Julie Maslowsky

The great sleep recession: Changes in sleep duration among US adolescents, 1991-2012

BACKGROUND: Average nightly sleep times precipitously decline from childhood through adolescence. There is increasing concern that historical shifts also occur in overall adolescent sleep time. METHODS: Data were drawn from Monitoring the Future, a yearly, nationally representative cross-sectional survey of adolescents in the United States from 1991 to 2012 (N = 272 077) representing birth cohorts from 1973 to 2000. Adolescents were asked how often they get ≥7 hours of sleep and how often they get less sleep than they should. Age-period-cohort models were estimated. RESULTS: Adolescent sleep generally declined over 20 years; the largest change occurred between 1991–1995 and 1996–2000. Age-period-cohort analyses indicate adolescent sleep is best described across demographic subgroups by an age effect, with sleep decreasing across adolescence, and a period effect, indicating that sleep is consistently decreasing, especially in the late 1990s and early 2000s. There was also a cohort effect among some subgroups, including male subjects, white subjects, and those in urban areas, with the earliest cohorts obtaining more sleep. Girls were less likely to report getting ≥7 hours of sleep compared with boys, as were racial/ethnic minorities, students living in urban areas, and those of low socioeconomic status (SES). However, racial/ethnic minorities and adolescents of low SES were more likely to self-report adequate sleep, compared with white subjects and those of higher SES. CONCLUSIONS: Declines in self-reported adolescent sleep across the last 20 years are concerning. Mismatch between perceptions of adequate sleep and actual reported sleep times for racial/ethnic minorities and adolescents of low SES are additionally concerning and suggest that health education and literacy approaches may be warranted.

Developmental trends in sleep duration in adolescence and young adulthood: Evidence from a national United States sample

PURPOSE To present normative values of mean sleep duration from adolescence through young adulthood (ages 13-32 years), prevalence of short (<6 hours) and long (>10 hours) sleep durations, and differences in each by sex and race/ethnicity. METHODS Mean sleep duration and prevalence of extremely short and long sleep were estimated using data from the United States National Longitudinal Study of Adolescent Health, Waves 1-4 (N = 15,701). RESULTS Sleep duration showed age-related trends, with decreases across the adolescent period from 8.5 hours per night at age 13 years to 7.3 hours at age 18 years, an increase through the emerging adulthood period to 8.5 hours at age 22, and a gradual decline across early adulthood to 7.7 hours at age 32 years. Prevalence of extremely long and short sleep followed similar developmental trends. Adolescent girls reported lower mean sleep duration than did boys, but women reported longer average sleep duration than did men from age 19 years onward. Short sleep duration was most common among African-Americans at all ages. Long sleep was most common among African-Americans in adolescence and emerging adulthood and among Hispanics in early adulthood. CONCLUSIONS Sleep duration is developmentally patterned from adolescence through early adulthood. Mean and extreme sleep durations vary systematically by sex and race/ethnicity as well as age. These normative data on sleep duration will inform studies of the role of sleep in the etiology of a wide range of health conditions affecting adolescents and young adults.

Estimating and interpreting latent variable interactions: A tutorial for applying the latent moderated structural equations method

Latent variables are common in psychological research. Research questions involving the interaction of two variables are likewise quite common. Methods for estimating and interpreting interactions between latent variables within a structural equation modeling framework have recently become available. The latent moderated structural equations (LMS) method is one that is built into Mplus software. The potential utility of this method is limited by the fact that the models do not produce traditional model fit indices, standardized coefficients, or effect sizes for the latent interaction, which renders model fitting and interpretation of the latent variable interaction difficult. This article compiles state-of-the-science techniques for assessing LMS model fit, obtaining standardized coefficients, and determining the size of the latent interaction effect in order to create a tutorial for new users of LMS models. The recommended sequence of model estimation and interpretation is demonstrated via a substantive example and a Monte Carlo simulation. Finally, extensions of this method are discussed, such as estimating quadratic effects of latent factors and interactions between latent slope and intercept factors, which hold significant potential for testing and advancing developmental theories.

What is a representative brain? Neuroscience meets population science

The last decades of neuroscience research have produced immense progress in the methods available to understand brain structure and function. Social, cognitive, clinical, affective, economic, communication, and developmental neurosciences have begun to map the relationships between neuro-psychological processes and behavioral outcomes, yielding a new understanding of human behavior and promising interventions. However, a limitation of this fast moving research is that most findings are based on small samples of convenience. Furthermore, our understanding of individual differences may be distorted by unrepresentative samples, undermining findings regarding brain–behavior mechanisms. These limitations are issues that social demographers, epidemiologists, and other population scientists have tackled, with solutions that can be applied to neuroscience. By contrast, nearly all social science disciplines, including social demography, sociology, political science, economics, communication science, and psychology, make assumptions about processes that involve the brain, but have incorporated neural measures to differing, and often limited, degrees; many still treat the brain as a black box. In this article, we describe and promote a perspective—population neuroscience—that leverages interdisciplinary expertise to (i) emphasize the importance of sampling to more clearly define the relevant populations and sampling strategies needed when using neuroscience methods to address such questions; and (ii) deepen understanding of mechanisms within population science by providing insight regarding underlying neural mechanisms. Doing so will increase our confidence in the generalizability of the findings. We provide examples to illustrate the population neuroscience approach for specific types of research questions and discuss the potential for theoretical and applied advances from this approach across areas.

Influence of Conduct Problems and Depressive Symptomatology on Adolescent Substance Use: Developmentally Proximal Versus Distal Effects

The identification of developmentally specific windows at which key predictors of adolescent substance use are most influential is a crucial task for informing the design of appropriately targeted substance use prevention and intervention programs. The current study examined effects of conduct problems and depressive symptomatology on changes in alcohol, cigarette, and marijuana from 8th through 12th grade. We examined the effects of relatively developmentally distal versus proximal mental health problems on adolescent substance use and tested for gender differences. With a national, longitudinal sample from the Monitoring the Future study (N = 3,014), structural equation modeling was used to test the effects of 8th and 10th grade conduct problems and depressive symptomatology on subsequent changes in alcohol, cigarette, and marijuana use from 8th through 12th grade. Results indicated that relatively distal (8th grade) mental health problems were stronger predictors of increases in alcohol, cigarette, and marijuana use than were relatively more proximal (10th grade) mental health problems. Eighth grade conduct problems had the strongest effects on alcohol and marijuana use, and 8th grade depressive symptomatology had the strongest effects on cigarette use. Few gender differences were observed. These results suggest that intervening in earlier appearing conduct problems and depressive symptomatology may lead to a reduction in adolescent substance use in 10th and 12th grades and beyond.

Interaction matters: quantifying conduct problem × depressive symptoms interaction and its association with adolescent alcohol, cigarette, and marijuana use in a national sample.

Substance use is a major contributor to morbidity and mortality among American adolescents. Conduct problems and depressive symptoms have each been found to be associated with adolescent substance use. Although they are highly comorbid, the role of the interaction of conduct problems and depressive symptoms in substance use is not clear. In national samples of 8th-, 10th-, and 12th-grade students from the Monitoring the Future study, latent moderated structural equation modeling was used to estimate the association of conduct problems, depressive symptoms, and their interaction to the use of alcohol (including binge drinking), cigarettes, and marijuana. Moderation by age and sex was tested. The interaction of conduct problems with depressive symptoms was a strong predictor of substance use, particularly among younger adolescents. With few exceptions, adolescents with high levels of both conduct problems and depressive symptoms used substances most frequently. Conduct problems were a strong positive predictor of substance use, and depressive symptoms were a weak positive predictor. Whereas conduct problems are often thought to be a primary predictor of substance use, this study revealed that depressive symptoms potentiate the relation of conduct problems to substance use. Therefore, substance use prevention efforts should target both depressive symptoms and conduct problems.

The Epidemiology and Etiology of Adolescent Substance Use in Developmental Perspective

If there were a time in life that was “built” for substance use onset and escalation, it would certainly be adolescence. Individual and social context changes are more pervasive and rapid during adolescence than during any other time of life. Amidst these ubiquitous developmental changes, it is no coincidence that interest in and opportunity for alcohol and other drug use begins for most young people. There are clear and numerous risks associated with alcohol and other drug use during adolescence; however, from the young person’s perspective, substance use experimentation can also serve positive social and identity functions. Our purpose in this chapter is to provide a selective summary and integration of the literature on the epidemiology and etiology of substance use during adolescence from a developmental perspective.

Sleep and substance use among US adolescents, 1991-2014

OBJECTIVES To examine associations between sleep and alcohol, amphetamine, cigarette, marijuana, and non-heroin narcotic use among US middle and high school students, trends in associations over time, and the comparative impact of select covariates on association strength. METHODS Data from the 1991-2014 nationally representative Monitoring the Future study of 8(th)-, 10(th)-, and 12(th)-grade US students were used to estimate standardized correlations between the frequency of getting at least 7 hours of sleep (7+ sleep) and substance use frequency while simultaneously regressing both outcomes on key covariate domains. RESULTS As 7+ sleep frequency increased, substance use frequency significantly decreased and vice versa. Overall, association strength was inversely associated with grade. Associations were generally modest, varied across substances, and weakened over the historical period examined for 8(th)- and 10(th)- graders. Associations showed little variance by sex and racial/ethnic subgroups. Controlling for deviance, psychosocial and general health covariates significantly attenuated association strength. CONCLUSIONS Among US secondary students, 7+ sleep/substance use associations were largely explained by individual deviance, psychosocial, and general health characteristics. Awareness and exploitation of these shared associations may be useful in improving substance use prevention and/or treatment efforts.

Substance Use Disorder in Early Midlife: A National Prospective Study on Health and Well-Being Correlates and Long-Term Predictors

This study used national multicohort panel data from the Monitoring the Future study (N = 25,536 from senior year classes 1977–1997 followed up to the age of 35 years in 1994–2014) to examine how early midlife (age 35 years) alcohol use disorder (AUD) and cannabis use disorder (CUD) are associated with adolescent and adult sociodemographics and health and well-being risk factors. Survey items adapted from DSM-5 diagnostic criteria were used to identify individuals who (a) showed symptoms consistent with criteria for AUD or CUD at age 35 years, (b) used the substance without qualifying for a disorder (nondisordered users), and (c) abstained from using alcohol or marijuana during the past five years. At age 35 years, the estimated prevalence of past five-year AUD was 28.0%, and that of CUD was 6.1%. Multinomial logistic regressions were used to identify variations in the relative risk of disorder symptoms as a function of sociodemographic characteristics, age 18 educational and social indices and substance use, and age 35 health and satisfaction indices and substance use. In the full models, age 18 binge drinking and marijuana use were found to be among the strongest predictors of age 35 AUD and CUD, respectively. Among age 35 health and well-being indicators, lower overall health, more frequent cognitive difficulties, and lower satisfaction with spouse/partner were consistently associated with greater risks of AUD and CUD. Some evidence was found for a J-shaped association between age 35 AUD or CUD status and health and well-being indices, such that nondisordered users were sometimes better off than both abstainers and those experiencing disorder. Finally, nondisordered cannabis use, but not CUD, was found to be more common in more recent cohorts. Implications are discussed regarding the importance of placing early midlife substance use disorder within the context of both adolescent substance use and adult health and well-being.

Longitudinal associations between diurnal cortisol slope and alcohol use across adolescence: A seven-year prospective study

A large body of research has linked hypothalamic-pituitary-adrenal (HPA) axis function and alcohol consumption, including work suggesting that flatter diurnal cortisol slopes are associated with greater alcohol use. A lack of longitudinal studies and a focus on adult and alcoholic populations leaves unclear whether such associations are also present in younger, non-clinical populations and whether flatter diurnal slopes are a consequence of or preexisting risk factor for alcohol use; however, theory suggests such associations may be mutually reinforcing. In a longitudinal, community sample of 200 (55% female) adolescents, the current study demonstrates that flatter diurnal cortisol slope at age 11 predicts higher levels of alcohol use from ages 15-18, and that heavier alcohol use in turn predicts further flattening of diurnal cortisol rhythm at age 18.5. This is the first study to demonstrate a longitudinal chain of associations between diurnal cortisol slope and alcohol use. Findings support contemporary theoretical models of the neurobiological processes underlying alcohol use and can inform future research on risk factors for and consequences of underage drinking.