivity.

Conclusions: Young adult cannabis users demonstrated higher discounting rates and impairments in learning cost-benefit contingencies, while reversal learning was unaffected. Self-reported impulsivity was elevated as well. None of these measures correlated with current or lifetime estimates of cannabis use, arguing against a dose-relationship. Interventions that target improvement in affected components of decision making may be helpful in reducing cannabis use and relapse.

Driving after marijuana use among U.S. adolescents: Prevalence profiles and related behaviors

OBJECTIVES

The interplay between marijuana legislation, perceptions of risks associated with marijuana use, and marijuana-related risk behaviors is an ever changing and complex issue. Marijuana impaired driving is of concern as legalization continues to expand in the United States. While driving after using marijuana has been shown to be prevalent among adults, little research has examined the behavior in adolescents. The aim of the present study was to examine the prevalence of driving after using marijuana among U.S. adolescents, with an examination of the relationship to age of marijuana initiation and marijuana usage patterns.

METHODS

We analyzed data from the 2017 Youth Risk Behavior Survey, a nationally representative sample of high schools students in the U.S. The sample was current marijuana users, defined as past 30 day use. Driving after using marijuana was the main outcome variable, with analyses examining the association between the outcome and age of initiation and patterns of use. Prevalence ratios were obtained by modeling Poisson regression to examine factors associated with driving under the influence of marijuana.

RESULTS

Nearly half of all marijuana users reported driving after use during the past 30 days, and did not differ between males and females. Prevalence of driving after using marijuana was significantly higher among heavy users (PR = 2.8; 95% CI 2.1-3.6). A higher prevalence of driving after drinking alcohol (PR = 1.7; 95% CI 1.5-1.9) was also found among those who had driven after using marijuana.

CONCLUSIONS

Among adolescent marijuana users, the prevalence of driving after using marijuana was high. Enhanced surveillance, prevention, and control measures are necessary to mitigate the negative impacts of marijuana consumption and related behaviors.

Cognitive Development and Cannabis Use in Adolescents

Heavy exposure to cannabis during adolescence can cause significant neurocognitive changes. It can alter emotional responsiveness and social behavior, and cause impairments in sustained attention, learning, working memory (WM), cognitive flexibility, and the speed of information processing. It also has a significant impact on executive functions. In this study we investigated how global cognitive functions can be affected by the frequency of cannabinoid consumption in different categories of consumers (chronic, occasional, and non-users), through the evaluation of executive functions. Statistical analysis showed a significant decrease in performance in working memory tasks and processing speed by subjects using cannabis chronically (group 1) as compared to non-consumers (group 3), and occasional consumers (group 2). Future studies could verify the extent of neurocognitive alterations through re-evaluations with controlled follow-up and the addition of neuro-functional data.

Which came first: Cannabis use or deficits in impulse control?

Impulse control deficits are often found to co-occur with substance use disorders (SUDs). On the one hand, it is well known that chronic intake of drugs of abuse remodels the brain with significant consequences for a range of cognitive behaviors. On the other hand, individual variation in impulse control may contribute to differences in susceptibility to SUDs. Both of these relationships have been described, thus leading to a "chicken or the egg" debate which remains to be fully resolved. Does impulsivity precede drug use or does it manifest as a function of problematic drug usage? The link between impulsivity and SUDs has been most strongly established for cocaine and alcohol use disorders using both preclinical models and clinical data. Much less is known about the potential link between impulsivity and cannabis use disorder (CUD) or the directionality of this relationship. The initiation of cannabis use occurs most often during adolescence prior to the brain's maturation, which is recognized as a critical period of development. The long-term effects of chronic cannabis use on the brain and behavior have started to be explored. In this review we will summarize these observations, especially as they pertain to the relationship between impulsivity and CUD, from both a psychological and biological perspective. We will discuss impulsivity as a multi-dimensional construct and attempt to reconcile the results obtained across modalities. Finally, we will discuss possible avenues for future research with emerging longitudinal data.

Associations of Regular Marijuana Use by Adolescent Boys With Verbal Memory and Perseveration

Many American and Dutch adolescents use marijuana regularly. There is concern that such use may impair cognitive function more in adolescents than adults. We examined effects of regular marijuana use on long-term memory and perseveration among American and Dutch adolescents. We administered Buschke's Selective Reminding Test (BSRT) to assess long-term memory and the Wisconsin Card Sorting Test (WCST) to assess perseveration in male teenagers. Usable test data were obtained for 12 American marijuana users, 13 American controls, 9 Dutch marijuana users, and 12 Dutch controls. In BSRT, users showed lower overall long-term storage than controls (adjusted means ± SE's for numbers of words per trial of 9.4 ± 0.2, 13.4 ± 0.3, 11.7 ± 0.2, and 12.4 ± 0.2 for American users, Dutch users, American controls, and Dutch controls, respectively). Marijuana was associated with memory effects only in American, not Dutch, users. Bivariate Pearson correlations for American and Dutch users combined showed associations of lower total recall with more uses in the previous year and lifetime (r = -0.61 and r = -0.53, respectively); and more perseverative errors with more uses in the previous year (r = 0.55). Some findings were consistent with the possibility that regular adolescent marijuana use causes deficits in cognition, especially memory. However, a causal interpretation cannot be inferred from our findings and is challenging to reconcile with the observation of memory deficits only in American users. Our study was novel in examining the influence of nationality on marijuana's cognitive effects. More studies of this topic should compare effects across nationalities or cultures.

The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review

Background: Cannabis is known to have a broad range of effects on behavior, including experiencing a "high" and tranquility/relaxation. However, there are several adverse behavioral sequalae that can arise from cannabis use, depending on frequency of use, potency (e.g., THC content), age of onset, and cumulative exposure. This systematic review examined evidence for cannabis-related adverse behavioral sequalae in otherwise healthy human subjects. Methods: Following PRISMA guidelines, we conducted a systematic review of cross-sectional and longitudinal studies from 1990 to 2020 that identified cannabis-related adverse behavioral outcomes in subjects without psychiatric and medical co-morbidities from PubMed and PsychInfo searches. Key search terms included "cannabis" OR "tetrahydrocannabinol" OR "cannabidiol" OR "marijuana" AND "anxiety" OR "depression" OR "psychosis" OR "schizophrenia" "OR "IQ" OR "memory" OR "attention" OR "impulsivity" OR "cognition" OR "education" OR "occupation". Results: Our search detected a total of 2,870 studies, from which we extracted 124 relevant studies from the literature on cannabis effects in the non-clinical population. Effects of cannabis on several behavioral sequelae including cognition, motivation, impulsivity, mood, anxiety, psychosis intelligence, and psychosocial functioning were identified. The preponderance of the evidence suggests that frequency of cannabis use, THC (but not CBD) content, age of onset, and cumulative cannabis exposure can all contribute to these adverse outcomes in individuals without a pre-existing medical condition or psychiatric disorder. The strongest evidence for the negative effects of cannabis are for psychosis and psychosocial functioning. Conclusions: Although more research is needed to determine risk factors for development of adverse behavioral sequelae of cannabis use, these findings underline the importance of understanding vulnerability to the adverse effects of cannabis, which has implications for prevention and treatment of problematic cannabis use.

The effectiveness of functional training on impulsiveness of females with intellectual disability

The aim of this study was to determine the effectiveness of Functional Training (FT) on impulsiveness of female students with Intellectual Disability (ID). The research method was pretestposttest- with a control group. The statistical population consisted of all female students with ID in elementary school of Shiraz studying under the auspices of the Special Education Organization in 2018-2019. The participants included 30 female students with ID selected through convenience sampling and randomly assigned to the experimental (n=14) and control (n=14) groups. The experimental group received the functional training for 15 sessions, while the control group did not receive any intervention. The Barratt Impulsiveness Scale Version 11 (BIS-11) was used for measuring the impulsiveness. The Impulsiveness pre-test was performed for both experimental and control groups. The experimental group received the FT for 15 sessions, while the control group did not receive any intervention. At the end of the intervention, post-test was performed for both groups. Mann-Whitney U test was used to analyze the data. The results showed that the mean scores of impulsivities and its subscales (motor impulsiveness, attentional impulsiveness and nonplanning impulsiveness) in the experimental group were significantly reduced. The results showed that FT had a significant effect on impulsiveness of female students with ID (p<0.001). Therefore, it is recommended to design and implement a FT program to improve impulsiveness in people with ID.

Risk factors associated with driving under the influence of drugs in the USA

BACKGROUND

Driving under the influence of drugs (DUID) is a burgeoning public health concern in the USA. Because little is known about individuals who engage in DUID, the purpose of this study was to analyse potential sociodemographic characteristics and behavioural risk factors associated with the behaviour.

METHODS

Self-reported data from drivers ≥18 years of age who ever used drugs and participated in the 2018 National Survey on Drug Use and Health were used. Characteristics of those who reported to engage and not engage in DUID were compared via frequencies, percentages and logistic regression analyses, which accounted for the multistage survey design.

RESULTS

Among eligible respondents, 10.4% (weighted n=117 275 154) reported DUID. DUID was higher among those aged 18-25 year (34%), males (65%), unmarried individuals (61%), lesbian/gay/bisexuals (13%), those whom abused or were drug dependent (45%), engaged in numerous risky lifestyle behaviours (12%) and those taking medication for a mental health issue (22%). Nearly 20% and 6% of respondents engaged in DUID abused or were dependent on marijuana or methamphetamine, respectively. The adjusted odds of DUID were greatest among those 18-25 years of age (OR 3.7; 95% CI 2.8 to 5.0), those never/not married (OR 1.8; 95% CI 1.5 to 2.2), those who abused or were drug dependent (OR 4.0; 95% CI 3.5 to 4.7), exhibited riskier lifestyle behaviours (OR 8.0; 95% CI 5.9 to 11.0), were employed (OR 1.3; 95% CI 1.1 to 1.6) or lesbian/gay/bisexuals (OR 1.4; 95% CI 1.1 to 1.7).

CONCLUSIONS

DUID was common among some population sub-groups who may benefit from intervention.

A preliminary risk prediction model for cannabis use disorder

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Substance use disorders are currently a major public health crisis in the US.

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The prevalence of cannabis use disorder is rising due to legalization of cannabis.

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This study built models to predict the risk of cannabis use disorder for a user.

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Risk factors include personality traits, impulsivity and initial smoking enjoyment.

The ongoing trend toward legalization of cannabis for medicinal/recreational purposes is expected to increase the prevalence of cannabis use disorder (CUD). Thus, it is imperative to be able to predict the quantitative risk of developing CUD for a cannabis user based on their personal risk factors. Yet no such model currently exists. In this study, we perform preliminary analysis toward building such a model. The data come from n = 94 regular cannabis users recruited from Albuquerque, New Mexico during 2007–2010. As the data are cross-sectional, we only consider risk factors that remain relatively stable over time. We apply statistical and machine learning classification techniques that allow n to be small relative to the number of predictors. We use predictive accuracy estimated using leave-one-out-cross-validation to evaluate model performance. The final model is a LASSO logistic regression model consisting of the following seven risk factors: age; level of enjoyment from initial cigarette smoking; total score on Impulsive Sensation-Seeking Scale questionnaire; score on cognitive instability factor of Barratt Impulsivity Scale questionnaire; and scores on neuroticism, openness, and conscientiousness personality traits of Neuroticism, Extraversion, and Openness inventory. This model has an overall accuracy of 0.66 and the area under its receiver operating characteristic curve is 0.65. In summary, a preliminary relative risk model for predicting the quantitative risk of CUD is developed. It can be employed to identify users at high risk of CUD who may be provided with early intervention.

Neural and behavioral correlates associated with adolescent marijuana use

Purpose of Review

Marijuana (MJ) is one of the most commonly used drugs among adolescents. Exposure to MJ during adolescence can lead to alterations in brain development, and, subsequently to the behavioral correlates regulated by the affected brain regions. In this review, we discuss findings from preclinical and human studies examining the relationship between adolescent MJ use and the neurobiological and behavioral correlates associated with it.

Recent Findings

Current findings indicate that adolescent MJ use is associated with alterations in brain structure and function, especially in regions that express high levels of the cannabinoid 1 receptor such as the prefrontal cortex, hippocampus, cerebellum and limbic regions. These alterations are correlated with changes in affective, cognitive and reward-seeking behavior. Furthermore, evidence suggests that exposure to MJ during adolescence can have long-lasting and pronounced neural and behavioral effects into adulthood.

Summary

The wide ranging neural and behavioral correlates associated with MJ use during adolescence highlight the need for further studies to better understand the potential risk factors and/or neurotoxic effects of adolescent MJ use.

Δ 9-Tetrahydrocannabinol Toxicity and Validation of Cannabidiol on Brain Dopamine Levels: An Assessment on Cannabis Duplicity

Δ9-tetrahydrocannabinol (THC) of cannabis is the main psychoactive component which is a global significant concern to human health. Evaluation on THC reported its drastic effect on the brain dopaminergic (DAergic) system stimulating mesolimbic DA containing neurons thereby increasing the level of striatal DA. Cannabidiol (CBD), with its anxiolytic and anti-psychotic property, is potent to ameliorate the THC-induced DAergic variations. Legal authorization of cannabis use and its analogs in most countries led to a drastic dispute in the elicitation of cannabis products. With a recent increase in cannabis-induced disorder rates, the present review highlighted the detrimental effects of THC and the effects of CBD on THC induced alterations in DA synthesis and release. Alongside the reported data, uses of cannabis as a therapeutic medium in a number of health complications are also being briefly reviewed. These evaluated reports led to an anticipation of additional research contradictory to the findings of THC and CBD activity in the brain DAergic system and their medical implementations as therapeutics.

Disentangling the effects of cannabis and cigarette smoking on impulsivity

BACKGROUND

Cannabis smoking and cigarette smoking often co-occur, yet limited research has investigated the potentially different role impulsivity may play when these behaviours occur in isolation, compared with in combination.

AIMS

This study examined trait and behavioural impulsivity as a function of both cigarette and cannabis smoking.

METHODS

Trait impulsivity (BIS-11) was compared between 44 non-smokers, 76 cigarette only, 47 cannabis only and 58 cannabis plus cigarette smokers. The effects of cigarette and cannabis smoking on behavioural impulsivity (stop-signal and information sampling tasks) were then assessed in 87 of these participants during a laboratory session.

RESULTS

Trait impulsivity was significantly higher in cigarette smokers than non-smokers, irrespective of cannabis use, except for motor impulsivity, where cigarette smoking was only associated with elevated trait impulsivity in non-smokers of cannabis. Dimensions of trait impulsivity were significantly positively related to cigarette smoking frequency and nicotine dependence, but not to cannabis smoking frequency or dependence. Smoking cigarettes or cannabis was associated with significantly impaired reflection impulsivity relative to not smoking either substance. However, no additional increases in reflection impulsivity were observed in those who smoked both cigarettes and cannabis. No group differences in response inhibition were detected.

CONCLUSIONS

Heightened trait impulsivity appears to be uniquely related to cigarette smoking, whilst the smoking of cigarettes or cannabis is associated with impairments in reflection impulsivity. Improved outcomes for treating cannabis dependence may result from encouraging concomitant cigarette smokers to cease using both drugs simultaneously in order to reduce heightened impulsivity and risk of relapse.

Is sense of belonging at school associated with cannabis use among secondary school students in Barbados?

The objective of this study was to assess whether students' sense of belonging at school was associated with cannabis use among secondary school students in Barbados. This was a cross-sectional study involving a nationally representative weighted sample of 8,538 students drawn from 2^nd to 6^th forms across public and private secondary schools in Barbados in 2013. Descriptive and inferential statistics was performed using SPSS. Students who had a sense of belonging at school, were attending public schools and were in the 2nd form, had higher odds of reporting past-year and past-month cannabis use. We conclude that there was a significant positive association between students' sense of belonging at school and cannabis use.

Youth marijuana use: a review of causes and consequences

The legalization of medical and recreational marijuana has raised concerns about a potential increase in the availability and illegal use of marijuana by adolescent minors. To better understand the etiology, patterns, and consequences of adolescent marijuana use, this article reviews high quality, methodologically rigorous, longitudinal studies that focus on the role of personality factors such as sensation-seeking in the etiology of use, developmental trajectories of use and the effects of chronic use, potential gateway effects of marijuana on other illicit drugs, and its role in the onset of psychiatric disorders in adolescents and young adults. Implications are discussed in terms of mechanisms that account for initial and continued use of marijuana by adolescents, how use is associated with key developmental milestones and adult role socialization, and the potential of marijuana use during adolescence in furthering later drug involvement.

Cannabis use among U.S. adolescents in the era of marijuana legalization: a review of changing use patterns, comorbidity, and health correlates

Decriminalization, medicalization, and legalization of cannabis use by a majority of U.S. states over the past 25 years have dramatically shifted societal perceptions and use patterns among Americans. How marijuana policy changes have affected population-wide health of U.S. youth and what the downstream public health implications of marijuana legalization are topics of significant debate. Cannabis remains the most commonly used federally illicit psychoactive drug by U.S. adolescents and is the main drug for which U.S. youth present for substance use treatment. Converging evidence indicates that adolescent-onset cannabis exposure is associated with short- and possibly long-term impairments in cognition, worse academic/vocational outcomes, and increased prevalence of psychotic, mood, and addictive disorders. Odds of negative developmental outcomes are increased in youth with early-onset, persistent, high frequency, and high-potency Δ-9-THC cannabis use, suggesting dose-dependent relationships. Cannabis use disorders are treatable conditions with clear childhood antecedents that respond to targeted prevention and early intervention strategies. This review indicates that marijuana policy changes have had mixed effects on U.S. adolescent health including potential benefits from decriminalization and negative health outcomes evidenced by increases in cannabis-related motor vehicle accidents, emergency department visits, and hospitalizations. Federal and state legislatures should apply a public health framework and consider the possible downstream effects of marijuana policy change on paediatric health.

Cannabis and the Developing Adolescent Brain

Purpose of Review

This review summarizes (1) recent trends in delta-9-tetrahydrocannabionol [THC] and cannabidiol (CBD) content in cannabis products, (2) neurobiological correlates of cannabis use on the developing adolescent brain, (3) effects of cannabis on psychiatric symptoms and daily functioning in youth (i.e., academic performance, cognition, sleep and driving), (4) cannabis products used to relieve or treat medical issues in youth, and (5) available treatments for cannabis use disorder in adolescence.

Recent findings

Despite marked increases in THC content and availability of cannabis, there has been a decline in perceived risk and an increase in use of THC extract products among youth in the United States. The primary psychiatric symptoms associated with cannabis use in youth are increased risk for addiction, depressive, and psychotic symptoms. Cannabis alters endocannabinoid system function which plays a central role in modulating the neurodevelopment of reward and stress systems. To date, few studies have examined neurobiological mechanisms underlying the psychiatric sequalae of cannabis exposure in youth. Adolescent cannabis exposure results in impaired cognition, sleep, and driving ability. There are very limited FDA-approved cannabinoid medications, none of them supporting their use for the treatment of psychiatric symptoms. Behavioral therapies are currently the mainstay of treating cannabis misuse, with no pharmacotherapies currently approved by the FDA for cannabis use disorder in youth.

Summary

Here, we summarize the most up-to-date knowledge on the neurobiological psychiatric, and daily function effects of the most commonly used cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). We then review FDA approved medical use of cannabinoid treatments as well as pharmacological and psychological treatments for cannabis use disorder in youth. Our current understanding of the effects of cannabis on the developing brain and treatments for cannabis misuse in youth remain limited. Future research aimed at examining the neurobiological effects of cannabis, with objective measures of exposure, over the course of pediatric development and in relation to psychiatric symptoms are needed.

Do Differences in Learning Performance Precede or Follow Initiation of Marijuana Use?

OBJECTIVE

Studies examining cross-sectional associations between age at marijuana initiation and memory deficits yield mixed results. Because longitudinal data are sparse, controversy continues regarding whether these deficits reflect premorbid risk factors or sequelae of early marijuana initiation; here, we examine this question in a community sample followed since birth.

METHOD

Masked examiners administered four subtests of the Wide Range Assessment of Memory and Learning (WRAML/WRAML2) from childhood until young adulthood to 119 urban, predominantly African American participants. Multivariable generalized estimated equation models measured longitudinal trajectories of learning. Participants were grouped as never users (n = 26), later initiators (≥16 years old; n = 31), and earlier initiators of marijuana use (n = 62).

RESULTS

Marijuana onset groups did not significantly differ on WRAML scaled scores or IQ in childhood, nor did they differ on WRAML scaled scores in adolescence. On most WRAML2 subtests, these groups did not significantly differ in young adulthood after taking into account sex and childhood IQ. However, on Story Memory, later initiators attained higher scaled scores in young adulthood, even after including additional covariates of anxiety, depression, postsecondary education, past-month marijuana use, and past-week high-risk drinking. They showed a significantly more positive trajectory than never users that was driven by within-group improvement after adolescence. Earlier initiators showed within-group decline in Story Memory after adolescence.

CONCLUSIONS

Differences in learning following earlier initiation of marijuana use may not be solely attributable to premorbid deficits.

Cannabis Use and Emotional Awareness Difficulties in Adolescents with Co-Occurring Substance Use and Psychiatric Disorders

Background: Assessing predictors of cannabis use following adolescent substance use treatment may inform essential treatment elements to be emphasized before discharge. Adolescents with low emotional awareness may have limited resources for identifying and overcoming negative emotions, and therefore, use cannabis to regulate emotions. Purpose/objectives: The purpose of this study was to test the hypothesis that emotional awareness difficulties are associated with increased cannabis use across the transition out of substance use treatment. This hypothesis was investigated by applying an autoregressive random-intercept cross-lagged panel-modeling framework to test the fit of alternative models and inform hypotheses about directional associations between cannabis use and emotional awareness difficulties over time. Methods: Participants were 110 adolescents with co-occurring disorders and their families participating in an intensive home-based treatment trial. Adolescents reported on past 7-day cannabis use and difficulties in emotional awareness at baseline and three follow-up assessments across 12 months. Results: At baseline, 54% of the sample reported past-week cannabis use. A directional effect was supported such that difficulties with emotional awareness at 3 months' post-baseline, which corresponded to the approximate end of the treatment program, were associated with increased cannabis use at 6 months' post-baseline, controlling for the stability of cannabis use, and emotional awareness over time. Cannabis use, however, was not associated with subsequent difficulties in emotional awareness (i.e., effects in the opposite direction were not supported). Conclusions/Importance: Emotional awareness difficulties toward the end of a course of intensive outpatient treatment may be associated with increased cannabis use after the completion of treatment.

Endocannabinoids as Therapeutic Targets

Most of the drugs of abuse affect the brain by interacting with naturally expressed molecular receptors. Marihuana affects a series of receptors including cannabinoid receptor 1 (CB1R) and CB2R, among others. Endogenous molecules with cannabinoid activity interact with these receptors naturally. Receptors, ligands, synthesizing and degrading enzymes, as well as transporters, have been described. This endocannabinoid system modulates behaviors and physiological processes, i.e. food intake, the sleep-waking cycle, learning and memory, motivation, and pain perception, among others. The rather broad distribution of endocannabinoids in the brain explains the different effects marihuana induces in its users. However, this very same anatomical and physiological distribution makes this system a useful target for therapeutic endeavors. In this review, we briefly discuss the potential of small molecules that target the endocannabinoids as therapeutic tools to improve behaviors and treat illnesses. We believe that under medical supervision, endocannabinoid targets offer new advantages for patients for controlling multiple medical disorders.

Effects of frequent marijuana use on risky decision-making in young adult college students

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Frequent marijuana users (MJ+) and controls completed the Iowa Gambling Task (IGT).

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MJ+ made significantly less advantageous decisions on the IGT relative to controls.

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Findings suggest frequent marijuana use may impair adaptive decision-making skills.

Marijuana (MJ) is the most widely used illicit substance among adolescents and young adults. Frequent MJ use has been associated with impairments in cognitive flexibility and inhibition, both of which play important roles in decision-making. However, the impact of frequent MJ use on decision-making performance is mixed and not well understood. The current study examined the influence of frequent MJ use on risky decision-making in college students, 18–22 years old. Methods: From 2017 to 2019, data was collected from young adult college students (n = 65) consisting of 32 healthy controls (HC) and 33 frequent marijuana users (MJ+). Participants completed the Iowa Gambling Task (IGT), a measure of risky decision-making, and net IGT scores (advantageous-disadvantageous decisions) were used as a measure of optimal decision-making. Results: The main finding indicated there was a significant effect of group on net IGT scores (p = 0.018), which remained significant when sex was included in the model (p = 0.006), such that MJ+ had lower net IGT scores than HC. Conclusions: These findings highlight potential differences in risky decision-making between MJ+ and HC, but it is uncertain whether these differences are pre-existing and increase vulnerability for frequent MJ use or if they are related to the effects of frequent MJ use on decision-making.