Nicotine, adolescence, and stress: A review of how stress can modulate the negative consequences of adolescent nicotine abuse

Nicotine as a female reproductive toxicant-A review

The preceding decades have seen an extensive emergence of the harmful effects of tobacco smoke on systemic health. Among the various compounds of tobacco, nicotine is one of the principal, potentially hazardous, and toxic components which is an oxidant agent that can affect both men's and women's fertility. Nicotine exerts its effect by modulating the expression of transmembrane ligand-gated ion channels called nicotinic acetylcholine receptors. The activities of female reproduction might be disrupted by exposure to nicotine at various sites, such as the ovary or reproductive tract. It's been demonstrated that nicotine might cause oxidative stress, apoptosis, hormonal imbalance, abnormalities in chromosomal segregation, impact oocyte development, and disruption in ovarian morphology and functions. This review paper summarizes the findings and provides an updated overview of the evidence on the harmful effects of nicotine use on women's reproductive health and the resulting detrimental impacts on the body. Additionally, it provides the detailed possible mechanisms involved in impairing reproductive processes like folliculogenesis, oocyte maturation, steroidogenesis, and pregnancy in different animal species.

Noteworthy trends in maladaptive coping strategies and hindrances to help-seeking behaviour among adolescents living in Malaysia's People's Housing Project (PPR) during the COVID-19 pandemic: A qualitative study

BACKGROUND

COVID-19 has greatly affected the population, especially those in the low socio-economic group, including residents of the People's Housing Project (PPR) in Malaysia. Adolescents residing in PPR communities are among the most vulnerable groups of young people in urban areas, given their pre-existing conditions of vulnerability, face even greater challenges due to the pandemic. Understanding their mental health and coping strategies is vital to grasp how the pandemic impacts their well-being. Hence, this study aims to explore the coping strategies and barriers to help-seeking behaviour among adolescents living in the Malaysia's PPR communities, focusing on the unique mental health challenges exacerbated by the COVID-19 pandemic. Given the socio-economic vulnerabilities and the heightened mental health challenges during the pandemic, this study provides critical insights into how adolescents in PPR communities navigate psychological distress and mental health support.

METHODS

This qualitative study used a phenomenological research design and was conducted from January to December 2022, involving 47 adolescents aged 10 to 17 years old from 37 PPRs in the Klang Valley. Participants were recruited using the purposive sampling method as this study purposely selected adolescents with moderate, moderately severe, and severe for PHQ-9 and/or moderate and severe for GAD-7 based on the screening. Participants who agreed to participate were recruited (with consent from parents/guardians) and interviews were set at the participants' convenience. Data were collected using a semi-structured interview guide to conduct the in-depth interviews (IDI). After each IDI session, the recorded interviews were transcribed. Data from the voice recorder were stored on a password-protected computer, and participants' names were replaced with specific codes to ensure confidentiality. The researchers coded all transcripts independently. The transcripts were analysed inductively using a thematic approach to identify recurring themes.

RESULTS

From the 37 PPRs, 194 adolescents were identified as having psychological distress based on the screening. Among them, 47 agreed to participate in the IDIs, which revealed that these adolescents utilized mainly maladaptive coping strategies, such as avoidance (cognitive distancing, externalization, and internalization), self-harm, vaping, and smoking to deal with stressors related to COVID-19. As for hindrances to help-seeking, three themes were identified such as lack of trust, perceived ineffectiveness of support, and personality.

CONCLUSION

Psychological distress among adolescents was prevalent during the pandemic, and they faced hindrances in seeking help. Coping strategies have been identified to help adolescents manage their psychological distress during the pandemic. It is concerning that some had resorted to maladaptive coping mechanisms. These findings emphasized the need for targeted mental health interventions and support systems tailored to vulnerable communities. These interventions could inform policies aimed at strengthening mental health services, fostering better coping strategies and promoting help-seeking behaviours among adolescents in socio-economically challenged communities.

Association between gender diversity and substance use experimentation in early adolescents

BACKGROUND

Gender diversity, encompassing gender identity beyond traditional binary frameworks, has been associated with substance use during adolescence. However, there is a paucity of studies that consider different dimensions of gender diversity. This study investigates associations between multiple dimensions of gender diversity and substance experimentation in early adolescents.

METHODS

Data from 10,092 adolescents aged 12-13 years from the Adolescent Brain Cognitive Development (ABCD) study were used to assess the relationship between gender diversity and substance experimentation. Gender diversity was measured using multiple dimensions, including identity (transgender), felt gender (congruence between gender identity and assigned sex), gender non-contentedness (dissatisfaction with one's gender), gender expression (adherence to gender expression norms), and place on the gender spectrum (masculine to feminine). Substance use was evaluated using self-reported lifetime and new experimentation (past year) of alcohol, nicotine, and cannabis use. Logistic regression models adjusted for sociodemographic factors were analyzed.

RESULTS

More gender-diverse responses for felt gender, gender non-contentedness, gender expression, and gender spectrum were associated with higher odds of lifetime alcohol experimentation. More gender-diverse responses for gender identity and gender non-contentedness were associated with higher odds of new nicotine experimentation, and more gender-diverse responses for gender identity, felt gender, gender non-contentedness, and gender expression were associated with higher odds of lifetime and new cannabis experimentation.

CONCLUSION

Gender diversity is differentially associated with new and lifetime substance experimentation in early adolescence. Different dimensions of gender diversity may be uniquely associated with substance use behaviors, highlighting the need for targeted interventions in gender-diverse adolescents.

Attention-Deficit/Hyperactivity Disorder and Unhealthy Lifestyle in Adolescence: Unforeseen Role of Allostatic Overload and Psychological Well-Being

Unhealthy lifestyle behaviors (ULBs) are common in early adolescence and could be worsened by Attention-Deficit/Hyperactivity Disorder (ADHD), as well as by specific psychosocial factors, such as stress and unbalanced (i.e., too high or low scores of) psychological well-being (PWB) dimensions. This multi-center study aimed to evaluate how interactions between ADHD symptoms and psychosocial factors associated with ULBs (i.e., Allostatic Overload and multidimensional Psychological Well-Being), considered as moderators, could affect the adoption of ULBs during adolescence. A total of 440 fourteen-year-old adolescents were recruited from six upper secondary schools in Bologna and Rome (Italy) and completed self-report questionnaires on ULBs, ADHD, and psychosocial factors. Relations between ADHD symptomatology and specific ULBs (i.e., impaired sleep, problematic Internet use) were moderated by variables deemed as "negative" (i.e., Allostatic Overload) or "positive" (i.e., PWB dimensions of Self-Acceptance, Personal Growth, Positive Relations, Purpose in Life, Environmental Mastery): when the "negative" moderator is absent and the levels of the "positive" moderators are higher, ULBs decrease among students with lower ADHD symptomatology but increase among students with more severe ADHD. Based on ADHD severity, interventions should aim at promoting a state of euthymia, which consists in balanced PWB dimensions and reflects the optimal level of well-being to fulfill one's own potential and self-realization.

Factors associated with smoking behaviour changes during the COVID-19 pandemic in Japan: a 6-month follow-up study

BACKGROUND

Smoking behaviour may have changed due to the COVID-19 pandemic, the April 2020 revised smoke-free policy and the high prevalence of heated tobacco product (HTP) use in Japan (10.9% in 2020). This study examined the association between these three events and smoking behaviour changes using 6-month follow-up data from before and during the pandemic.

METHOD

Using longitudinal data from an internet survey conducted in February 2020 (baseline) and follow-up in August to September 2020, prevalence ratios (PR) and 95% confidence intervals (95% CIs) for smoking behaviour changes (increase and quit) were calculated using multivariable Poisson regression with adjustments for potential covariates including three event-related five factors: fear of COVID-19, living in a COVID-19 endemic area, workplace smoking rules, self-imposed smoking rules at home and type of tobacco use (cigarette only/HTP only/dual use). A smoker who reported an increase in smoking intensity in the last month was defined as an increase. A smoker who had stopped both cigarettes and HTPs at follow-up was defined as a quit.

RESULTS

We analysed 1810 tobacco users (1448 males (80%); mean age 50.8 years±13.2 SD). At baseline, 930 participants used cigarettes only, 293 HTPs only and 587 both. While 214 (11.8%) users increased smoking intensity, 259 (14.3%) quit both tobacco products. Those who feared COVID-19 were less likely to quit (PR=0.77, 95% CI 0.68 to 0.95), while living in a COVID-19 endemic area was not associated with either smoking behaviour change. Workplace smoking rules were not associated with either smoking behaviour change, but those with no home smoking ban were less likely to quit. Compared with cigarette-only users, HTP-only users were more likely to quit (PR=1.57, 95% CI 1.17 to 2.11), while dual users were more likely to increase smoking intensity (PR=1.35, 95% CI 1.01 to 1.79).

CONCLUSION

During the pandemic, dual cigarette and HTP use increased smoking intensity, whereas HTP-only use was associated with quitting but fear of COVID-19 and not having a home smoking ban made it harder to quit.

Individual Differences in Substance Use Motives, Trauma, and Stress Among College-Based Polysubstance Users

Background: Co-use of alcohol and other drugs within a certain time frame (i.e., polysubstance use) has become increasingly prevalent, particularly among college-aged individuals, but understanding motives for co-use remains limited. Polysubstance use has been associated with a higher likelihood of negative health consequences as compared to single substance use. Objectives: The current study examined associations between motivations for using alcohol, tobacco, and cannabis among college students who use multiple substances versus students using only one substance or no substances. Additionally, we examined the effect of trauma and daily stress on polysubstance use in self-report data from individuals (N=134) participating in the MAPme Study. Results: First, the observed prevalence of polysubstance use was greater than expected by chance, with most individuals co-using alcohol and cannabis. "Alcohol and Other Drug Users" were more frequently motivated to drink for social (β=0.27, CI=[0.07, 0.44]), enhancement (β=0.26, CI=[0.01, 0.42]) and coping (β=0.21, CI=[0.06, 0.47]) reasons compared to individuals who consumed alcohol alone. Conclusions: Individual differences in motivations for use were partly explained by frequency of alcohol use and alcohol problem severity, but not by history of trauma or stress. Finally, while patterns of correlations among motivations for use across substances suggested a general tendency to be motivated to use substances for similar reasons, this was not supported by confirmatory factor models. Overall, shared motives may inform potential behavioral patterns for co-use of substances during college and might advise future treatment efforts.

Co-occurrence of non-communicable disease risk factors among adolescents in Jos, Nigeria

BACKGROUND

The co-occurrence and clustering of risk factors for non-communicable disease (NCD) is a global public health concern.

AIM

This study aimed to assess the co-occurrence and clustering of risk factors for NCDs among in-school and out-of-school adolescents in Jos North Local Government Area, Plateau State, Nigeria.

SETTING

Secondary schools and markets in Jos North Local Government Area.

METHODS

A comparative cross-sectional study was conducted among 377 in-school and 377 out-of-school adolescents, aged 10-19 years of age. An interviewer-administered questionnaire was used to collect information on behavioural and physical risk factors for NCDs. Chi-square and Mann-Whitney U tests were used for comparisons at a 5% level of significance. Statistical analysis was carried out using Statistical Product and Service Solutions (SPSS) version 23.0.

RESULTS

Of the 754 sampled adolescents, 386 (51.2%) were females and 368 (48.8%) were males. Adolescents aged 10-14 years made up 37.8% of the participants, 15 to 17 years of age accounted for 46.9% and 18-19 years 15.3%. Risk factors with the highest prevalence were a sedentary lifestyle (94.2%) and an unhealthy diet (92.4%). Majority (97.2%) had two or more risk factors while 1.9% of adolescents had no risk factor. More in-school adolescents (24.1%) had two risk factors compared to 14.1% of out-of-school adolescents (p 0.001); 14.1% of out-of-school adolescents had five or more risk factors compared to 2.9% of those in school (p 0.001).

CONCLUSION

Co-occurrence and clustering of behavioural and physical risk factors was found among both in-school and out-of-school adolescents.Contribution: This study highlighted the burden of risk factors for NCDs among both in-school and out-of-school adolescents in the North-Central part of Nigeria. This is especially useful in developing targeted interventions to tackle these risk factors.

Age-dependent memory impairment induced by co-exposure to nicotine and a synthetic cannabinoid in mice

Co-use of marijuana and tobacco products is the second most common drug combination among adolescents. Nicotine (NIC) and cannabinoid use during adolescence induce similar detrimental changes, raising the hypothesis that simultaneous exposure could result in even more severe outcomes. Thus, we investigated whether the co-exposure to NIC and the synthetic cannabinoid WIN 55,212-2 (WIN) in adolescent mice causes behavioral outcomes different from those observed after exposure to a single drug. Male Swiss mice were exposed twice daily to NIC, WIN, or NIC + WIN during adolescence (PND28-47) or adulthood (PND70-89). Drug combination led to a greater reduction in weight gain in adolescent mice, while NIC-induced weight loss was observed in adults. During administration, NIC provoked hypothermia, and WIN produced hyperlocomotion in adolescent and adult mice. Animals exposed to NIC + WIN presented a profile of changes similar to those exposed to NIC. After drug exposure, changes in locomotion, thigmotaxis, social preference, prepulse inhibition, and working and recognition memory were evaluated. Adolescent but not adult mice exposed to NIC showed withdrawal-related hyperlocomotion unaffected by WIN co-administration. An age-specific impairment in object recognition memory was induced only by drug co-exposure during adolescence, which resolved spontaneously before reaching early adulthood. A transient decrease in hippocampal α7 nAChR subunit and CB1 receptor mRNA levels was induced by NIC exposure, which may be involved but is not enough to explain the memory impairment. Our work confirms the potential of NIC and cannabinoids association to aggravate some of the individual drug effects during critical neurodevelopmental periods.

Relationship of cardiorenal risk factors with albuminuria based on age, smoking, glycaemic status and BMI: a retrospective cohort study of the UK Biobank data

Introduction

Smoking is harmful, and its cessation is recommended to prevent chronic kidney disease, which often begins with abnormal leakage of albumin in the urine, called albuminuria. Smoking cessation's effect on albuminuria depends on the pack-years smoked, length of abstinence, body mass index (BMI) and glycosylated haemoglobin (HbA1c). Using the UK Biobank data, we examined the relationship between these cardiorenal variables and albuminuria.

Methods

For this study, we selected a UK Biobank cohort with urinary albumin concentration (UAC) in the first and second visits. Participants were divided into progressor and regressor groups, where progressors were defined as those with increased UAC value, and regressors were those with decreased UAC value. Three different logistic regression models were fitted. In model 1, with a cohort design, we explored the impact of a change in age, HbA1c and BMI between the first and second visits and the UAC. In model 2 and 3, in a cross-sectional design, we explored which cardiorenal risk factors were associated with a rise or fall of UAC at the time point of the second visit. Results are expressed in OR and 95% CI.

Results

The prevalence of albuminuria was highest in ex-smokers who started smoking between the ages of 13 and 18. With a mean duration of 51 months, there was no statistically significant relationship between smoking status and BMI with albuminuria. Each year of ageing and each unit of increase in HbA1c (mmol/mol) increased the odds of progression of albuminuria by 20% and 3%, respectively. In ex-smokers, at the time point of the second visit, each year of smoking increased, and each year of abstinence decreased the odds by 4% and 6%, respectively.

Conclusion

Smokers should be supported to stop smoking and remain abstinent despite short-term weight gain. Childhood smoking should be actively discouraged.

Stress effects on spatial memory retrieval and brain c-Fos expression pattern in adults are modulated by early nicotine exposure

The cognitive effects of nicotine are linked to persistent modifications in extended neural systems that regulate cognitive and emotional processes, and these changes occur during development. Additionally, acute stress has modulatory effects on cognition that involve broad neural systems and can be influenced by prior environmental challenges. The effects of nicotine and stress may be interconnected, leading to modifications in a network of shared brain substrates. Here, we explored the interaction between nicotine and stress by evaluating the effects of acute stress exposure in spatial memory retrieval for animals pretreated with nicotine during adolescence or adulthood. Adolescent (35 days old) and adult (70 days old) male Wistar rats were treated for 21 days with one daily subcutaneous injection of nicotine 0.14 mg/ml (free base). 30 days after the last injection, rats were trained in the Barnes maze and tested 24 h later, half the rats were tested under regular conditions, and half of them were exposed to 1 h of restraining stress before the retrieval test, and brain samples were collected and c-Fos immunopositive cells were stained. Prolonged nicotine withdrawal or acute stress improved spatial memory retrieval. Acute stress in nicotine pretreated adults impaired spatial memory retrieval. Nicotine exposure during early adulthood resulted in long-lasting brain adaptations that amplified emotional responses to acute stress after prolonged drug withdrawal.

Comprehensive review of the national surveys that assess E-cigarette use domains among youth and adults in the United States

Surveillance of e-cigarette use among different population groups is important for the timely implementation and evaluation of tobacco regulatory policies. In this review, we identified 13 nationally representative, repeatedly conducted epidemiologic surveys that assess e-cigarette use among U.S. youth and/or adults and have been instrumental in e-cigarette surveillance. These surveys included National Youth Tobacco Survey, Youth Risk Behavior Surveillance System, Monitoring the Future Survey, International Tobacco Control Policy Evaluation Project (ITC) Youth Tobacco and Vaping Survey, Behavioral Risk Factor Surveillance System, National Health Interview Survey, Tobacco Use Supplement of the Current Population Survey, Health Information National Trends Survey, Tobacco Products and Risk Perception Surveys, ITC Four Country Smoking and Vaping Survey, National Health and Nutrition Examination Survey, National Survey on Drug Use and Health, and Population Assessment of Tobacco and Health. These surveys vary in scope and detail, with their unique strengths and the regulatory questions that can be answered using each survey data. We also highlighted the gaps in these surveys and made recommendations for improvement.

The association between substance use and subsequent employment among students: prospective findings from the CONSTANCES cohort

PURPOSE

To examine prospectively associations between substance use and subsequent employment among young students.

METHODS

From the French population-based CONSTANCES cohort, 1427 students who never worked were included between 2012 and 2018 and followed up for 2.1 years on average. Generalized estimating equations computed the odds of being unemployed versus employed according to substance use at baseline controlling for sociodemographic factors and depressive state. Tobacco use (smoking status and number of cigarettes), cannabis use frequency, and at-risk alcohol use according to the Alcohol Use Disorder Identification Test (total score > 7) were introduced separately in the models.

RESULTS

Tobacco use was not significantly associated with employment. Cannabis use at least weekly was associated with increased odds of being unemployed OR 1.73 (1.16-2.57). At-risk alcohol use was no longer significantly associated with employment after adjustment for depressive state, while analyses on sub-scores of alcohol use suggested that alcohol dependence was associated with increased odds of being unemployed OR 1.65 (1.16-2.34).

CONCLUSION

Public health campaigns targeting youth should include lower chances of getting employed among the detrimental roles of regular cannabis use and at-risk alcohol use.

Perceptions of and adherence to early COVID-19-related restrictions and associations with substance use among youth in Canada

INTRODUCTION

As a largely social behaviour, substance use may have decreased for some youth overall in Canada during the COVID-19 pandemic; however, continued use may indicate nonadherence to pandemic-related restrictions and social distancing measures. In a sample of Canadian adolescents (aged 12-19 years), our objective was to examine how substance use (cannabis, binge drinking, cigarettes, vaping) is associated with perceptions of, and adherence to, early COVID-19-related public health measures, taking into consideration sociodemographic factors.

METHODS

Cross-sectional data were retrieved from online data collected during Year 8 of the COMPASS school-based study, during the early months of the COVID-19 pandemic (May-July 2020) in British Columbia, Ontario and Quebec. We fitted two models using generalized estimating equations to examine how substance use was associated with separate measures of (1) perceptions of, and (2) adherence to early COVID-19 restrictions.

RESULTS

In our sample, 10% of adolescents perceived COVID-19 restrictions as too weak and 14% perceived them as too strict. Nearly half (46%) reported taking restrictions very seriously, and 5% did not take them seriously at all. Binge drinking, cigarette use and vaping were associated with perceptions that restrictions were too strict and with nonadherence. However, adolescents who used cannabis were less likely to perceive COVID-19-related restrictions as too strict.

CONCLUSION

This study highlights the association of adolescent substance use with perceptions of, and adherence to, COVID-19-related public health restrictions in Canada. Our findings emphasize a need for continual monitoring of substance use behaviours during the COVID-19 pandemic to better characterize adolescent risk and further inform targeted public health strategies accordingly.

Momentary Associations Among Minority Stress, Craving, Affect, and Nicotine Use Among Sexual Minority Youth

OBJECTIVES

Sexual minority youth are more likely to use nicotine relative to heterosexual youth. The minority stress model posits these disparities are partly due to unique stress (i.e., minority stress) specific to their stigmatized identities. However, there is a dearth of research exploring the fine-grained dynamic interplay between minority stressors, mediating processes, and nicotine use in sexual minority youth's daily lives and natural environment. We leveraged ecological momentary assessment over a 30-day monitoring period to test the mediating effects of craving and negative and positive affect on the momentary associations between minority stressors and subsequent nicotine use among sexual minority youth who were active nicotine users and recruited from the community.

METHODS

Participants were 85 nicotine users, ages 15-19 years old (M age = 17.96, SD = 1.10; 56.6% cisgender female; 56.6% bisexual; 73.5% non-Hispanic White) and half (51.8%) were daily nicotine users.

RESULTS

Results indicated that exposure to a minority stressor was associated with momentary elevations in nicotine craving and negative affect and decreases in positive affect. Nicotine craving and positive affect were also associated with greater probability of subsequent nicotine use. The associations between minority stressors and subsequent nicotine use were mediated through craving and positive, but not negative affect.

CONCLUSIONS

Our findings provide the first ecological momentary assessment evidence of these associations among sexual minority youth and help support and advance both addictions and sexual minority-specific models (e.g., minority stress) of nicotine use among youth.

Altered Development of Prefrontal GABAergic Functions and Anxiety-like Behavior in Adolescent Offspring Induced by Prenatal Stress

Maternal stress can afflict fetal brain development, putting the offspring at risk of cognitive deficits, including anxiety. The prefrontal cortex (PFC), a protracted maturing region, is notably affected by prenatal stress (PS). However, it remains unclear how PS interferes with the maturation of the GABAergic system, considering its functional adjustment in the PFC during adolescence. The present study thus investigated the long-lasting consequences of PS on the prefrontal GABAergic functions of adolescent offspring. Pregnant Sprague–Dawley rats were divided into controls and the PS group, which underwent restraint stress during the last week of gestation. Male pups from postnatal days (PND) 40–42 were submitted to the elevated plus maze (EPM) test. Proteins essentially involved in GABAergic signaling were then examined in PFC tissues, including the K+-Cl− cotransporter (KCC2), Na+-K+-Cl− cotransporter (NKCC1), α1 and α5 subunits of GABA type A receptors (GABAA receptors), and parvalbumin (PV), along with cAMP response element-binding protein phosphorylation (pCREB), which reacts in the plasticity regulation of PV-positive interneurons. The results revealed that the higher anxiety-like behavior of PS adolescent rats concurred with the significant decreases of the KCC2 and α1 subunits, with PV- and pCREB-lowered levels. The findings suggested that PS disrupts the continuance of PFC maturity by reducing the essential elements of GABAergic functions. These changes likely underlie the anxiety emerging in adolescence, possibly progressing to mental disorders.

Perceived stress and E-cigarette use during emerging adulthood: A longitudinal examination of initiation, progression, and continuation

E-cigarettes are the most commonly used tobacco product among youth and young adults in the US. Limited research has examined how stress impacts e-cigarette use among young people. We examine the longitudinal associations between perceived stress scale (PSS) score and e-cigarette use behaviors among a diverse cohort of emerging adults. We analyzed two waves of data collected in Fall 2019 (baseline) and Spring 2020 (6-month follow-up) of the Texas Adolescent Tobacco and Marketing Surveillance (TATAMS) system. Participants were classified into three mutually exclusive subsamples at baseline: (1) n = 1177 never e-cigarette users; (2) n = 806 ever but not current (past 30-day) e-cigarette users (i.e., ever users); and (3) n = 257 current (past 30-day) e-cigarette users. Three multivariate logistic regression models examined the relationship between PSS at baseline and: (1) initiation among never users; (2) progression to current use among ever users; and (3) continuation among current users, at 6-month follow-up. PSS scores were standardized using z-scores. Models controlled for race/ethnicity, sex, age, ever marijuana use, and ever use of other tobacco products. Mean age ranged from 18.6 to 19.4 among cohorts. Risk for e-cigarette progression among ever users (aOR: 1.30; 95%CI: 1.01-1.69) and e-cigarette continuation among current users (aOR: 1.33 (95%CI: 1.01-1.75) increased with each unit increase in PSS score at baseline. PSS at baseline was not associated with e-cigarette initiation among never users. PSS predicted greater risk of e-cigarette progression and continuation but not initiation among a diverse cohort of emerging adults. E-cigarette prevention and cessation strategies should consider perceived stress an important risk factor for e-cigarette use during emerging adulthood.

Health effects of electronic cigarettes

E-cigarettes cause harm to adolescent users. The devices and constituents create multiple substances which are toxic on inhalation, including nicotine, metallic nanoparticles, particulate matter, and carbonyls. In addition, there is a robust relationship between youth vaping and use of combustible cigarettes as adults. This finding is based on longitudinal research and is found among youth who were at low risk for use of combustible cigarettes. Therefore, the most substantially confirmed health hazard of youth vaping is creating a new generation of smokers of combustible cigarettes and the documented health risks of such use. The physiological and psychological harms of nicotine dependence during adolescence also have been well documented. Additionally, population-based research has shown a consistent link between current vaping and respiratory issues during adolescence itself. Significant lung disease (EVALI) has occurred in adolescents and not all cases are linked to vitamin E acetate. Finally, extrapolating research on adults to adolescents raises the possibility that e-cigarette use is linked to pre-symptomatic cardiovascular dysfunction and may have a significant health impact during adulthood. The combination of this evidence, from pre-clinical to population-based longitudinal studies, conclusively demonstrates that e-cigarettes are not safe for youth.

Unique effects of nicotine across the lifespan

Smoking remains the leading cause of preventable death in the United States. Although combustible cigarettes are largely being replaced by tobacco-free products, nicotine use continues to increase in vulnerable populations, including youth, adolescents, and pregnant women. Nicotine exerts unique effects on specific brain regions during distinct developmental periods due to the dynamic expression of nicotinic acetylcholine receptors (nAChRs) throughout the lifespan. Nicotine exposure is a health concern not only for adults but also has neurotoxic effects on the fetus, newborn, child, and adolescent. In this review, we aim to highlight the dynamic roles of nAChRs throughout gestation, adolescence, and adulthood. We also provide clinical and preclinical evidence of the neurodevelopmental, cognitive, and behavioral consequences of nicotine exposure at different developmental periods. This comprehensive review highlights unique effects of nicotine throughout the lifespan to help elucidate interventions and public health measures to protect sensitive populations from nicotine exposure.

Tobacco smoking and mental disorders in Australian adolescents

OBJECTIVES

This study aimed to (1) examine the strength of the association between mental disorders/mental health problems, risk behaviours and tobacco smoking among Australian adolescents, (2) compare rates of tobacco smoking among Australian adolescents with major depressive disorder, attention-deficit/hyperactivity disorder and/or conduct disorder in 2013/14 vs 1998, and (3) identify the extent to which an association between tobacco smoking and mental health problems among adolescents can be attributed to non-mental health risk factors.

METHODS

The study utilised data from the first (1998) and second (2013/14) child and adolescent components of the National Surveys of Mental Health and Wellbeing. Both surveys identified nationally representative samples of Australian young people aged 4-17 years, living in private dwellings. Information was collected from parents and 13- to 17-year-olds about mental disorders, mental health problems, risk behaviours and tobacco smoking.

RESULTS

In the 2013/14 survey, the rate of current tobacco smoking among those with a mental disorder was 20% compared to 5% in those without a mental disorder. Rates were highest for young people with conduct disorder (50%), major depressive disorder (24%) and anxiety disorders (19%). In 2013/14, 38% of current tobacco smokers had a mental disorder and 32% reported self-harm and/or suicidal ideation vs 10% and 5%, respectively, among adolescents who had never smoked. Females with mental disorders or reporting self-harm or suicidal ideation had higher rates of current smoking than males. Other significant factors associated with current smoking included school-related problems, binge eating and having had more than one sexual partner.

CONCLUSION

While smoking rates in 13- to 17-year-olds with mental disorders had declined since 1998, the strength of the association between mental disorders and smoking had increased, especially among females. Our findings highlight the need to address the tobacco smoking among adolescents with mental disorders, particularly females.

Ginseng alleviates folliculogenesis disorders via induction of cell proliferation and downregulation of apoptotic markers in nicotine-treated mice

Background

Ginseng is a powerful phytoestrogen with high antioxidant properties.

Objective

This study aimed to evaluate the effect of Panax Ginseng (PG) on folliculogenesis, proliferation, and apoptosis in the ovary impaired by nicotine.

Methods

Forty adult mice were divided into five groups. Control, sham, and nicotine groups, and co-treated groups of nicotine and ginseng in doses of 0.5 and 1 g/kg. Folliculogenesis was assessed via histopathology and serum evaluation of estradiol, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) by ELISA. Lipid peroxidation and antioxidant enzyme activities both in homogenate tissue and serum were assayed by colorimetric analysis. Apoptotic markers of cytochrome c (Cyt c), Bax, and Bcl-2 were evaluated by RT-PCR. Proliferative index was studied by the Ki-67 immunostaining procedure.

Results

In comparison to the control or sham groups, nicotine significantly reduced the levels of FSH, LH, and estradiol hormones. An insignificant reduction was observed in the progesterone hormone. Nicotine reduced all healthy follicle numbers, except primordial (P = 0.001). Malondialdehyde (MDA) was increased in tissue and serum in the nicotine group (P = 0.01). Serum catalase (CAT) and enzymatic activity of superoxide dismutase (SOD) both were reduced in tissue and the serum, in the nicotine group. Nicotine induced a reduction in the proliferative indexes of granulosa and theca cells in pre-antral and antral follicles (P = 0.001). However, its effect on the proliferative index of stroma cells was not significant. Apoptotic markers were elevated in the nicotine group (P = 0.001). Co-treatment with ginseng elevated all sex hormones, increased healthy follicles, and reduced tissue or serum lipid peroxidation, compared with the nicotine group (p < 0.05). Co-Treatment with ginseng also reduced the expression of apoptotic markers and increased the proliferative indexes in granulosa and theca cells in pre-antral and antral follicles and also in stroma cells, in comparison to the nicotine group (P = 0.001). All above-mentioned alterations following treatment with ginseng were remarkable, especially in the dose of 1 g/kg.

Conclusion

This study showed ginseng protects folliculogenesis via alteration of hypothalamic- pituitary–gonadal (HPG) axis, induction of proliferation in ovarian somatic cells, reduction of lipid peroxidation, and downregulation of apoptotic markers in the mouse ovary, treated with nicotine.

Lacidipine Attenuates Symptoms of Nicotine Withdrawal in Mice

Nicotine-withdrawal after daily exposure manifests somatic and affective symptom including a range of cognitive deficits. Earlier studies suggested participation of L-type calcium channels (LTCCs) in development of nicotine dependence and expression of withdrawal signs. An upsurge in Ca2+-induced oxidative stress in brain underlies the biochemical events and behavioral signs of nicotine-withdrawal. The present study is aimed to explore the effects of lacidipine (LTCC antagonist) against nicotine-withdrawal. Swiss albino mice were administered ( -)-nicotine hydrogen tartrate (3.35 mg/kg, t.i.d.) from days 1 to 7 and alongside lacidipine (0.3, 1, and 3 mg/kg, i.p.) given from days 1 to 14. Somatic withdrawal signs were noted 48 h after last dose of nicotine. Bay-K8644 (LTCC agonist) was administered in mice subjected to nicotine-withdrawal and lacidipine (3 mg/kg) treatments. Behavioral tests of memory, anxiety, and depression were conducted on days 13 and 14 to assess the effects of lacidipine on affective symptoms of nicotine-withdrawal. Biomarkers of oxido-nitrosative were quantified in the whole brain. Nicotine-withdrawal significantly enhanced somatic signs and symptoms of anxiety, depression, and memory impairment in mice. Lacidipine (1 and 3 mg/kg) attenuated nicotine-withdrawal induced somatic symptoms and also ameliorated behavioral abnormalities. Nicotine-withdrawal triggered an upsurge in brain lipid peroxidation, total nitrite content, and decline in antioxidants, and these effects were attenuated by lacidipine. Bay-K8644 significantly abolished improvement in somatic and affective symptoms, and antioxidant effects by lacidipine in mice subjected to nicotine-withdrawal. Lacidipine mitigated nicotine-withdrawal triggered somatic and affective symptoms owing to decrease in brain oxido-nitrosative stress.

The impact of adolescent nicotine exposure on alcohol use during adulthood: The role of neuropeptides

Nicotine and alcohol abuse and co-dependence represent major public health crises. Indeed, previous research has shown that the prevalence of alcoholism is higher in smokers than in non-smokers. Adolescence is a susceptible period of life for the initiation of nicotine and alcohol use and the development of nicotine-alcohol codependence. However, there is a limited number of pharmacotherapeutic agents to treat addiction to nicotine or alcohol alone. Notably, there is no effective medication to treat this comorbid disorder. This chapter aims to review the early nicotine use and its impact on subsequent alcohol abuse during adolescence and adulthood as well as the role of neuropeptides in this comorbid disorder. The preclinical and clinical findings discussed in this chapter will advance our understanding of this comorbid disorder's neurobiology and lay a foundation for developing novel pharmacotherapies to treat nicotine and alcohol codependence.

"I smoked that cigarette, and it calmed me down": A qualitative analysis of intrapersonal, social, and environmental factors influencing decisions to smoke among youth experiencing homelessness

INTRODUCTION

Approximately 70% of youth experiencing homelessness smoke cigarettes; many try to quit and are interested in formal smoking cessation programs. The purpose of this study was to describe the intrapersonal, social, and environmental contexts associated with the most recent smoking experience among youth experiencing homelessness and (2) identify differences in contextual factors by age and willingness to quit.

METHODS

Thirty-six youth experiencing homelessness aged 14-24 years and who reported current smoking were recruited from a drop-in center in a Midwestern city. Semi-structured in-person interviews were analyzed to understand smoking behaviors.

RESULTS

Two-thirds of participants reported stress and nicotine dependence as primary reasons for smoking, and older youth (aged 18-24 years) reported smoking to de-escalate negative emotions associated with stressful events. For 25% of participants, and especially older youth, smoking was described as part of a routine. Over 80% of participants smoked outside at the homeless drop-in center or the places they lived. Social prompts from drop-in center peers regularly preempted smoking. Younger youth (aged 14-17 years) reported smoking socially while older youth were more likely to smoke alone.

CONCLUSIONS

For youth experiencing homelessness, smoking is integrated into daily life and is often used to manage stress associated with homelessness and engage socially with homeless peers. Multicomponent interventions to reduce structural stressors specific to homelessness, change social smoking norms (environmental and social context), and address stress management and nicotine dependence (intrapersonal context) are needed to support smoking cessation among youth experiencing homelessness.

IMPLICATIONS

Youth experiencing homelessness overwhelmingly described how daily stressors associated with homelessness and nicotine dependence preceded recent smoking. Older youth (aged 18-24 years) also reported smoking as "routine", which likely underscores nicotine dependence in this group. Younger youth (aged 14-17 years) described social smoking. Researchers must develop optimized multilevel interventions to support youth experiencing homelessness who want to quit smoking. Interventions directly targeting social determinants of stress (e.g., poverty, housing instability, food insecurity) and linkages to supportive services are needed. Complementary strategies to address stress coping and nicotine dependence (intrapersonal context) and social smoking norms (social and environmental context) are also necessitated.

The Role of Snack Choices, Body Weight Stereotypes and Smoking Behavior in Assessing Risk Factors for Adolescent Overweight and Obesity

This study investigated the relationship of behavioral factors, such as snack choices, obesity stereotypes and smoking with adolescents’ body weight. Individual-level data for 1254 Greek youths were selected via a formal questionnaire. Snack choices seem to be gender specific with girls showing a stronger preference for healthier snacks. Frequent consumption of high-calorie and more filling snacks was found to increase Body Mass Index (BMI) in both genders. Fruit/vegetable snacks were associated with lower body weight in females, whereas cereal/nut snacks had a negative influence in males’ BMI. The majority of participants expressed anti-fat attitudes and more boys than girls assigned positive attributes to lean peers. The endorsement of the thin-ideal was positively associated with the BMI of both adolescent boys and girls. This study also revealed that neglecting potential endogeneity issues can lead to biased estimates of smoking. Gender may be a crucial moderator of smoking–BMI relationships. Male smokers presented a higher obesity risk, whereas female smokers were more likely to be underweight. Nutrition professionals should pay attention to increase the acceptance of healthy snack options. Gender differences in the influence of weight stereotypes and smoking on BMI should be considered in order to enhance the efficacy of obesity prevention interventions.

Inside the adolescent voice: A qualitative analysis of the appeal of different tobacco products

INTRODUCTION

While cigarette use has decreased, adolescents’ overall use of tobacco (e.g. e-cigarettes, cigars, and hookah) has increased. The purpose of this qualitative study is to highlight the decision-making process of adolescents to use certain products over others and why certain tobacco products appeal to them.

METHODS

Twenty-five participants were recruited from a larger study surveying adolescents’ perceptions and tobacco use (772 high school students). The participants were involved in one-on-one semi-structured phone interviews on the appeal of different tobacco products. Interviews were recorded, transcribed verbatim, and analyzed by identifying relevant codes and themes.

RESULTS

Participants for this study had a mean age of 16.4 (SD=1.2) years; over half (14/25) were female. Three major themes emerged from the interviews: 1) social context and circumstances to use, including using and sharing with peers, and reducing boredom; 2) importance of flavors, smell, taste, smoke tricks, and accessibility of products; and 3) misperceptions and misinformation of product risks.

CONCLUSIONS

The findings that emerged showed why participants favored certain tobacco products, especially e-cigarettes, over others. The results support areas for future research and practice, and inform how interventions can better address the appeal of different tobacco products to ultimately prevent adolescent use.

Factors associated with smoking susceptibility among high school students in western Spain

The Expanded Susceptibility to Smoking Index (ESSI) is based on the combination of susceptibility to smoking and curiosity about smoking. The ESSI can identify young people who are at risk of starting to smoke cigarettes and related products. The objective of this study was to analyse the ESSI results and to examine factors associated with ESSI scores in students between 12 and 16 years of age. Sociodemographic, social/environmental and personal variables were analysed, and the ESSI value was determined for non-smoking students recruited from three schools in western Spain. Regression models were used to examine the factors associated with smoking for the entire sample and the factors associated with ESSI scores in the non-smoking population. Of the 377 participants who were analysed, 20.4% were smokers. Among the non-smokers, 53.5% and 55.3% presented medium-high ESSI scores for cigarettes and e-cigarettes, respectively, and 39.8% presented medium-high ESSI scores for hookah use. A higher ESSI score was associated with greater exposure to people smoking in the home, having more friends who smoke, alcohol consumption, and a higher impulsivity scale score. These findings reinforce the importance of reducing peer pressure and suggest the important role of resolve under conditions of positive affect on reducing impulsivity. Approaches based on self-efficacy could be addressed in preventive programmes developed in educational settings.

Associations between the Type of Tobacco Products and Suicidal Behaviors: A Nationwide Population-Based Study among Korean Adolescents

The relationships between multiple tobacco products, such as heated tobacco products (HTPs), electronic cigarettes (ECs), and combustible cigarettes (CCs), and suicide-related behaviors among adolescents have not been extensively researched. This study examined the associations between the type of tobacco products used and suicidal thoughts, plans, and attempts among Korean adolescents. Data from the 2019 Korea Youth Risk Behavior Web-Based Survey were analyzed, and participants included 57,069 individuals aged 13–18 years. A multivariable logistic regression analysis was performed. Of the total participants, 13.0%, 4.0%, and 2.9% reported suicidal thoughts, suicidal plans, and suicidal attempts, respectively. After adjusting for confounding variables, all tobacco product users showed a greater likelihood of having suicidal behavior. However, compared with never users, dual users of CCs and HTPs were not significantly associated with having suicidal thoughts and attempts. Among tobacco product users, dual users of ECs and HTPs and triple users of CCs, ECs, and HTPs showed a greater likelihood of having suicidal behavior. Considering the prevalence of suicide and the increasing trend of using multiple tobacco products among Korean adolescents, tobacco control policies should monitor the effects of different products.

Social Learning, Social Bonds, Self-Control and Adolescent Nicotine Vaping

The aim of this study was to examine whether three theories of adolescent substance use-social learning, social bonding, and self-control-were useful for predicting adolescent nicotine vaping. Methods: The analysis utilized data on U.S. 8th and 10th grade students from the 2017 and 2018 Monitoring the Future (MTF) studies, repeated cross-sectional surveys that included 11,624 youth who responded to questions about past 12-month nicotine vaping. Measures from each of the three theories were used to predict the outcome using a zero-inflated negative binomial model. Results: The results demonstrated that variables from social learning and self-control theories were key predictors of nicotine vaping. Friends' substance use appeared as the most consequential predictor, followed by low self-control or higher risk-taking propensities. An interaction effect also suggested that friends' substance use had a stronger association with nicotine vaping among youth who reported higher self-control. Conclusions/Importance: The findings suggested that adolescent nicotine vaping is a consequence of social learning influences and low self-control. Future research should explore these and similar factors in more detail.

Expression analysis of hippocampal and amygdala CREB-BDNF signaling pathway in nicotine-induced reward under stress in rats

Extensive research has shown that individuals are more sensitive to develop addiction and drug taking under stress state. The present study includes an expression analysis to identify the possible role of hippocampal and amygdala CREB (cAMP response element-binding protein) and BDNF (Brain-derived neurotrophic factor) activation in nicotine-induced conditioned place preference (CPP) under exposure to acute or sub-chronic stress. Using western-blot technique, CREB phosphorylation was shown to increase in the hippocampus and the amygdala following nicotine-induced CPP. The hippocampal level of BDNF was increased following nicotine administration and in the nicotine-treated animals exposed to acute stress. In animals exposed to acute stress, the amygdala ratios of the pCREB/CREB decreased, while pre-treatment of the animals with nicotine (0.1 mg/kg) decreased this ratio only in the hippocampus. Sub-chronic stress decreased the pCREB/CREB ratios in the hippocampus and the amygdala. Interestingly, sub-chronic stress-induced increase of nicotine reward only decreased the hippocampal pCREB/CREB ratio. The levels of BDNF in the hippocampus and the amygdala decreased under acute stress. Acute stress-induced increase of nicotine reward increased BDNF levels in the hippocampus. Moreover, the animals' exposure to the CPP apparatus without any drug administration increased the ratios of pCREB/tCREB and BDNF/β-actin in the targeted sites. In summary, the present study indicate that the alterations of the ratio of pCREB/CREB and also the level of BDNF in the hippocampus may be critical for enhancing nicotine reward under stress condition. The evidence from this study suggests the distinct roles of the hippocampus and the amygdala in mediating nicotine reward under stress.

Prevalence and factors associated with smoking among Tunisian secondary school-adolescents

OBJECTIVES

This study aimed to estimate the extent of smoking experience among high and middle school adolescents in Southern Tunisia and to delineate its potential associated factors.

METHODS

We conducted a cross-sectional study among middle and high school-adolescents in the governorate of Sfax, South of Tunisia in the 2017-2018 school-years. A questionnaire was anonymously administered to a representative sample of 1,210 school-adolescents randomly drawn.

RESULTS

The mean age of the school-adolescents was 15.6 ± 4.2 years. The prevalence of lifetime smoking was 16.7% (95% CI=[14.7-18.8%]) (boys 32.6%; girls 5.9%;p<0.001). Among the respondents, 13.9% (95% CI=[11.9-15.8%]) were current smokers. In multivariate logistic regression analysis, independent associated factors of current smoking were male gender (Adjusted (AOR)=10.2; p<0.001), 16-17 and 18-19-year age-groups (AOR=2; p=0.005 and AOR=2.6; p=0.001, respectively), below average academic performance (AOR=5.2; p=0.012), divorced parents (AOR=3.9; p=0.007), family monthly income ≥800 dollars (AOR=2.1; p=0.001), having a part time job (AOR=3.9; p<0.001) and a perceived high stress level (AOR=1.98; p=0.008). Secondhand smoke (AOR=1.8; p=0.011) and concomitant alcohol drink (AOR=14.56; p<0.001) were independent predictors of current smoking, while high education level of the father was independently associated with lower prevalence of current smoking (AOR=0.17; p<0.001).

CONCLUSION

The prevalence of lifetime and current smoking were relatively high in Southern Tunisian middle and high schools. Multilevel influences on youth smoking behavior had been identified, which reflected the need to conceive appropriate school interventions and effective antismoking education program.

The Effects of Nicotine on Development

Recently, there has been a significant increase in the use of noncombustible nicotine-containing products, including electronic cigarettes (e-cigarettes). Of increasing popularity are e-cigarettes that can deliver high doses of nicotine over short periods of time. These devices have led to a rise in nicotine addiction in adolescent users who were nonsmokers. Use of noncombustible nicotine products by pregnant mothers is also increasing and can expose the developing fetus to nicotine, a known teratogen. In addition, young children are frequently exposed to secondhand and thirdhand nicotine aerosols generated by e-cigarettes, with little understanding of the effects these exposures can have on health. With the advent of these new nicotine-delivery systems, many concerns have arisen regarding the short- and long-term health effects of nicotine on childhood health during all stages of development. Although health studies on nicotine exposure alone are limited, educating policy makers and health care providers on the potential health effects of noncombustible nicotine is needed because public acceptance of these products has become so widespread. Most studies evaluating the effects of nicotine on health have been undertaken in the context of smoke exposure. Nevertheless, in vitro and in vivo preclinical studies strongly indicate that nicotine exposure alone can adversely affect the nervous, respiratory, immune, and cardiovascular systems, particularly when exposure occurs during critical developmental periods. In this review, we have included both preclinical and clinical studies to identify age-related health effects of nicotine exposure alone, examining the mechanisms underlying these effects.

Stressful life events are associated with perinatal cigarette smoking

Perinatal smoking, including smoking during pregnancy and postpartum smoking relapse, is a persistent public health problem. While childhood trauma has been linked to perinatal smoking, less is known about the association with more proximal stressful life events (SLEs). The objective of this study was to examine the association between SLEs that occurred during the year prior to childbirth with perinatal smoking. Using the Pregnancy Risk Assessment Monitoring System 2009-2011, perinatal smoking was assessed at three time points: (1) three months prior to pregnancy, (2) the last three months of pregnancy, and (3) two to six months postpartum. Survey respondents endorsed up to 13 SLEs (i.e., death of someone close). SLEs were analyzed individually, as well as using a cumulative score (range 0-13). Weighted analyses included unadjusted and adjusted logistic regression. Among those who smoked prior to pregnancy (n = 15,316), 48% (n = 7308) reported quitting smoking during pregnancy. Of those, 44% (n = 3126) reported postpartum smoking relapse. A total of 11 SLEs were associated with smoking during pregnancy and 2 SLEs were associated with postpartum smoking relapse. The odds of continued smoking during pregnancy was 12% higher for each SLE endorsed (adjusted odds ratio [aOR] = 1.12, 95% confidence interval [CI]: 1.09, 1.15) and this association was attenuated in relation to the odds of postpartum smoking relapse (aOR = 1.03, 95% CI: 0.99, 1.08). SLEs are associated with perinatal smoking. Additional research is needed to elucidate the mechanisms of action and to develop interventions specific to the needs of women who experience SLEs.

Stress, attention deficit hyperactivity disorder (ADHD) symptoms and tobacco smoking: The i-Share study

BACKGROUND

The contribution of mental health to the risk of smoking is increasingly acknowledged but still insufficiently studied during the key period of student life. In particular, the simultaneous action of stress and Attention Deficit Hyperactivity Disorder (ADHD) symptoms on the risk of smoking remains poorly understood.

AIMS

To assess the effects of stress and ADHD symptoms on tobacco smoking.

METHOD

Multivariate modeling was conducted on the French i-Share study (n=8110, median age 20.3 years, 74.8% females, 32.9% regular/occasional smokers) to evaluate the associations between stress, ADHD symptoms and tobacco smoking, adjusting for potential family/socio-demographic confounders.

RESULTS

Students with high levels of stress were more likely to smoke>10 cigarettes/day (adjusted odds ratio (aOR): 1.48, 95% CI: 1.12-1.96) than those with low levels of stress. Students with high levels of ADHD symptoms were more likely to smoke>10 cigarettes/day (aOR: 2.08, 95% CI: 1.58-2.75) than those with low levels of ADHD symptoms.

CONCLUSIONS

Stress and ADHD contribute independently to the risk of smoking. Interventions targeting each condition are likely to reduce the burden of tobacco use in students.

Bi-directional associations of electronic and combustible cigarette use onset patterns with depressive symptoms in adolescents

Whether well-documented patterns of mental health comorbidity with adolescent combustible cigarette use extend to e-cigarette use is unclear. Demonstrating associations between e-cigarette and combustible cigarette use with mental health symptomatology across adolescence may be important for promoting accurate perceptions of populations at risk for and potential consequences of tobacco product use. Adolescents (N=2460; mean age at baseline=14.1; 53.4% female; 44.1% Hispanic) who had never previously used combustible or e-cigarettes were assessed at baseline, and 6- and 12-month follow-ups in Los Angeles, CA (2013-2014). Logistic regression was used to examine associations between baseline depressive symptoms and onset of e-cigarette and cigarette single product and dual use at follow-ups. Latent growth modeling was used to examine associations between sustained use of either product (vs. non-use) and changes in depressive symptoms over 12-months. Higher baseline depressive symptoms predicted subsequent onset of cigarette (OR=1.024, 95% C.I.=1.009-1.055), e-cigarette (OR=1.015, C.I.=1.003-1.023), and dual use of both products (OR=1.021, C.I.=1.003-1.043). Sustained use of e-cigarettes over the 12-month observation (vs. non-use) was associated with a greater rate of increase in depressive symptoms over time (b=1.272, SE=0.513, p=0.01). Among those who sustained use of e-cigarettes, higher frequency of use was associated with higher depressive symptoms at the final follow-up (B=1.611, p=0.04). A bi-directional association of depressive symptoms with e-cigarette use onset across mid adolescence was observed. Further research on the causal nature, etiological underpinnings, and intervention implications of mental health and tobacco product use comorbidity is warranted.

The effects of nicotine in the neonatal quinpirole rodent model of psychosis: Neural plasticity mechanisms and nicotinic receptor changes

Neonatal quinpirole (NQ) treatment to rats increases dopamine D2 receptor sensitivity persistent throughout the animal's lifetime. In Experiment 1, we analyzed the role of α7 and α4β2 nicotinic receptors (nAChRs) in nicotine behavioral sensitization and on the brain-derived neurotrophic factor (BDNF) response to nicotine in NQ- and neonatally saline (NS)-treated rats. In Experiment 2, we analyzed changes in α7 and α4β2 nAChR density in the nucleus accumbens (NAcc) and dorsal striatum in NQ and NS animals sensitized to nicotine. Male and female Sprague-Dawley rats were neonatally treated with quinpirole (1mg/kg) or saline from postnatal days (P)1-21. Animals were given ip injections of either saline or nicotine (0.5mg/kg free base) every second day from P33 to P49 and tested on behavioral sensitization. Before each injection, animals were ip administered the α7 nAChR antagonist methyllycaconitine (MLA; 2 or 4mg/kg) or the α4β2 nAChR antagonist dihydro beta erythroidine (DhβE; 1 or 3mg/kg). Results revealed NQ enhanced nicotine sensitization that was blocked by DhβE. MLA blocked the enhanced nicotine sensitization in NQ animals, but did not block nicotine sensitization. NQ enhanced the NAcc BDNF response to nicotine which was blocked by both antagonists. In Experiment 2, NQ enhanced nicotine sensitization and enhanced α4β2, but not α7, nAChR upregulation in the NAcc. These results suggest a relationship between accumbal BDNF and α4β2 nAChRs and their role in the behavioral response to nicotine in the NQ model which has relevance to schizophrenia, a behavioral disorder with high rates of tobacco smoking.