Age at first use and later substance use disorder: Shared genetic and environmental pathways for nicotine, alcohol, and cannabis

Age- and sex-driven alterations in alcohol consumption patterns: Role of brain ethanol metabolism and the opioidergic system in the nucleus accumbens

Alcohol consumption leads to significant neurochemical and neurobiological changes, contributing to the development of alcohol use disorders (AUDs), which exhibit sex- and age-dependent variations according to clinical data. However, preclinical studies often neglect these factors when investigating alcohol consumption patterns. In this study, we present data on male and female rats continuously exposed to a 20 % ethanol solution for one month. The animals were divided into two groups based on their age at the onset of drinking (8 and 12 weeks old). Interestingly, 12-week-old males consumed significantly less alcohol than both 12-week-old females and 8-week-old animals, indicating that alcohol consumption patterns vary with sex and age in our model. Additionally, to advance in the study of the neurobiological alterations induced by ethanol intake in the mesocorticolimbic system (MCLS) that may participate in its reinforcing properties and the maintenance of alcohol drinking behavior, we measured catalase activity-an enzyme involved in alcohol metabolism and related to ethanol reinforcement-in the nucleus accumbens (NAc) of these animals. Furthermore, we measured the levels of mu (MOR), kappa (KOR), delta (DOR), and nociceptin (NOP) opioid receptors in the NAc, as the endogenous opioidergic system plays a pivotal role in regulating the MCLS and alcohol reinforcement. MOR levels were lower in high alcohol-consuming groups (8-week-old males and all females). Both DOR and NOP levels decreased with age, whereas KOR levels remained unchanged. Our findings suggest that the age at onset of alcohol consumption critically influences alcohol intake, particularly in males. Additionally, females consistently showed higher alcohol intake regardless of age, highlighting inherent sex-specific differences. The dynamic changes in catalase activity and opioid receptor expression suggest the involvement of these factors in modulating alcohol consumption.

A Bivariate Twin Study of Lifetime cannabis Initiation and Lifetime Regular Tobacco Smoking Across Three Different Countries

Regular cigarette smoking and cannabis consumption are strongly positively related to each other, yet few studies explore their underlying variation and covariation. We evaluated the genetic and environmental decomposition of variance and covariance of these two traits in twin data from three countries with different social norms and legislation. Data from the Netherlands Twin Register, FinnTwin12/16, and the Minnesota Center for Twin Family Research (total N = 21,617) were analyzed in bivariate threshold models of lifetime regular smoking initiation (RSI) and lifetime cannabis initiation (CI). We ran unstratified models and models stratified by sex and country. Prevalence of RSI was lowest in the Netherlands and prevalence of CI was highest in Minnesota. In the unstratified model, genetic (A) and common environmental factors (C) contributed substantially to the liabilities of RSI (A = 0.47, C = 0.34) and CI (A = 0.28, C = 0.51). The two liabilities were significantly phenotypically (rP = 0.56), genetically (rA = 0.74), and environmentally correlated in the unstratified model (rC = 0.47and rE = 0.48, representing correlations between common and unique environmental factors). The magnitude of phenotypic correlation between liabilities varied by country but not sex (Minnesota rP ~ 0.70, Netherlands rP ~ 0.59, Finland rP ~ 0.45). Comparisons of decomposed correlations could not be reliably tested in the stratified models. The prevalence and association of RSI and CI vary by sex and country. These two behaviors are correlated because there is genetic and environmental overlap between their underlying latent liabilities. There is heterogeneity in the genetic architecture of these traits across country.

Kratom (Mitragyna speciosa) Use and Mental Health: A Systematic Review and Multilevel Meta-Analysis

INTRODUCTION

Kratom (Mitragyna speciosa) is a medicinal tree native to Southeast Asia. The present multilevel meta-analysis describes the association between kratom use and the positive and negative indicators of mental health.

METHODS

A total of thirty-six articles were included in the meta-analysis to examine the associations, using a random-effects model.

RESULTS

The pooled effect size showed a very small positive association between kratom use and negative indicators of mental health {r = 0.092, 95% confidence interval (CI) = [0.020, 0.164], p < 0.05}, while no significant association was found with positive indicators of mental health (r = -0.031, 95% CI = [-0.149, 0.087], p > 0.05). Pooled effect sizes of specific mental health outcomes indicated that kratom use showed only a small positive correlation with externalizing disorders (r = 0.201, 95% CI = [0.107, 0.300], p < 0.001). No significant association was found between kratom use and quality of life (r = 0.069, 95% CI = [-0.104, 0.242], p > 0.05) and internalizing disorders (r = -0.001, 95% CI = [-0.115, 0.095], p > 0.05). Multilevel moderator analysis showed that the pooled effect size of the association between kratom use and substance use disorder was stronger in Malaysia (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001), and with the mean age (β1 = -0.035, 95% CI = [-0.055, -0.014], p = 0.003), and the drug profile of those who were not co-using other drugs (r = 0.347, 95% CI = [0.209, 0.516], p < 0.001).

CONCLUSION

The meta-analysis supports the kratom instrumentalization concept, in that a positive gain from kratom consumption can be achieved without any significant adverse associations with mental health.

Generalized genetic liability to substance use disorders

Lifetime and temporal co-occurrence of substance use disorders (SUDs) is common and compared with individual SUDs is characterized by greater severity, additional psychiatric comorbidities, and worse outcomes. Here, we review evidence for the role of generalized genetic liability to various SUDs. Coaggregation of SUDs has familial contributions, with twin studies suggesting a strong contribution of additive genetic influences undergirding use disorders for a variety of substances (including alcohol, nicotine, cannabis, and others). GWAS have documented similarly large genetic correlations between alcohol, cannabis, and opioid use disorders. Extending these findings, recent studies have identified multiple genomic loci that contribute to common risk for these SUDs and problematic tobacco use, implicating dopaminergic regulatory and neuronal development mechanisms in the pathophysiology of generalized SUD genetic liability, with certain signals demonstrating cross-species and translational validity. Overlap with genetic signals for other externalizing behaviors, while substantial, does not explain the entirety of the generalized genetic signal for SUD. Polygenic scores (PGS) derived from the generalized genetic liability to SUDs outperform PGS for individual SUDs in prediction of serious mental health and medical comorbidities. Going forward, it will be important to further elucidate the etiology of generalized SUD genetic liability by incorporating additional SUDs, evaluating clinical presentation across the lifespan, and increasing the granularity of investigation (e.g., specific transdiagnostic criteria) to ultimately improve the nosology, prevention, and treatment of SUDs.

Evidence for sex differences in the impact of cytochrome P450 genotypes on early subjective effects of cannabis

Early positive subjective effects of cannabis predict the development of cannabis use disorder (CUD). Genetic factors, such as the presence of cytochrome P450 genetic variants that are associated with reduced Δ9-tetrahydrocannabinol (THC) metabolism, may contribute to individual differences in subjective effects of cannabis. Young adults (N = 54) with CUD or a non-CUD substance use disorder (control) provided a blood sample for DNA analysis and self-reported their early (i.e., effects upon initial uses) and past-year positive and negative subjective cannabis effects. Participants were classified as slow metabolizers if they had at least one CYP2C9 or CYP3A4 allele associated with reduced activity. Though the CUD group and control group did not differ in terms of metabolizer status, slow metabolizer status was more prevalent among females in the CUD group than females in the control group. Slow metabolizers reported greater past year negative THC effects compared to normal metabolizers; however, slow metabolizer status did not predict early subjective cannabis effects (positive or negative) or past year positive effects. Post-hoc analyses suggested males who were slow metabolizers reported more negative early subjective effects of cannabis than female slow metabolizers. Other sex-by-genotype interactions were not significant. These initial findings suggest that genetic variation in CYP2C9 and CYP3A4 may have sex-specific associations with cannabis-related outcomes. Slow metabolizer genes may serve as a risk factor for CUD for females independent of subjective effects. Male slow metabolizers may instead be particularly susceptible to the negative subjective effects of cannabis.

A survey of educator perspectives toward teaching harm reduction cannabis education

INTRODUCTION

Substance use is common among youth which can adversely affect youth health. Despite the legalization of cannabis in Canada and much of the United States, there is a lack of harm reduction cannabis education in schools. In addition, educators may not feel prepared to teach students about cannabis.

METHODS

A cross-sectional survey explored educator perceptions toward teaching harm reduction substance use education to students in grades 4-12. Data analysis included descriptive statistics to evaluate demographic variables, ANOVAs to identify subgroup differences, and inductive thematic analysis to establish themes from open-ended responses. From the sample of 170 educators, the majority were female (77%) and worked as classroom teachers (59%).

RESULTS

Ninety-two percent of educators felt harm reduction was an effective approach to substance use education, and 84% stated that they would feel comfortable teaching cannabis harm reduction education to students. While 68% of educators believed they would be able to recognize if a student was under the influence of cannabis, only 39% felt certain about how to respond to student cannabis use, and just 8% felt that their current teacher training allowed them to intervene and prevent cannabis-related harms. Most educators (89%) expressed interest in harm reduction training, particularly interactive training (70%) and instructor-led lessons (51%). Online curriculum resources were preferred by 57%. Responses differed by gender and age group, with females of any age and educators under 40 reporting greater support of harm reduction approaches and more interest in training.

CONCLUSION

Educators expressed considerable support for harm reduction substance use education, but many felt unprepared to address this topic with students. The findings identified a need for educator training on harm reduction substance use education, so that educators can help students make informed choices around substance use, thereby promoting youth health and safety.

Use of tobacco and other illicit drugs among adolescent boys and young men in Kampala, Uganda: A result of low parental attention?

INTRODUCTION

Although the use of illicit drugs is common among young people, limited data exists on the use of illicit drugs among adolescent boys and young men (ABYM). We assessed the use of tobacco, marijuana and khat among ABYM to inform the design of harm-reduction interventions.

METHODS

This secondary analysis uses data from a formative study conducted among 2,500 ABYM across the five divisions of Kampala between July and August 2020. Survey questions were adopted from the Global Youth Tobacco Survey and Global School-based Student Health Survey. We computed proportions of ABYM that had ever used any form of tobacco or marijuana or khat in the past year and the proportion that had used any of these products in the past 30 days (i.e. 'current users'). In a sub-group analysis, we assessed if any patterns existed between ABYM's use of illicit drugs and selected parental attention attributes.

RESULTS

Of 2,500 ABYM, 47.3% (n = 1,182) were aged 15-19 years. Overall, 16.4% (n = 410) reported past-year use of tobacco products while 11.6% (n = 289) and 10.5% (n = 263) reported past-year use of marijuana and khat, respectively. Current use of any illicit drugs was higher among past-year khat (46%, n = 133) and marijuana users (36.9%, n = 97) than past-year tobacco users (4%, n = 17). Current use of any illicit drugs was higher among out-of-school than in-school ABYM and increased with increasing age and education levels. However, parental attention was lower among out-of-school than in-school ABYM and decreased with increasing age and education levels.

CONCLUSION

Use of illicit drugs is common among ABYM and increased with age and education levels but parental attention among current illicit drug users decreased with increasing age and education levels. These findings suggest that interventions intended to improve parental attention among illicit drug users may help to reduce the prevalence of illicit drug use among ABYM.

Patterns of substance use among adolescents in and out of foster care: An analysis of linked health and child welfare administrative data

BACKGROUND

Young adults with a history of foster care have higher risk for substance use disorders. Social systems can deliver substance use prevention to youth; however, the timing of intervention delivery and how needs differ for youth in foster care are unclear.

OBJECTIVE

To compare initiation and rates of substance use among adolescents in foster care to demographically similar adolescents never in foster care as identified by the healthcare system, and identify factors associated with increased substance use.

PARTICIPANTS AND SETTING

Youth in foster care (n = 2787, ages 10-20, inclusive) and demographically matched youth never in foster care (n = 2787) were identified using linked child welfare and electronic health records from a single pediatric children's hospital and county over a five-year period (2012-2017).

METHODS

All healthcare encounters were reviewed and coded for substance use by type (alcohol, tobacco, cannabis, other). Age of first reported or documented substance use was also captured. Demographic and child welfare information was extracted from administrative records. Survival and logistic regression models were estimated.

RESULTS

In adjusted models, youth in foster care initiated substance use at earlier ages (HR = 2.50, p < .01) and had higher odds of engaging in use (AOR = 1.54; p < .01) than youth never in care. By age 12, substance use initiation was more likely while youth were in foster care than when they were not in foster care (HR = 1.42, p < .01). Placement stability and family care settings reduced odds of lifetime substance use.

CONCLUSIONS

Foster care placement is associated with substance use. Screening may be important for prevention.

Evaluation of the Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Questionnaire and its Relations to Cannabis-Related Problems

Cannabis use and the prevalence of cannabis use disorder (CUD) among emerging adults are on the rise. Several indicators of cannabis use (e.g., quantity, frequency) as they relate to negative outcomes have been posited in the extant literature. Despite research examining links between indicators and cannabis outcomes, few assessments of cannabis use indicators exist. The Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use Inventory (DFAQ-CU) was developed to assess cannabis use across a range of factors. However, the factor structure of the DFAQ-CU has not been replicated. Further, the DFAQ-CU was modeled using reflective strategies despite formative strategies being conceptually appropriate. The present study utilized principal components analyses (PCA) and principal axis factoring (PAF) to evaluate the structure of the DFAQ-CU. PCA yielded a four-component solution; PAF resulted in a five-factor solution. Linear regression found significant relations between PCA components and PAF factors with CUD symptoms and cannabis-related problems; however, effect sizes were larger for the PAF suggesting possible misdisattenuation. The PCA components demonstrated evidence of discriminant and convergent validity with measures of cannabis and alcohol behavior. The study informs research and clinical work through the refinement of cannabis use assessment and enhancing our understanding of the importance of model selection.

A scoping review of smoking cessation pharmacogenetic studies to advance future research across racial, ethnic, and ancestral populations

Abstinence rates among smokers attempting to quit remain low despite the wide availability and accessibility of pharmacological smoking cessation treatments. In addition, the prevalence of cessation attempts and abstinence differs by individual-level social factors such as race and ethnicity. Clinical treatment of nicotine dependence also continues to be challenged by individual-level variability in effectiveness to promote abstinence. The use of tailored smoking cessation strategies that incorporate information on individual-level social and genetic factors hold promise, although additional pharmacogenomic knowledge is still needed. In particular, genetic variants associated with pharmacological responses to smoking cessation treatment have generally been conducted in populations with participants that self-identify as White race or who are determined to be of European genetic ancestry. These results may not adequately capture the variability across all smokers as a result of understudied differences in allele frequencies across genetic ancestry populations. This suggests that much of the current pharmacogenetic study results for smoking cessation may not apply to all populations. Therefore, clinical application of pharmacogenetic results may exacerbate health inequities by racial and ethnic groups. This scoping review examines the extent to which racial, ethnic, and ancestral groups that experience differences in smoking rates and smoking cessation are represented in the existing body of published pharmacogenetic studies of smoking cessation. We will summarize results by race, ethnicity, and ancestry across pharmacological treatments and study designs. We will also explore current opportunities and challenges in conducting pharmacogenomic research on smoking cessation that encourages greater participant diversity, including practical barriers to clinical utilization of pharmacological smoking cessation treatment and clinical implementation of pharmacogenetic knowledge.

The risk assessment of relapse among newly enrolled participants in methadone maintenance treatment: A group-LASSO based Bayesian network study

Background

Relapse is a great barrier to improving the effectiveness of methadone maintenance treatment (MMT). Participants with different treatment durations could vary in their compliance with MMT, which may lead to different levels of relapse risk. This study aims to identify the risk factors for relapse and assess the relapse risk of MMT participants of different treatment durations.

Method

This retrospective study used data collected from seven MMT clinics in Guangdong Province, China, from January 2010 to April 2017. Newly enrolled participants who received 6 (n = 903) and 12 (n = 710) months of consecutive treatment with complete data were included. We selected significant risk factors for relapse through the group lasso regression and then incorporated them into Bayesian networks to reveal relationships between factors and predict the relapse risk.

Results

The results showed that participants who received 6-month treatment had a lower relapse rate (32.0%) than those of 12-month treatment (39.0%, P < 0.05). Factors including personal living status and daily methadone dose were only influential to those who received the 6-month treatment. However, age, age at the initial drug use, HIV infection status, sexual behaviors, and continuous treatment days were common factors of both durations. The highest relapse risk for those after the 6-month treatment was inferred as 66.7% while that of the 12-month treatment was 83.3%. Farmers and those who have high accessibility to MMT services may require additional attention.

Conclusion

It is necessary to implement targeted interventions and education based on the treatment durations of participants to decrease the relapse rate. Meanwhile, those about HIV/sexually transmitted infection prevention and anti-narcotics should be held in the whole process.

Parental divorce and nicotine addiction in Lebanese adolescents: the mediating role of child abuse and bullying victimization

BACKGROUND

Lebanon ranks first amongst Middle-Eastern countries in terms of cigarette and waterpipe smoking. Understanding the mediating factors for nicotine addiction in adolescents who have experienced parental divorce is vital to take effective measures that will help in lowering its prevalence in our community. The objective of this study was to investigate the association between the increasingly concerning parental divorce and nicotine addiction in Lebanese adolescents while taking into consideration the plausible mediating effect of abuse and bullying victimization.

METHODS

This was a cross-sectional survey-based study that was conducted between January and May 2019. A total of 1810 adolescents aged between 14 and 17 years was enrolled from 16 Lebanese schools. Linear regressions taking the cigarette and waterpipe dependence scores as dependent variables were conducted respectively, using the SPSS software. PROCESS v3.4 model 4 was used for mediation analysis.

RESULTS

A total of 11.9% of the enrolled participants had divorced parents. Higher cigarette and waterpipe dependence were found in adolescents whose parents were divorced compared to those living together. More child psychological abuse, having divorced parents vs living together, and more child physical abuse were significantly associated with higher cigarette dependence. More child psychological and physical, and having divorced parents vs living together were significantly associated with more waterpipe dependence. In addition, all forms of abuse (except neglect) and bullying victimization had a partially mediating effect in the associations between parental divorce and nicotine dependence (cigarette and waterpipe) in adolescents.

CONCLUSION

This study results may serve as a first step towards enrolling separated parents and their children in special prevention programs to help them create a protective and supportive environment.

Effects of the Fyn kinase inhibitor saracatinib on ventral striatal activity during performance of an fMRI monetary incentive delay task in individuals family history positive or negative for alcohol use disorder. A pilot randomised trial

Altered striatal regulation of the GluN2B subunit of N-methyl-D-aspartate (NMDA) glutamate receptors by the Fyn/Src family of protein tyrosine kinases has been implicated in animal alcohol consumption. Previously, we have described differences between individuals positive (FHP) and negative (FHN) for familial alcohol use disorder (AUD) in the ventral striatal (VS) activation associated with monetary incentive delay task (MIDT) performance during functional magnetic resonance imaging (fMRI). Here, we used AZD0530 (saracatinib), a centrally active Fyn/Src inhibitor to probe the role of Fyn/Src regulation of NMDA receptors (NMDAR) in VS activation differences between FHP and FHN individuals during fMRI MIDT performance. We studied 21 FHN and 22 FHP individuals, all without AUD. In two sessions, spaced 1 week apart, we administered 125 mg of saracatinib or placebo in a double-blind manner, prior to measuring VS signal during fMRI MIDT performance. MIDT comprises reward prospect, anticipation, and outcome phases. During the initial (prospect of reward) task phase, there was a significant group-by-condition interaction such that, relative to placebo, saracatinib reduced VS BOLD signal in FHP and increased it in FHN individuals. This study provides the first human evidence that elevated signaling in striatal protein kinase A-dependent pathways may contribute to familial AUD risk via amplifying the neural response to the prospect of reward. As Fyn kinase is responsible for NMDAR upregulation, these data are consistent with previous evidence for upregulated NMDAR function within reward circuitry in AUD risk. These findings also suggest a possible therapeutic role for Src/Fyn kinase inhibitors in AUD risk.

Subtypes of inhibitory and reward activation associated with substance use variation in adolescence: A latent profile analysis of brain imaging data

The present study identified subgroups based on inhibitory and reward activation, two key neural functions involved in risk-taking behavior, and then tested the extent to which subgroup differences varied by age, sex, behavioral and familial risk, and substance use. Participants were 145 young adults (18-21 years old; 40.0% female) from the Michigan Longitudinal Study. Latent profile analysis (LPA) was used to establish subgroups using task-based brain activations. Demographic and substance use differences between subgroups were then examined in logistic regression analyses. Whole-brain task activations during a functional magnetic resonance imaging go/no-go task and monetary incentive delay task were used to identify beta weights as input for LPA modeling. A four-class model showed the best fit with the data. Subgroups were categorized as: (1) low inhibitory activation/moderate reward activation (39.7%), (2) moderate inhibitory activation/low reward activation (22.7%), (3) moderate inhibitory activation/high reward activation (25.2%), and (4) high inhibitory activation/high reward activation (12.4%). Compared with the other subgroups, Class 2 was older, less likely to have parental alcohol use disorder, and had less alcohol use. Class 4 was the youngest and had greater marijuana use. Classes 1 and 3 did not differ significantly from the other subgroups. These findings demonstrate that LPA applied to brain activations can be used to identify distinct neural profiles that may explain heterogeneity in substance use outcomes and may inform more targeted substance use prevention and intervention efforts.

Sex Differences in the Brain Transcriptome Related to Alcohol Effects and Alcohol Use Disorder

There is compelling evidence that sex and gender have crucial roles in excessive alcohol (ethanol) consumption. Here, we review some of the data from the perspective of brain transcriptional differences between males and females, focusing on rodent animal models. A key emerging transcriptional feature is the role of neuroimmune processes. Microglia are the resident neuroimmune cells in the brain and exhibit substantial functional differences between males and females. Selective breeding for binge ethanol consumption and the impacts of chronic ethanol consumption and withdrawal from chronic ethanol exposure all demonstrate sex-dependent neuroimmune signatures. A focus is on resolving sex-dependent differences in transcriptional responses to ethanol at the neurocircuitry level. Sex-dependent transcriptional differences are found in the extended amygdala and the nucleus accumbens. Telescoping of ethanol consumption is found in some, but not all, studies to be more prevalent in females. Recent transcriptional studies suggest that some sex differences may be due to female-dependent remodeling of the primary cilium. An interesting theme appears to be developing: at least from the animal model perspective, even when males and females are phenotypically similar, they differ significantly at the level of the transcriptome.

Familial perceptions of appropriate treatment types and goals for a family member who has opioid use disorder

BACKGROUND

Despite effective, evidence-based medications for opioid use disorder (MOUD), these treatments remain underutilized. This may be due to multiple reasons. Family members may impact patient decision-making when choosing an opioid use disorder (OUD) treatment. While there has been work on patient preferences and attitudes towards opioid use disorder (OUD) treatment, to date, there has been minimal work assessing the attitudes of family member towards OUD treatment and recovery.

METHODS

Participants were ≥ 18 years of age and endorsed having a first-degree family member with past-year treatment for OUD. Participants were recruited via online crowdsourcing and were asked a number of questions regarding their desired outcomes for OUD treatment, and their familiarity, approval, and perceived effectiveness of various OUD treatment options.

RESULTS

The most commonly reported desired treatment outcome (50 %) was for family members to never use any kind of opioid, including maintenance therapies or opioid analgesics. Mean familiarity ratings for MOUD (rated 0-100) were relatively low, with naltrexone being the least familiar (32.3). Among those who endorsed a familiarity rating of at least 30 for a given treatment, mean approval and effectiveness ratings were relatively low-buprenorphine (approve 55.1; effective 54.1), methadone (approve 51.9; effective 49.3), naltrexone (approve 61.6; effective 55.9). These were lower than approval and effectiveness ratings for all non-MOUD treatments queried.

CONCLUSIONS

These findings highlight a need for clinicians and researchers to engage with family members' regarding their preferences and understanding of treatment, and to better understand how this might impact patient engagement with treatment.

Neurochemical and Behavioral Characterization after Acute and Repeated Exposure to Novel Synthetic Cannabinoid Agonist 5-MDMB-PICA

Since the early 2000s, herbal mixtures containing synthetic cannabinoids (SCs), broadly known as Spice/K2, have been marketed as a legal marijuana surrogate and have become very popular among adolescents. Adolescence is a critical period of development, which is associated with an increased vulnerability to the central effects of drugs. Despite growing concerns about the negative effects of the use of SCs, newly synthetized compounds are increasingly detected in drugs seized by the authorities, posing a serious threat to public health. 5F-MDMB-PICA has been recently detected and classified as a highly potent agonist of CB1 and CB2 cannabinoid receptors. Here, we first investigated the rewarding properties of 5F-MDMB-PICA in C57BL/6 adolescent and adult mice by in vivo brain microdialysis. Data showed that acute administration of a selected dose of 5F-MDMB-PICA (0.01 mg/kg i.p.) stimulates the release of dopamine in the nucleus accumbens shell of adolescent, but not of adult, mice. To further investigate the consequences of repeated exposure to this dose of 5F-MDMB-PICA, a separate group of adolescent mice was treated for 14 consecutive days and evaluated for behavioral abnormalities at adulthood, starting from 7 days after drug discontinuation. Data showed that this group of adult mice displayed an anxiety-like and compulsive-like state as revealed by an altered performance in the marble burying test. Our study suggests an alarming vulnerability of adolescent mice to the effects of 5F-MDMB-PICA. These findings provide a useful basis for understanding and evaluating both early and late detrimental effects that may derive from the use of SCs during adolescence.

Transitions in alcohol use over time: a survival analysis

Background

The current study examined the predictors of the onset of alcohol use as well as predictors of remission and relapse, both from heavy drinking and from alcohol dependence. Similarities and differences in both clinical and psychosocial predictors across the transitions were examined.

Methods

A sample of men from the Vietnam Era Twin Registry (N = 1769) completed an assessment of lifetime drinking history, which allowed age markers for starting and stopping different drinking patterns. The men also completed various assessments regarding personality, alcohol motives, and psychiatric diagnoses. Survival analyses were used to examine the predictors of the three transitions of onset, remission, and relapse for the phenotypes of heavy drinking and of alcohol dependence, censoring the individuals who had not yet experienced an event.

Results

As expected, predictors of onset for drinking, heavy drinking, and alcohol dependence were largely consistent and included externalizing symptomology, nicotine dependence, and cotwin history of drinking as risk factors. Predictors of remission from heavy drinking, somewhat similarly to remission from alcohol dependence, included the risk factor of externalizing disorders but also, as predicted, included more risk and protective factors in the psychosocial realm that were not predictors of onset. Contrary to our prediction, relapse to heavy drinking and alcohol dependence were predicted largely by unique psychosocial risk and protective factors including social and coping motives.

Conclusion

Current findings extend the findings of past research to remission and relapse in the later decades of life and have implications for treatment of alcohol use problems.

Parent hazardous drinking and their children's alcohol use in early and mid-adolescence: prospective cohort study

BACKGROUND

Why adolescents' drinking is associated with their parents' drinking remains unclear. We examined associations in a prospective cohort study, adjusting for socio-demographic characteristics and family factors.

METHODS

We recruited 1927 children from grade 7 classes (mean age 13 years), and one of their parents, in three Australian states, contacted participants annually from 2010 to 2014, and analysed data from assessments at ages 13, 14, 15 and 16 years. We used the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) subscale to identify hazardous drinking in parents (score ≥5) and children (score ≥3) and constructed mixed-effect logistic regression models, accounting for clustering within school and adjusting for likely confounders. We evaluated the sensitivity of estimates by imputing missing values assuming the data were missing at random vs. missing not at random.

RESULTS

Parent hazardous drinking predicted mid-adolescent hazardous drinking, e.g. 15 years olds whose parents [adjusted odds ratio (aOR) 2.00; 95% confidence interval 1.51-2.64] or parents' partners (aOR 1.94; 1.48-2.55) were hazardous drinkers had higher odds of being hazardous drinkers at age 16. The magnitude of univariate associations changed little after adjusting for covariates, and sensitivity analyses confirmed the robustness of the association, across a wide range of assumptions about the missing data.

CONCLUSIONS

The associations between parents' and their adolescent children's hazardous drinking are unlikely to be due to confounding by socio-demographic and family factors. Parents should be encouraged, and supported by public policy, to reduce their own alcohol consumption in order to reduce their children's risk of becoming hazardous drinkers.

Does Drinking Initiation of Young Thai Drinkers Vary Over Time and Generation? Results of the National Surveys on Tobacco and Alcohol Consumption of the Thai Populations 2007 to 2017

BACKGROUND

Early age at drinking initiation may be one factor responsible for underage drinking in Thailand and this may be affected by cultural and generational changes over certain periods of time. This study aimed to explore the effects of time period and generation on drinking onset of young Thai drinkers in the past decade.

METHODS

We analyzed data from a total of 60,018 Thais aged 15 to 24 years from 4 national surveys conducted in 2007, 2011, 2014, and 2017. We used multilevel and event history analysis to examine the effects of period (survey year) and cohort (birth year of participants), adjusted for sex, age, area of residence, and region on drinking onset.

RESULTS

The overall prevalence of past-year drinking was 23.6 % (95% confidence interval [CI]: 23.2, 23.9) among participants of all surveys. Cox proportional hazards model revealed significantly different probabilities to have initiated drinking between participants of different surveys and birth years, indicating significant period and cohort effects. After adjusting for sex, age, cohort, living region, and area of residence, participants in the 2014 survey had the highest likelihood to have started drinking (hazard ratio [HR]: 1.25 CI: 1.15 to 1.36), compared to the participants of the same age in the 2007 survey while those in the 2011 (HR: 0.89, CI: 0.85, 0.93) and 2017 (HR: 0.63, CI: 0.58, 0.68) surveys had less likelihood. Participants born in 1993 to 2002 (later cohort) had higher probability to have started drinking than those born in 1983 to 1992 (HR: 1.80, CI: 1.69, 1.92).

CONCLUSION

Thai youths of the recent generations living in recent years tend to have a higher probability of initiating drinking than those in the past. Interventions to prevent underage drinking should begin earlier for the young generation.

Role of genetic background in the effects of adolescent nicotine exposure on mesolimbic dopamine transmission

Smoking during adolescence may increase the likelihood to develop nicotine dependence and to abuse other drugs such as cocaine. Despite great efforts to understand underlying neurobiological mechanisms of this progression, less attention has been paid to the role of genetic factors. Here, we investigated the influence of both genetic background and age at first nicotine exposure in the long-lasting effects on mesolimbic dopamine transmission including the increased cocaine-rewarding effect. Mid-adolescent and adult rats of inbred strains Lewis (addiction prone) and Fischer 344 (addiction resistant) were administered nicotine (0.4 mg/kg) or vehicle once daily for 5 days. Changes in dopamine transmission were investigated by in vivo microdialysis and electrophysiology after 30 days of withdrawal, whereas changes in cocaine-rewarding effect were assessed via conditioned place preference paradigm. Nicotine pre-exposure differentially changed mesolimbic dopamine transmission depending on strain and age of pre-exposure. A potentiation of dopamine response to nicotine was observed in nucleus accumbens (NAc) core of both strains and age groups, whereas dopamine response in NAc shell was enhanced exclusively in Lewis rats exposed to nicotine during adolescence. A similar response was observed following cocaine challenge at adulthood. Changes in VTA dopamine cell population and activity were observed only in adolescent nicotine-pretreated Lewis rats, which also showed an increased cocaine-rewarding effect at adulthood. These results highlight the influence of genetic background in the long-lasting effects of nicotine exposure and suggest that exposure during adolescence might increase nicotine and cocaine-rewarding properties in genetically vulnerable individuals, thereby facilitating progression toward dependence.

Individualized approach to primary prevention of substance use disorder: age-related risks

Background

The misuse of legal and illegal substances has led to an increase in substance use disorder (SUD) in the United States. Although primary prevention strategies have been successfully used to target chronic physical diseases, these strategies have been less effective with SUD, given misconceptions of SUD, shortages in behavioral health professionals, and the population-based focus on specific substances. A developmental approach to the identification and primary prevention of SUD that does not fully rely upon behavioral health workers is needed. The purpose of this paper was to examine age related risk factors for developing SUD and present a novel individualized approach to SUD prevention.

Methods

A literature search was conducted to identify risk factors for SUD among children, young adults, adults, and older adults. We searched CINAHL, PsycINFO, and PubMed between the years 1989–2019, and extracted data, analyzing similarities and differences in risk factors across life stages. Broader categories emerged that were used to group the risk factors.

Results

More than 370 articles were found. Across all age groups, risk factors included adverse childhood experiences, trauma, chronic health diseases, environmental factors, family history, social determinants, and grief and loss. Despite the similarities, the contextual factors and life challenges associated with these risks varied according to the various life stages. We proposed an approach to primary prevention of SUD based on risk factors for developing the disease according to different age groups. This approach emphasizes screening, education, and empowerment (SEE), wherein individuals are screened for risk factors according to their age group, and screening results are used to customize interventions in the form of education and empowerment. Given that trained persons, including non-healthcare providers, close to the at-risk individual could conduct the screening and then educate and mentor the individual according to the risk level, the number of people who develop SUD could decrease.

Conclusions

The risk factors for developing SUD vary across the various life stages, which suggests that individualized approaches that do not overtax behavioral healthcare workers are needed. Using SEE may foster early identification and individualized prevention of SUD.

Factors Related to Relapse in Patients with Substance-related Disorders under Methadone Maintenance Therapy: Decision Tree Analysis

Objectives

We sought to determine the main factors related to relapse in patients with substance-related disorders (SRDs) who received methadone maintenance therapy (MMT) using decision tree (DT) analysis.

Methods

We conducted a cross-sectional study of 4175 patients referred to the 45 MMT centers in Kermanshah province, west of Iran. We included all patients who were under MMT for at least one year. All information was collected through an interview by a psychologist. Descriptive statistics and univariate and multiple regression models were used in statistical analysis. The Gini index was calculated to determine the cut-off point of nodes. We used the Classification and Regression Trees algorithm to create the DT.

Results

The relapse rate was 76.6% for all participants, with no significant gender differences. The DT resulted in a five-level model of significant factors affecting substance abuse relapse. These included lower cost for buying substances, lower age at first substance use, history of quitting substances without medication, frequency of substances utilization per month, and frequency of methadone therapy.

Conclusions

Knowing the main factors associated with substance abuse relapse could be important for health care providers to make better decisions for improving the treatment outcomes of SRDs.

Adolescence versus adulthood: Differences in basal mesolimbic and nigrostriatal dopamine transmission and response to drugs of abuse

Epidemiological studies have shown that people who begin experimenting drugs of abuse during adolescence are more likely to develop substance use disorders, and the earliest is the beginning of their use, the greatest is the likelihood to become dependent. Understanding the neurobiological changes increasing adolescent vulnerability to drug use is becoming imperative. Although all neurotransmitter systems undergo relevant developmental changes, dopamine system is of particular interest, given its role in a variety of functions related to reward, motivation, and decision making. Thus, in the present study, we investigated differences in mesolimbic and nigrostriatal dopamine transmission between adolescent (5, 6, 7 weeks of age) and adult rats (10-12 weeks of age), in basal conditions and following drug challenge, by using in vivo brain microdialysis. Although no significant difference between adolescents and adults was observed in dopamine basal levels in the nucleus accumbens (NAc)shell and core, reduced DA levels were found in the dorsolateral striatum (DLS) of early and mid-adolescent rats. Adolescent rats showed greater increase of dopamine in the NAc shell following nicotine (0.4 mg/kg), THC (1.0 mg/kg), and morphine (1.0 mg/kg), in the NAc core following nicotine and morphine, and in the DLS following THC, morphine, and cocaine (10 mg/kg). These results, while adding new insight in the development and functionality of the dopamine system during different stages of adolescence, might provide a neurochemical basis for the greater vulnerability of adolescents to drugs of abuse and for the postulated gateway effect of nicotine and THC toward abuse of other illicit substances.

Predictors of Substance Use Latent Classes Among American Indian Youth Attending Schools On or Near Reservations

BACKGROUND AND OBJECTIVES

Identical latent classes of substance use for 7 to 8 grade and 9 to 12 grade American Indian (AI) youth living on or near reservations suggest that patterns of substance use are established early among these youth. This study examines relationships of substance-related factors to latent class membership and whether these relationships differ by grade group.

METHODS

In-school surveys were administered to 1503 7 to 8 grade and 1995 9 to 12 grade students from 46 schools on or near reservations during the 2009/2010 to 2012/2013 school years. Four-class latent class models of substance use were specified and five classes of substance-related factors (peers, substance availability, perceived harm, family, early initiation), plus grade level and gender, were evaluated as predictors.

RESULTS

For 7 to 8 grade students, substance-related factors differentiated nonusers from users, while for 9 to 12 graders, these factors also differentiated types of users. Early initiation and peer factors were strongly related to class membership, while other factors were less strongly related.

DISCUSSION AND CONCLUSIONS

Early initiation of alcohol or marijuana is strongly related to being in a substance-using class for AI youth. Because these youth tend to initiate use earlier that other US youth, prevention resources should be targeted to reaching them and their families before age 12.

SCIENTIFIC SIGNIFICANCE

Predictors of latent classes of substance use were identified for reservation-based AI youth. While the classes were identical for 7 to 8 grade and 9 to 12 grade youth, predictors varied across grade group, which may inform how best to develop prevention efforts unique to middle and high school AI youth.

The utility and impact of the addiction comprehensive health enhancement support system (ACHESS) on substance abuse treatment adherence among youth in an intensive outpatient program

Youth experiencing substance use disorders often are susceptible to relapse because traditional support systems can be expensive, geographically dispersed, operated on limited schedules and lacking in peer support. The continuity of care offered via the digital Addiction Comprehensive Health Enhancement Support System (ACHESS) system holds promise in preventing relapse because of its portability and capability to foster virtually anytime/anywhere, cost-effective access to supportive interventions. The aim of this mixed-methods study was to evaluate the utility and impact of ACHESS on treatment adherence among youth with substance use disorders in an intensive outpatient program in the US Midwest. Data on 28 clients using ACHESS during 2016-17 were compared to retrospective data on 28 carefully-matched others treated without ACHESS during 2014-16. Fifty-four percent of the study group successfully completed treatment as opposed to 42.9% of those in the comparison group. Staff focus group findings highlighted how some features of ACHESS were effectively integrated into the care model and appeared to positively impact outcomes, while other elements of the application offered little utility. We suggest further study of ACHESS among larger samples of youth with substance use disorders in intensive outpatient programs to assess its efficacy in supporting adherence to treatment.

Should Excess Topical Decongestant Use Raise a Red Flag? Rhinitis Medicamentosa and Opioid Use Disorder

OBJECTIVE

The objective of this study was to determine whether patients with rhinitis medicamentosa (RM) have an increased odds of having an opioid use disorder (OUD) and which characteristics may predict this association.

METHODS

The authors conducted a retrospective case control study of patients 18 years and older who presented to the otolaryngology clinic at an academic medical center from January 2013 through December 2017. Cases, defined as patients who presented with excessive decongestant nasal spray usage based on history, were matched to control patients who presented with chronic rhinitis and did not report regular nasal decongestant usage. The charts were reviewed for patients that carried a problem of opioid abuse, identified using ICD-9 codes 304.XX or ICD-10 codes F11.XX. The primary outcome of this study was the odds of having an OUD. Secondary outcomes were assessed by summary statistics.

RESULTS

One hundred and thirty-one cases of RM were matched to 1871 controls of chronic rhinitis. Seven cases (5.3%) and 24 (1.3%) controls had a diagnosis of OUD, consistent with an odds ratio of 3.98 for opioid abuse in patients with RM (95% CI: 1.47-9.71). Oxymetazoline was used by 85.5% (n = 112) of patients with RM. Thirty-six patients (27.1%) with RM underwent nasal surgery following a diagnosis of RM, of which twenty patients (55.6%) were prescribed opioids following the procedure.

CONCLUSIONS

RM is associated with increased odds of having an OUD.

Factors Associated with the Initial Sensations of Smoking among Smokers with Mental Illness

People with mental illnesses (MI) have a disproportionate smoking prevalence and associated disease burden. Smoking initiation among people with MI is poorly understood. However, the sensations experienced during smoking initiation predict continued smoking and nicotine dependence. Yet, few studies have examined the initial experiences of smoking among people with MI. Thus, the aim of this study was to explore factors associated with the initial sensations of smoking in people with MI. Smokers in an inpatient psychiatric facility (n = 123) were surveyed. Data obtained included information on demographics, smoking and secondhand smoke (SHS) exposure, psychiatric diagnoses, and sensations of initial smoking. Spearman correlations explored associations among initial smoking sensation variables; and binary logistic regression analyses examined the associations between study variables and groupings derived from initial sensations (i.e., "pleasant + buzz," "unpleasant + buzz," and "all" sensations). The most frequently reported initial smoking sensation was feeling dizzy (87%) and there were low to moderate correlations between unpleasant (e.g., cough, sick, nervous) and pleasant (e.g., good, relaxed) sensations. In logistic regression analyses, having higher perceived SHS exposure was significantly associated with the "pleasant + buzz" sensation grouping; and lower past week SHS exposure was associated with the "unpleasant + buzz" sensation grouping; but, no variables were associated with "all" sensation group. Initial smoking sensations are an uncharted avenue of exploration in understanding smoking initiation among people with MI. SHS exposure may be an important factor associated with the report of both unpleasant and pleasant initial sensations. Future studies are needed to further explore initial sensations in relation to the context of smoking initiation among people with MI.

Gene-Environment Interactions in Psychiatry: Recent Evidence and Clinical Implications

PURPOSE OF REVIEW

We identify the recent evidence for gene-by-environment interaction studies in relation to psychiatric disorders. We focus on the key genotypic data as well as environmental exposures and how they interact to predict psychiatric disorders and psychiatric symptomatology. We direct our focus on the psychiatric outcomes that were focused on by the Psychiatric Genetics Consortium.

RECENT FINDINGS

Many of the studies focus on candidate gene approaches, with most of the studies drawing upon previous literature to decide the genes of interest. Other studies used a genome-wide approach. While some studies demonstrated positive replication of previous findings, replication is still an issue within gene-by-environment interaction studies. Gene-by-environment interaction research in psychiatry globally suggests some susceptibility to environmental exposures based on genotype; however, greater clarity is needed around the idea that genetic risk may not be disorder specific.

The protective roles of ethnic identity and community cohesion on substance use among Black women experiencing adversity

This study employs a strengths-based approach to explore associations of ethnic identity and community cohesion with substance use among Black women experiencing adversity. Black women (N = 107; M_age = 34.2, SD = 7.7) completed interviews about their sociodemographics, HIV status, intimate partner violence exposure, ethnic identity, community connectedness, and substance use. Hierarchical linear regression analysis was used to examine associations of ethnic identity and community cohesion with substance use, accounting for age and socioeconomic status. The overall model was significant, with greater ethnic identity (β = -.25, p < .01) and more community cohesion (β = -.29, p < .01) associated with lower substance use. Findings highlight the value of contextual factors in substance use prevention among Black women.

Big Five personality traits and alcohol, nicotine, cannabis, and gambling disorder comorbidity

The Diagnostic and Statistical Manual of Mental Disorders (DSM; 5th ed.) reassignment of gambling disorder as an addictive disorder alongside the substance-related addictive disorders encourages research into their shared etiologies. The aims of this study were to examine: (a) the associations of Big Five personality dimensions with alcohol, nicotine, cannabis, and gambling disorders, (b) the comorbidity between these disorders, (c) the extent to which common personality underpinnings explain comorbidity, (d) whether results differed for men and women, and (e) the magnitude of personality differences corresponding to the 4 disorders. Participants were 3,785 twins and siblings (1,365 men, 2,420 women; M_age = 32 years, range = 21-46 years) from the Australian Twin Registry who completed psychiatric interviews and Big Five personality inventories. The personality profile of high neuroticism, low agreeableness, and low conscientiousness was associated with all 4 addictive disorders. All but 1 of the pairwise associations between the disorders were significant. After accounting for Big Five traits, the associations were attenuated to varying degrees but remained significant. The results were generally similar for men and women. The results suggest that the Big Five traits of neuroticism, agreeableness, and conscientiousness are associated with the general propensity to develop an addictive disorder and may in part explain their co-occurrence; however, they may be more broadly associated with the propensity for any psychiatric disorder. The effect sizes of the personality associations suggest that the diagnosis of gambling disorder as operationalized by the DSM may be more severe than the other addictive disorders. Calibration of the diagnosis of gambling disorder to the other addictive disorders may be warranted. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Association of variants of prodynorphin promoter 68-bp repeats in caucasians with opioid dependence diagnosis: Effect on age trajectory of heroin use

The dynorphin/kappa opioid receptor (Dyn/KOR) system is involved in reward processing and dysphoria/anhedonia. Exposure to mu-opioid receptor agonists such as heroin increases expression of the prodynorphin gene (PDYN) in the brain. In this study in a Caucasian cohort, we examined the association of the functional PDYN 68-bp repeat polymorphism with opioid use disorders. In this case-control study, 554 subjects with Caucasian ancestry (142 healthy controls, 153 opioid-exposed, but never opioid dependent, NOD, and 259 with an opioid dependence diagnosis, OD) were examined for association of the PDYN 68-bp repeats with the diagnosis of opioid dependence (DSM-IV criteria), with a dimensional measure of heroin exposure (KMSK scale), and age trajectory parameters of heroin use (age of heroin first use, and age of onset of heaviest use). The PDYN 68-bp repeat genotype (classified as: "short-short" [SS], "long-long" [LL], and "short-long" [SL], based on the number of repeats) was not associated with categorical opioid dependence diagnoses. However, the LL genotype was associated with later age of first heroin use than the SS + SL genotype (19 versus 18 years; p < 0.01). This was also confirmed by a significant positive correlation between the number of repeats and the age of first use of heroin, in volunteers with OD (Spearman r = 0.16; p = 0.01). This suggests that the functional PDYN 68-bp repeat genotype is associated with the age of first use of heroin in Caucasians diagnosed with opioid dependence.

How far can you go? Association between illicit drug use and academic migration

ABSTRACT Objective: To measure the prevalence of illicit drugs use in the lifetime, last year and last month, as well as the factors associated to the last year's use and its association with academic migration, among undergraduate students of a university in southern Brazil. Methods: In this cross-sectional study, data were collected through self-administered questionnaire. It was conducted a clustered systematic sampling. For multivariate analyses, it was used Poisson regression. Results: 1,423 students participated. The prevalence of illicit drug use in the lifetime, last year and last month were 42.4%, 25.5% and 17.7%, respectively. Regarding illicit substances, marijuana use was the most prevalent. The variables independently associated with illicit drugs use in the last year were academic migration, being male, younger, single, high parent's educational level, living with peers, tobacco use in the last year, and having friend and relative that have used illicit drugs. Religious practice had a protective effect. Conclusion: Individuals who migrated from their cities to study at the university are more exposed to the main risk factors pointed out by this research and hence to the use of illicit drugs. Based on these results, we suggest that universities develop evaluation, prevention, treatment or referral strategies considering specific needs of this population

An Examination of the Age of Substance Use Onset and Adult Severity of Use Among Offenders Entering Treatment

Early onset of substance use has demonstrated a robust relationship with later severity of use, yet this relationship has been less examined in criminal justice contexts or examined differentially by gender. The present study utilized secondary data from a sample of offenders in one small Midwestern state entering corrections-based substance abuse treatment in prison, jail, or community settings to address these gaps in the literature. Findings indicated that age of regular cigarette use did not uniquely affect severity of illicit drug use in adulthood, defined as the frequency of use or endorsement of substance use disorder criteria. In comparison, ages of onset for alcohol and illicit drug use were significantly associated with multiple severity variables examined. Gender was not found to moderate these relationships. These findings emphasize that age of use onset for alcohol and illicit drugs can be valuable in identifying offenders at risk of severe substance use in adulthood.

Genome-wide association meta-analysis of age at first cannabis use

BACKGROUND AND AIMS

Cannabis is one of the most commonly used substances among adolescents and young adults. Earlier age at cannabis initiation is linked to adverse life outcomes, including multi-substance use and dependence. This study estimated the heritability of age at first cannabis use and identified associations with genetic variants.

METHODS

A twin-based heritability analysis using 8055 twins from three cohorts was performed. We then carried out a genome-wide association meta-analysis of age at first cannabis use in a discovery sample of 24 953 individuals from nine European, North American and Australian cohorts, and a replication sample of 3735 individuals.

RESULTS

The twin-based heritability for age at first cannabis use was 38% [95% confidence interval (CI) = 19-60%]. Shared and unique environmental factors explained 39% (95% CI = 20-56%) and 22% (95% CI = 16-29%). The genome-wide association meta-analysis identified five single nucleotide polymorphisms (SNPs) on chromosome 16 within the calcium-transporting ATPase gene (ATP2C2) at P < 5E-08. All five SNPs are in high linkage disequilibrium (LD) (r2  > 0.8), with the strongest association at the intronic variant rs1574587 (P = 4.09E-09). Gene-based tests of association identified the ATP2C2 gene on 16q24.1 (P = 1.33e-06). Although the five SNPs and ATP2C2 did not replicate, ATP2C2 has been associated with cocaine dependence in a previous study. ATP2B2, which is a member of the same calcium signalling pathway, has been associated previously with opioid dependence. SNP-based heritability for age at first cannabis use was non-significant.

CONCLUSION

Age at cannabis initiation appears to be moderately heritable in western countries, and individual differences in onset can be explained by separate but correlated genetic liabilities. The significant association between age of initiation and ATP2C2 is consistent with the role of calcium signalling mechanisms in substance use disorders.

Transition to drug co-use among adolescent cannabis users: The role of decision-making and mental health

BACKGROUND

Co-use of cannabis and drugs other than cannabis (DOTC) influences the risk of experiencing cannabis disorders. Accordingly, we explored whether speed of transition to drug co-use, the number of DOTC used, and/or being an experimental cannabis-only user, a regular cannabis-only user, or a regular cannabis user who co-uses DOTC (i.e., cannabis-plus user) were associated with decision-making (DM), mental health disorder symptoms, or cannabis use-related characteristics.

METHODS

We analyzed baseline data from a sub-sample of 266 adolescent (ages 14 to 16) cannabis users (CU) participating in an ongoing longitudinal study. Assessments included semi-structured interviews, self-report questionnaires, and measures of drug use, DM (measured via the Iowa Gambling Task), mental health disorders, and cannabis use-related problems.

RESULTS

Endorsing a larger number of mood disorders symptoms was associated with being a regular cannabis-plus user rather than a regular cannabis-only user (AOR = 1.08, C.I.95% 1.01, 1.15). Poorer DM was associated with a faster transition to co-use, such that for each one unit increase in DM performance, the years to onset of drug co-use increased by 1% (p = 0.032). Endorsing a larger number of cannabis use-related problems was positively associated with endorsing a larger number of DOTC used (p = 0.001).

CONCLUSIONS

This study provides new evidence on the process of drug co-use among CU. Specifically, mood disorder symptoms were associated with use of DOTC among regular CU. Furthermore, poorer DM was associated with a faster transition to drug co-use. Poorer DM and mood disorder symptoms may aggravate or accelerate the onset of adverse consequences among adolescent CU.

A Co-Twin Control Study of the Relationship Between Adolescent Drinking and Adult Outcomes

OBJECTIVE

The effect of drinking during adolescence on adult functioning is a public health concern. A variety of mechanisms have been proposed where drinking in adolescence has an adverse impact on later outcomes; unfortunately, few studies have included methodologies that account for confounding influences that might link adolescent drinking with subsequent problems. To address this limitation, the current study used a co-twin control design, which uses members of twin pairs that differ from each other on their adolescent drinking.

METHOD

We used a prospective longitudinal sample drawn from the Minnesota Twin Family Study, consisting of 2,764 twins (1,434 female) assessed at regular follow-ups from age 17 to age 29. Adolescent drinking was defined by measures of early initiation of use and a measure of overall consumption at age 17. Adult outcomes included indicators of substance use, antisocial behavior, personality, socioeconomic status, and social functioning.

RESULTS

The co-twin control analyses suggested that many of the associations between adolescent drinking and later outcomes were largely influenced by genetic confounding. However, for the measure of adolescent alcohol consumption, results were consistent with a small causal impact of drinking on multiple domains of adult functioning. This pattern was less consistently observed for the measures of early initiation.

CONCLUSIONS

These results provide empirical justification for policies designed to alleviate long-term consequences associated with adolescent drinking by reducing the level of alcohol consumption in adolescence. In contrast, the evidence did not suggest that delaying drinking would have a broad impact on later-life adjustment.

A Co-Twin Control Study of the Relationship Between Adolescent Drinking and Adult Outcomes

OBJECTIVE

The effect of drinking during adolescence on adult functioning is a public health concern. A variety of mechanisms have been proposed where drinking in adolescence has an adverse impact on later outcomes; unfortunately, few studies have included methodologies that account for confounding influences that might link adolescent drinking with subsequent problems. To address this limitation, the current study used a co-twin control design, which uses members of twin pairs that differ from each other on their adolescent drinking.

METHOD

We used a prospective longitudinal sample drawn from the Minnesota Twin Family Study, consisting of 2,764 twins (1,434 female) assessed at regular follow-ups from age 17 to age 29. Adolescent drinking was defined by measures of early initiation of use and a measure of overall consumption at age 17. Adult outcomes included indicators of substance use, antisocial behavior, personality, socioeconomic status, and social functioning.

RESULTS

The co-twin control analyses suggested that many of the associations between adolescent drinking and later outcomes were largely influenced by genetic confounding. However, for the measure of adolescent alcohol consumption, results were consistent with a small causal impact of drinking on multiple domains of adult functioning. This pattern was less consistently observed for the measures of early initiation.

CONCLUSIONS

These results provide empirical justification for policies designed to alleviate long-term consequences associated with adolescent drinking by reducing the level of alcohol consumption in adolescence. In contrast, the evidence did not suggest that delaying drinking would have a broad impact on later-life adjustment.

Tobacco and cannabis use in college students are predicted by sex-dimorphic interactions between MAOA genotype and child abuse

BACKGROUND

Postsecondary students in Western countries exhibit a high prevalence of cannabis and tobacco use disorders. The etiology of these problems is contributed by several psychosocial factors, including childhood adversity and trauma; however, the mechanisms whereby these environmental determinants predispose to the use of these substances remain elusive, due to our poor knowledge of genetic and biological moderators. Converging evidence points to the monoamine oxidase A (MAOA) gene as a moderator of the effects of lifetime stress on the initiation of substance use.

AIMS

Building on these premises, in this study, we analyzed whether MAOA upstream variable number tandem repeat (uVNTR) alleles interact with child maltreatment history to predict for lifetime cannabis and tobacco consumption.

MATERIALS AND METHODS

Five hundred college students (age: 18-25 years) from a large Midwestern University were surveyed for their child maltreatment history (encompassing emotional, physical, and sexual abuse, as well as emotional and physical neglect) and lifetime consumption of cannabis and tobacco. Saliva samples were obtained to determine the MAOA uVNTR genotype of each participant.

RESULTS

In female students, lifetime tobacco and cannabis use was predicted by the interaction of physical and emotional abuse with high-activity MAOA allelic variants; conversely, in males, the interaction of low-activity MAOA alleles and physical abuse was associated with lifetime use of tobacco, but not cannabis.

DISCUSSION

These findings collectively suggest that the vulnerability to smoke tobacco and cannabis is predicted by sex-dimorphic interactions of MAOA gene with childhood abuse.

CONCLUSION

These biosocial underpinnings of tobacco and cannabis use may prove important in the development of novel personalized preventive strategies for substance use disorders in adolescents.

The Impact of Combinations of Alcohol, Nicotine, and Cannabis on Dynamic Brain Connectivity

Alcohol, nicotine, and cannabis are among the most commonly used drugs. A prolonged and combined use of these substances can alter normal brain wiring in different ways depending on the consumed cocktail mixture. Brain connectivity alterations and their change with time can be assessed using functional magnetic resonance imaging (fMRI) because of its spatial and temporal content. Here, we estimated dynamic functional network connectivity (dFNC) as derived from fMRI data to investigate the effects of single or combined use of alcohol, nicotine, and cannabis. Data from 534 samples were grouped according to their substance use combination as controls (CTR), smokers (SMK), drinkers (DRN), smoking-and-drinking subjects (SAD), marijuana users (MAR), smoking-and-marijuana users (SAM), marijuana-and-drinking users (MAD), and users of all three substances (ALL). The DRN group tends to exhibit decreased connectivity mainly in areas of sensorial and motor control, a result supported by the dFNC outcome and the alcohol use disorder identification test. This trend dominated the SAD group and in a weaker manner MAD and ALL. Nicotine consumers were characterized by an increment of connectivity between dorsal striatum and sensorimotor areas. Where possible, common and separate effects were identified and characterized by the analysis of dFNC data. Results also suggest that a combination of cannabis and nicotine have more contrasting effects on the brain than a single use of any of these substances. On the other hand, marijuana and alcohol might follow an additive effect trend. We concluded that all of the substances have an impact on brain connectivity, but the effect differs depending on the dFNC state analyzed.

Associations of parental alcohol use disorders and parental separation with offspring initiation of alcohol, cigarette and cannabis use and sexual debut in high-risk families

BACKGROUND AND AIMS

Parental alcohol use disorders (AUDs) and parental separation are associated with increased risk for early use of alcohol in offspring, but whether they increase risks for early use of other substances and for early sexual debut is under-studied. We focused on associations of parental AUDs and parental separation with substance initiation and sexual debut to (1) test the strength of the associations of parental AUDs and parental separation with time to initiation (age in years) of alcohol, tobacco and cannabis use and sexual debut and (2) compare the strength of association of parental AUD and parental separation with initiation.

DESIGN

Prospective adolescent and young adult cohort of a high-risk family study, the Collaborative Study on the Genetics of Alcoholism (COGA).

SETTING

Six sites in the United States.

PARTICIPANTS

A total of 3257 offspring (aged 14-33 years) first assessed in 2004 and sought for interview approximately every 2 years thereafter; 1945 (59.7%) offspring had a parent with an AUD.

MEASUREMENTS

Diagnostic interview data on offspring substance use and sexual debut were based on first report of these experiences. Parental life-time AUD was based on their own self-report when parents were interviewed (1991-2005) for most parents, or on offspring and other family member reports for parents who were not interviewed. Parental separation was based on offspring reports of not living with both biological parents most of the time between ages 12 and 17 years.

FINDINGS

Parental AUDs were associated with increased hazards for all outcomes, with cumulative hazards ranging from 1.19 to 2.71. Parental separation was also an independent and consistent predictor of early substance use and sexual debut, with hazards ranging from 1.19 to 2.34. The strength of association of parental separation with substance initiation was equal to that of having two AUD-affected parents, and its association with sexual debut was stronger than the association of parental AUD in one or both parents.

CONCLUSIONS

Parental alcohol use disorders (AUDs) and parental separation are independent and consistent predictors of increased risk for early alcohol, tobacco and cannabis use and sexual debut in offspring from families with a high risk of parental AUDs.

Universal School-Based Implementation of Screening Brief Intervention and Referral to Treatment to Reduce and Prevent Alcohol, Marijuana, Tobacco, and Other Drug Use: Process and Feasibility

Screening, Brief Intervention, and Referral to Treatment (SBIRT) is an evidence-based approach to reducing substance use in adolescents. An emerging literature shows the promise of school-based SBIRT. However, most school-based SBIRT has only targeted substance-using adolescents and used school-based health clinics, which most schools lack. This project aimed to describe the following: a model for implementing universal SBIRT in high schools without school-based clinics, reasons students most commonly endorsed for reducing or avoiding substance use, students’ perceptions of SBIRT, and students’ intentions to change substance use or remain abstinent following SBIRT. Participants were N = 2513, 9th to 10th grade students in 10 high schools. Students rated SBIRT positively and indicated substantial intentions to reduce or delay substance use following SBIRT. Results support SBIRT’s potential to delay substance use among current abstainers in addition to reducing substance use among current users. This project demonstrates SBIRT’s feasibility as a universal method in high schools without in-school clinics.

Parental reflective functioning and executive functioning in mothers with substance use disorder

Having a substance use disorder (SUD) may adversely affect caregiving capacities. Reflective functioning (RF) and executive functioning (EF) are both important capacities for sensitive parenting, and are often impaired in a SUD. Only a few studies have explored the possible association between the two phenomena. In this study, we used a neuropsychological test battery to assess EF, and the Parent Development Interview to assess RF in a sample of mothers with a SUD (N = 43). Although parental RF (PRF) was associated with EF, when controlled for intelligence (IQ) and mental health, there was no significant association between EF and PRF. Mental health, however, showed a significant negative association with PRF. Splitting the group in two based on PRF level, mothers with a negative to low PRF exhibited more severe difficulties in SUD-related aspects, as well as in several EF components, compared to mothers with an adequate to high PRF, highlighting the association between EF and PRF. The results from this study contribute to enhance our understanding of the dynamics underlying vulnerability in PRF that mothers with small children may experience. We suggest EF to be a prerequisite for adequate PRF, and for interventions to be customized accordingly regarding parents with a SUD.

Age of initiation and substance use progression: A multivariate latent growth analysis

An individual's age at first substance use may be associated with their risk for progression toward heavier substance involvement. To our knowledge, however, no studies within nationally representative samples have examined the relation between the timing of initiation and progression in use of multiple substances. The present study employed a sample of 9,421 participants from the National Longitudinal Study of Adolescent to Adult Health who reported on their ages of tobacco, alcohol, and cannabis initiation; frequency of tobacco, alcohol, and cannabis use; and quantity of tobacco and alcohol use across 4 waves. We fit latent growth models to examine (a) associations between the age of initiation and initial status and rate of change in substance involvement, and (b) the degree to which the timing of first substance use accounted for differences in trajectories. There were significant relations between all ages of initiation and rates of change in tobacco (βs = -0.21 to -0.31, ps < .01) and alcohol use frequency (βs = 0.14 to 0.31, ps < .001), age of cannabis initiation and rate of change in tobacco use quantity (β = 0.23, p < .01), and age of tobacco initiation and rate of change in cannabis use frequency (β = -0.14, p < .01). After adjusting for age of initiation, significant associations were observed between trajectories for tobacco and alcohol (r = .43, p < .0001) and alcohol and cannabis (r = .20, p < .05). Results highlight differences in within- and cross-substance relations between the age of initiation and rate of change in use across substances. They suggest that differences in substance use trajectories are partly accounted for by age at first use. (PsycINFO Database Record

Genetic and environmental sources of covariation between early drinking and adult functioning

The vast majority of individuals initiate alcohol consumption for the first time in adolescence. Given the widespread nature of its use and evidence that adolescents may be especially vulnerable to its effects, there is concern about the long-term detrimental impact of adolescent drinking on adult functioning. While some researchers have suggested that genetic processes may confound the relationship, the mechanisms linking drinking and later adjustment remain unclear. The current study utilized a genetically informed sample and biometric modeling to examine the nature of the familial influences on this association and identify the potential for genetic confounding. The sample was drawn from the Minnesota Twin Family Study (MTFS), a longitudinal study consisting of 2,764 twins assessed in 2 cohorts at regular follow-ups from age 17 to age 29 (older cohort) or age 11 to age 29 (younger cohort). A broad range of adult measures was included assessing substance use, antisocial behavior, personality, socioeconomic status, and social functioning. A bivariate Cholesky decomposition was used to examine the common genetic and environmental influences on adolescent drinking and each of the measures of adult adjustment. The results revealed that genetic factors and nonshared environmental influences were generally most important in explaining the relationship between adolescent drinking and later functioning. While the presence of nonshared environmental influences on the association are not inconsistent with a causal impact of adolescent drinking, the findings suggest that many of the adjustment issues associated with adolescent alcohol consumption are best understood as genetically influenced vulnerabilities. (PsycINFO Database Record

The cannabis withdrawal syndrome: current insights

The cannabis withdrawal syndrome (CWS) is a criterion of cannabis use disorders (CUDs) (Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition) and cannabis dependence (International Classification of Diseases [ICD]-10). Several lines of evidence from animal and human studies indicate that cessation from long-term and regular cannabis use precipitates a specific withdrawal syndrome with mainly mood and behavioral symptoms of light to moderate intensity, which can usually be treated in an outpatient setting. Regular cannabis intake is related to a desensitization and downregulation of human brain cannabinoid 1 (CB1) receptors. This starts to reverse within the first 2 days of abstinence and the receptors return to normal functioning within 4 weeks of abstinence, which could constitute a neurobiological time frame for the duration of CWS, not taking into account cellular and synaptic long-term neuroplasticity elicited by long-term cannabis use before cessation, for example, being possibly responsible for cannabis craving. The CWS severity is dependent on the amount of cannabis used pre-cessation, gender, and heritable and several environmental factors. Therefore, naturalistic severity of CWS highly varies. Women reported a stronger CWS than men including physical symptoms, such as nausea and stomach pain. Comorbidity with mental or somatic disorders, severe CUD, and low social functioning may require an inpatient treatment (preferably qualified detox) and post-acute rehabilitation. There are promising results with gabapentin and delta-9-tetrahydrocannabinol analogs in the treatment of CWS. Mirtazapine can be beneficial to treat CWS insomnia. According to small studies, venlafaxine can worsen the CWS, whereas other antidepressants, atomoxetine, lithium, buspirone, and divalproex had no relevant effect. Certainly, further research is required with respect to the impact of the CWS treatment setting on long-term CUD prognosis and with respect to psychopharmacological or behavioral approaches, such as aerobic exercise therapy or psychoeducation, in the treatment of CWS. The up-to-date ICD-11 Beta Draft is recommended to be expanded by physical CWS symptoms, the specification of CWS intensity and duration as well as gender effects.

Genetic variation in the exome: Associations with alcohol and tobacco co-use

Shared genetic factors represent one underlying mechanism thought to contribute to high rates of alcohol and tobacco co-use and dependence. Common variants identified by molecular genetic studies tend to confer only small disease risk, and rare protein-coding variants are posited to contribute to disease risk, as well. However, given that genotyping technologies allowing for their inclusion in association studies have only recently become available, the magnitude of their contribution is poorly understood. The current study examined genetic variation in protein-coding regions (i.e., the exome) for associations with measures of lifetime alcohol and tobacco co-use. Participants from the UCSF Family Alcoholism Study (N = 1,862) were genotyped using an exome-focused genotyping array, and assessed for DSM-IV diagnoses of alcohol and tobacco dependence and quantitative consumption measures using a modified version of the Semi-Structured Assessment for the Genetics of Alcoholism. Analyses included single variant, gene-based, and pathway-based tests of association. One EMR3 variant and a pathway related to genes upregulated in mesenchymal stem cells during the late phase of adipogenesis met criteria for statistical significance. Suggestive associations were consistent with previous findings from studies of substance use and dependence, including variants in the CHRNA5-CHRNA3-CHRNB4 gene cluster with cigarettes smoked per day. Further, several variants and genes demonstrated suggestive association across phenotypes, suggesting that shared genetic factors may underlie risk for increased levels of alcohol and tobacco use, as well as psychopathology more broadly, providing insight into our understanding of the genetic architecture underlying these traits. (PsycINFO Database Record