This is your teen brain on drugs: In search of biological factors unique to dependence toxicity in adolescence

Time to first report of signs of nicotine dependence among youth who use e-cigarettes and cigarettes in the United States: A nationally representative cohort study, findings from the Population Assessment of Tobacco and Health, 2013-2019

OBJECTIVE

To determine the time to first report of signs of nicotine dependence among youth exclusive e-cigarette users and compare this time to that for exclusive cigarette users.

METHODS

Secondary analysis of data (Waves 1-5; 2013-2019) from the Population Assessment of Tobacco and Health was conducted. Youth never tobacco users in the United States who reported exclusive past-30-day (P30D) e-cigarette or cigarette use (n = 2940, N = 5,391,642) in at least one wave were included in the current analysis. Survival analysis was used to estimate the time to the first report of three nicotine dependence indicators (i.e., "use within 30 minutes of waking"; "cravings" and "really needing to use") following the first report of P30D use. Multivariable Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR).

RESULTS

There were no significant differences in the time to first report of "use within 30 minutes of waking" (aHR = 1.1, 95% CI = 0.87-1.40) and "cravings" (aHR = 1.09, 95% CI = 0.81-1.47) between exclusive P30D e-cigarette use and exclusive P30D cigarette use. However, compared to exclusive P30D e-cigarette use, the hazard of first reporting "really needing to use" tobacco was 39% (aHR 1.39; 95% CI: 1.05-1.84) times higher for those who reported exclusive P30D cigarette use after controlling for covariates.

CONCLUSION

Compared to exclusive P30D cigarette use, no differences in the time to first report of signs of nicotine dependence ("use within 30 minutes" and "cravings") were observed among exclusive P30D e-cigarette users. Policymakers and regulatory agencies should consider this evidence when assessing the abuse liability of e-cigarette products.

Consequences of adolescent drug use

Substance use in adolescence is a known risk factor for the development of neuropsychiatric and substance use disorders in adulthood. This is in part due to the fact that critical aspects of brain development occur during adolescence, which can be altered by drug use. Despite concerted efforts to educate youth about the potential negative consequences of substance use, initiation remains common amongst adolescents world-wide. Additionally, though there has been substantial research on the topic, many questions remain about the predictors and the consequences of adolescent drug use. In the following review, we will highlight some of the most recent literature on the neurobiological and behavioral effects of adolescent drug use in rodents, non-human primates, and humans, with a specific focus on alcohol, cannabis, nicotine, and the interactions between these substances. Overall, consumption of these substances during adolescence can produce long-lasting changes across a variety of structures and networks which can have enduring effects on behavior, emotion, and cognition.

Keepin' It REAL-Mantente REAL in Mexico: Longitudinal Examination of Youth Drug Resistance Strategies and Substance Use Among Early Adolescents

PURPOSE

This study examined if culturally and linguistically adapted versions of a US-developed adolescent substance use prevention intervention, keepin' it REAL (kiREAL), for Mexico increases the use of drug resistance strategies and if increased use of resistance strategies subsequently leads to a reduction in the frequency of substance use (i.e., alcohol, cigarette, marijuana, and inhalants).

METHODS

Students (N = 5,522, 49% female, age range = 11-17) in 36 middle schools across three cities in Mexico were randomized into three conditions: (1) Mantente REAL (MREAL), the culturally adapted version, (2) kiREAL-S, the linguistically adapted version, and (3) Control. Using survey data collected at four time points, random intercept cross-lagged path analyses tested the direct and indirect effects of MREAL and kiREAL-S compared to Control.

RESULTS

At time 2, the number of drug resistance strategies used by students increased in both MREAL (β = 0.103, p = .001) and kiREAL-S (β = 0.064, p = .002) compared to Control. However, only MREAL lead to less frequent use of alcohol (β = -0.001, p = .038), cigarettes (β = -0.001, p = .019), marijuana (β = -0.002, p = .030), and inhalants (β = -0.001, p = .021) at time 4, mediated through increased use of drug resistance strategies.

DISCUSSION

This study provides evidence that MREAL and kiREAL-S are successful in spurring use of the drug resistance strategies that are the core component of the intervention. Only MREAL achieved long-term effects on substance use behaviors, the ultimate objective of these interventions. These findings provide support for the value and importance of rigorous cultural adaptation of efficacious prevention programs as a necessary condition for enhancing prevention benefits for participating youth.

Modulation of neuronal excitability by binge alcohol drinking

Drug use poses a serious threat to health systems throughout the world. The number of consumers rises every year being alcohol the drug of abuse most consumed causing 3 million deaths (5.3% of all deaths) worldwide and 132.6 million disability-adjusted life years. In this review, we present an up-to-date summary about what is known regarding the global impact of binge alcohol drinking on brains and how it affects the development of cognitive functions, as well as the various preclinical models used to probe its effects on the neurobiology of the brain. This will be followed by a detailed report on the state of our current knowledge of the molecular and cellular mechanisms underlying the effects of binge drinking on neuronal excitability and synaptic plasticity, with an emphasis on brain regions of the meso-cortico limbic neurocircuitry.

Effects of prenatal opioid exposure on synaptic adaptations and behaviors across development

In this review, we focus on prenatal opioid exposure (POE) given the significant concern for the mental health outcomes of children with parents affected by opioid use disorder (OUD) in the view of the current opioid crisis. We highlight some of the less explored interactions between developmental age and sex on synaptic plasticity and associated behavioral outcomes in preclinical POE research. We begin with an overview of the rich literature on hippocampal related behaviors and plasticity across POE exposure paradigms. We then discuss recent work on reward circuit dysregulation following POE. Additional risk factors such as early life stress (ELS) could further influence synaptic and behavioral outcomes of POE. Therefore, we include an overview on the use of preclinical ELS models where ELS exposure during key critical developmental periods confers considerable vulnerability to addiction and stress psychopathology. Here, we hope to highlight the similarity between POE and ELS on development and maintenance of opioid-induced plasticity and altered opioid-related behaviors where similar enduring plasticity in reward circuits may occur. We conclude the review with some of the limitations that should be considered in future investigations. This article is part of the Special Issue on 'Opioid-induced addiction'.

Substance Use Disorder among Hospitalized Adolescents in North Carolina

OBJECTIVES

Individuals who began using alcohol or other drugs before the age of 15 are 7 times more likely to develop a substance use disorder (SUD) in adulthood. This study sought to determine the common characteristics of SUD-related hospitalizations and patterns of discharge diagnoses among adolescents in North Carolina.

METHODS

Using the 2014 State Inpatient Database (SID), discharge records associated with the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes for SUD were identified. Adolescents between the ages of 13 and 19 years were included. SUD and non-SUD groups were compared using the Student t test for continuous variables and the χ² test for categorical variables. A total of 1.1 million hospital discharges were analyzed. A uniform and standardized coding system called Clinical Classifications Software was used to identify cases. The Clinical Classifications Software collapses the ICD-9-CM codes into 679 clinically meaningful categories. A cluster of 3900 ICD-9-CM procedure codes also was used to identify clinically relevant groups of procedures performed during hospitalization.

RESULTS

An estimated 3276 adolescents associated with SUD were discharged from North Carolina hospitals during the study year. Discharged patients with a SUD spent a total of 21,242 inpatient days, at a cost of $62 million. Among the adolescents with a SUD, 53% were boys, 62% were White, 24% were Black, 8% were Hispanic (8%), and 6% were of other races. Compared with patients without a SUD, those with a SUD had longer mean hospital stays (6.5 days vs 4.7 days; P < 0.0001) and lower mean hospital charge per hospitalization ($18,932 vs 24,532; P < 0.0001). Adolescents with a SUD also were diagnosed primarily as having mood disorders (44.78%), followed by schizophrenia and other psychological disorders, upon discharge. Approximately 37% of the SUD-related discharges occurred in areas, denoted in this study using ZIP code designations, with mean household annual incomes <$38,999. A large proportion of the SUD-related hospitalizations (44%) were billed to Medicaid. Frequently observed diagnoses associated with adolescents with a SUD were mood disorders (45%), schizophrenia (7%), and poisoning by other medications and drugs (4%). In 16% of hospitalized adolescents with a SUD, there were at least 2 procedures performed. There was a statistically significant mean hospital charge difference of $5600 between SUD and non-SUD teens.

CONCLUSIONS

The literature reflects the connection between adolescent use and the propensity for diagnosis with a SUD in adulthood; it is evident that this is a growing public health crisis. This study identified patterns of adolescent substance use that, based on the current literature, are indicative of problematic futures for these individuals. The concerning data and literature identify a significant need to address prevention, treatment, and recovery services for adolescents, not only in North Carolina but throughout the United States. The need for focused interventions, access to care, and funding of substance-specific adolescent education and services is greatly needed to change the trajectory of these adolescents' lives.

Sex-Dependent Alterations of Regional Homogeneity in Cigarette Smokers

Biological sex may play a large role in cigarette use and cessation outcomes and neuroimaging studies have demonstrated that cigarette smoking is associated with sex-related differences in brain structure and function. However, less is known about sex-specific alterations in spontaneous brain activity in cigarette smokers. In this study, we investigated the sex-related effects of cigarette smoking on local spontaneous brain activity using regional homogeneity (ReHo) based on resting-state fMRI. Fifty-six smokers (24 females) and sixty-three (25 females) healthy non-smoking controls were recruited. Whole-brain voxelwise 2-way analysis of covariance of ReHo was performed to detect brain regions with sex-dependent alterations on the spontaneous brain activity. Compared to non-smokers, smokers exhibited significant ReHo differences in several brain regions, including the right medial orbitofrontal cortex extended to the ventral striatum/amygdala/parahippocampus, left precuneus, and bilateral cerebellum crus. Smoking and sex interaction analysis revealed that male smokers showed significantly lower ReHo in the right ventral striatum, left cerebellum crus1, and left fusiform gyrus compared to male non-smokers, whereas there are no significant differences between female smokers and non-smokers. Furthermore, the ReHo within the left cerebellum crus1 was negatively correlated with craving scores in male smokers but not in female smokers. Such sex-dependent differences in spontaneous brain activity lays a foundation for further understanding the neural pathophysiology of sex-specific effects of nicotine addiction and promoting more effective health management of quitting smoking.

Smartphone Apps for Vaping Cessation: Quality Assessment and Content Analysis

Background

As the prevalence of electronic cigarette (e-cigarette) use, or vaping, continues to grow, particularly among young people, so does the need for research and interventions to address vaping.

Objective

This study examines the quality of free vaping cessation apps, their contents and features, popularity among users, and adherence to evidence-based principles.

Methods

A systematic search of existing apps for vaping cessation was conducted in December 2020. Eligible apps were free, in English, and included features specifically targeting vaping cessation. Each app included in the analysis was used daily for at least seven consecutive days, assessed using the Mobile App Rating Scale, and rated by at least two authors (AK, EL, or SS) based on adherence to evidence-based practices. Intraclass correlation coefficient (ICC) estimates were computed to assess interrater reliability (excellent agreement; ICC 0.92; 95% CI 0.78-0.98).

Results

A total of 8 apps were included in the quality assessment and content analysis: 3 were developed specifically for vaping cessation and 5 focused on smoking cessation while also claiming to address vaping cessation. The mean of app quality total scores was 3.66 out of 5. Existing vaping cessation apps employ similar approaches to smoking cessation apps. However, they are very low in number and have limited features developed specifically for vaping cessation.

Conclusions

Given the lack of vaping cessation interventions at a time when they are urgently needed, smartphone apps are potentially valuable tools. Therefore, it is recommended that these apps apply evidence-based practices and undergo rigorous evaluations that can assess their quality, contents and features, and popularity among users. Through this process, we can improve our understanding of how apps can be effective in helping users quit vaping.

Review of rodent models of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a polygenic neurodevelopmental disorder that affects 8-12 % of children and >4 % of adults. Environmental factors are believed to interact with genetic predispositions to increase susceptibility to ADHD. No existing rodent model captures all aspects of ADHD, but several show promise. The main genetic models are the spontaneous hypertensive rat, dopamine transporter knock-out (KO) mice, dopamine receptor subtype KO mice, Snap-25 KO mice, guanylyl cyclase-c KO mice, and latrophilin-3 KO mice and rats. Environmental factors thought to contribute to ADHD include ethanol, nicotine, PCBs, lead (Pb), ionizing irradiation, 6-hydroxydopamine, neonatal hypoxia, some pesticides, and organic pollutants. Model validation criteria are outlined, and current genetic models evaluated against these criteria. Future research should explore induced multiple gene KOs given that ADHD is polygenic and epigenetic contributions. Furthermore, genetic models should be combined with environmental agents to test for interactions.

Neurochemical mechanisms and neurocircuitry underlying the contribution of stress to cocaine seeking

In individuals with substance use disorders, stress is a critical determinant of relapse susceptibility. In some cases, stressors directly trigger cocaine use. In others, stressors interact with other stimuli to promote drug seeking, thereby setting the stage for relapse. Here, we review the mechanisms and neurocircuitry that mediate stress-triggered and stress-potentiated cocaine seeking. Stressors trigger cocaine seeking by activating noradrenergic projections originating in the lateral tegmentum that innervate the bed nucleus of the stria terminalis to produce beta adrenergic receptor-dependent regulation of neurons that release corticotropin releasing factor (CRF) into the ventral tegmental area (VTA). CRF promotes the activation of VTA dopamine neurons that innervate the prelimbic prefrontal cortex resulting in D1 receptor-dependent excitation of a pathway to the nucleus accumbens core that mediates cocaine seeking. The stage-setting effects of stress require glucocorticoids, which exert rapid non-canonical effects at several sites within the mesocorticolimbic system. In the nucleus accumbens, corticosterone attenuates dopamine clearance via the organic cation transporter 3 to promote dopamine signaling. In the prelimbic cortex, corticosterone mobilizes the endocannabinoid, 2-arachidonoylglycerol (2-AG), which produces CB1 receptor-dependent reductions in inhibitory transmission, thereby increasing excitability of neurons which comprise output pathways responsible for cocaine seeking. Factors that influence the role of stress in cocaine seeking, including prior history of drug use, biological sex, chronic stress/co-morbid stress-related disorders, adolescence, social variables, and genetics are discussed. Better understanding when and how stress contributes to drug seeking should guide the development of more effective interventions, particularly for those whose drug use is stress related.

Use and abuse of dissociative and psychedelic drugs in adolescence

Adolescence is a period of profound developmental changes, which run the gamut from behavioral and neural to physiological and hormonal. It is also a time at which there is an increased propensity to engage in risk-taking and impulsive behaviors like drug use. This review examines the human and preclinical literature on adolescent drug use and its consequences, with a focus on dissociatives (PCP, ketamine, DXM), classic psychedelics (LSD, psilocybin), and MDMA. It is the case for all the substances reviewed here that very little is known about their effects in adolescent populations. An emerging aspect of the literature is that dissociatives and MDMA produce mixed reinforcing and aversive effects and that the balance between reinforcement and aversion may differ between adolescents and adults, with consequences for drug use and addiction. However, many studies have failed to directly compare adults and adolescents, which precludes definitive conclusions about these consequences. Other important areas that are largely unexplored are sex differences during adolescence and the long-term consequences of adolescent use of these substances. We provide suggestions for future work to address the gaps we identified in the literature. Given the widespread use of these drugs among adolescent users, and the potential for therapeutic use, this work will be crucial to understanding abuse potential and consequences of use in this developmental stage.