First Used Nicotine/Cannabis Product and Associated Outcomes in Late Adolescents.

BACKGROUND: Nicotine and tobacco product (NTP) and cannabis use are common in adolescence/young adulthood and increase risk for negative psychosocial outcomes. This study investigated associations among adolescent/young adults' initial experiences with NTPs, lifetime frequency of substance use, substance-related problems, and mental health symptoms. METHOD: Adolescents and young adults enrolled in a study on NTP and cannabis use were asked at what age they initiated the use of NTPs and were assigned to groups based on which product or substance(s) they reported using at the earliest age. Participants who reported use of NTPs (in isolation, without cannabis) first (N = 78, "NTP-only"), simultaneous use of NTPs and cannabis first (e.g., blunt or bowl; N = 25, "Simult-only"), use of both NTPs in isolation and simultaneous use at the same age (N = 48, "NTP + Simult"), and no NTP use (N = 53, "NTP-naïve") were compared on substance use, substance-related problems, and mental health symptoms. RESULTS: Groups differed on lifetime frequency of NTP, simultaneous, and cannabis use, with NTP users reporting more substance use episodes and substance-related problems than the NTP-naïve group. The lifetime frequency of cannabis use did not differ across NTP use groups. NTP use was associated with increased anxiety and depression, with no significant differences between groups. CONCLUSIONS: Adolescents and young adults who use nicotine may be at increased risk for greater nicotine use and mental health consequences, but initiating NTP use simultaneously with cannabis may not increase the risk of negative outcomes above and beyond nicotine initiation. Prospective longitudinal research is needed to establish temporal associations between first-used NTP/cannabis products and relevant outcomes.

The effects of nicotine use during adolescence and young adulthood on gray matter cerebral blood flow estimates.

Nicotine and tobacco product (NTP) use remains prevalent in adolescence/young adulthood. The effects of NTPs on markers of brain health during this vulnerable neurodevelopmental period remain largely unknown. This report investigates associations between NTP use and gray matter cerebral blood flow (CBF) in adolescents/young adults. Adolescent/young adult (16-22 years-old) nicotine users (NTP; N = 99; 40 women) and non-users (non-NTP; N = 95; 56 women) underwent neuroimaging sessions including anatomical and optimized pseudo-continuous arterial spin labeling scans. Groups were compared on whole-brain gray matter CBF estimates and their relation to age and sex at birth. Follow-up analyses assessed correlations between identified CBF clusters and NTP recency and dependence measures. Controlling for age and sex, the NTP vs. non-NTP contrast revealed a single cluster that survived thresholding which included portions of bilateral precuneus (voxel-wise alpha < 0.001, cluster-wise alpha < 0.05; ≥7 contiguous voxels). An interaction between NTP group contrast and age was observed in two clusters including regions of the left posterior cingulate (PCC)/lingual gyrus and right anterior cingulate cortex (ACC): non-NTP exhibited positive correlations between CBF and age in these clusters, whereas NTP exhibited negative correlations between CBF and age. Lower CBF from these three clusters correlated with urine cotinine (rs=-0.21 - - 0.16; ps < 0.04) and nicotine dependence severity (rs=-0.16 - - 0.13; ps < 0.07). This is the first investigation of gray matter CBF in adolescent/young adult users of NTPs. The results are consistent with literature on adults showing age- and nicotine-related declines in CBF and identify the precuneus/PCC and ACC as potential key regions subserving the development of nicotine dependence.

Associations between nicotine product use and craving among stable daily and non-daily users.

Nicotine craving typically develops shortly after last use and is conceptualized as essential to the development, maintenance, and treatment of nicotine dependence. Previous research has primarily examined the relationship between craving and use among individuals trying to quit smoking, and less is known about this relationship among active users, particularly e-cigarette users. The current study evaluated the association between craving and use by assessing both constructs twice daily over 7 days in a sample of daily (n = 80) and non-daily (n = 34) users of combustible tobacco and e-cigarette products. We used negative binomial regression modeling to analyze the relationship between nicotine craving and use in two ways. First, we evaluated a lagged model in which craving at the time of assessment predicted use during the next time period. Next, we evaluated a model in which maximum craving since the last assessment predicted use during the same time period. Maximum craving was significantly and positively associated with nicotine product use (p <.05) while craving at the time of assessment was not. These associations did not differ depending on use frequency or on specific products used. Findings provide evidence that self-report ratings of craving are associated with greater nicotine and tobacco product use for both frequent and intermittent users. Furthermore, these results may be useful in developing or modifying interventions for a wide variety of nicotine users, including those who are not yet intending to make a change to their nicotine use.

Associations between Tobacco Use, Surges, and Vaccination Status over Time in the COVID-19 Era.

Because COVID-19 is a respiratory and cardiovascular disease, understanding behaviors that impact cardiopulmonary health, such as tobacco use, is particularly important. While early studies suggested no change in prevalence of tobacco use as COVID-19 emerged, pandemic fatigue, shifting levels of COVID-19 transmission, and vaccine availability have all changed since the start of the pandemic. The current study examined whether time, COVID-19 surges, and/or vaccination status were associated with likelihood of daily and non-daily tobacco use over the first 24 months of the pandemic. Data were obtained from electronic health records of healthcare visits (n = 314,787) to four Southern California VA healthcare systems. Multinomial logistic regression analyses indicated that the likelihood of reporting both daily and non-daily tobacco use (versus non-use) increased over time. Daily and non-daily tobacco use were less common at visits that occurred during COVID-19 surges, as well as among veterans vaccinated against COVID-19. Our findings provide new insight into changes of tobacco use patterns and correlates across the first two years of this pandemic, and understanding these associations may facilitate understanding of health-related behaviors and inform clinical treatment of tobacco use disorder during the COVID-19 pandemic.

Non-daily Cigarette Smoking: Stability and Transition to Abstinence in Young Adults.

INTRODUCTION: There is increasing recognition that non-daily cigarette smoking is common in early adulthood but less is known about its stability over time, or what influences transitions to heavier or nonsmoking. We examined the stability of non-daily smoking in a sample of young adults, and tested whether social and cognitive factors predicted transitions to other smoking patterns over time. AIMS AND METHODS: Participants were 579 young adults (18-24 years old at enrollment, 52% male) who were non-daily and never-daily cigarette smokers and California residents. Participants completed 13 waves of assessment over 3 years. We used descriptive statistics to evaluate the frequency of consistent abstinence, defined as no cigarette use at two consecutive waves and no cigarette use at any subsequent waves. Cox and logistic regression were used to test predictors of consistent abstinence. RESULTS: We found that 55% of participants smoked intermittently throughout the study, while 43% were consistently abstinent by the end of the study; few transitioned to daily smoking. Stopping smoking was associated with having fewer smoking friends, smoking less in social situations, having lower positive reinforcement expectancies for smoking, and having stronger intent to quit. Post hoc analyses indicated those who stopped smoking tended to report reductions in positive reinforcement expectancies and increased intent to quit in the 6 months before stopping. CONCLUSIONS: Findings suggest a substantial minority of young adult non-daily smokers may stop on their own, but that the majority continue smoking and may require intervention. Interventions for this population should address social motives and reinforcement expectancies. IMPLICATIONS: The majority of young adults who are non-daily cigarette smokers appear to maintain this habit over an extended period and may require intervention. Interventions that focus on reducing expectancies for positive effects of and social motives for cigarette use and on increasing intent to quit smoking may be most effective.

Evaluation of Risk Perception of Smoking after the Implementation of California's Tobacco 21 Law.

Decreasing smoking initiation remains a public health priority. In 2016, California, in the United States, enacted the Tobacco 21 law, which raised the minimum age for the purchase of tobacco products from age 18 to age 21. This paper evaluates whether the enactment and implementation of the Tobacco 21 law changed how young adults perceive the risk(s) of smoking. Data were drawn from a cohort of emerging adults (n = 575) in California who were non-daily smokers at enrollment and followed quarterly for 3 years. Data were collected during 2015-2019. Piecewise multilevel regression models were used to test for changes in smoking status and perceived risks of cigarettes after Tobacco 21 enforcement began. Findings indicated that the prevalence of current smoking and perceived risks of smoking both declined following Tobacco 21 implementation (ps < 0.001). Post-hoc analyses suggested that post-implementation changes in perceived risk occurred primarily among ongoing smokers. Findings suggest that Tobacco 21 and associated public health measures have been effective, but additional research is needed to disentangle the effects of specific components. Understanding the impact and efficacy of tobacco laws provides great social value to research and implement policies that create intervention(s) on reducing tobacco use initiation.

Young Adult E-Cigarette and Combustible Tobacco Users Attitudes, Substance Use Behaviors, Mental Health, and Neurocognitive Performance.

Nicotine and tobacco product (NTP) use has escalated, largely due to the advent of e-cigarettes. The NTP administration method (i.e., combustible cigarette, e-cigarette) may be an important differentiator. We assessed young adult substance use history, nicotine attitudes, mental health, and neurocognition by the NTP use method. Emerging adults (16-22 year olds) were divided into combustible NTP users (Combustible+ = 79, had used any combustible NTP in the last 6 months), non-combustible users (E-Cig = 43, had used non-combustible NTP, in the past 6 months), and NTP Naïve (n = 79; had not used NTP in the past 6 months) based on past 6-month NTP use patterns. Participants completed self-report and objective neurocognition measures. Analysis of covariance assessed mental health and neurocognition by group, controlling for confounds and correcting for multiple comparisons. Nicotine groups reported more favorable attitudes toward combustible cigarette and e-cigarette use, with taste as the primary reason for e-cigarette use. Combustible+ reported more nicotine dependence and craving. Substance use differed by group, with Combustible+ using the most NTP, alcohol, and cannabis. Nicotine groups reported higher depression and stress symptoms; male Combustible+ reported higher depression symptoms than other same-gender groups. Groups did not differ on neurocognition, though cannabis use was associated with inaccurate emotional Stroop responses. Overall, research suggests that young adult combustible users are likely qualitatively different from non-combustible users. Understanding the unique characteristics related to NTP product use will help guide intervention and prevention development.

Impulsivity-Related Personality Traits as Predictors of E-Cigarette Use among Young Adults over Time.

Introduction: There has been rising concern about e-cigarette usage among teenagers and young adults. As knowledge about the adverse health effects of e-cigarettes accumulates, it is critical to identify factors that may increase risk of vaping initiation and frequency of use. One potential risk factor known to increase risk for other substance use is impulsivity. This study tested the hypothesis that impulsivity prospectively predicts vaping over time. Methods: Active e-cigarette users (n = 137; 51.8% male; Mean age 20 years at baseline) completed 8 waves of assessment over 21 months (2017-2020). The S-UPPS-P impulse behavior scale was used at baseline to measure impulsivity, and frequency of e-cigarette, cigarette, marijuana and alcohol use was calculated at each wave thereafter. Results: Vaping frequency declined over time [Incidence Rate Ratio (IRR) = 0.92]. There were significant, stable, positive associations between e-cigarette use and lack of premeditation (IRR = 1.06) and sensation seeking (IRR = 1.09). Vaping frequency was inversely associated with negative urgency (IRR = 0.95). Positive urgency and lack of perseverance were not associated with frequency of vaping. Conclusion: These findings suggest that young adults who have higher impulsivity of certain types may use e-cigarettes more frequently. Thus, vaping interventions for young adults should address these factors to ensure the greatest impact on public health.

The Effects of Nicotine and Cannabis Co-Use During Late Adolescence on White Matter Fiber Tract Microstructure.

OBJECTIVE: Co-use of cannabis and nicotine and tobacco products (NTPs) in adolescence/young adulthood is common and associated with worse outcomes than the use of either substance in isolation. Despite this, little is known about the unique contributions of co-use to neurostructural microstructure during this neurodevelopmentally important period. This study sought to investigate the interactive effects of nicotine and cannabis co-use on white matter fiber tract microstructure in emerging adulthood. METHOD: A total of 111 late adolescent (16-22 years old) nicotine (NTP; n = 55, all past-year cannabis users) and non-nicotine users (non-NTP; n = 56, 61% reporting cannabis use in the past year) completed demographic and clinical interviews and a neuroimaging session comprising anatomical and diffusion-weighted imaging scans. Group connectometry analysis identified white matter tracts significantly associated with the interaction between nicotine group and past-year cannabis use according to generalized fractional anisotropy (GFA). RESULTS: Nicotine Group × Cannabis Use interactions were observed in the right and left cingulum and left fornix tracts (false discovery rate = 0.053), where greater cannabis use was associated with increased GFA in the cingulum and left fornix, but only when co-used with nicotine. CONCLUSIONS: This report represents the first group connectometry analysis in late adolescent/young adult cannabis and/or NTP users. Results suggest that co-use of cannabis and NTPs results in a structurally distinct white matter phenotype as compared with cannabis use only, although to what extent this may change over time with more chronic nicotine and cannabis use remains to be examined in future work.

Using Virtual Reality to Induce and Assess Objective Correlates of Nicotine Craving: Paradigm Development Study.

BACKGROUND: Craving is a clinically important phenotype for the development and maintenance of nicotine addiction. Virtual reality (VR) paradigms are successful in eliciting cue-induced subjective craving and may even elicit stronger craving than traditional picture-cue methods. However, few studies have leveraged the advances of this technology to improve the assessment of craving. OBJECTIVE: This report details the development of a novel, translatable VR paradigm designed to both elicit nicotine craving and assess multiple eye-related characteristics as potential objective correlates of craving. METHODS: A VR paradigm was developed, which includes three Active scenes with nicotine and tobacco product (NTP) cues present, and three Neutral scenes devoid of NTP cues. A pilot sample (N=31) of NTP users underwent the paradigm and completed subjective measures of nicotine craving, sense of presence in the VR paradigm, and VR-related sickness. Eye-gaze fixation time ("attentional bias") and pupil diameter toward Active versus Neutral cues, as well as spontaneous blink rate during the Active and Neutral scenes, were recorded. RESULTS: The NTP Cue VR paradigm was found to elicit a moderate sense of presence (mean Igroup Presence Questionnaire score 60.05, SD 9.66) and low VR-related sickness (mean Virtual Reality Sickness Questionnaire score 16.25, SD 13.94). Scene-specific effects on attentional bias and pupil diameter were observed, with two of the three Active scenes eliciting greater NTP versus control cue attentional bias and pupil diameter (Cohen d=0.30-0.92). The spontaneous blink rate metrics did not differ across Active and Neutral scenes. CONCLUSIONS: This report outlines the development of the NTP Cue VR paradigm. Our results support the potential of this paradigm as an effective laboratory-based cue-exposure task and provide early evidence of the utility of attentional bias and pupillometry, as measured during VR, as useful markers for nicotine addiction.

Changes in Tobacco Use Patterns among Veterans in San Diego during the Recent Peak of the COVID-19 Pandemic.

The prevalence of tobacco use increases in times of stress; however, during the initial stage of the COVID-19 pandemic, tobacco use rates stayed the same in most populations. Previous work focused on the initial months of the pandemic, while this study examined the changes in tobacco use during a later peak period of the pandemic. We used data from 61,852 visits to the VA San Diego Healthcare System from November 2019 to February 2021, divided into pre-, early, and peak pandemic periods. Multinomial logistic regression was used to test whether the odds of being a daily or non-daily tobacco user varied over time, by demographic group, or with the presence of specific psychiatric diagnoses. Younger Veterans had a greater reduction in the prevalence of non-daily tobacco use between the early and peak periods, while older Veterans had a rise in daily use from pre- to the early pandemic, which returned to baseline during the peak. Individuals with substance use disorder and serious mental illness diagnoses were more likely to report tobacco use, but psychiatric diagnoses did not predict change over time. These findings demonstrate factors that potentially contribute to changes in tobacco use during a public health crisis and may help guide future targeted cessation efforts.

Associations between veteran encounters with suicide prevention team and suicide-related outcomes.

OBJECTIVE: Suicide rates have been of increasing concern across the United States, particularly among military veterans. The Veterans Health Administration has initiated multiple suicide prevention initiatives, but little research has examined the impact of these programs. The purpose of this study was to test the hypothesis that more frequent contact with suicide prevention clinicians would predict lower odds of suicidal behavior. METHOD: Retrospective medical record review was performed for 1364 veterans identified as high risk for suicide during 2012-2018. Logistic regression was used to test whether the number of suicide prevention contacts predicted the odds of suicide attempt, any self-directed violence, or reactivation of high-risk status in the next year, accounting for age, sex, length of high-risk episode, and other mental health contacts. RESULTS: Each additional suicide prevention coordinator contact was associated with 4%-5% lower odds of suicide attempt, suicidal behavior, and reactivation of high-risk status in the next year (ps < 0.05). For suicide attempt and self-directed violence, associations were stronger when considering only initial high-risk episodes (8%-10% lower odds, ps < 0.05). CONCLUSIONS: Findings suggest ongoing support from suicide prevention clinicians can have a significant protective effect. Additional research is needed to identify mechanisms by which this support reduces risk.

Psychiatric Comorbidity and Multimorbidity in the EAGLES Trial: Descriptive Correlates and Associations With Neuropsychiatric Adverse Events, Treatment Adherence, and Smoking Cessation.

INTRODUCTION: Psychiatric and substance use disorders represent barriers to smoking cessation. We sought to identify correlates of psychiatric comorbidity (CM; 2 diagnoses) and multimorbidity (MM; 3+ diagnoses) among smokers attempting to quit and to evaluate whether these conditions predicted neuropsychiatric adverse events (NPSAEs), treatment adherence, or cessation efficacy (CE). AIMS AND METHODS: Data were collected from November 2011 to January 2015 across sixteen countries and reflect the psychiatric cohort of the EAGLES trial. Participants were randomly assigned to receive varenicline, bupropion, nicotine replacement therapy, or placebo for 12 weeks and were followed for an additional 12 weeks posttreatment. NPSAE outcomes reflected 16 moderate-to-severe neuropsychiatric symptom categories, and CE outcomes included continuous abstinence at weeks 9-12 and 9-24. RESULTS: Of the 4103 participants included, 36.2% were diagnosed with multiple psychiatric conditions (20.9% CM, 15.3% MM). Psychiatric CM and MM were associated with several baseline factors, including male gender, nonwhite race or ethnicity, more previous quit attempts, and more severe mental health symptoms. The incidence of moderate-to-severe NPSAEs was significantly higher (p < .01) in participants with MM (11.9%) than those with CM (5.1%) or primary diagnosis only (4.6%). There were no significant (ps > .05) main effects or interactions with treatment condition for diagnostic grouping on treatment adherence or CE outcomes. CONCLUSIONS: While having multiple psychiatric diagnoses increased risk of developing moderate-to-severe NPSAEs during a quit attempt, neither CM nor MM were associated with treatment adherence or odds of quitting. These findings reassure providers to advise smokers with multiple stable psychiatric conditions to consider using Food and Drug Administration (FDA)-approved medications when trying to quit. IMPLICATIONS: Psychiatric MM may be associated with development of NPSAEs when smokers make a medication-assisted quit attempt, but it does not appear to be differentially associated with medication compliance or efficacy. Prescribing healthcare professionals are encouraged to not only promote use of FDA-approved pharmacotherapies by smokers with complex psychiatric presentations, but also to closely monitor such smokers for neuropsychiatric side effects that may be related to their mental health conditions. NCT #: NCT01456936.

Post-legalization changes in marijuana use in a sample of young California adults.

INTRODUCTION: Increasing marijuana use among young adults is a concern due to substantial acute and chronic health risks. More widespread use of marijuana may also lead to increased use of nicotine and tobacco products. California legalized commercial sales of marijuana for recreational use as of January 2018. To our knowledge no studies to date have examined subsequent changes in marijuana use. The goal of this study was to test the hypothesis that marijuana use frequency increased following legalization of recreational sales. We also hypothesized that increased marijuana frequency would predict greater frequency of nicotine/tobacco consumption. METHODS: The study was a secondary analysis of a longitudinal study of tobacco use among non-daily cigarette smokers. Participants were 563 young adults (aged 18-24) enrolled in 2015-16 and followed quarterly for 3 years. RESULTS: A piecewise multilevel regression model indicated that marijuana use frequency did not change over time, including following legalization. More frequent use was associated with younger age and identifying as white (ps < 0.001, which did not change after legalization. Marijuana frequency was moderated by sex (p < .001), with women reporting increasing and men decreasing use over time. It was also associated with tobacco use, and particularly with e-cigarette use following legalization (ps < 0.05). CONCLUSIONS: Findings suggest legalization of recreational marijuana sales had a negligible overall impact on days of use among young adults, but may have prompted increased interest in marijuana among some, particularly women and e-cigarette users. The continuously evolving landscape around these products indicates that ongoing surveillance is critical.

The Association Between Smoking Abstinence and Pain Trajectory Among Veterans Engaged in U.S. Department of Veterans Affairs Mental Health Care.

OBJECTIVE: To prospectively examine associations between smoking and nicotine abstinence and pain trajectory over 12 months among smokers with low, moderate, and severe pain and to assess whether these associations differ over time. DESIGN: A secondary analysis of the "Proactive Outreach for Smokers in VA Mental Health" study, a randomized controlled trial of proactive outreach for veteran smokers engaged in U.S. Department of Veterans Affairs (VA) mental health care. METHODS: Participants were categorized into "low" (n = 616), "moderate" (n = 479), and "severe" pain (n = 656) groups according to baseline pain score. Associations between self-reported abstinence from smoking and nicotine at 6 and 12 months and pain trajectory, measured via the PEG scale (Pain intensity, Enjoyment of life, General activity) composite score, were assessed through the use of general linear mixed models. Interaction tests assessed whether these associations differed at 6 and 12 months. Analyses were conducted within the overall sample and within the separate pain groups. RESULTS: There were significant interactions in the overall sample and the low and moderate pain groups, such that 7-day point prevalence smoking abstinence was associated with lower pain scores at 6 but not 12 months. In the severe pain group, 7-day abstinence from both smoking and nicotine was associated with lower pain scores across both time points. Six-month prolonged abstinence was not associated with pain scores. CONCLUSIONS: In this prospective analysis conducted among veteran smokers engaged in mental health services, 7-day abstinence from smoking and nicotine was associated with significantly lower levels of pain. Education efforts could help better inform smokers on the relationship between smoking and pain.

JUUL E-Cigarette Quit Attempts and Cessation Perceptions in College Student JUUL E-Cigarette Users.

PURPOSE: This study describes the frequency of JUUL e-cigarette (referred to as JUUL) quit attempts and identifies characteristics associated with confidence in quitting and perceived difficulty quitting JUUL. DESIGN: Cross-sectional study from a self-administered online survey. SETTING: Two public southern California universities. PARTICIPANTS: A total of 1,001 undergraduate students completed the survey from February to May 2019. MEASURES: Self-report measures about JUUL included use, history of quit attempts, time to first use, perceived difficulty with cessation/reduction, and confidence in quitting. ANALYSIS: Binary logistic regressions were used to identify demographic and tobacco-related behavioral correlates of JUUL cessation-related perceptions and behaviors. RESULTS: Nearly half of ever-JUUL users (47.8%) reported a JUUL quit attempt. Adjusting for demographic factors and other tobacco product use, shorter time to first JUUL use after waking was associated with lower confidence in quitting JUUL (aOR = 0.02, 0.00-0.13) and greater perceived difficulty in quitting JUUL (aOR = 8.08, 2.15-30.35). Previous JUUL quit attempt history was also associated with greater odds of perceived difficulty quitting JUUL (aOR = 5.97, 1.74-20.53). CONCLUSIONS: History of JUUL quit attempts among college students was common. Those who had previously tried quitting were more likely to perceive difficulty with cessation. Time to first JUUL use, a marker of dependence, was linked with greater perceived cessation difficulty and lower confidence in quitting. These findings suggest that there is a need for cessation and relapse prevention support for college student JUUL users.

The effects of nicotine and cannabis co-use during adolescence and young adulthood on white matter cerebral blood flow estimates.

RATIONALE: Co-use of cannabis and nicotine is common among adolescents/young adults and is associated with poorer psychological and physical outcomes, compared with single substance use. Little is known about the impact of co-use on the developing brain. OBJECTIVES: Preliminary investigation of the effects of nicotine on white matter (WM) cerebral blood flow (CBF) in adolescents/young adults and its potential moderation by cannabis use. METHODS: Adolescent/young adult (16-22 years old) nicotine and tobacco product users (NTP; N = 37) and non-nicotine users (non-NTP; N = 26) underwent a neuroimaging session comprised of anatomical, optimized pseudo-continuous arterial spin labeling, and diffusion tensor imaging scans. Groups were compared on whole-brain WM CBF estimates and their relation to past-year cannabis use. Follow-up analyses assessed correlations between identified CBF clusters and corresponding fractional anisotropy (FA) values. RESULTS: Group by cannabis effects were observed in five clusters (voxel-wise alpha < 0.001, cluster-wise alpha < 0.05; ≥ 11 contiguous voxels): non-NTP exhibited positive correlations between CBF and cannabis use in all clusters, whereas no significant relationships were observed for NTP. Greater CBF extracted from one cluster (including portions of right superior longitudinal fasciculus) was associated with reduced FA for non-NTP group only. CONCLUSIONS: This is the first investigation of WM health as indexed by CBF, and its association with FA, in adolescents/young adults with nicotine and/or cannabis use. Results suggest that cannabis use by itself may be related to increased CBF in WM fiber tracts demonstrating poorer structural intergrity, yet the occurrence of even infrequent NTP use (greater than once per month) appears to diminish this relationship.

Co-occurring Use of Cannabis and Tobacco and the Presence of Acute Respiratory Symptoms among Young Adult Light and Intermittent Smokers.

BACKGROUND: Cannabis use and intermittent smoking are becoming increasingly prevalent among young adults. Thus, identifying health consequences of co-occurring use of these substances represents an emerging research priority. Purpose/Objectives: This study evaluated the relationship between tobacco/cannabis co-use and acute symptoms of respiratory illness among young adult intermittent smokers. We hypothesized that tobacco/cannabis co-use would be more strongly associated with respiratory symptoms relative to use of neither or one product. Methods: A secondary analysis of a three-year observational study was conducted. Non-daily smokers (n = 563) aged 18-24 were recruited via social media and completed electronic surveys at baseline and annually for two years, producing three total assessments. Past-two-week use of tobacco and cannabis was measured at each assessment, as was severity of six acute respiratory symptoms. The respiratory measure was dichotomized to indicate the presence or absence of symptoms. Results: Tobacco/cannabis co-use decreased from 54.8% at baseline to 43.4% at year two (p < .001). Mean respiratory symptoms also declined significantly over time (ps < .05). At each timepoint, co-use was more strongly associated with presence of respiratory symptoms than the use of neither product (aORs = 2.73-4.39, ps ≤ .013). Co-users were also 38%-183% more likely to endorse the presence of respiratory symptoms than single product users at each timepoint (aORs = 1.38-2.83, ps = .023-.212). Conclusions/Importance: Although co-occurring use of tobacco and cannabis by young adults may represent experimental use of multiple substances, it may also promote or exacerbate acute symptoms of respiratory illness. Further exploration with more granular patterns of co-use and across different routes of administration is warranted.

Associations Between Self-Reported and Biological Measures of Nicotine Consumption Among Young Adult Nondaily Cigarette Smokers.

BACKGROUND AND OBJECTIVES: Intermittent, dual use of cigarettes and e-cigarettes is a common pattern among youth and young adults. However, little is known about the validity of self-report measures of nicotine consumption in these populations. The goal of the present study was to examine associations between self-reported frequency of cigarette and e-cigarette use and nicotine levels in hair samples at two assessments 1 year apart. METHODS: Participants (n = 90; 65% female) were 19- to 25-year-old intermittent cigarette smokers recruited from the community for a longitudinal study of tobacco use. They submitted hair samples via mail, 1 and 2 years after enrollment in the parent study. RESULTS: Findings indicated that days of use of both cigarettes and e-cigarettes in the past 30 days independently predicted hair nicotine in the full sample, and when examining only timepoints at which any cigarette use was reported. Timepoints when any e-cigarette use was reported, hair nicotine was positively associated with e-cigarette but not cigarette frequency. DISCUSSION AND CONCLUSIONS: Data suggest that self-report measures are valid methods of assessing intermittent use of both cigarettes and e-cigarettes. Findings also suggest that dual users may tend to consume more nicotine and thus be at greater risk for dependence than single product users. SCIENTIFIC SIGNIFICANCE: These results are among the first to indicate that hair analysis can be used to detect intermittent nicotine exposure via both cigarettes and e-cigarettes. (Am J Addict 2020;29:471-475).

Polytobacco use among young adult smokers: prospective association with cigarette consumption.

BACKGROUND: The risks of polytobacco use among young adults are unclear because we know relatively little about the consistency of multiproduct patterns over time and how these patterns impact cigarette smoking. The purpose of this study was to examine changes in multiple tobacco product use over time and associations with cigarette smoking quantity. METHODS: Participants (n=335; 55% male) were 18-24 years old non-daily cigarette smokers living in California. Polytobacco use patterns were assessed quarterly for 2 years. RESULTS: Transition analyses showed that while the number of products that had been used recently was volatile, the most common pattern was stability between timepoints. A longitudinal negative binomial regression model indicated that those who used more non-cigarette products also reported greater cigarette quantity. The strength of this relationship increased over time. CONCLUSIONS: Findings suggest that individuals who use more tobacco products are at greater risk for increased cigarette smoking and maintaining a multiple product use pattern.