Daytime Sleepiness, Circadian Preference, Caffeine Consumption and Use of Other Stimulants among Thai College Students

A systematic review and meta-analysis of the association between young adults' sleep habits and substance use, with a focus on self-medication behaviours

Young adults (18-30 years) are vulnerable to sleep-wake disturbances and substance use, which are bi-directionally associated. The present work aims to organise the literature that deals with the association between sleep and substance use in young adults, also considering self-medication behaviours. We adopted a framework that accounts for the multidimensionality of sleep and the effect of different substances. We considered sleep disturbances (insomnia symptoms, sleep quality), sleep health dimensions (duration, satisfaction, efficiency, timing, daytime alertness), circadian characteristics (chronotype). Substances were alcohol, caffeine, nicotine, cannabis, others. We included 46 studies. The use of caffeine and nicotine was associated with higher odds of sleep disturbances. No significant effect was detected for sleep duration. In narrative findings, daytime dysfunction was associated with alcohol and caffeine use, and poor sleep satisfaction with nicotine use. Few evidence were available for the other sleep health dimensions. Evening chronotype was associated with alcohol, caffeine, and nicotine use. Few studies focused on cannabis or self-medication. Longitudinal results were inconclusive. We found a distinct pattern of associations between different substances and different sleep outcomes. Further investigation considering the multidimensionality of sleep would create a better understanding of the complex relationship between substance use and sleep health in young adults.

Snacking behavior differs between evening and morning chronotype individuals but no differences are observed in overall energy intake, diet quality, or food cravings

There is a growing body of literature that links chronotype to certain undesirable eating behaviors. However, the relationship between chronotype and dietary intake is poorly characterized among adults in the United States (U.S.). This cross-sectional study examined the associations among chronotype, snacking habits, dietary intake and quality, and food cravings. One-hundred adults living in the U.S. completed the study. Based on the Horne-Östberg Morningness-Eveningness Questionnaire score, an individual was categorized as having either a morning (M)-type, intermediate (I)-type, or evening (E)-type chronotype. Snack intake was assessed using a previously published specialized food frequency questionnaire. Sugar-sweetened beverage (SSB) intake was assessed using the updated version of the Beverage Intake Questionnaire-15. Alcohol misuse was measured using the Alcohol Use Disorders Identification Test-Consumption. Diet quality was obtained using the Diet History Questionnaire III. The validated General Food Cravings Questionnaire-Trait measured participants' food cravings. E-type individuals reported consuming snacks more often over the course of a week than M-types (p = .002) but not I-types. In terms of timing of snacking, E-type individuals consumed more snacks after dinner than M-types (p < .001). E-type individuals consumed more energy-dense snacks (p = .005), especially candies (p = .005), than M-types. However, there were no significant differences in healthy snack frequency, diet quality, energy and macronutrient intake, SSB consumption, alcohol misuse, or food cravings among chronotypes (p > .05, for all). In conclusion, E-type individuals consumed snacks more frequently and later than M-types; however, chronotype was not associated with an individual's energy intake, diet quality, and food cravings, which suggests that chronotype is negligibly associated with weight gain-related behaviors in this population.

Differences between male and female university students in sleepiness, weekday sleep loss, and weekend sleep duration

INTRODUCTION

Women and men experience sleep differently and the difference in intrinsic desire for sleep might underlie some of the observed male-female differences. The objective of this cross-sectional questionnaire study of university students was to determine male-female differences in self-reported sleepiness and sleep-wake patterns.

METHODS

Five questionnaires were completed by 1650 students at four Russian universities.

RESULTS

Compared to male students, female students reported a lower subjective sleep quality score, had a higher morning sleepability score and lower nighttime and daytime wakeability scores. They more often reported excessive daytime sleepiness and expected to be sleepier at any time of the day with the largest male-female difference around the times of sleep onset and offset. On free days, they reported a longer sleep duration and an earlier sleep onset. Free-weekday difference was larger for sleep duration and smaller for sleep onset. Such male-female differences showed similarity to the differences observed in university and high school students from different countries around the globe. There was no significant male-female difference in weekly averaged sleep duration, weekday sleep duration, hours slept, midpoint of sleep on free days, free-weekday difference in sleep offset, social jetlag, and morningness-eveningness score. Therefore, when studies rely on these self-reports, the most salient male-female differences might not be immediately evident.

CONCLUSIONS

It seems that the intrinsic desire for longer sleep duration might contribute to a higher susceptibility of female students to weekday sleep loss. Among these students, negative effects of reduced sleep duration might be more common and more detrimental.

Diurnal Preference and Grey Matter Volume in a Large Population of Older Adults: Data from the UK Biobank

Eveningness (a diurnal preference for evening time) is associated with a number of negative health outcomes and risk and prevalence for psychiatric disorder. Our understanding of the anatomical substrates of diurnal preference, however, is limited. The current study used Voxel-Based Morphometry to compare grey matter volume in a large sample (N = 3730) of healthy adults determined by questionnaire to be either definite morning-type or definite evening-type. Eveningness was associated with increased grey matter volume in precuneus, brain regions implicated in risk and reward processing (bilateral nucleus accumbens, caudate, putamen and thalamus) and orbitofrontal cortex. These results indicate an anatomical-basis for diurnal preference which may underlie reported differences in behaviour and brain function observed in these individuals.

Gender differences in the relationships between sleep disturbances and academic performance among nursing students: A cross-sectional study

BACKGROUND

Sleep disturbances, such as insomnia, excessive daytime sleepiness, and poor-quality sleep, are common among nursing students and are closely linked with academic performance.

OBJECTIVES

To examine the prevalence of sleep disturbances and academic performances in male and female nursing students and to determine gender-specific effects on the relationship between sleep disturbances and academic performance.

DESIGN

A cross-sectional study design was adopted.

SETTINGS

This study was conducted in a school of nursing in Indonesia.

PARTICIPANTS

A total of 492 undergraduate students (103 males and 389 females) were included.

METHODS

Data pertaining to the biosociodemographic characteristics, Pittsburgh Sleep Quality Index, Insomnia Severity Index, Epworth Sleepiness Scale, Morningness-Eveningness Questionnaire, and Beck Depression Inventory were collected from July 1, 2018 to September 30, 2018. Academic performance was measured using grade point average of the academic year 2017-2018. A multivariate logistic regression model was used for data analyses.

RESULTS

The prevalence of poor sleep quality, insomnia, and daytime sleepiness was 66.0%, 45.6%, and 24.3%, respectively, in male nursing students and 71.5%, 52.4%, and 28.8%, respectively, in female nursing students. For circadian rhythm preferences, 66% male and 51.7% female nursing students were categorized as intermediate- and morning-type people, respectively. Insomnia was the only variable among sleep disturbances that significantly correlated with the risk of poor academic performance in female nursing students even after adjustment of covariates.

CONCLUSIONS

Sleep disturbances were highly prevalent among female and male nursing students, and insomnia was substantially associated with poor academic performance in female nursing students. Identifying sleep disturbances among nursing students and designing effective interventions to specifically target them are required to improve academic performance of female nursing students.

Chronotypes and its association with psychological morbidity and childhood parasomnias

BACKGROUND

The relationship between chronotypes and sleeping problems is not clear. The objective of the study was to identify the relative occurrence of chronotypes among college students and to explore adult psychological morbidity and childhood sleeping problems across chronotypes.

MATERIALS AND METHODS

One hundred and fifty undergraduate medical students were assigned into different chronotypes by Morningness-Eveningness Questionnaire and they were further assessed using Self-Reporting Questionnaire, Parasomnia Questionnaire (adapted from the Adult Sleep Disorders Questionnaire), and Pittsburgh Sleep Quality Index.

RESULTS

Intermediate chronotype was the most common, seen in 87 (58%) students, followed by evening type in 34 (22.7%). Evening types have more difficulties in making a decision, becoming exhausted more easily and feeling worthless than other chronotypes. Evening-oriented students showed a significantly higher frequency of initial insomnia and poorer overall sleep quality than the other groups. The current bedwetting was more in evening types; there was no difference in any other current and childhood parasomnias.

CONCLUSIONS

Evening chronotypes had greater difficulty in decision-making, and they were more vulnerable to feel worthless. No significant association was found between childhood parasomnias and chronotypes except persistent bedwetting during adulthood in evening types.

Eye-Blink Parameters Detect On-Road Track-Driving Impairment Following Severe Sleep Deprivation

STUDY OBJECTIVES

Drowsiness leads to 20% of fatal road crashes, while inability to assess drowsiness has hampered drowsiness interventions. This study examined the accuracy of eye-blink parameters for detecting drowsiness related driving impairment in real time.

METHODS

Twelve participants undertook two sessions of 2-hour track-driving in an instrumented vehicle following a normal night's sleep or 32 to 34 hours of extended wake in a randomized crossover design. Eye-blink parameters and lane excursion events were monitored continuously.

RESULTS

Sleep deprivation increased the rates of out-of-lane driving events and early drive terminations. Episodes of prolonged eyelid closures, blink duration, the ratio of amplitude to velocity of eyelid closure, and John's Drowsiness Score (JDS, a composite score) were also increased following sleep deprivation. A time-on-task (drive duration) effect was evident for out-of-lane events rate and most eye-blink parameters after sleep deprivation. The JDS demonstrated the strongest association with the odds of out-of-lane events in the same minute, whereas measures of blink duration and prolonged eye closure were stronger indicators of risk for out-of-lane events over longer periods of 5 minutes and 15 minutes, respectively. Eye-blink parameters also achieved moderate accuracies (specificities from 70.12% to 84.15% at a sensitivity of 50%) for detecting out-of-lane events in the same minute, with stronger associations over longer timeframes of 5 minutes to 15 minutes.

CONCLUSIONS

Eyelid closure parameters are useful tools for monitoring and predicting drowsiness-related driving impairment (out-of-lane events) that could be utilized for monitoring drowsiness and assessing the efficacy of drowsiness interventions.

CLINICAL TRIAL REGISTRATION

This study is registered with the Australian New Zealand Clinical Trial Registry (ANCTR), http://www.anzctr.org.au/TrialSearch.aspx ACTRN12612000102875.

CITATION

Shekari Soleimanloo S, Wilkinson VE, Cori JM,Westlake J, Stevens B, Downey LA, Shiferaw BA, Rajaratnam SMW, Howard ME. Eye-blink parameters detect on-road track-driving impairment following severe sleep deprivation. J Clin Sleep Med. 2019;15(9):1271-1284.

Chronotype: Implications for Epidemiologic Studies on Chrono-Nutrition and Cardiometabolic Health

Chrono-nutrition is an emerging research field in nutritional epidemiology that encompasses 3 dimensions of eating behavior: timing, frequency, and regularity. To date, few studies have investigated how an individual's circadian typology, i.e., one's chronotype, affects the association between chrono-nutrition and cardiometabolic health. This review sets the directions for future research by providing a narrative overview of recent epidemiologic research on chronotype, its determinants, and its association with dietary intake and cardiometabolic health. Limited research was found on the association between chronotype and dietary intake in infants, children, and older adults. Moreover, most of the evidence in adolescents and adults was restricted to cross-sectional surveys with few longitudinal cohorts simultaneously collecting data on chronotype and dietary intake. There was a gap in the research concerning the association between chronotype and the 3 dimensions of chrono-nutrition. Whether chronotype modifies the association between diet and cardiometabolic health outcomes remains to be elucidated. In conclusion, further research is required to understand the interplay between chronotype, chrono-nutrition, and cardiometabolic health outcomes.

The prevalence and association of stress with sleep quality among medical students

Introduction: Medical students tend to reduce their sleep, in an effort to adjust and cope with their workload and stressful environment. This study estimated the prevalence of and the relationship between poor sleep quality and stress among medical students.

Methods: This cross-sectional study was conducted using a stratified random sample of male and female medical students in King Saud bin Abdulaziz University for Health Sciences in Riyadh, Saudi Arabia. A self-administered questionnaire was distributed to assess sleep quality using the Pittsburgh Sleep Quality Index, and the stress level by using the Kessler Psychological Distress Scale.

Results: A high prevalence of poor sleep quality (76%) and stress (53%) were found, with a statistically significant association (p < 0.001). Logistic regression indicated that students who are not suffering from stress are less likely to have poor sleep quality (OR = 0.28, p < 0.001), and the risk of having poor sleep quality is almost four times higher in students whose cumulative grade point average (GPA) is less than 4.25 (OR = 3.83, p = 0.01).

Conclusion: The study documents a statistically significant association between stress and poor sleep quality. A recommendation for the management of medical college is to establish academic counseling centers focusing in promoting good sleep hygiene and strengthening students’ study skills and coping with their stressful environment.

Differential effects of circadian typology on sleep-related symptoms, physical fatigue and psychological well-being in relation to resilience

Various physiological and psychological functions are influenced by circadian typology (CT), which was reported to be related to resilience. However, few studies have assessed the effects of CT in relation to resilience. The aim of the present study was to assess the influence of CT on sleep-related symptoms, physical fatigue and psychological well-being in relation to resilience. The present study included a total of 1794 healthy hospital employees, and they completed the Morningness-Eveningness Questionnaire, Connor-Davidson Resilience Scale, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Fatigue Severity Scale, Hospital Anxiety and Depression Scale and World Health Organization Quality of Life Scale Abbreviated Version. Subjects with evening type showed lower sleep quality, more daytime sleepiness and physical fatigue than neither types and morning types. Additionally, evening types were more depressed and anxious and reported a poorer quality of life. CT was found to be a significant predictor of sleep quality, but CT was minimally associated with physical fatigue and psychological well-being in the regression analysis. Instead, resilience was substantially related to all of the variables measured. In conclusion, CT independently predicts sleep quality, but the effects of CT on physical fatigue and psychological well-being are negligible compared to those of resilience.

Excessive daytime sleepiness and its pattern among Indian college students

The objective of this study was to determine the prevalence and pattern of excessive daytime sleepiness (EDTS) in Indian college students. This was a cross-sectional study that was conducted among 1215 undergraduate students, using the Epworth Sleepiness Scale (ESS) and a sociodemographic survey. A high proportion (45%) of EDTS was observed, and the problem was significantly greater in participants from professional courses. A probability of association of EDTS with coffee/tea consumption, alcohol consumption and smoking was also observed in the study.

The association between chronotype and perceived academic stress to depression in medical students

Depression is a multifactorial illness that is highly prevalent among medical students (MS). Chronotypes, which reflect circadian preference in humans, as well as academic stress have been associated with depression in different populations. However, it is not known how chronotype and stress might alone or in combination, associate with depression in MS. Thus, we aimed to evaluate the association between stress, chronotype and depression in MS. In a cross-sectional study, we evaluated a total of 1068 medical students from a public Medical School in Mexico City. The Patient Health Questionnaire-9 (PHQ-9) was used to evaluate depressive symptom severity and the presence of a current depressive episode with a cutoff score of 10 or higher. The Morning-Evening Questionnaire (MEQ) was used to establish chronotype and the Academic Stress Inventory was used to measure perceived academic stress (PAS). We observed that depressive symptom severity was higher in non-morning chronotypes and moderate/severe PAS groups. A factorial ANOVA showed an association between PAS groups and depressive symptom severity. Linear regression showed an association between depressive symptom severity and variables such as PAS scores (p = 0.001), family history of depression (p = 0.001), gender (p = 0.001) and academic year (p = 0.029). Logistic regression analysis showed that evening chronotype (OR: 2.3, 95% CI: 1.2-4.3, p = 0.01) and severe PAS (OR: 4.4, 95% CI: 2.8-7.0, p = 0.0001) were associated with depression. Further, MS with the combination of severe PAS and morning (OR: 5.9, 95% CI: 1.6-22.2, p = 0.01), intermediate (OR: 7.5, 95% CI: 2.3-24.4, p = 0.001) or evening (OR: 10.6, 95% CI: 2.8-40.0, p = 0.001) chronotypes showed a greater association with depression than any PAS or chronotype group alone. Being female, perceiving restricted or limited economic resources, having severe scores of academic stress, and evening chronotype were associated with an increased probability to suffer a current depressive episode. Collectively, these results show that chronotype and PAS are factors associated with depression in MS, and when combined promote this association. Our results might aid in early identification of MS susceptible to depression. Future research could focus on the implementation of simple, low cost preventive strategies, such as chronotype-oriented academic schedules.

Chronotype, gender and general health

BACKGROUND

Light-dark alternation has always been the strongest external circadian "zeitgeber" for humans. Due to its growing technological preference, our society is quickly transforming toward a progressive "eveningness" (E), with consequences on personal circadian preference (chronotype), depending on gender as well. The aim of this study was to review the available evidence of possible relationships between chronotype and gender, with relevance on disturbances that could negatively impact general health, including daily life aspects.

METHODS

Electronic searches of the published literature were performed in the databases MEDLINE and Web of Science, by using the Medical Subject Heading (MeSH), when available, or other specific keywords.

RESULTS

Results were grouped into four general areas, i.e. (a) "General and Cardiovascular Issues", (b) "Psychological and Psychopathological Issues", (c) "Sleep and Sleep-Related Issues" and (d) "School and School-Related Issues". (a) E is associated with unhealthy and dietary habits, smoking and alcohol drinking (in younger subjects) and, in adults, with diabetes and metabolic syndrome; (b) E is associated with impulsivity and anger, depression, anxiety disorders and nightmares (especially in women), risk taking behavior, use of alcohol, coffee and stimulants, psychopathology and personality traits; (c) E has been associated, especially in young subjects, with later bedtime and wake-up time, irregular sleep-wake schedule, subjective poor sleep, school performance and motivation, health-related quality of life; (d) E was associated with lowest mood and lower overall grade point average (especially for women).

CONCLUSIONS

Eveningness may impact general health, either physical or mental, sleep, school results and achievements, especially in younger age and in women. The role of family support is crucial, and parents should be deeply informed that abuse of technological devices during night hours may lead to the immature adjustment function of children's endogenous circadian pacemakers.

Characteristics Associated with Sleep Duration, Chronotype, and Social Jet Lag in Adolescents

Sleep is a complex behavior with numerous health implications. Identifying sociodemographic and behavioral characteristics of sleep is important for determining those at greatest risk for sleep-related health disparities. In this cross-sectional study, general linear models were used to examine sociodemographic and behavioral characteristics associated with sleep duration, chronotype, and social jet lag in adolescents. One hundred and fifteen participants completed Phase I (self-reported sleep measures), and 69 of these participants completed Phase II (actigraphy-estimated sleep measures). Black adolescents had shorter free night sleep than Hispanics. Youth with later chronotypes ate fewer fruits and vegetables, drank more soda, were less physically active, and took more daytime naps. Based on these findings, recommendations for individual support and school policies are provided.

Validation of the Italian Version of the Morningness-Eveningness Questionnaire for Adolescents by A. Lancry and Th. Arbault

Background

This study aimed to validate the Italian version of the Morningness-Eveningness questionnaire for adolescents by Lancry and Arbault.

Material/Methods

The Morningness-Eveningness Questionnaire by Lancry and Arbault was translated from French into Italian by using forward-backward translation. Students aged 11–15 years old were enrolled from two schools in Milan (Italia). Validation of the questionnaire was performed in subsequent phases. A pre-test was given to 66 students aged 11–15 years (males 57.4%, females 42.6%) from a convenience sample. Syntactic aspects of the pre-test were improved, and the questionnaire in a revised version was re-administered to 292 students of same age (males 43.8%, females 54.1%) from a convenience sample.

Results

Factor analysis was performed on pre-test data, using the principal component method accounting for Morningness-Eveningness. Problematic items possibly uncorrelated with the extracted factor were identified, and reliability produced a Cronbach’s Alpha close to 0.7. In the test phase factor analysis was performed using the principal component method. Based on reliability analyses, we excluded a number of items because of their low performance, giving rise to a Cronbach’s Alpha of 0.819. Pearson product-moment external correlations between Morningness-Eveningness disposition and temperament, behavioral, and cognitive aspects were evaluated.

Conclusions

A factor analysis, Cronbach’s alpha and concurrent validity coefficients with disposition, behavior, and cognition, were performed, suggesting potential reliability and validity. The questionnaire is a useful and relevant tool for measuring Morningness-Eveningness disposition in adolescents, which has seldom been investigated with adequate psychometric instruments.

Car Crashes and Central Disorders of Hypersomnolence: A French Study

Background

Drowsiness compromises driving ability by reducing alertness and attentiveness, and delayed reaction times. Sleep-related car crashes account for a considerable proportion of accident at the wheel. Narcolepsy type 1 (NT1), narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) are rare central disorders of hypersomnolence, the most severe causes of sleepiness thus being potential dangerous conditions for both personal and public safety with increasing scientific, social, and political attention. Our main objective was to assess the frequency of recent car crashes in a large cohort of patients affected with well-defined central disorders of hypersomnolence versus subjects from the general population.

Methods

We performed a cross-sectional study in French reference centres for rare hypersomnia diseases and included 527 patients and 781 healthy subjects. All participants included needed to have a driving license, information available on potential accident events during the last 5 years, and on potential confounders; thus analyses were performed on 282 cases (71 IH, 82 NT2, 129 NT1) and 470 healthy subjects.

Results

Patients reported more frequently than healthy subjects the occurrence of recent car crashes (in the previous five years), a risk that was confirmed in both treated and untreated subjects at study inclusion (Untreated, OR = 2.21 95%CI = [1.30–3.76], Treated OR = 2.04 95%CI = [1.26–3.30]), as well as in all disease categories, and was modulated by subjective sleepiness level (Epworth scale and naps). Conversely, the risk of car accidents of patients treated for at least 5 years was not different to healthy subjects (OR = 1.23 95%CI = [0.56–2.69]). Main risk factors were analogous in patients and healthy subjects.

Conclusion

Patients affected with central disorders of hypersomnolence had increased risk of recent car crashes compared to subjects from the general population, a finding potentially reversed by long-term treatment.

Guarana provides additional stimulation over caffeine alone in the planarian model

The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose.