Adolescent precursors of cannabis dependence: findings from the Victorian Adolescent Health Cohort Study

The mediation roles of self-regulation and problematic internet use: How maladaptive parenting during the COVID-19 pandemic influenced adolescents' academic procrastination in the postpandemic era

INTRODUCTION

In the transition to the postpandemic era, adolescents are working to shift their focus back to school. However, the prevalence of academic procrastination is reflective of that the aftereffects of the pandemic are persisting. Literature documents the increases in the negative parenting behaviors and internet use of adolescents during the pandemic. The excessive internet use has to do with adolescents' self-regulatory capabilities and self-regulation is profoundly shaped by parents' parenting practices. Given the connections among these factors, the present study seeks to understand how maladaptive parenting practices during the pandemic influenced adolescents' academic procrastination postpandemic through the mediation of self-regulation and problematic internet use.

METHOD

Using three waves of data from a total of 1062 Chinese adolescents (Mage = 14.9 years old, SD = 1.6, 13-18 years old; 45% female), we used structural equation modeling to examine the direct effect of maladaptive parenting on academic procrastination and its indirect effect via self-regulation and problematic internet use.

RESULTS

Maladaptive parenting during the pandemic did not directly predict adolescent academic procrastination post-pandemic. Yet, maladaptive parenting indirectly influenced academic procrastination both through self-regulation solely and self-regulation and problematic internet use sequentially.

CONCLUSION

The findings demonstrate that parents can contribute to adolescents' academic procrastination by influencing their self-regulation ability, which further impacts their internet use. Self-regulation serves as a robust mediator between parenting and adolescents' problematic behaviors related to internet use and learning. Implications for parents and intervention oriented toward adolescents are discussed.

Life-course Accumulated Cannabis Use and Recent Cannabis-related Problems in the Washington Panel Survey

BACKGROUND

Previous studies have only investigated the short-term association of recent cannabis use with cannabis-related problems, without accounting for the onset, duration, and variations in frequency of use in the life-course.

METHODS

We obtained data from the Washington panel survey during 2014-2016. We constructed accumulated lifetime exposure to cannabis use, heavy drinking (5+ drinks on one occasion), and cigarette pack-years from age of onset based on a series of decades-based questions on cannabis use and heavy drinking, and tobacco use history. We used Generalized Estimating Equation with Poisson distribution to investigate the association between accumulated cannabis use and the past-6-month CUDIT score. We adjusted for accumulated heavy drinking and cigarette pack-years, substance co-use variables, demographics, and applied survey weights.

RESULTS

We found strong and statistically significant correlations for the lifetime measures across the four panel surveys, indicating that the life-course measures of cannabis use and heavy drinking were largely reliable. We found a statistically significant relationship between the lifetime accumulated exposure to cannabis and CUDIT. The results were robust to the inconsistencies in reported frequencies and onset age across panel surveys.

CONCLUSIONS

This study established the relationship between lifetime exposure to cannabis and cannabis-related problems in a representative sample of drinkers and marijuana users in Washington state. We have also provided test-retest validity and question details for the decades-based cannabis and heavy drinking measures to facilitate their use in future studies of cannabis and alcohol-related outcomes.

Cannabis and Cannabinoids in Adults With Cancer: ASCO Guideline

PURPOSE

To guide clinicians, adults with cancer, caregivers, researchers, and oncology institutions on the medical use of cannabis and cannabinoids, including synthetic cannabinoids and herbal cannabis derivatives; single, purified cannabinoids; combinations of cannabis ingredients; and full-spectrum cannabis.

METHODS

A systematic literature review identified systematic reviews, randomized controlled trials (RCTs), and cohort studies on the efficacy and safety of cannabis and cannabinoids when used by adults with cancer. Outcomes of interest included antineoplastic effects, cancer treatment toxicity, symptoms, and quality of life. PubMed and the Cochrane Library were searched from database inception to January 27, 2023. ASCO convened an Expert Panel to review the evidence and formulate recommendations.

RESULTS

The evidence base consisted of 13 systematic reviews and five additional primary studies (four RCTs and one cohort study). The certainty of evidence for most outcomes was low or very low.

RECOMMENDATIONS

Cannabis and/or cannabinoid access and use by adults with cancer has outpaced the science supporting their clinical use. This guideline provides strategies for open, nonjudgmental communication between clinicians and adults with cancer about the use of cannabis and/or cannabinoids. Clinicians should recommend against using cannabis or cannabinoids as a cancer-directed treatment unless within the context of a clinical trial. Cannabis and/or cannabinoids may improve refractory, chemotherapy-induced nausea and vomiting when added to guideline-concordant antiemetic regimens. Whether cannabis and/or cannabinoids can improve other supportive care outcomes remains uncertain. This guideline also highlights the critical need for more cannabis and/or cannabinoid research.Additional information is available at www.asco.org/supportive-care-guidelines.

A School-Based Program for Problematic Internet Use for Adolescents in Japan

Despite the serious influence of problematic Internet use on mental health among Japanese adolescents, no randomized clinical trials have investigated universal school-based interventions for this potential health challenge. Therefore, this study aimed to assess the efficacy of a school-based educational program. This two-armed, parallel, cluster-based randomized clinical trial included 5312 students from 13 high schools situated in a mid-sized Japanese city. The students in the intervention arm received 10 weekly standardized sessions, including a combination of information provision and interactive sessions by schoolteachers. The students in the control group followed a standard school curriculum. A generalized estimating equation model was applied to assess the primary (Korean Scale for Internet Addiction [K-scale] score) and secondary (behavioral change status according to changes in the transtheoretical model smartphone addiction score and Internet usage time) outcomes two months after intervention completion. The intention-to-treat analysis included 2597 (97.2%) and 2504 (94.9%) students in the intervention and control groups, respectively. Nevertheless, a significant discrepancy emerged regarding the behavioral change status. Therefore, this school-based program did not improve the Internet or smartphone addiction scores among Japanese adolescents. Further studies are needed to develop appropriate interventions for adolescents.

Risk factors for cannabis use disorders and cannabis psychosis in Japan: Second report of a survey on cannabis-related health problems among community cannabis users using social networking services

AIM

To determine the risk factors for cannabis use disorders and cannabis psychosis in Japan based on a 2021 online survey among Japanese users of social network services.

METHODS

The 3142 respondents who had used cannabis within the preceding year were categorized into two groups based on the development of cannabis use disorder and/or cannabis psychosis. Analyses were performed to determine these conditions' risk factors.

RESULTS

Multivariate analysis revealed that factors significantly associated with cannabis use disorders were "cannabis-use initiation at a young age" (p = 0.004, OR: 0.951, 95% CI [0.920-0.984]), "family history of mental health problems" (p < 0.001, OR: 1.988, 95% CI [1.545-2.556]), "psychiatric disorders preceding cannabis use" (p = 0.039, OR: 1.672, 95% CI [1.026-2.722]), and "use of cannabis products other than dry flower" (p < 0.001, OR: 2.725, 95% CI [1.844-4.026]). Factors significantly associated with cannabis psychosis were "cannabis-use initiation at a young age" (p = 0.011, OR: 0.888, 95% CI [0.811-0.973]) and "family history of mental health problems" (p = 0.002, OR: 2.531, 95% CI [1.400-4. 576]).

CONCLUSION

Risk factors for problematic cannabis use were cannabis initiation at a young age, pre-cannabis psychiatric disorders, family history of mental health problems, and the use of cannabis products other than dry flower. However, the causal relationship among these factors remains ambivalent.

Investigating problematic uses of Facebook and other Internet activities among university students in Bangladesh during the COVID-19 pandemic

Problematic use of Internet (PUI) and problematic use of Facebook (PUF) has been linked to escalating behavioral health issues among university students and has increased during the COVID-19 pandemic. This study estimated the prevalence of and explored associated factors for PUI and PUF among Bangladeshi university students during the COVID-19 pandemic. A cross-sectional online survey was undertaken among 1101 Bangladeshi university students between November and December 2020. The Internet Addiction Test and Facebook Addiction Scale were used to assess PIU and PUF, respectively. A multiple linear regression analysis was performed to adjust for confounders. Among the participants, PUI and PUF were found in 39.3% and 37.1%, respectively. The multiple linear regression model indicated PUI was significantly associated with participants residing in a village, arts majors, those unsatisfied with their major, having mediocre parental relationships, failure in romantic relationships, physical comorbidities, longer use of the Internet, using the Internet for purposes other than education, using social media, and downloading movies/TV series. PUF was significantly associated with village residence, lower income, arts majors, failure in romantic relationships, longer use of the Internet, using the Internet for purposes other than education, and downloading movies/TV series. Both PUI and PUF have been prevalent among Bangladeshi university students during the COVID-19 pandemic. Longitudinal & exploratory studies are warranted in the future to identify causal factors for PUI and PUF and appropriate interventions should be designed quickly for this population.

Identifying risk-thresholds for the association between frequency of cannabis use and development of cannabis use disorder: A systematic review and meta-analysis

BACKGROUND

Cannabis use disorder (CUD) affects one-in-five cannabis users, presenting a major contributor to cannabis-associated disease burden. Epidemiological data identify the frequency of cannabis use as a risk factor for CUD. This review aimed to determine quantifiable risk-thresholds of the frequency of cannabis use for developing CUD.

METHODS

Systematic search of Medline, EMBASE, PsycInfo, CINAHL, and Web of Science for cohort/case-control studies that assessed the association between frequency of cannabis use and CUD from 2000 to 2022. Effect estimates were converted to risk ratios (RR). A random-effects multi-level multivariate meta-analytic approach was utilized, and sensitivity analyses conducted. Quality of included studies was assessed with the Newcastle Ottawa Scale.

RESULTS

Six prospective cohort studies were included in this review, drawn from two main source studies. Random-effect modeling showed a significant log-linear dose-response association between the frequency of cannabis use and CUD risk (p < 0.0001). The risk of CUD increased from RR:2.03 (95% CI:1.85-2.22) for 'yearly' use, to RR:4.12 (95% CI:3.44-4.95) for 'monthly" use, RR:8.37 (95% CI:6.37-11.00) for 'weekly' use, and RR:16.99 (95% CI:11.80-24.46) for 'daily' use. Multi-level modeling showed an absolute risk increase (ARI) from 3.5% (95% CI:2.6-4.7) for 'yearly' use, to 8.0% (95% CI:5.3-12.1) for 'monthly' use, to 16.8% (95% CI:8.8-32.0) for 'weekly' use, and 36% (95% CI:27.047.9) for 'daily' use.

CONCLUSION

A limited risk of CUD as a potential outcome of cannabis use exists even at infrequent levels of use, but significantly increases as frequency of use increases. Corresponding information should be conveyed to cannabis users as part of targeted prevention messaging to promote safer cannabis use.

Characteristics and reasons for use associated with solitary alcohol and marijuana use among U.S. 12th Grade Students, 2015-2021

BACKGROUND

Little is known regarding what sociodemographic characteristics and reasons for use are associated with adolescent solitary alcohol and marijuana use.

METHODS

Data from 7845 12th grade students participating in the nationally-representative Monitoring the Future study from 2015 to 2021 were used to examine cross-sectional associations between sociodemographics, heavy drinking/marijuana use, reasons for use, and past 12-month solitary alcohol or marijuana use among past 12-month users. Historical trends and possible differences related to the COVID-19 pandemic also were examined.

RESULTS

Solitary use prevalence increased from 2015 to 2021 with no evidence of significant COVID-19 deviations. In 2021, solitary alcohol use was reported by 32.1% (SE 3.01) and solitary marijuana use by 55.8% (4.72) of those reporting past 12-month use. Common and substance-specific sociodemographic risk factors were observed. Binge drinking was associated with solitary alcohol use; frequent marijuana use was associated with solitary marijuana use. Reasons for use related to coping with negative affect were associated with solitary use. Compulsive use reasons were more strongly associated with solitary alcohol than marijuana use. Drinking to have a good time with friends was negatively associated with solitary alcohol use but this association was not seen for solitary marijuana use.

CONCLUSIONS

The percentage of adolescents who use alcohol or marijuana when they were alone has increased among those who report using each substance. Associations between solitary use and (a) higher levels of consumption and (b) coping with negative affect highlight the importance of solitary use as a risk indicator.

Prevalence and correlates of cannabis use disorder among Australians using cannabis products to treat a medical condition

INTRODUCTION

Prior research has examined the prevalence and correlates of cannabis use disorder (CUD) in people who use cannabis; however, these are poorly described for people using cannabis for medical reasons.

METHODS

Data came from a 2018 to 2019 online, anonymous, cross-sectional survey of Australians reporting using either illicit or licit cannabis for medical reasons within the past year. Included were questions on demographics, current and lifetime patterns of cannabis use, clinical conditions for which medical cannabis was used, and individual criteria for CUD and cannabis withdrawal syndrome. Bayesian Horseshoe logistic regression models were used to identify covariates associated with meeting CUD DSM-5 conditions for any-CUD (≥2/11 criteria) and moderate-severe-CUD (≥4/11).

RESULTS

A total of 905 participants were included in the analysis. The majority (98%) used illicit cannabis products. Criteria for any-CUD criteria were met by 290 (32.0%), and 117 (12.9%) met criteria for moderate-severe-CUD. Tolerance (21%) and withdrawal (35%) were the most commonly met criteria. Correlates with the strongest association with CUD were inhaled route of administration [odds ratio (OR) = 2.96, 95% credible interval 1.11, 7.06], frequency of cannabis use (OR = 1.24, 1.11-1.35), proportion of cannabis for medical reasons (OR = 0.83, 0.74, 0.94), frequency of tobacco use (OR = 1.10, 1.03, 1.17), age (OR = 0.75, 0.64, 0.90) and pain as main clinical indication (OR = 0.58, 0.36, 1.00).

DISCUSSION AND CONCLUSIONS

Prevalence of CUD in medical cannabis users appears comparable to 'recreational' users, with many similar correlates. CUD was associated with using cannabis to treat mental health rather than pain conditions and inhaled over other routes of administration.

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.

Who Is at Risk of Developing Cannabis Dependence? Findings From an Extensive Online Study on Cannabis Users

OBJECTIVES

Although frequency of cannabis use is considered to be the strongest risk factor for developing cannabis dependence, only up to half of daily users become dependent. In this study, we explored an array of risk factors and moderators of cannabis dependence symptoms from the International Classification of Diseases, Tenth Edition endorsed by participants.

METHODS

A sample of 1,635 cannabis users completed an Internet survey consisting of measures of cannabis and other drug use. Multiple linear regression with a backward elimination method was employed to identify predictors of cannabis dependence symptoms. After that, a series of hierarchical multiple regression analyses were performed to test the predictive validity of the interactions between frequency of cannabis use and other predictors.

RESULTS

Frequency of cannabis use appeared to be the strongest predictor of developing cannabis dependence symptoms; other significant predictors of cannabis dependence symptoms were substance-dependency-related treatment seeking, mental health problems in the family and pattern of substance use. Duration of cannabis use, relationship status, and drug use history in the family were identified as significant moderators of the relationship between frequency of cannabis use and the number of cannabis dependence symptoms.

CONCLUSIONS

This study confirms that the frequency of cannabis use is the strongest predictor of cannabis dependence symptoms but this relationship is significantly moderated by three abovementioned factors.

Variations of cannabis-related adverse mental health and addiction outcomes across adolescence and adulthood: A scoping review

INTRODUCTION

Evidence supporting associations between cannabis use and many health outcomes is growing, however it remains unclear how such associations vary across the lifespan. We therefore aim to answer the following questions: (1) Are the risks of cannabis's adverse effects on mental health and addiction-related outcomes different in adolescents than in adults? (2) What are the relationships between these cannabis's adverse effects and (a) an individual's age at first cannabis use, (b) age at assessment, and (c) duration of cannabis use?

METHODS

We searched Medline, Embase, CINAHL, and PsychINFO from inception to 18 October 2021. Two reviewers independently screened studies and descriptively synthesized results.

RESULTS

We included 140 studies. Cannabis effects on mental health and addiction-related outcomes were worse in adolescents, early cannabis initiators and cannabis users who consumed for longest periods. Evidence of worse long-term adverse effects in adolescents was substantial for psychosis, cannabis, and nicotine use disorders; mixed for depression, suicidality, other substance use and disorders; and limited for anxiety. Additionally, acute cannabis exposure had the opposite trend with adults more often reporting adverse effects than adolescents.

CONCLUSION

The available evidence suggests that cannabis use should be delayed as late as possible in adulthood and shortened in duration across the lifespan to decrease the risk of negative outcomes, while emphasizing the need for adapted harm reduction approaches. This scoping review provides evidence on the role of age and duration of exposure as determinants of cannabis-related adverse effects, which may inform prevention and harm reduction strategies.

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/OSF.IO/BYG72.

Youth in transition: Study protocol of a prospective cohort study into the long-term course of addiction, mental health problems and social functioning in youth entering addiction treatment

BACKGROUND

Substance use disorders (SUDs) are prevalent in the general population, tend to follow a chronic course, are associated with many individual and social problems, and often have their onset in adolescence. However, the knowledge base from prospective population surveys and treatment-outcome studies on the course of SUD in adolescents is limited at best. The present study aims to fill this gap and focuses on a subgroup that is particularly at risk for chronicity: adolescents in addiction treatment. We will investigate the rate of persistent SUD and its predictors longitudinally from adolescence to young adulthood among youth with DSM-5 SUD from the start of their addiction treatment to 2 and 4 years following treatment-entry. In addition to SUD, we will investigate the course of comorbid mental disorders, social functioning, and quality of life and their association with SUD over time.

METHODS/DESIGN

In a naturalistic, multi-center prospective cohort design, we will include youths (n = 420), who consecutively enter addiction treatment at ten participating organizations in the Netherlands. Inclusion is prestratified by treatment organization, to ensure a nationally representative sample. Eligible youths are 16 to 22 years old and seek help for a primary DSM-5 cannabis, alcohol, cocaine or amphetamine use disorder. Assessments focus on lifetime and current substance use and SUD, non-SUD mental disorders, family history, life events, social functioning, treatment history, quality of life, chronic stress indicators (hair cortisol) and neuropsychological tests (computerized executive function tasks) and are conducted at baseline, end of treatment, and 2 and 4 years post-baseline. Baseline data and treatment data (type, intensity, duration) will be used to predict outcome - persistence of or desistance from SUD.

DISCUSSION

There are remarkably few prospective studies worldwide that investigated the course of SUD in adolescents in addiction treatment for longer than 1 year. We are confident that the Youth in Transition study will further our understanding of determinants and consequences of persistent SUD among high-risk adolescents during the critical transition from adolescence to young adulthood.

TRIAL REGISTRATION

The Netherlands National Trial Register Trial NL7928 . Date of registration January 17, 2019.

Opioid analgesic use and its sequelae: Opioid and other substance use disorders

OBJECTIVES

While use of opioids is a well-established risk factor for opioid use disorder (OUD), its association with lifetime use of other addictive substances and the emergence of other lifetime substance use disorders (SUDs) has not been studied.

METHODS

We used data from 36 309 US adults in the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions III to identify those with lifetime opioid use (n = 4090; 11.3%). Of these individuals, we quantified use of other addictive substances; development of OUD and other SUDs; and whether use of opioids and development of OUD came before or after use of other substances and the emergence of other SUDs.

RESULTS

Of the 11.3% of adults who reported any opioid use, 98.2% of such users reported use of other addictive substances. Of these opioid users, 18.1% met criteria for lifetime OUD but only 3.5% had OUD alone; 47.6% had SUDs other than OUD and 14.6% had OUD plus another SUD. In most instances, opioid use followed use of other substances and OUD followed development of other SUDs.

CONCLUSION

Opioid use is typically linked to use of multiple substances and while less than 20% developed OUD, more than half developed either OUD or another SUD. Opioid use and OUD most often followed other substance use and the emergence of other SUDs. Early intervention in OUD should consider potential complications of other present or past SUDs, and both prevention and treatment development efforts should focus on the multi-morbid dimensions of the current opioid epidemic.

Social-Emotional Learning Competencies and Problematic Internet Use among Chinese Adolescents: A Structural Equation Modeling Analysis

To advance the understanding about social-cognitive factors related to Chinese adolescents’ experience with problematic Internet use (PIU), we examined the associations between social-emotional learning (SEL) competencies (i.e., responsible decision-making, social awareness, self-management, self-awareness, and social relationship) and problematic Internet use (PIU) among 1141 11th grade high school students from Southwest China. Through comparing the latent means of PIU across students with different demographic background (i.e., gender, social-economic status, left-behind status), the study found that male students endorsed higher levels of overall PIU and more problematic time management with Internet use than female students. No latent PIU mean differences were observed across family income and students’ left-behind status. Using structural equation modeling (SEM) while controlling for demographic factors, overall SEL competencies were found to have a significantly negative association with PIU. Meanwhile, all five SEL domains were also negatively associated with students’ PIU. The findings imply the importance of fostering SEL competencies in preventing PIU among Chinese adolescents. The study provides important practical implications for informing school-based SEL competencies programs for PIU prevention among Chinese youths.

Cannabis use and cannabis use disorder

Cannabis use disorder (CUD) is an underappreciated risk of using cannabis that affects ~10% of the 193 million cannabis users worldwide. The individual and public health burdens are less than those of other forms of drug use, but CUD accounts for a substantial proportion of persons seeking treatment for drug use disorders owing to the high global prevalence of cannabis use. Cognitive behavioural therapy, motivational enhancement therapy and contingency management can substantially reduce cannabis use and cannabis-related problems, but enduring abstinence is not a common outcome. No pharmacotherapies have been approved for cannabis use or CUD, although a number of drug classes (such as cannabinoid agonists) have shown promise and require more rigorous evaluation. Treatment of cannabis use and CUD is often complicated by comorbid mental health and other substance use disorders. The legalization of non-medical cannabis use in some high-income countries may increase the prevalence of CUD by making more potent cannabis products more readily available at a lower price. States that legalize medical and non-medical cannabis use should inform users about the risks of CUD and provide information on how to obtain assistance if they develop cannabis-related mental and/or physical health problems.

Early, Chronic, and Acute Cannabis Exposure and Their Relationship With Cognitive and Behavioral Harms

Background: Cannabis is the third most consumed drug worldwide. Thus, healthcare providers should be able to identify users who are in need for an intervention. This study aims to explore the relationship of acute, chronic, and early exposure (AE, CE, and EE) to cannabis with cognitive and behavioral harms (CBH), as a first step toward defining risky cannabis use criteria. Methods: Adults living in Spain who used cannabis at least once during the last year answered an online survey about cannabis use and health-related harms. Cannabis use was assessed in five dimensions: quantity on use days during the last 30 days (AE), frequency of use in the last month (AE), years of regular use (YRCU) (CE), age of first use (AOf) (EE), and age of onset of regular use (AOr) (EE). CBH indicators included validated instruments and custom-made items. Pearson correlations were calculated for continuous variables, and Student's t-tests for independent samples were calculated for categorical variables. Effect sizes were calculated for each of the five dimensions of use (Cohen's d or r Pearson correlation) and harm outcome. Classification and Regression Trees (CART) analyses were performed for those dependent variables (harms) significantly associated with at least two dimensions of cannabis use patterns. Lastly, logistic binary analyses were conducted for each harm outcome. Results: The mean age of participants was 26.2 years old [standard deviation (SD) 8.5]. Out of 2,124 respondents, 1,606 (75.6%) reported at least one harm outcome (mean 1.8 and SD 1.5). In our sample, using cannabis on 3 out of 4 days was associated with an 8-fold probability of scoring 4+ on the Severity Dependence Scale (OR 8.33, 95% CI 4.91-14.16, p <0.001), which is indicative of a cannabis use disorder. Also, a start of regular cannabis use before the age of 25 combined with using cannabis at least once per month was associated with a higher probability of risky alcohol use (OR 1.33, 95% CI 1.12-1.57, p = 0.001). Besides, a start of regular cannabis use before the age of 18 combined with a period of regular use of at least 7.5 years was associated with a higher probability of reporting a motor vehicle accident (OR 1.81, 95% CI 1.41-2.32, p < 0.0001). Results were ambiguous regarding the role that age of first use and milligrams of THC per day of use might play regarding cannabis-related harms. Conclusions: The relationship among AE, CE, and EE with CBH indicators is a complex phenomenon that deserves further studies. The pattern of cannabis use should be carefully and widely evaluated-(not just including frequency but also other dimensions of pattern of use)-in research (preferably in longitudinal studies) to assess cannabis-related harms.

Risk factors for the onset of dependence and chronic psychosis due to cannabis use: Survey of patients with cannabis-related psychiatric disorders

AIM

The objective of the current study was to identify risk factors that affect the onset of dependence and chronic psychosis due to cannabis use.

METHODS

We examined clinical genetic factors, psychiatric disorders prior to cannabis use, starting age of cannabis use, duration and frequency of cannabis use, types of cannabis products used, combined use of other psychoactive substances, and the psychiatric diagnosis of 71 patients with cannabis-related psychiatric disorders who underwent treatment at nine mental health hospitals in Japan. Information was collected from cross-sectional interview surveys conducted by each patient's attending psychiatrist.

RESULTS

For the diagnosis of dependence syndrome due to the use of cannabis, we found associations with the number of years of cannabis use and the use of cannabis products with a high Δ9-tetrahydrocannabinol (THC) content. However, we found no association between diagnosis of residual and late-onset psychotic disorders and clinical genetic factors, presence of preceding psychiatric disorders, duration and frequency of cannabis use, starting age of cannabis use, or combined use of other psychoactive substances; an association was found only for the absence of use of cannabis products other than dried cannabis.

CONCLUSION

The onset of cannabis dependence was related to long-term cannabis use and the use of cannabis products with a high THC content. However, chronic psychosis was not associated with total THC intake or psychiatric vulnerability. Thus, unknown factors appear to be involved in the onset of chronic psychosis.

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.

Acute separate and combined effects of cannabinoid and nicotinic receptor agonists on MMN-indexed auditory deviance detection in healthy humans

The high prevalence of concomitant cannabis and nicotine use has implications for sensory and cognitive processing. While nicotine tends to enhance function in these domains, cannabis use has been associated with both sensory and cognitive impairments, though the underlying mechanisms are unclear. Additionally, the interaction of the nicotinic (nAChR) and cannabinoid (CB₁) receptor systems has received limited study in terms of sensory/cognitive processes. This study involving healthy volunteers assessed the acute separate and combined effects of nabilone (a CB₁ agonist) and nicotine on sensory processing as assessed by auditory deviance detection and indexed by the mismatch negativity (MMN) event-related potential. It was hypothesized that nabilone would impair auditory discriminability as shown by diminished MMN amplitudes, but not when administered in combination with nicotine. 20 male non-smokers and non-cannabis-users were assessed using a 5-stimulus 'optimal' multi-feature MMN paradigm within a randomized, placebo controlled design (placebo; nabilone [0.5 mg]; nicotine [6 mg]; and nicotine + nabilone). Treatment effects were region- and deviant-dependent. At the temporal regions (mastoid sites), MMN was reduced by nabilone and nicotine separately, whereas co-administration resulted in no impairment. At the frontal region, MMN was enhanced by co-administration of nicotine and nabilone, with no MMN effects being found with separate treatment. These neural effects have relevance for sensory/cognitive processes influenced by separate and simultaneous use of cannabis and tobacco and may have treatment implications for disorders associated with sensory dysfunction and impairments in endocannabinoid and nicotinic cholinergic neurotransmission.

Which biological and self-report measures of cannabis use predict cannabis dependency and acute psychotic-like effects?

BACKGROUND

Changes in cannabis regulation globally make it increasingly important to determine what predicts an individual's risk of experiencing adverse drug effects. Relevant studies have used diverse self-report measures of cannabis use, and few include multiple biological measures. Here we aimed to determine which biological and self-report measures of cannabis use predict cannabis dependency and acute psychotic-like symptoms.

METHOD

In a naturalistic study, 410 young cannabis users were assessed once when intoxicated with their own cannabis and once when drug-free in counterbalanced order. Biological measures of cannabinoids [(Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN) and their metabolites)] were derived from three samples: each participant's own cannabis (THC, CBD), a sample of their hair (THC, THC-OH, THC-COOH, CBN, CBD) and their urine (THC-COOH/creatinine). Comprehensive self-report measures were also obtained. Self-reported and clinician-rated assessments were taken for cannabis dependency [Severity of Dependence Scale (SDS), DSM-IV-TR] and acute psychotic-like symptoms [Psychotomimetic State Inventory (PSI) and Brief Psychiatric Rating Scale (BPRS)].

RESULTS

Cannabis dependency was positively associated with days per month of cannabis use on both measures, and with urinary THC-COOH/creatinine for the SDS. Acute psychotic-like symptoms were positively associated with age of first cannabis use and negatively with urinary THC-COOH/creatinine; no predictors emerged for BPRS.

CONCLUSIONS

Levels of THC exposure are positively associated with both cannabis dependency and tolerance to the acute psychotic-like effects of cannabis. Combining urinary and self-report assessments (use frequency; age first used) enhances the measurement of cannabis use and its association with adverse outcomes.

Association of Cohort and Individual Substance Use With Risk of Transitioning to Drug Use, Drug Use Disorder, and Remission From Disorder: Findings From the World Mental Health Surveys

IMPORTANCE

Limited empirical research has examined the extent to which cohort-level prevalence of substance use is associated with the onset of drug use and transitioning into greater involvement with drug use.

OBJECTIVE

To use cross-national data to examine time-space variation in cohort-level drug use to assess its associations with onset and transitions across stages of drug use, abuse, dependence, and remission.

DESIGN, SETTING, AND PARTICIPANTS

The World Health Organization World Mental Health Surveys carried out cross-sectional general population surveys in 25 countries using a consistent research protocol and assessment instrument. Adults from representative household samples were interviewed face-to-face in the community in relation to drug use disorders. The surveys were conducted between 2001 and 2015. Data analysis was performed from July 2017 to July 2018.

MAIN OUTCOMES AND MEASURES

Data on timing of onset of lifetime drug use, DSM-IV drug use disorders, and remission from these disorders was assessed using the Composite International Diagnostic Interview. Associations of cohort-level alcohol prevalence and drug use prevalence were examined as factors associated with these transitions.

RESULTS

Among the 90 027 respondents (48.1% [SE, 0.2%] men; mean [SE] age, 42.1 [0.1] years), 1 in 4 (24.8% [SE, 0.2%]) reported either illicit drug use or extramedical use of prescription drugs at some point in their lifetime, but with substantial time-space variation in this prevalence. Among users, 9.1% (SE, 0.2%) met lifetime criteria for abuse, and 5.0% (SE, 0.2%) met criteria for dependence. Individuals who used 2 or more drugs had an increased risk of both abuse (odds ratio, 5.17 [95% CI, 4.66-5.73]; P < .001) and dependence (odds ratio, 5.99 [95% CI, 5.02-7.16]; P < .001) and reduced probability of remission from abuse (odds ratio, 0.86 [95% CI, 0.76-0.98]; P = .02). Birth cohort prevalence of drug use was also significantly associated with both initiation and illicit drug use transitions; for example, after controlling for individuals' experience of substance use and demographics, for each additional 10% of an individual's cohort using alcohol, a person's odds of initiating drug use increased by 28% (odds ratio, 1.28 [95% CI, 1.26-1.31]). Each 10% increase in a cohort's use of drug increased individual risk by 12% (1.12 [95% CI, 1.11-1.14]).

CONCLUSIONS AND RELEVANCE

Birth cohort substance use is associated with drug use involvement beyond the outcomes of individual histories of alcohol and other drug use. This has important implications for understanding pathways into and out of problematic drug use.

Cross-domain correlates of cannabis use disorder severity among young adults

BACKGROUND

Correlates of cannabis use and dependence among young adults have been widely studied. However, it is not known which factors are most strongly associated with severity of cannabis use dependence (CUD) severity. Identification of the salient correlates of CUD severity will be of increasing clinical significance as use becomes more socially normative.

METHODS

This study used a data-driven, hypothesis-free approach to examine the most robust correlates of CUD severity among a sample of 76 young adults (ages 18 to 25 years) who used cannabis at least weekly. Seventy-one candidate variables were examined for association with CUD severity. These included demographic variables, self-reported and psychodiagnostic assessments of mood and anxiety, self-reported measures of personality, cannabis and other substance use characteristics, and objective and subjective measures of cognition.

RESULTS

Of the 71 candidate variables considered, 27 were associated with CUD severity on a univariate level at a p-value ≤.20. Correlates of CUD severity in the multivariable model using stepwise selection were: more frequent cannabis use in the past 90 days, greater expectancies that cannabis causes cognitive and behavioral impairment, greater self-reported metacognitive deficits, greater anxiety, and lower reaction time variability on a test of sustained attention. Internal validation tests support high prediction accuracy of all variables in the multivariable model, except for lower reaction time variability.

CONCLUSIONS

Cannabis use frequency, beliefs about use, perceived cognitive abilities, and anxiety are robustly associated with CUD severity in young adult, regular cannabis users, and may be important in guiding prevention and treatment efforts.

Age of Cannabis Use Onset and Adult Drug Abuse Symptoms: A Prospective Study of Common Risk Factors and Indirect Effects

The present study examined 1) whether the associations between cannabis use (CU) age of onset and drug abuse by 28 y remain when controlling for risk factors in childhood, adolescence and early adulthood; and 2) the developmental pathways from early risk factors to drug abuse problems. Participants from a longitudinal sample of boys of low socioeconomic status ( N = 1,030) were followed from 6 to 28 y. We examined the self-reported CU onset between the ages of 13 and 17 y and drug abuse symptoms by 28 y. The odds of developing any drug abuse symptoms by 28 y were reduced by 31% for each year of delayed CU onset (OR = 0.69). Cannabis, alcohol and other drug frequency at 17 y mediated this association. Still, even when taking that frequency of use into account, adolescents who started using cannabis before 15 y were at a higher risk of developing drug abuse symptoms by age 28 y. Significant indirect effects were found from early adolescent delinquency and affiliation with deviant friends to drug abuse symptoms at 28 y through CU age of onset and substance use frequency at 17 y. The results suggest more clearly than before that prevention programs should aim at delaying CU onset to prevent or reduce drug abuse in adulthood. Furthermore, prevention programs targeting delinquency and/or affiliation with deviant friends in childhood or early adolescence could indirectly reduce substance abuse in adulthood without addressing substance use specifically.

The impact of cohort substance use upon likelihood of transitioning through stages of alcohol and cannabis use and use disorder: Findings from the Australian National Survey on Mental Health and Wellbeing

INTRODUCTION AND AIMS

We used population-level Australian data to estimate prevalence, age of onset and speed of transitions across stages of alcohol and cannabis use, abuse and dependence, and remission from disorder, and consider the potential impacts that an individual's age cohort's level of substance use predicted transitions into and out of substance use.

DESIGN AND METHODS

Data on use, DSM-IV use disorders, and remission from these disorders were collected from participants (n = 8463) in the 2007 Australian National Survey of Mental Health and Wellbeing using the Composite International Diagnostic Interview.

RESULTS

Lifetime prevalence (95% confidence interval) of alcohol use, regular use, abuse and dependence were 94.1% (93.3-94.8%), 64.5% (62.9-66.2%), 18.7% (17.4-19.9%) and 4.0% (3.4-4.6%). Lifetime prevalence of cannabis use, abuse and dependence were 19.8% (18.6-20.9%), 4.4% (3.8-5.0%) and 1.9% (1.5-2.4%). Among those with the disorder, rates of remission from cannabis abuse, alcohol abuse, cannabis dependence and alcohol dependence were 90.5% (87.4-93.6%), 86.2% (83.8-88.7%), 79.6% (71.1-88.1%) and 53.8% (46.6-61.0%). Increases in the estimated proportion of people in the respondent's age cohort who used alcohol/cannabis as of a given age were significantly associated with most transitions from use through to remission beginning at the same age.

DISCUSSION AND CONCLUSIONS

Clear associations were documented between cohort-level prevalence of substance use and personal risk of subsequent transitions of individuals in the cohort from use to greater substance involvement. This relationship remained significant over and above associations involving the individual's age of initiation. These findings have important implications for our understanding of the causal pathways into and out of problematic substance use.

Unemployment, drugs and attitudes among European youth

This paper studies changes in the patterns of drug consumption and attitudes towards drugs in relation to sky-high (youth) unemployment rates brought about by the Great Recession. Our analysis is based on data for 28 European countries that refer to young people. We find that the consumption of cannabis and 'new substances' is positively related to increasing unemployment rates. An increase of 1% in the regional unemployment rate is associated with an increase of 0.7 percentage points in the ratio of young people who state that they have consumed cannabis at some point in time. Our findings also indicate that higher unemployment may be associated with more young people perceiving that access to drugs has become more difficult, particularly access to ecstasy, cocaine and heroin. According to young Europeans, when the economy worsens, anti-drug policies should focus on the reduction of poverty and unemployment, and not on implementing tougher measures against users.

Patterns of cannabis use and clinical correlates among individuals with Major Depressive Disorder and Bipolar Disorder

BACKGROUND

Major Depressive Disorder (MDD) and Bipolar Disorder (BPD) are the most severe mood disorders globally. Previous reports indicate high co-occurrence of cannabis use and cannabis use disorders (CUDs) associated with both disorders, yet studies comparing patterns of cannabis use between individuals with MDD and BPD are scarce.

METHODS

Data were drawn from Wave 1 (2001-2002) of the National Epidemiologic survey on Alcohol and Related Conditions (NESARC). Cannabis users who qualified for a diagnosis of past-year MDD (N=217) were compared to those with BPD (N=168) in frequency and daily dose of cannabis use, rates of comorbid psychiatric disorders including specific criteria of CUDs, treatment utilization and suicidality.

RESULTS

Among past-year cannabis users, individuals with BPD reported using cannabis more frequently and smoking more joints per day compared to those with MDD. They were also more likely to suffer from comorbid personality disorders and qualify for specific CUD-criteria, including use in physically hazardous situations and unsuccessful efforts to control substance use.

CONCLUSIONS

Our results indicate that individuals with BPD may present more intensive patterns of cannabis use compared to those with MDD. This may have potential effects on the course of BPD and should be further explored in longitudinal studies.

Measurement Invariance of the Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) between the United States of America, India and the United Kingdom

The Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) has been extensively used worldwide to assess Internet Gaming Disorder (IGD) behaviors. Therefore, investigating cultural limitations and implications in its applicability is necessary. The cross-cultural feasibility of a test can be psychometrically evaluated with measurement invariance analyses. Thus, the present study used Multigroup Confirmatory Factor Analysis (MGCFA) to examine the IGDS9-SF measurement invariance across gamers from the United States of America (USA), India, and the United Kingdom (UK). A total of 1013 gamers from the USA (n = 405), India (n = 336), and the UK (n = 272) were recruited. Although the one-factor structure of the IGD construct was supported, cross-country variations were demonstrated considering the way that this was reflected on items assessing preoccupation/salience, tolerance, deception, gaming escapism/mood modification, as well as daily activities' impairment related to gaming. Furthermore, the same scores on items assessing withdrawal symptoms, tolerance, lack of control over gaming engagement, escapism/mood modification and daily activities impairment associated to gaming, have been found to reflect various levels of IGD severity across the three groups. The implications of these results are further discussed in the context of existing evidence regarding the assessment of IGD.

Predictive validity of cannabis consumption measures: Results from a national longitudinal study

BACKGROUND

Validating the utility of cannabis consumption measures for predicting later cannabis related symptomatology or progression to cannabis use disorder (CUD) is crucial for prevention and intervention work that may use consumption measures for quick screening. This study examined whether cannabis use quantity and frequency predicted CUD symptom counts, progression to onset of CUD, and persistence of CUD.

METHODS

Data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) at Wave 1 (2001-2002) and Wave 2 (2004-2005) were used to identify three risk samples: (1) current cannabis users at Wave 1 who were at risk for having CUD symptoms at Wave 2; (2) current users without lifetime CUD who were at risk for incident CUD; and (3) current users with past-year CUD who were at risk for persistent CUD. Logistic regression and zero-inflated Poisson models were used to examine the longitudinal effect of cannabis consumption on CUD outcomes.

RESULTS

Higher frequency of cannabis use predicted lower likelihood of being symptom-free but it did not predict the severity of CUD symptomatology. Higher frequency of cannabis use also predicted higher likelihood of progression to onset of CUD and persistence of CUD. Cannabis use quantity, however, did not predict any of the developmental stages of CUD symptomatology examined in this study.

CONCLUSIONS

This study has provided a new piece of evidence to support the predictive validity of cannabis use frequency based on national longitudinal data. The result supports the common practice of including frequency items in cannabis screening tools.

Measurement Invariance of the Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) Between Australia, the USA, and the UK

The Internet Gaming Disorder Scale–Short-Form (IGDS9-SF) is widely used to assess Internet Gaming Disorder behaviors. Investigating cultural limitations and implications in its applicability is imperative. One way to evaluate the cross-cultural feasibility of the measure is through measurement invariance analysis. The present study used Multigroup Confirmatory Factor Analysis (MGCFA) to examine the IGDS9-SF measurement invariance across gamers from Australia, the United States of America (USA), and the United Kingdom (UK). To accomplish this, 171 Australian, 463 USA, and 281 UK gamers completed the IGDS9-SF. Although results supported the one-factor structure of the IGD construct, they indicated cross-country variations in the strength of the relationships between the indicators and their respective factor (i.e., non-invariant loadings of items 1, 2, 5), and that the same scores may not always indicate the same level of IGD severity across the three groups (i.e., non-invariant intercepts for items 1, 5, 7, 9).

What are the Patterns Between Depression, Smoking, Unhealthy Alcohol Use, and Other Substance Use Among Individuals Receiving Medical Care? A Longitudinal Study of 5479 Participants

To evaluate and characterize the structure of temporal patterns of depression, smoking, unhealthy alcohol use, and other substance use among individuals receiving medical care, and to inform discussion about whether integrated screening and treatment strategies for these conditions are warranted. Using the Veterans Aging Cohort Study (VACS) we measured depression, smoking, unhealthy alcohol use and other substance use (stimulants, marijuana, heroin, opioids) and evaluated which conditions tended to co-occur within individuals, and how this co-occurrence was temporally structured (i.e. concurrently, sequentially, or discordantly). Current depression was associated with current use of every substance examined with the exception of unhealthy alcohol use. Current unhealthy alcohol use and marijuana use were also consistently associated. Current status was strongly predicted by prior status (p < 0.0001; OR = 2.99-22.34) however, there were few other sequential relationships. Associations in the HIV infected and uninfected subgroups were largely the same with the following exceptions. Smoking preceded unhealthy alcohol use and current smoking was associated with current depression in the HIV infected subgroup only (p < 0.001; OR = 1.33-1.41 and p < 0.001; OR = 1.25-1.43). Opioid use and current unhealthy alcohol use were negatively associated only in the HIV negative subgroup (p = 0.01; OR = 0.75). Patterns of depression, smoking, unhealthy alcohol use, and other substance use were temporally concordant, particularly with regard to depression and substance use. These patterns may inform future development of more integrated screening and treatment strategies.

Marijuana Use, Recent Marijuana Initiation, and Progression to Marijuana Use Disorder Among Young Male and Female Adolescents Aged 12-14 Living in US Households

Marijuana initiation during adolescence, and early adolescence in particular, is associated with adverse health consequences. Our study used 2005–2014 data from the annual, cross-sectional National Survey on Drug Use and Health to study the prevalence and correlates of marijuana initiation, use, and marijuana use disorder (MUD; abuse or dependence) among 12- to 14-year olds living in civilian US households (n = 84 954). Examined correlates included age, sex, race/ethnicity, poverty status, metropolitan status, year of survey, depression, tobacco use, alcohol use, and fighting at school. Sex differences in the correlates of lifetime use and past year marijuana initiation were tested via interaction. Lifetime prevalence of marijuana use was 5.5%; 3.2% reported past year initiation. About 1 in 6 (16.8%) past year initiates progressed to MUD within 12 months of first use. Although men had higher prevalence of lifetime use than women, past year initiation did not differ by sex. On examining the sex*race/ethnicity interaction effects, findings determined that non-Hispanic black and Hispanic men had higher prevalence estimates of ever using marijuana and incidence of past year initiation as compared with non-Hispanic white men; these race/ethnicity differences were not found among women. Identifying correlates of initiation and progression to MUD among young adolescents is critical to improve prevention and treatment program targets.

Self-reported reasons for voluntary abstinences by adolescent cannabis users

Purpose

Factors influencing cannabis use have been previously identified mainly using multivariate approaches. However, there is a dearth of information collected from the perspective of the adolescent cannabis user, in particular for voluntary abstinences. The paper aims to discuss these issues.

Design/methodology/approach

In total, 38 cannabis users were identified from a sample of 261 adolescents recruited from schools. They completed open-ended questions identifying reasons for voluntary abstinences. Thematic analysis was used to assess their responses.

Findings

Voluntary abstinences by cannabis users were influenced by both internal and external factors. These were the user’s state of mind, an attempt to quit, negative effects of cannabis, prior to important events, prior to family interactions and peers.

Research limitations/implications

The results show that adolescent cannabis users are flexible in their approach to using cannabis, being able to briefly stop when the situation warrants it. However, the study is limited by a lack of in depth and rich data, limiting the scope of the analysis.

Originality/value

This is the first study to identify reasons for voluntary abstinences from the user’s perspective in adolescent cannabis users.

Cannabis Use and Disorder From Childhood to Adulthood in a Longitudinal Community Sample With American Indians

OBJECTIVE

Recent changes in DSM criteria require new documentation of the prevalence and developmental sequences of cannabis use disorder (CUD). The goal of this study was to investigate the early course of DSM-5 CUD and its overlap with DSM-IV and consumption constructs in a community-representative sample of American Indians.

METHOD

Data came from the prospective, longitudinal, population-based Great Smoky Mountains Study in North Carolina (N = 1,420, including 349 American Indians). Cannabis use and disorder were assessed during yearly interviews from 9 to 16 years of age and at 19, 21, 26, and 30 years of age (up to 11 assessments per participant from 1993 through 2015).

RESULTS

By 30 years of age, approximately 70% of participants had used cannabis, 34% had used cannabis daily, and 18% had met criteria for DSM-5 CUD. Approximately 1 in 4 cannabis users met criteria for CUD at some point. Those who met criteria initiated use more than 2 years previously (at 13.3 years old) compared with other users. Despite higher risks from increased poverty, American Indians' patterns of use were similar to those of the rest of the sample. Concordance between DSM-5 CUD and DSM-IV abuse or dependence was substantial but was even higher between DSM-5 CUD and daily use.

CONCLUSION

It was common to have used cannabis daily or to have met criteria for DSM-5 CUD by adulthood. DSM-5 CUD was an improvement over DSM-IV diagnostic constructs by raising the threshold for diagnosis.

Definitions of Risky and Problematic Cannabis Use: A Systematic Review

Although cannabis is widely used, it remains unclear which consumption patterns are more likely to produce future consequences (risky/hazardous use) or current damage (problematic/harmful use). This unresolved issue contributes to cannabis public health implications. In order to facilitate further consensus, this review analyzes previously used definitions in the literature.

METHODS

This systematic review was performed following the PRISMA guidelines. Articles published before October 2015 in the Medline, Scopus-Elsevier, ISI-Web of Knowledge and Cochrane databases and fulfilling a-priori decided criteria were retrieved. Definitions in preselected websites of national and international organizations addressing drug problems were also included.

RESULTS

Definitions identified in articles (n = 46) and official websites (n = 3) widely varied from each other. Weekly cannabis use was mostly considered risky. Problematic cannabis use was mostly described with the Cannabis Abuse and Screening Test. Evidence-based definitions as well as information on quantities consumed, time-frames and special considerations for risky groups were very limited.

CONCLUSIONS

Working on official definitions is highly necessary as criteria used remain incomplete, leading to increased confusion in the field. Recommendations to improve existing definitions are given.

From cannabis initiation to daily use: educational inequalities in consumption behaviours over three generations in France

AIMS

The diffusion of cannabis initiation has been accompanied by a reversal in the educational gradient: contrary to older generations, the less educated in recent generations are more likely to initiate than the more educated. We tested whether the educational gradient for the transition from initiation to daily use evolved in the same way.

DESIGN/SETTING

A French telephone random survey conducted in 2010 (21 818 respondents aged 15-64 years), asking interviewees about their ages at initiation to daily use, if any.

PARTICIPANTS

A total of 6824 cannabis initiators aged 18-64 years at data collection. Three birth cohort groups (generations) were compared: 1946-60 (n = 767), 1961-75 (n = 2632) and 1976-92 (n = 3425) with, respectively, 47, 42 and 45% of women.

MEASURES

Risks of transition to daily use from ages 11-34 were compared through time-discrete logistic regressions and educational gradients were quantified through a relative index of inequality (RII). Control variables include age and time-varying variables (ages at tobacco daily use, at first drunkenness and at first other use of an illicit drug in a list of 13 products).

FINDINGS

Twenty-four per cent of the initiators reported daily use before age 35, the proportions tripling from the oldest to the youngest generation (from 11.7 to 38.6% in men, from 7.7 to 22.2% in women). Whatever the generation, the less educated initiators more often shifted to daily use than the most educated: from the oldest to the youngest generation, RII = 2.13, 95% confidence interval (CI) = [0.65, 7.02]; 2.19 95% CI = [1.33, 3.63]; and 2.24, 95% CI = [1.60, 3.15] in men; RII = 3.31, 95% CI = [0.75, 14.68]; 3.17, 95% CI = [1.49, 6.76]; and 3.56, 95% CI = [2.07, 6.14] in women, respectively.

CONCLUSION

In France, the risk of transition from cannabis initiation to daily use has remained consistently higher among less educated cannabis initiators over three generations (1946-60, 1961-75, 1976-92), in contrast to what is observed for initiation.

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users

Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users.

Methods: A large sample (n=2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy.

Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial.

Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes.

Cannabis Use in Adolescence and Young Adulthood: A Review of Findings from the Victorian Adolescent Health Cohort Study

The Victorian Adolescent Health Cohort Study (VAHCS) is a long-term Australian cohort study that has documented cannabis use in young Australians from the mid-teens to the mid-30s. The study findings have described the natural history of early cannabis use, remission, and escalation and the social and mental health consequences of different patterns of use. The adverse consequences of cannabis use are most clear-cut in heavy early adolescent users. These consequences include educational failure, persisting mental health problems, and progression to other substance use. For later onset and occasional users, the risks are lower and appear to entail modest elevations in risk for other drug use compared with never users. With growing evidence of health consequences, there is a strong case for actions around early heavy adolescent users. Prevention of early use, identification and treatment of early heavy users, and harm reduction through diversion of early heavy users away from the custodial justice system into health care are all priority responses.

Keep off the grass? Cannabis, cognition and addiction

In an increasing number of states and countries, cannabis now stands poised to join alcohol and tobacco as a legal drug. Quantifying the relative adverse and beneficial effects of cannabis and its constituent cannabinoids should therefore be prioritized. Whereas newspaper headlines have focused on links between cannabis and psychosis, less attention has been paid to the much more common problem of cannabis addiction. Certain cognitive changes have also been attributed to cannabis use, although their causality and longevity are fiercely debated. Identifying why some individuals are more vulnerable than others to the adverse effects of cannabis is now of paramount importance to public health. Here, we review the current state of knowledge about such vulnerability factors, the variations in types of cannabis, and the relationship between these and cognition and addiction.

Adolescent Δ(9)-Tetrahydrocannabinol Exposure Alters WIN55,212-2 Self-Administration in Adult Rats

Cannabis is the most commonly used illicit drug worldwide, and use is typically initiated during adolescence. The endocannabinoid system has an important role in formation of the nervous system, from very early development through adolescence. Cannabis exposure during this vulnerable period might lead to neurobiological changes that affect adult brain functions and increase the risk of cannabis use disorder. The aim of this study was to investigate whether exposure to Δ(9)-tetrahydrocannabinol (THC) in adolescent rats might enhance reinforcing effects of cannabinoids in adulthood. Male adolescent rats were treated with increasing doses of THC (or its vehicle) twice/day for 11 consecutive days (PND 45-55). When the animals reached adulthood, they were tested by allowing them to intravenously self-administer the cannabinoid CB1-receptor agonist WIN55,212-2. In a separate set of animals given the same THC (or vehicle) treatment regimen, electrophysiological and neurochemical experiments were performed to assess possible modifications of the mesolimbic dopaminergic system, which is critically involved in cannabinoid-induced reward. Behavioral data showed that acquisition of WIN55,212-2 self-administration was enhanced in THC-exposed rats relative to vehicle-exposed controls. Neurophysiological data showed that THC-exposed rats displayed a reduced capacity for WIN55,212-2 to stimulate firing of dopamine neurons in the ventral tegmental area and to increase dopamine levels in the nucleus accumbens shell. These findings-that early, passive exposure to THC can produce lasting alterations of the reward system of the brain and subsequently increase cannabinoid self-administration in adulthood-suggest a mechanism by which adolescent cannabis exposure could increase the risk of subsequent cannabis dependence in humans.

Excessive substance use among young people consulting family doctors: a cross-sectional study

BACKGROUND

Family doctors can only play a role in the prevention of excessive substance use in young people if those affected are seen in the practice.

OBJECTIVE

To describe the prevalence of excessive substance use among young people consulting family doctors in a European context.

METHODS

As part of a trial of an intervention addressing substance use we collected data from young people consulting 32 family doctors in the French-speaking part of Switzerland. Before the consultation, consecutive patients aged 15-24 years completed a self-administered questionnaire on their general health and substance use. Outcomes were excessive alcohol (defined as ≥1 episode of binge drinking), excessive cannabis (use ≥1/week), regular tobacco (≥1 cigarettes a day) and/or any other substance use in the past 30 days. Prevalence data were computed with 95% confidence intervals (CIs) adjusted for clustering within practices, stratified by age and gender.

RESULTS

Between February 2009 and November 2010, 636 patients were eligible. Participation rate was 93.4% (n=594, 53% female). The prevalence of excessive use in the past 30 days was alcohol 44.9% (95% CI: 37.8-52.1), cannabis 11.1% (95% CI: 8.0-14.1), tobacco 23.4% (95% CI: 19.0-28.1) and any other drug 2.6 (95% CI: 1.4-4.2). Excessive use was higher in males than in females. Except for tobacco prevalence of excessive use was only slightly higher in young adults compared to adolescents.

CONCLUSION

Excessive substance use is frequent among young people consulting family doctors in a European context. Future research should provide guidance about how to best seize this window of opportunity for prevention and early intervention.

Comorbidity and temporal relations of alcohol and cannabis use disorders from youth through adulthood

BACKGROUND

Alcohol and cannabis are among the most widely used and abused drugs in industrialized societies. Investigations of patterns in comorbidity and temporal sequencing between alcohol use disorders (AUDs) and cannabis use disorders (CUDs) from childhood to adulthood are important for understanding the etiologies of these disorders.

METHODS

The sample comprised 816 individuals (59% male, 89% white). Dichotomous measures indicated whether or not a participant was in an AUD or CUD episode during three developmental periods-youth (childhood through adolescence), early adulthood, and adulthood. Structural equation modeling was used to determine relations between AUDs and CUDs across the three developmental periods, and to test for gender differences.

RESULTS

Concurrent associations between AUD and CUD were significant. Both AUD and CUD in previous developmental periods significantly predicted the same substance disorders in subsequent periods. Cross-lagged paths from youth AUD to young adult CUD and youth CUD to young adult AUD were both significant. However, only the cross-lagged path from youth CUD to adult AUD was significant. The cross-lagged paths from young adult AUD to adult CUD and young adult CUD to adult AUD were both nonsignificant. Males and females were mostly similar with only three differences found between genders.

CONCLUSIONS

Comorbidity of AUDs and CUDs was evident from youth through adulthood but the strength of the relationship lessened in adulthood. Temporal sequencing influences of AUDs and CUDs on each other were similar in youth and adulthood but not young adulthood. Same substance stability was greatest in adulthood.

Antecedents and consequences of cannabis use among racially diverse cannabis users: an analysis from Ecological Momentary Assessment

BACKGROUND

Cannabis remains the most commonly used illicit substance and use rates are rising. Notably, the prevalence of cannabis use disorders (CUD) nearly equals that of other illicit substance use disorders combined. Thus, the present study aimed to identify cognitive, affective, and situational predictors and consequences of ad-lib cannabis use in a racially diverse sample.

METHODS

The sample consisted of 93 current cannabis users (34.4% female; 57.1% non-Hispanic Caucasian), 87.1% of whom evinced a current CUD. Ecological Momentary Assessment was used to collect frequent ratings of cannabis withdrawal, craving, affect, cannabis use motives, and peer cannabis use over two weeks. Mixed effects linear models examined within- and between-day correlates and consequences of cannabis use.

RESULTS

Withdrawal and craving were higher on cannabis use days than non-use days. Withdrawal, craving, and positive and negative affect were higher immediately prior to cannabis use compared to non-use episodes. Withdrawal and craving were higher among those who subsequently used cannabis than those who did not. Cannabis use resulted in less subsequent withdrawal, craving, and negative affect. Enhancement and coping motives were the most common reasons cited for use. Withdrawal and negative affect were related to using cannabis for coping motives and social motives. Participants were most likely to use cannabis if others were using, and withdrawal and craving were greater in social situations when others were using.

CONCLUSIONS

Data support the contention that cannabis withdrawal and craving and affect and peer use play important roles in the maintenance of cannabis use.

Two patterns of cannabis use among adolescents: results of a 10-year prospective study using a growth mixture model

BACKGROUND

The present study aimed to distinguish cannabis consumption patterns among adolescents and to relate these to life satisfaction, academic achievement, and the use of other psychoactive substances.

METHODS

This study used a prospective design. Cannabis use was measured 14 times over the course of 10 years. Participants were 318 adolescents aged 14 to 15 at the beginning of the study.

RESULTS

Growth mixture modeling identified 2 latent classes. Class 1 was defined by phases of high-frequency cannabis use, and Class 2 was defined by low-frequency use or nonuse. Class 1 reported decreased satisfaction with life and one's own academic and professional achievement at the age of 24 as well as higher use of tobacco and illicit substances.

CONCLUSIONS

High-frequency use of cannabis predicts a decreased satisfaction with life and one's own academic and professional achievement as well as an increased use of other substances.

Natural course of cannabis use disorders

BACKGROUND

Despite its importance as a public health concern, relatively little is known about the natural course of cannabis use disorders (CUDs). The primary objective of this research was to provide descriptive data on the onset, recovery and recurrence functions of CUDs during the high-risk periods of adolescence, emerging adulthood and young adulthood based on data from a large prospective community sample.

METHOD

Probands (n = 816) from the Oregon Adolescent Depression Project (OADP) participated in four diagnostic assessments (T1-T4) between the ages of 16 and 30 years, during which current and past CUDs were assessed.

RESULTS

The weighted lifetime prevalence of CUDs was 19.1% with an average onset age of 18.6 years. Although gender was not significantly related to the age of initial CUD onset, men were more likely to be diagnosed with a lifetime CUD. Of those diagnosed with a CUD episode, 81.8% eventually achieved recovery during the study period. Women achieved recovery significantly more quickly than men. The recurrence rate (27.7%) was relatively modest, and most likely to occur within the first 36 months following the offset of the first CUD episode. CUD recurrence was uncommon after 72 months of remission and recovery.

CONCLUSIONS

CUDs are relatively common, affecting about one out of five persons in the OADP sample prior to the age of 30 years. Eventual recovery from index CUD episodes is the norm, although about 30% of those with a CUD exhibit a generally persistent pattern of problematic use extending 7 years or longer.