Cigarette use trajectories in young adults: Analyses of predictors across system levels.

BACKGROUND: Cigarette smoking escalates most in early to middle young adulthood. However, little research has examined a range of multilevel factors in relation to smoking trajectories during this time. METHODS: We examined: 1) trajectories of cigarette smoking among 2967 US college students (aged 18-25) in a two-year, six-wave longitudinal study (using growth mixture modeling); and 2) intrapersonal- (i.e., other substance use, depressive symptoms, ADHD symptoms,); interpersonal- (i.e., adverse childhood events, social support, parental tobacco and marijuana use), and community-level (i.e., type of college, rural vs. urban setting) predictors of differing trajectories (using multinomial logistic regression). RESULTS: We identified three trajectory classes: 1) Dabblers, who used cigarettes at one point in their life or not at all (85.6%); 2) College Onset Smokers, who began smoking regularly during the college years (6.2%); and 3) Later Onset Smokers, who began smoking during the mid- to late-20 s (8.2%). Multinomial regression (with Dabblers as the reference group) showed that predictors of being College Onset Smokers included being male (p = .031); Asian (p = .001) but not Black (p = .008; Ref: White); early onset smokers (i.e., initiation before age 15; p = .006); past 30-day users of little cigars/cigarillos (p = .024), alcohol (p < .001), and marijuana (p = .008); children of tobacco users (p = .050); and public (p = .031) or a technical college students (p < .001; Ref: private college); predictors of being Later Onset Smokers were being male (p = .019) and technical college students (p = .005). CONCLUSIONS: Despite some young adults' smoking initiating/escalating in middle young adulthood, few risk factors were documented. This understudied period warrants greater examination to inform intervention.

Measuring and Advancing Experimental Design Ability in an Introductory Course without Altering Existing Lab Curriculum.

Introductory biology courses provide an important opportunity to prepare students for future courses, yet existing cookbook labs, although important in their own way, fail to provide many of the advantages of semester-long research experiences. Engaging, authentic research experiences aid biology students in meeting many learning goals. Therefore, overlaying a research experience onto the existing lab structure allows faculty to overcome barriers involving curricular change. Here we propose a working model for this overlay design in an introductory biology course and detail a means to conduct this lab with minimal increases in student and faculty workloads. Furthermore, we conducted exploratory factor analysis of the Experimental Design Ability Test (EDAT) and uncovered two latent factors which provide valid means to assess this overlay model's ability to increase advanced experimental design abilities. In a pre-test/post-test design, we demonstrate significant increases in both basic and advanced experimental design abilities in an experimental and comparison group. We measured significantly higher gains in advanced experimental design understanding in students in the experimental group. We believe this overlay model and EDAT factor analysis contribute a novel means to conduct and assess the effectiveness of authentic research experiences in an introductory course without major changes to the course curriculum and with minimal increases in faculty and student workloads.

Social Influences on College Student Use of Tobacco Products, Alcohol, and Marijuana.

OBJECTIVE: This study investigated associations between the use of alternative tobacco products (e.g., cigarettes, little cigars/cigarillos, hookah, e-cigarettes), alcohol, and marijuana among college students and use by their parents, siblings, and friends. A large literature exists for social influences on adolescent substance use, but few studies have focused on college samples. PARTICIPANTS: 3,418 college students from seven universities in the state of Georgia participated in this study. METHODS: Web-based surveys were completed by students (45-60 minutes) during the fall semester, 2014. RESULTS: Findings largely indicated specificity of associations between college student use and use by social influences for similar tobacco products and other substances. For each tobacco product or substance, the highest associations were for friends' use. Structural equation analyses further supported the specificity of associations and highlighted the relative strength of friends' use on student use. CONCLUSION: Similar to findings with adolescents, the use of alternative tobacco products, alcohol, and marijuana by parents, siblings, and friends is associated with higher levels of use among college students, and friends' use was the most potent correlate for this phase of the lifespan.

Chronic methamphetamine exposure significantly decreases microglia activation in the arcuate nucleus.

Methamphetamine is a powerful psychostimulant drug and its use and abuse necessitates a better understanding of its neurobiobehavioral effects. The acute effects of binge dosing of methamphetamine on the neurons in the CNS are well studied. However, the long-term effects of chronic, low-dose methamphetamine are less well characterized, especially in other cell types and areas outside of the major dopamine pathways. Mice were administered 5mg/kg/day methamphetamine for ten days and brain tissue was analyzed using histochemistry and image analysis. Increased microglia activity in the striatum confirmed toxic effects of methamphetamine in this brain region using this dosing paradigm. A significant decrease in microglia activity in the arcuate nucleus of the hypothalamus was observed with no effect noted on dopamine neurons in the arcuate nucleus. Given the importance of this area in homeostatic and neuroendocrine regulation, the current study highlights the need to more fully understand the systemic effects of chronic, low-dose methamphetamine use. The novel finding of microglia downregulation after chronic methamphetamine could lead to advances in understanding neuroinflammatory responses towards addiction treatment and protection from psychostimulant-induced neurotoxicity.

DECOY: Documenting Experiences with Cigarettes and Other Tobacco in Young Adults.

OBJECTIVES: We examined psychographic characteristics associated with tobacco use among Project DECOY participants. METHODS: Project DECOY is a 2-year longitudinal mixed-methods study examining risk for tobacco use among 3418 young adults across 7 Georgia colleges/universities. Baseline measures included sociodemographics, tobacco use, and psychographics using the Values, Attitudes, and Lifestyle Scale. Bivariate and multivariable analyses were conducted to identify correlates of tobacco use. RESULTS: Past 30-day use prevalence was: 13.3% cigarettes; 11.3% little cigars/cigarillos (LCCs); 3.6% smokeless tobacco; 10.9% e-cigarettes; and 12.2% hookah. Controlling for sociodemographics, correlates of cigarette use included greater novelty seeking (p < .001) and intellectual curiosity (p = .010) and less interest in tangible creation (p = .002) and social conservatism (p < .001). Correlates of LCC use included greater novelty seeking (p < .001) and greater fashion orientation (p = .007). Correlates of smokeless tobacco use included greater novelty seeking (p = .006) and less intellectual curiosity (p < .001). Correlates of e-cigarette use included greater novelty seeking (p < .001) and less social conservatism (p = .002). Correlates of hookah use included greater novelty seeking (p < .001), fashion orientation (p = .044), and self-focused thinking (p = .002), and less social conservatism (p < .001). CONCLUSIONS: Psychographic characteristics distinguish users of different tobacco products.

Adolescent exposure to cocaine, amphetamine, and methylphenidate cross-sensitizes adults to methamphetamine with drug- and sex-specific effects.

The increasing availability, over-prescription, and misuse and abuse of ADHD psychostimulant medications in adolescent populations necessitates studies investigating the long-term effects of these drugs persisting into adulthood. Male and female C57Bl/6J mice were exposed to amphetamine (AMPH) (1.0 and 10 mg/kg), methylphenidate (MPD) (1.0 and 10 mg/kg), or cocaine (COC) (5.0 mg/kg) from postnatal day 22 to 31, which represents an early adolescent period. After an extended period of drug abstinence, adult mice were challenged with a subacute methamphetamine (METH) dose (0.5 mg/kg), to test the long-term effects of adolescent drug exposures on behavioral cross-sensitization using an open field chamber. There were no sex- or dose-specific effects on motor activity in adolescent, saline-treated controls. However, AMPH, MPD, and COC adolescent exposures induced cross-sensitization to a subacute METH dose in adulthood, which is a hallmark of addiction and a marker of long-lasting plastic changes in the brain. Of additional clinical importance, AMPH-exposed male mice demonstrated increased cross-sensitization to METH in contrast to the female-specific response observed in MPD-treated animals. There were no sex-specific effects after adolescent COC exposures. This study demonstrates differential drug, dose, and sex-specific alterations induced by early adolescent psychostimulant exposure, which leads to behavioral alterations that persist into adulthood.

Cocaine selectively increases proliferation in the adult murine hippocampus.

Cocaine abuse continues to be a significant problem in the USA and elsewhere. Cocaine is an indirect agonist for dopamine, norepinephrine and serotonin with numerous potential downstream effects, including processes and signals associated with adult neurogenesis. Since drug addiction is associated with brain plasticity, we hypothesized that cocaine exposure would alter cellular proliferation in two adult neurogenic regions (the subventricular and subgranular zones). We used bromodeoxyuridine (BrdU) to track newly generated cells in the brains of adult mice after chronic cocaine or saline exposures. No differences were found in the number or migration patterns of BrdU-labeled cells in the forebrain neurogenic areas. However, cocaine produced a significant increase in the number of hippocampal BrdU-labeled cells.

Molecular velocity distributions and generalized scale invariance in the turbulent atmosphere.

Airborne observations of ozone, temperature and the spectral actinic photon flux for ozone in the Arctic lower stratosphere April-September 1997 and January-March 2000 allow a connection to be made between the rate of production of translationally hot atoms and molecules via ozone photodissociation and the intermittency of temperature. Seen in the context of non-equilibrium statistical mechanics literature results from molecular dynamics simulations, the observed correlation between the molecular scale production of translationally hot atoms and molecules and the macroscopic fluid mechanical intermittency of temperature may imply a departure from Maxwell-Boltzmann distributions of molecular velocities, with consequences for chemistry, radiative line shapes and turbulence in the atmosphere, arising from overpopulated high velocity tails of the probability distribution functions (PDFs).

Regional differences in cortical dendrite morphology following in utero exposure to cocaine.

In utero exposure to cocaine has been shown to affect dopaminergic populations of developing neurons in the central nervous system (CNS). To determine if this was a regionally specific effect or the result of a global phenomenon, we used a Golgi-Cox analysis to measure several parameters of neuronal development in murine neurons from frontal cortex, a region of the cortex containing monoamine innervation, and somatosensory cortex, a monoamine sparse part of the cortex. Results of these analyses show that in utero exposure to cocaine affects total dendrite length in histotypical layers III and IV and dendritic volume in layer III of the frontal cortex. These effects are not present in the somatosensory cortex.