Comparing factor, class, and mixture models of cannabis initiation and DSM cannabis use disorder criteria, including craving, in the Brisbane longitudinal twin study

Cannabis and Alcohol Use by U.S. Young Adults, 2008-2019: Changes in Prevalence After Recreational Cannabis Legalization

INTRODUCTION

Young adults' cannabis and alcohol use patterns have changed after state recreational cannabis legalization according to studies based on college samples but not nationally representative samples. Associations between recreational cannabis legalization and changes in cannabis and alcohol use outcomes among young adults were examined, including differences by college enrollment and minor status (ages 18-20 vs 21-23 years).

METHODS

Repeated cross-sectional data (2008-2019) were collected from college-eligible participants aged 18-23 years in the National Survey on Drug Use and Health. Self-reported past-month cannabis use and frequent use (≥20 days) and a proxy for past-year DSM-5 cannabis use disorder were primary outcomes; past-month frequent alcohol use and binge drinking were secondary outcomes. Multilevel logistic regression models quantified changes in outcome prevalence from the study years before to after recreational cannabis legalization, adjusting for secular trends. Analyses were conducted on March 22, 2022.

RESULTS

Prevalence increased from before to after recreational cannabis legalization for past-month cannabis use (from 21% to 25%) and past-year proxy cannabis use disorder (from 11% to 13%); the increases were statistically significant [adjusted odds ratio (95% CI) = 1.20 (1.08-1.32) and 1.14 (1.003-1.30), respectively]. Increases were detected for young adults who were not in college and who were aged 21-23 years. Recreational cannabis legalization impacts were not detected for secondary outcomes.

CONCLUSIONS

Some young adults appear sensitive to state recreational cannabis legalization, including in terms of cannabis use disorder risk. Additional prevention efforts should be directed to young adults who are not in college and timed to occur before age 21 years.

Patterns of COVID-19 related lifestyle disruptions and their associations with mental health outcomes among youth and young adults

The COVID-19 pandemic is a socionatural disaster that has disrupted the lives of individuals, families, and communities. Youth and young adults (YYA) were uniquely vulnerable to the proximal mental health effects of the pandemic; however, few studies have examined the long-term mental health effects of the pandemic. In the present study, we sought to (a) identity distinctive profiles of COVID-related lifestyle disruptions experienced by YYA, (b) investigate sociodemographic characteristics correlates of profile membership, and (c) examine the extent to which profile membership was prospectively associated with changes in depressive and anxiety symptoms. Hypothesis were tested using latent profile analysis with data from 1055 YYA collected across two time-points, 6-months apart. Results produced a three-class model: low- (11%), moderate- (61%), and high-levels of (28%) disruption. Members of the high levels of disruption group were more likely to identify as Black or Latinx American, bisexual/pansexual, or as transgender or gender diverse in comparison to the low levels of disruption group. Inclusion in the high levels of disruption group was associated with increases in depressive and anxiety symptoms from T1 to T2. YYA from multiple marginalize communities (i. e. those who identified as both racial/ethnic and sexual/gender minorities) experienced the greatest levels of lifestyle disruption related to COVID-19. Consequently, disruptive effects of the COVID-19 pandemic prospectively eroded their mental health. YYA are in urgent need of developmentally appropriate resources to effectively recovery from the pandemic.

Associations of polygenic risk scores for smoking heaviness and lifetime cannabis use with tobacco and cannabis co-use trajectories among African Americans

BACKGROUND

We aimed to identify distinct trajectories of tobacco, cannabis, and their co-use among African Americans, and to investigate whether these patterns were associated with polygenic risk scores (PRS) for tobacco and cannabis use.

METHOD

Participants (N=428 participants; 50.9% male) were initially recruited for an elementary school-based prevention in a Mid-Atlantic city when they were in first grade. From ages 14-26, participants reported on their frequency of tobacco and cannabis use in the past year during annual assessments. DNA was collected from participants at age 21. PRS for smoking heaviness (i.e., cigarettes per day) and lifetime cannabis use were created based on genome-wide association study results derived from Liu et al. (2019) and Pasman et al. (2018), respectively.

RESULTS

We identified five distinct trajectories of tobacco and cannabis co-use, including (1) Low Tobacco and Cannabis Use, (2) Adolescent Limited Tobacco and Cannabis Use, (3) Experimental Cannabis, Young Adult Increasing Tobacco, (4) Experimental Tobacco, Young Adult Increasing Cannabis, and (5) High, Chronic Tobacco and Cannabis Use. Compared to the Low Tobacco and Cannabis Use subgroup, individuals in the High, Chronic Tobacco and Cannabis Use subgroup had greater PRS for smoking heaviness, and individuals in the Experimental Cannabis, Young Adult Increasing Tobacco subgroup had higher PRS for lifetime cannabis use.

CONCLUSIONS

Polygenic risk for lifetime cannabis use and smoking heaviness is associated with the developmental progression of tobacco and cannabis co-use among African Americans, furthering knowledge on the etiology of co-use in this population.

The genetic aetiology of cannabis use: from twin models to genome-wide association studies and beyond

Cannabis is among the most widely consumed psychoactive substances worldwide. Individual differences in cannabis use phenotypes can partly be explained by genetic differences. Technical and methodological advances have increased our understanding of the genetic aetiology of cannabis use. This narrative review discusses the genetic literature on cannabis use, covering twin, linkage, and candidate-gene studies, and the more recent genome-wide association studies (GWASs), as well as the interplay between genetic and environmental factors. Not only do we focus on the insights that these methods have provided on the genetic aetiology of cannabis use, but also on how they have helped to clarify the relationship between cannabis use and co-occurring traits, such as the use of other substances and mental health disorders. Twin studies have shown that cannabis use is moderately heritable, with higher heritability estimates for more severe phases of use. Linkage and candidate-gene studies have been largely unsuccessful, while GWASs so far only explain a small portion of the heritability. Dozens of genetic variants predictive of cannabis use have been identified, located in genes such as CADM2, FOXP2, and CHRNA2. Studies that applied multivariate methods (twin models, genetic correlation analysis, polygenic score analysis, genomic structural equation modelling, Mendelian randomisation) indicate that there is considerable genetic overlap between cannabis use and other traits (especially other substances and externalising disorders) and some evidence for causal relationships (most convincingly for schizophrenia). We end our review by discussing implications of these findings and suggestions for future work.

Cannabis use in college: Genetic predispositions, peers, and activity participation

BACKGROUND

Among adult college students in the US, cannabis use is common and associated with considerable negative consequences to health, cognition, and academic functioning, underscoring the importance of identifying risk and protective factors. Cannabis use is influenced by genetic factors, but genetic risk is not determinative. Accordingly, it is critical to identify environments that reduce risk among those who are at elevated genetic risk. This study examined the impact of polygenic scores for cannabis initiation, various forms of social activity participation, and peer deviance on recent cannabis use. Our aim was to test whether these environments moderate genetic risk for cannabis use.

METHODS

Data came from a longitudinal sample of undergraduate college students of European American (EA; NEA = 750) and African American (AA; NAA = 405) ancestry. Generalized estimating equations with a logit link function were used to examine main effects and two-way interactions.

RESULTS

Engagement with church activities was associated with lower probability of cannabis use. Peer deviance was associated with higher probability of cannabis use. Engagement with community activities moderated the influence of the polygenic risk score in the EA sample, such that PRS was associated with recent cannabis use among those who never engaged in community activities. This effect did not replicate in AAs, which may have been due to the portability of PRS based on EA discovery samples.

CONCLUSIONS

Results suggest that community activities may limit the influence of genetic risk, as associations between PRS and cannabis use were only observed among individuals who never engaged in community activities.

Cannabis use disorders among adults in the United States during a time of increasing use of cannabis

BACKGROUND

Using U.S. National Surveys on Drug Use and Health (NSDUH) data, researchers found that prevalence of cannabis use among adults increased in recent years, but prevalence of DSM-IV cannabis use disorder (CUD) was stable. Examining trends of all individual CUD criteria and of CUD severity may elucidate reasons for the lack of increases in CUD.

METHODS

Data were from 749,500 persons aged 18 or older who participated in the 2002-2017 NSDUH. Descriptive analyses and logistic regressions were applied.

RESULTS

Among adults during 2002-2017, past-year prevalence of DSM-IV CUD remained stable at 1.5% to 1.4%, but cannabis use increased from 10.4% to 15.3%, daily/near daily use increased from 1.9% to 4.2%, and mild DSM-5 CUD increased from 1.4% to 1.9%. Among adult cannabis users, past-year prevalence of DSM-IV CUD decreased from 14.8% to 9.3%, daily/near daily use increased from 18.0% to 27.2%, and DSM-5 moderate (4-5 criteria) and severe (6+ criteria) CUD decreased from 4.3% to 3.1% and from 2.4% to 1.3%, respectively. Examining trends in individual CUD criteria during 2002-2017 among adults overall revealed increases in two criteria (tolerance; spending a lot of time getting/using cannabis or getting over cannabis effects) and decreases/no changes in other criteria; among adult cannabis users, there was no change in one criterion (tolerance) and decreases in other criteria.

CONCLUSIONS

DSM-5's single dimension CUD measure may be more sensitive to diagnosis prevalence changes than the separate DSM-IV cannabis dependence and abuse categories. Future diagnostic approaches to assessing CUD may benefit from quantitatively oriented criteria.

Associations between personality disorders and cannabis use and cannabis use disorder: a population-based twin study

BACKGROUND AND AIMS

Individual differences in DSM-IV personality disorders (PDs) are associated with increased prevalence of substance use disorders. Our aims were to determine which combination of PDs trait scores best predict cannabis use (CU) and cannabis use disorder (CUD), and to estimate the size and significance of genetic and environmental risks in PD traits shared with CU and CUD.

DESIGN

Linear mixed-effects models were used to identify PD traits for inclusion in twin analyses to explore the genetic and environmental associations between the traits and cannabis use.

SETTING

Cross-sectional data were obtained from Norwegian adult twins in a face-to-face interview in 1999-2004 as part of a population-based study of mental health.

PARTICIPANTS

Subjects were 1419 twins (μage  = 28.2 years, range = 19-36) from the Norwegian Institute of Public Health Twin Panel with complete PD and cannabis data.

MEASUREMENTS

PD traits were assessed using DSM-IV criteria. Life-time CU and CUD were based on DSM-IV abuse and dependence criteria, including withdrawal and craving.

FINDINGS

After adjusting for age and sex, antisocial [β = 0.23, 95% confidence interval (CI) = 0.19-0.28] and borderline PDs (β = 0.20, 95% CI = 0.14-0.26) were associated strongly with CU. Antisocial (β = 0.26, 95% CI = 0.21-0.31) and borderline PDs (β = 0.12, 95% CI = 0.06-0.18) were also linked strongly to CUD. Genetic risks in antisocial and borderline PD traits explained 32-60% of the total variance in CU and CUD. Dependent and avoidant PDs explained 11 and 16% of the total variance in CU and CUD, respectively.

CONCLUSIONS

Individual differences in the liability to cannabis use and cannabis use disorder appear to be linked to genetic risks correlated with antisocial and borderline personality disorder traits.

Concordance of ICD-11 and DSM-5 definitions of alcohol and cannabis use disorders: a population survey

The proposed criteria for alcohol and cannabis use disorders in the 11th edition of ICD (ICD-11) will be presented to the World Health Assembly in 2017, but the beta-phase descriptions have been released. We compared them with those in the tenth edition (ICD-10) and the American Psychiatric Association's DSM fourth edition (DSM-IV) and fifth edition (DSM-5), in a nationally representative sample of adult Australians. Disorders were assessed with the WHO World Mental Health Composite International Diagnostic Interview. The proportions classified as being dependent on alcohol and cannabis were similar with ICD-10, ICD-11, and DSM-IV, whereas for DSM-5, the proportion of lifetime users meeting the criteria for moderate to severe use (most comparable to dependence in the other systems) was far higher. We assessed whether criteria for alcohol and cannabis use described unidimensional syndromes for each, and all definitions seemed to do so. Classification of alcohol and cannabis use disorders, although simplified in ICD-11, was in almost perfect agreement with the classifications of ICD-10 and DSM-IV. With DSM-5, use disorder seemed to capture a different aspect of problematic use and selected a different group of individuals from the other systems. How the newest definitions will become used remains to be seen. The choice of classification might depend on the clinical population of interest.