Alternatively, it may be that during the COVID-19 pandemic and the resulting social distancing and isolation, engaging with people including clinicians, counselors, and peers during substance use treatment respondents could have relatively higher social connection which may have served as a protective factor . Finally, it may be that people whose drinking was well-controlled were more likely to be able to remain engaged in substance use treatment . Similar factors of engaging in HIV care where people are more likely asked about alcohol use and being advised to reduce or abstain from alcohol based given the known poor HIV outcomes with alcohol use may be contributing to the lower alcohol use in these persons. A limitation of this study is the varying time at which the participants completed the survey.The rapidly changing circumstances of each location in-terms of COVID-19 transmission and mitigation burden likely varied between cohorts. Participants completing surveys early in the pandemic might be systematically different compared to participants completing surveys later. While we controlled for cohort and survey wave, our estimates may skew towards less alcohol use because early participants had yet to experience the burden of COVID-19 and subsequently increased alcohol consumption. Alternatively, people who could be reached to respond to a survey during the pandemic might have had a lower prevalence of alcohol use than all people eligible to complete such a survey. As the cohorts complete new survey waves there will be opportunities to see how alcohol and other drug use changed over time. We did not have measurements of depression or depressive symptoms,commercial greenhouse supplies which we would expect to also be associated with alcohol consumption and which may have provided a richer picture of alcohol consumption in this population during the COVID-19 pandemic .
Finally, when compared to our cross-sectional design, longitudinal data would improve the understanding of how alcohol use and its risk factors have changed during the COVID-19 pandemic. Adolescent and young adult nicotine use has experienced a resurgence in the past decade with the rise in popularity of electronic nicotine delivery systems , with 4% of 12th graders smoking cigarettes in the past month and 20% vaping nicotine in 2021 . Once initiated, the use of nicotine and tobacco products may become a persistent issue for emerging adults, as e-cigarette use increases the odds of combustible cigarette consumption. Despite a plateau in overall substance use prevalence during the COVID-19 pandemic , and evidence of fewer individuals initiating use during the pandemic as compared to recent pre-pandemic years, the 2021 National Youth Tobacco Survey still found that NTP use is a serious public health issue for youth. During the global pandemic, more than 2 million middle schoolers and high schoolers identified as current e-cigarette users and 44% of high schoolers using e-cigarettes reported use on >20 out of 30 days. Further, the vast majority of emerging adults ages 16–24 reported maintaining or increasing their e-cigarette or cigarette use during the pandemic. With this rapidly evolving landscape of combustible and non-combustible NTP use, greater understanding is needed of the unique relationships between motivations for NTP use, modes of use, and behavioral outcomes that can contribute to the development of timely and relevant prevention and intervention approaches. Initiation of NTP use in adolescence and young adulthood is particularly concerning, given the vast neuro developmental changes occurring in this life stage. Changes in gray and white matter tissue sub-serve neural maturation and specialization and contribute to complex thinking abilities and efficient neurocognitive processing. Neuromaturational changes are regionally specific and vary in timing across adolescence and young adulthood; they may leave some youth susceptible to the rewarding effects of substances such as nicotine, and to downstream cognitive and mental health deficits.
The dynamic changes occurring in brain circuitry underlying motivation, reward, and control underscore the importance of investigating how NTP use, and what levels of NTP use, may influence brain structure during unique developmental periods. There have been conflicting findings regarding the neuro developmental correlates of NTP use in youth. In one of our first papers focused on the co-use of nicotine and cannabis, our team found that higher levels of urinary cotinine significantly predicted decreased memory performance among both single substance users and co-users of cannabis and nicotine ages. In a follow-up paper examining differences in structural brain metrics with an overlapping yet larger sample of the same age, we found no evidence of poorer white matter tissue and blood flow integrity among co-users of nicotine and cannabis , although there was evidence of significantly poorer brain health outcomes among cannabis only users. Others also failed to find poor structural brain integrity in young adult nicotine smokers. One study found significantly decreased hippo campal volume in cannabis and NTP co-users, but that decreased volume related to significantly better memory performance. Notably, frequency and amount of cannabis and nicotine use varied by study. Thus, it remains unclear whether nicotine counteracts some of the effects of cannabis-related neural alterations early in life, or if observations are revealing unique brain phenotypes of co-users, or both. It may be that some of these disparate findings are due to different modes of administration of NTP that is not typically well assessed, as research comparing combustible versus non-combustible NTPs is limited. Indeed, only two studies have considered the specific impact of e-cigarette use on cognition, finding that both adolescents and adults self-report cognitive difficulties; however, no objective measurement of cognition has been reported to date.
A growing body of literature also suggests that the use of combustible cigarettes may be particularly important, as it is linked to significantly more severe nicotine dependence and other behavioral outcomes, which may in turn impact neurodevelopment. Finally, there is also evidence of mental health and attitudinal differences between e-cigarette and combustible NTP users, though this has not been studied extensively or in concert with overall attitudes, substance use history, neurocognition, and mental health. Here, we assessed NTP use attitudes, mental health, and neurocognition in NTP users ages. We focus on exploring differences in those who used combustible products within the past six months, compared to e-cigarette only users and individuals who did not use any NTP. We first describe and examine differences in substance use history, motivations for nicotine use, and attitudes by nicotine product user group. We then investigate differences in mental health and neurocognitive performance by nicotine group status . In each instance, we expected both nicotine groups to exhibit more cumulative substance use, stronger positive attitudes toward nicotine use, more mental health distress, and poorer neurocognitive performance than NTP naïve participants. Given that we anticipated increased dependence and substance use among our combustible users, cannabis dry rack we hypothesized that within each of these domains, combustible product users would demonstrate poorer outcomes as compared to e-cigarette only users. Participants: Participants included young adults aged 16 to 22 in an ongoing study of the effects of cannabis and nicotine use on adolescent brain development. Participants were recruited via flyers posted at high schools, universities, and community colleges, as well as postings on social media sites. Interested individuals contacted the laboratory through an email or phone call to schedule an initial screening interview to determine eligibility. Individuals aged 18 years or older provided verbal informed consent prior to the screening. For those younger than 18, permission was obtained from their parent or legal guardian before receiving verbal assent to participate from the youth. The screening interview consisted of questions related to their substance use, medical, and mental health histories. Socio-demographics: Participants self-reported age, gender, education, race, and ethnicity. Mother’s education level was used as a proxy for socioeconomic status. We note that sociodemographic characteristics often are social constructs and proxies for other factors which need to be appropriately contextualized. Therefore, while sociodemographics are important to describe a sample, given the relatively small sample and restricted range of sociodemographic characteristics presented here, comprehensive analysis of appropriate contextualizing factors is not possible. We therefore will present the data but limit interpretation. Inclusion criteria: Group status was based on 6-month history of combustible product or NTP use and defined as follows. NTP-Naïve participants had used no NTP products in their lifetime ; E-Cig-only users reported they used e-cigarettes and had not used combustible NTP products in the past six months ; Combustible+ had used combustible NTPs within the past six months . The E-Cig group was so named, as all participants reported e-cigarette use in the past six months. Of note, 82% of Combustible+ had also used e-cigarettes in the past month. Non-combustible NTP use was defined as use of any of the following products: electronic cigarettes , smokeless tobacco , and nicotine replacement products . Combustible NTP use included tobacco cigarettes, tobacco pipe, hookah with tobacco, and cigars; cigarettes were the primary type of combustible product used, with 73% of Combustible+ reporting cigarette use in the past six months. Cannabis and alcohol users were included across groups, and levels of cannabis and alcohol use covaried as relevant in subsequent analyses. Exclusion criteria: Exclusion criteria included a history of major medical or neurological issues; past major head injuries; past or current DSM-5 diagnoses other than cannabis use disorder, nicotine use disorder, or anxiety and depression disorders ; learning and developmental disorders; use of medications that may affect the brain; excessive alcohol use ; excessive prenatal exposure to alcohol , drugs, or tobacco; other gestational or birth complications, including premature birth and low birth weight ; hearing or vision problems that were non-correctable; MRI contraindications, including implanted/irremovable metallic objects and pregnancy; and intoxication at the time of their study session.
Participants reported all other substance use, including spice, opiates, amphetamines , barbiturates, hallucinogens, cocaine, inhalants, benzodiazepines, MDMA, ketamine, GHB, and PCP. Procedures. Participation entailed the completion of a four-hour study session, consisting of questionnaires related to substance use and mental health, neurocognitive testing, and a magnetic resonance imaging scan . All participants gave written informed consent or parental consent and participant assent before beginning the study session. Prior to their appointment, participants were asked to abstain from all drug use, aside from nicotine, for 12 h. Participants were able to use NTP during the study session to avoid withdrawal effects. Most recent NTP use was recorded during the study session . All procedures were approved by the University of California, San Diego Institutional Research Board. Substance use history: A modified version of the Customary Drinking and Drug Use Record was administered to assess quantity and frequency of use of NTP, cannabis, and alcohol. Past six months and lifetime use were measured in terms of independent episodes, allowing for multiple uses to be reported within a single day . Participants were asked to provide additional details related to each substance reported, including age at first use, onset of regular use, product type, potency , and perceived intensity during use. High potency was defined as >15% THC for flower and >80% for concentrates. Further, urinary analysis was used to assess objective and quantified levels of nicotine and cannabis exposure . Mental health: Participants completed self-report measures designed to examine mental health and emotional states. The Beck Depression Inventory measures the severity level for various physical and psychological symptoms related to depression . A cut-off of 14 was used to indicate a clinical threshold for depression on the BDI. The Depression Anxiety Stress Scale short form consists of 21 items examining the frequency of negative emotional experiences within the last seven days, with scores on depression, anxiety, and stress sub-scales. The State-Trait Anxiety Inventory was used to measure participants’ state of anxiety on the day of the assessment. Raw scores were used on each scale. Substance use attitudes: Several additional self-report questionnaires were given to assess motivations for use and outcome expectancies for both combustible and noncombustible NTP. Participants were instructed to provide their opinion regardless of whether they had ever used combustible or non-combustible NTP. They completed an adapted Smoking Consequences Questionnaire, with questions specific to ecigarette use and four sub-scales calculated: negative consequences, positive reinforcement, negative reinforcement, and weight control. Similarly, both NTP naïve and users completed the Tobacco Motives Inventory, a 15-item instrument describing different reasons for smoking combustible cigarettes.