Validation of the MESSi among adult workers and young students: General health and personality correlates

Influence of ultraviolet A1 exposures on mood states: a randomized controlled study

We investigated the effects of daily ultraviolet A1 (UV-A1, 340-400 nm) exposures on mood states (#R19055, approval on 21 October 2020). Based on our earlier findings of the influence of diurnal preference on mood, we investigated further whether diurnal preference plays a role in the influence of UV-A1 on mood states. Forty-one healthy participants aged 19-55 years were randomized to receive either UV-A1 (n = 21) or control (n = 20) exposures (violet light, 390-440 nm). The irradiations were administered on three consecutive mornings on the skin of the buttocks and middle back. Diurnal preference was assessed with the modified 6-item Morningness-Eveningness Questionnaire (mMEQ). Changes in mood were assessed with Total Mood Disturbance (TMD) score of the 40-item Profile of Mood States (POMS) before the first irradiation, immediately after each irradiation and one week after the last irradiation. Mood improved among those subjected to UV-A1 exposures compared with the controls (p = 0.031). Individuals with more pronounced morningness had mood improvement (p = 0.011), whereas those with more pronounced eveningness did not (p = 0.41). At follow-up of one week after the last irradiation the mood improvement had disappeared.

Bimodal diurnal preference in undergraduate students is associated with negative health and sleep outcomes

The bimodal preference is a fourth diurnal preference proposed by re-scoring the Morningness-Eveningness Questionnaire. The present work aimed to describe the prevalence of the bimodal preference in a sample of undergraduate students and to characterize the bimodal type in terms of their health and sleep-related outcomes. A web-based cross-sectional study conducted between September 2018 and March 2021 (convenience sampling method). The sample was composed of undergraduate students who completed an electronic form that included the Morningness and Eveningness Questionnaire, the Pittsburgh Sleep Quality Index, the Self-Compassion Scale, the Epworth Sleepiness Scale, the Hospital Anxiety and Depression Scale, and the World Health Organization Subjective Well-Being Index. The final sample consisted of 615 students (82% female, mean age: 23.4 ± 6.5 years), of whom 108 (18%) had positive bimodality indexes. Bimodal subjects comprised 48 students, 8% of the total sample. Bimodal subjects had poorer subjective sleep quality, more daytime sleepiness, lower subjective well-being, greater anxiety and depression symptoms, and lower self-compassion than morning and/or intermediate types; they did not differ from evening types. The description of bimodal diurnal preference in this population may be of interest for the design of academic policies more in line with the circadian reality of students.

Causal dynamics of sleep, circadian rhythm, and mood symptoms in patients with major depression and bipolar disorder: insights from longitudinal wearable device data

BACKGROUND

Sleep and circadian rhythm disruptions are common in patients with mood disorders. The intricate relationship between these disruptions and mood has been investigated, but their causal dynamics remain unknown.

METHODS

We analysed data from 139 patients (76 female, mean age = 23.5 ± 3.64 years) with mood disorders who participated in a prospective observational study in South Korea. The patients wore wearable devices to monitor sleep and engaged in smartphone-delivered ecological momentary assessment of mood symptoms. Using a mathematical model, we estimated their daily circadian phase based on sleep data. Subsequently, we obtained daily time series for sleep/circadian phase estimates and mood symptoms spanning >40,000 days. We analysed the causal relationship between the time series using transfer entropy, a non-linear causal inference method.

FINDINGS

The transfer entropy analysis suggested causality from circadian phase disturbance to mood symptoms in both patients with MDD (n = 45) and BD type I (n = 35), as 66.7% and 85.7% of the patients with a large dataset (>600 days) showed causality, but not in patients with BD type II (n = 59). Surprisingly, no causal relationship was suggested between sleep phase disturbances and mood symptoms.

INTERPRETATION

Our findings suggest that in patients with mood disorders, circadian phase disturbances directly precede mood symptoms. This underscores the potential of targeting circadian rhythms in digital medicine, such as sleep or light exposure interventions, to restore circadian phase and thereby manage mood disorders effectively.

FUNDING

Institute for Basic Science, the Human Frontiers Science Program Organization, the National Research Foundation of Korea, and the Ministry of Health & Welfare of South Korea.

Changes in lifestyle and physical and mental health related to long-confinement due COVID-19: a study during the first and second pandemic waves in Mexico and Chile

We investigate changes in lifestyle, physical, and mental health during the confinement period of the first and second waves of COVID-19, as well as their relation to sociodemographic parameters and confinement status. Sociodemographic data and information regarding changes in their lifestyle behavior and changes in body weight and physical activity (PA) were collected. The SF-36 questionnaire was implemented for measuring the domains related to physical health (PH) and mental health (MH). The growth frequency of weight gain in the Mexican (4.8%) and Chilean (10.9%) populations was observed during the second wave. The MH component decreased in the Mexican and the Chilean population (p < 0.05). Moreover, the MH decreased significantly according to the degree of confinement (p < 0.01). Although some sociodemographic factors were related to the presence of a very low score (<50 scores) for the MH component during the first wave, it is perceived as a higher relative risk during the second wave in both populations. The long confinement due to COVID-19 is associated to negative changes in nutritional and physical lifestyle behavior, affecting mainly the MH component.

The moderating and mediating effects of personality on the association between morningness and well-being

Background

Morningness (morning-eveningness preference or chronotypes) and personality can be both associated with well-being, but few studies have directly compared these two constructs as correlates of well-being. Thus, the first purpose of this study was to test the effects of interactions between stable personality traits (temperaments) and morningness on well-being. Furthermore, personality factors are often composed of both stable biological factors (temperament) and socio-cultural factors (character), and little is known about personality interplay of temperament and character factors with respect to morningness and well-being. The second purpose of this study was therefore to examine the sequential mediating effects of temperament and character factors on the relationship between morningness and well-being.

Methods

The Composite Scale of Morningness, the Korean version of the Temperament and Character Inventory-Revised Short Version (TCI-RS), and the Satisfaction with Life Scale were used to measure morningness, personality dimensions, and well-being, respectively, in 287 Korean university students. Moderating and sequentially mediating effects of temperament and character traits were determined using Hayes' PROCESS macro in SPSS after controlling for sex and age.

Results

First, novelty-seeking (NS) and persistence (PS) temperaments have demonstrated the moderating effect in the association between morningness and well-being. The positive effects of morningness on life satisfaction increased with lower NS and PS, respectively. However, other temperaments such as harm avoidance (HA) and reward dependence (RD) have not shown the moderation in the relationship between morningness on well-being. Second, HA temperament and self-directedness (SD) character sequentially mediated the relationship between morningness and well-being. The combination of low scores of HA and high scores of SD have shown the positive effect on the relationship between morningness and well-being.

Discussion

This study demonstrated that both the interactions between temperaments and morningness, and combination of specific TCI-RS temperament and character traits play important roles in influencing the association between morningness and well-being. The significance of the mature SD character and its implications for well-being are discussed with limitation of the present study.

Distress symptoms and alcohol consumption: anxiety differentially mediates drinking across gender

Introduction

The consumption of alcohol remains a significant health concern and represents a prevalent form of substance use worldwide. Previous research has identified sex differences in the consumption of alcohol. This study explores the relationship between drinking and the presence of distress symptoms across gender. Based on previous research, it was hypothesized that presence of distress symptoms, defined as increases in anxiety and depression, would be prominent features associated with alcohol consumption among women compared to men.

Methods

A sample of undergraduate students (N = 448) participated in an online-based questionnaire (71% female; M age = 22.1; 42.9% Hispanic/Latino). The questionnaire contained assessments related to demographic information and alcohol consumption over the past 30 days. Anxiety and depression symptoms were assessed using the Hospital Anxiety and Depression Scale.

Results

Gender differences were observed with men consuming more alcoholic drinks than women. However, women who consumed alcohol reported having more distress symptoms relative to their male counterparts. A logistic regression revealed that this gender difference was moderated by anxiety, such that greater anxiety scores associates with whether women consumed alcohol. However, an ordinary least squares regression revealed that for men, anxiety scores significantly related to the amount of drinks consumed. Gender differences were not detected in relation to alcohol consumption and depression.

Conclusion

Our findings contribute to the literature by indicating that the mere presence of distress symptoms reveals distinctive gender-specific differences in relation to alcohol consumption in a non-clinical population. Identifying the distinct associations linked with alcohol use for men and women can aid in reducing drinking disparities among young adults.

Psychological consequences of experiencing the COVID-19 coronavirus pandemic: early maladaptive schemas and mental health and quality of life

The research presented here aimed to determine the psychological consequences of experiencing Poland's coronavirus disease 2019 (COVID-19) pandemic. We focused on changes in mental health (anxiety and depression symptoms, morbid thoughts, and suicidal ideation) and quality of life. Our retrospective study included 499 adults comprising 316 women and 173 men (aged 18-72, Me = 27, SD = 12.48). We employed the following research tools: the General Health Questionnaire (GHQ-30), the shortened version of the World Health Organization Quality of Life Questionnaire (WHOQOL-BREF), and the abridged version of the Harkavy Asnis Suicide Survey (HASS-BREF) scale to assess the severity of suicidal ideations and behaviors, as well as the Young Schema Questionnaire (YSQ-S3-PL). The questionnaires' instructions for the subjects were modified to obtain information for three specific periods: before the pandemic, at the most difficult time of the pandemic for individuals, and in the last two weeks (the time period preceding data collection; January/February 2021). It emerged that both mental health and quality of life had deteriorated significantly in the studied population. In addition, early maladaptive schemas (Abandonment, Vulnerability to Harm, and Insufficient Self-Control) were likely predictors of mental health deterioration at the most difficult time of the COVID-19 pandemic. The schema of Defectiveness was likely predictor of a lower severity of symptoms of mental health disturbances. If psychological diagnosis covered the identification of thinking patterns typical of maladaptive schemas, which may be a risk factor for mental health deterioration, psychologists could better adapt forms and ways of psychological assistance to the patient's needs.

Exploring the associations between the Morningness-Eveningness-Stability-Scale improved (MESSi) and the higher-order personality factors

Morningness-eveningness refers to individual differences in the sleep-wake cycle. Research indicates that morningness-eveningness is associated with the Big Five (neuroticism, extraversion, openness to experience, agreeableness, conscientiousness) and the Big Two (alpha-stability, beta-plasticity) personality factors. However, the latter has not yet been tested within the multidimensional approach to morningness-eveningness. In the present study, we have adapted the Morningness-Eveningness-Stability-Scale improved (MESSi) to Polish (https://osf.io/rcxb5) to explore the associations between its subscales (morning affect, eveningness, distinctness) and the Big Two personality traits in a sample of 1106 participants (559 women and 547 men) aged 18 to 55 (M = 36.26, SD = 9.90). In bivariate correlations, morning affect was positively related to alpha-stability and beta-plasticity, distinctness was correlated negatively with alpha-stability and beta-plasticity, while eveningness was positively correlated only with beta-plasticity. Furthermore, the confirmatory factor analysis supported the original three-factor structure of the Polish version of MESSi, while the associations with affect and the symptoms of depression and anxiety attested to its validity. Overall, the present study provides the first evidence for the associations between MESSi subscales and the Big Two personality traits, as well as shows a good fit of the three-factor structure of MESSi in the Polish population.

The moderating role of dispositional mindfulness in the associations of morningness-eveningness with depressive and anxiety symptoms

Several studies have shown that eveningness is positively related to both depressive and anxiety symptoms. However, little is known about factors that may play a protective role against the undesirable emotional consequences of evening preference. Thus, in the present study, we explored the moderating effects of dispositional mindfulness on the relationship between morningness-eveningness and the presence of depressive symptoms, as well as between morningness-eveningness and the presence of anxiety symptoms. The study was conducted on a group of 1107 individuals (559 women and 548 men) aged 18-55 years (M = 36.26, SD = 9.89). Consistent with previous findings, eveningness was positively related to the presence of both depressive and anxiety symptoms. The magnitude of these effects decreased with higher dispositional mindfulness. The latter result remained significant when the analogical moderating effects of personality, established in earlier studies, were controlled for in the regression models. This leads to the conclusion that dispositional mindfulness may act as a protective factor against the elevated depressive and anxiety symptoms reported by evening-oriented individuals.

Morning affect or sleep inertia? Comparing the constructs and their measurement

The construct of Morning Affect (MA; alertness upon awakening/time required to feel fully awake) emerged from exploratory factor analysis of morningness-eveningness questionnaires, and while it has been equated with morningness-eveningness preference it has much conceptual overlap with sleep inertia (SI; the transitional state between sleep and being fully awake). The current study compared questionnaire measures of these constructs to help clarify their inter-relationships. A volunteer sample of 453 students at an English-medium university in China completed an online survey including the Sleep Inertia Questionnaire (SIQ), the Morningness-Eveningness-Stability-Scale-improved (MESSi), with subscales for MA, Eveningness, and Distinctness (amplitude of diurnal variation), and the reduced Morningness-Eveningness Questionnaire (rMEQ). Measures of depression, sleep quality, mindfulness, and personality were also included. Exploratory factor analysis of the SIQ, MESSi, and rMEQ items revealed seven factors: Cognitive, Emotional, and Physiological SI, Responses to SI (including one MA item), and Duration of SI (one SIQ item, 3/5 MA items, and one rMEQ item); Morningness-Eveningness (MESSi Eveningness items, plus 3/5 rMEQ items); Distinctness (3/5 MESSi items). These results suggest that Morning Affect may be better characterised as a general measure of sleep inertia, and may contribute to ongoing development/refinement of questionnaire measures of circadian functioning.

The effect of brain-derived neurotrophic factor Val66Met polymorphism on adolescent activity and rest rhythms, circadian preferences and attentional performance

BACKGROUND

Variations in circadian regulating mechanisms generate different individual preferences in respect of sleep and activity timing, which are known as chronotypes. In this sense, specifically during adolescence, there is a greater tendency for an eveningness chronotype. One factor that has been shown to have an impact on circadian rhythm patterns, as well as on some aspects of cognitive function, is the relatively common Val66Met (rs6265) polymorphism in the human brain-derived neurotrophic factor gene.

OBJECTIVE

This study aimed to evaluate the effect of the BDNF Val66Met polymorphism on the performance of adolescents in attentional tests, circadian preferences and activity-rest rhythm.

METHODS

85 healthy high school students completed the Morningness-Eveningness Questionnaire to assess their circadian preferences; were evaluated using the Psychological Battery for Attention Assessment; and were categorized as carriers and non-carriers of the rs6265 polymorphism using the TaqMan rt-PCR technique. A subsample of 42 students had their activity/rest rhythm recorded by actigraphy for nine days from which sleep parameters were estimated.

RESULTS

Circadian preference did not affect attentional performance (p > 0.1), but the time that the students attended school had an impact on all types of attention with morning shift students scoring higher, regardless of chronotype (p < 0.05). The presence of the BDNF Val66Met polymorphism was associated only with alternate attention performance (p < 0.05). Regarding actigraphy evaluation, the carriers of the polymorphism demonstrated significantly higher total time in bed, total sleep time, social jetlag, and earlier sleep onset.

CONCLUSIONS

The results indicate some degree of adaptation in the students' attentional performance, according to their school schedules. The presence of BDNF polymorphism demonstrated a counterintuitive impact on attentional performance, comparing to previous findings. The findings reinforce the effect of genetic traits on sleep-wake rhythm parameters, when objectively evaluated.

Morning affect, eveningness, and amplitude distinctness: Associations with behavioural indicators of conscientiousness

Morningness is associated with well-being, better sleep quality, and more conscientiousness, while eveningness is associated with negative emotionality, poorer sleep quality, and less conscientiousness. The current study aimed to further understanding of associations with conscientiousness by assessing specific behavioural indicators of conscientiousness, morningness-eveningness, and also the Morning Affect and Distinctness (amplitude of diurnal variation) aspects of circadian functioning. A survey of Chinese university students (N = 369, aged 18-30, mean = 19.48, SD = 1.922; 108 males, 261 females), included the Morningness-Eveningness-Stability-Scale, measures of conscientiousness, mindfulness, life satisfaction, aspects of sleep, and the Behavioural Indicators of Conscientiousness (BIC) scale. Morningness and Morning Affect were positively correlated with life satisfaction, mindfulness, better sleep quality, more conscientiousness, and with BIC including Hardworking, Self-control, and Punctuality. Distinctness showed negative correlations with these variables. Negative correlations between Eveningness and conscientiousness, and the BIC subscales of Hardworking and Cleanliness were no longer significant after controlling for Morning Affect. Mediation analysis showed that the associations between Eveningness and conscientiousness/BIC were mediated by Morning Affect. These results extend previous research by showing associations between circadian functioning and specific behavioural indicators of conscientiousness, and suggest that low Morning Affect may provide a mechanism for the relationship between Eveningness and conscientiousness.

Chronotype and poor sleep quality in young adults - a pilot study on the role of rumination

BACKGROUND

Eveningness has been associated with poor sleep quality and depression. However, chronotype has also been shown to be a multidimensional construct, not limited to a merely morningness-eveningness orientation. It has also been proposed that other factors may also mediate the relationship between chronotype and its mental health sequelae. This pilot study explores the role of rumination as a mediator between chronotype and sleep quality, chronotype and depressive symptoms.

METHODS

A sample of 144 participants completed The Morningness-Eveningness-Stability-Scale Improved (MESSi), Pittsburgh Sleep Quality Index (PSQI), Rumination-Reflection Questionnaire (RRQ) and Center for Epidemiologic Studies Depression Scale (CES-D)). The results were tested using Spearman's rank correlation coefficient, multiple linear regression and the Sobel test.

RESULTS

Rumination was linked to poor sleep quality and increased depression. Morning affect and Distinctness (i.e. rigidity, or the subjective amplitude of the circadian rhythm) correlated with rumination. Rumination was a partial mediator of the associations between Morning Affect and sleep quality, Morning Affect and depression.

CONCLUSIONS

Rumination may play a role in the association between chronotype (particularly Morning Affect and Distinction) and sleep quality and depression. The recognition of this association might serve as a basis for clinical psychoeducational and therapeutic programs targeting both adjustment of the circadian rhythm and rumination as a psychopathological sign.

The psychometric properties of the Spanish version of the Morningness-Eveningness Stability Scale improved (MESSi) in adolescents

The aim of the present study was to adapt the Morningness-Eveningness-Stability Scale improved (MESSi) to the Spanish adolescent population, testing its factor structure and construct validity. The participants were 725 adolescents (52.9% girls; M = 14.8, SD = 1.99) who completed the MESSi, the Morningness Eveningness Scale of Children (MESC), questions about sleep habits adapted from the School Sleep Habits Survey, and self-reported academic performance. The psychometric results support a three-factor model with the factors of morning affect, eveningness, and distinctness, which show good internal consistency. The pattern of correlations between MESSi and the other measures was in the expected direction. The MESC correlated positively with morning affect and negatively with eveningness, whereas distinctness was uncorrelated. Boys reported higher morningness, whereas girls reported higher distinctness. Eveningness was negatively related to academic performance. Overall, the results support the validity and reliability of the Spanish adolescent version of the MESSi.

Seasonal changes in mood and behavior contribute to suicidality and worthlessness in a population-based study

Limited evidence suggests that the seasonal changes in mood and behavior may associate with suicidality and the feelings of worthlessness, but these associations have not been analyzed in large population-based data. A random sample of adults (n = 4069), representative of the general population living in Finland, attended a nationwide health examination survey. Seasonal variations (seasonality) in mood and behavior were analyzed with the six items of global seasonality score (GSS) and the experienced problem due to these variations. Their impact on suicidality as well as on the feelings of worthlessness were analyzed using logistic regression models. After adjusting for age and gender, the GSS, each of its six items and the experienced problem due to the seasonal variations in mood and behavior all showed separately a significant association with suicidality as well as with worthlessness. After further adjustment for the education level and region of residence, the GSS, its mood item and the experienced problem remained significantly associated with both suicidality and worthlessness. Seasonal variations in mood and behavior have a significant association with both suicidality and worthlessness.

Probing different aspects of short and ill-timed sleep in adolescents using the Morningness-Eveningness Scale for Children

Sleep problems among adolescents are believed to be related to the circadian changes that occur at this age. Therefore, most self-report instruments that measure sleep patterns in adolescence focus solely on measuring circadian rhythms. However, sleep-wake cycles reflect both circadian and homeostatic processes. Recently, it was shown that answers to the Morningness-Eveningness Questionnaire for adults, which is used to assess circadian typology, were able to identify three interrelated latent factors: two that can be conceptualized as homeostatic (sensitivity to the build-up of sleep pressure and efficiency of dissipation of sleep pressure) and a less well-defined factor related to activity preference time (APT). To better understand self-reported changes in sleep patterns in adolescents we applied confirmatory factor analysis to explore whether responses to the Morningness-Eveningness Scale for Children (MESC) could also identify these three factors. The sample comprised 397, 9- to 17-year-olds. A three-correlated and a bifactor-(S-1) model (with sleep onset characteristics as a reference factor) had acceptable/good fit indices. This indicates that the MESC captures dissociable, but interrelated, homeostatic and circadian processes in addition to APT. These factors correlated with corresponding reported sleep habits, showing individual differences that may be more associated with sleep difficulties than the effects of age, which only correlated very modestly with some sleep habits. Our results indicate that the MESC can show distinct individual differences in three sleep factors that can help identify adolescents at higher risk of sleep-related problems that may require factor-specific interventions.

A six-factor structure of individual variation in the tendencies to become sleepy and to sleep at different times of the day

A multidimensional approach has been previously applied for modeling and assessment of individual differences in the ability to sleep or to stay awake at certain clock hours. More recently the 19 time-point Visuo-verbal Judgment Task (VJT) has been proposed to predict changes in sleepiness level from the morning hours to the next day afternoon. The dimensionality of the VJT has not been explored so far. We applied a structural model of individual variation in sleep-wake behavior and habits for explaining the pattern of relationship between the VJT's dimensions yielded by rotation of principal components with eigenvalue>1. The responses to 19 items of the VJT, 72 items of 6-scale Sleep Wake Pattern Assessment Questionnaire (SWPAQ) and 60 items of 6-scale Sleep-Wake Adaptability Test (SWAT) were collected from 1037 survey participants. Factor analyses yielded 4 factorial dimensions of morning (08:00-11:00), daytime (12:00-20:00), nighttime (21:00-04:00), and after 24 h sleepiness (06:00-12:00 next day). The model was found to be capable to explain the correlations among 4 constructs of the VJT as well as the correlations among previously developed scales of the SWPAQ and SWAT. The results confirmed the predictive power of the model and its applicability for multidimensional assessments in chronobiological and chronopsychological studies.

Relationship Between Big Five Personality Dimensions, Chronotype, and DSM-V Personality Disorders

Morningness-eveningness (M/E) is an important variable in individual differences and has an impact on many areas of life including general and mental health. In previous work eveningness has shown to correlate to personality disorders (PDs) and mental instability such as psychoticism, depression, and bipolar disorders. Therefore, a relationship between M/E and PDs can be assumed but has never been tested. The aim of this study was to assess a possible relationship between DSM-5-PDs and circadian timing (chronotype; M/E). We used the Morningness-Eveningness Stability Scale improved and clock time-based measurements, the PID-5 brief version, and the Big Five brief version. Sample: N = 630; mean age: 27.76 years, SD: 11.36 years; 137 male, 489 female, 4 diverse. In this short screening a relationship between eveningness and DSM-5-personality traits, (evening-oriented participants showing a higher PID-5 score: morningness -0.208/p < 0.001; eveningness: 0.153/p < 0.001) was found. Moreover, participants with high levels of distinctness (fluctuations of the perceived energy level during the day) are prone to PDs too, with distinctness being the best predictor for a high PID-5 score in this sample (0.299/p < 0.001). In the regression analysis, neuroticism, agreeableness, conscientiousness, and extraversion contributed significantly to the model with higher scores on extraversion, agreeableness and conscientiousness being related to lower scores on the PID-5. Neuroticism was positively related to PID-5 scores. Later midpoint of sleep (higher eveningness) was associated with higher PID-5 scores, as were higher fluctuations/amplitude during the day.

Changes in sleep schedule and chronotype due to COVID-19 restrictions and home office

Background and objective

In this study, we researched the effects of the COVID-19 restriction measures on the sleep health of N = 681 German residents (mean age: 28.63 years, SD: 10.49 years).

Methods

The data were collected with an anonymous online survey composed of validated questionnaires and additional questions to quantify changed circumstances during the pandemic. Data were collected from May 18 to June 17, 2020, while governmental restrictions were imposed in Germany. We exclusively analysed participants working in home office during this time.

Results

Participants woke up about 1 hour later during the COVID-19 restriction phase, while going to bed at almost the same time as before. During the week, participants slept about an hour longer, while sleep at weekends did not differ significantly. Social jetlag decreased from 1:39 ± 1:00 to 0:49 ± 0:42 min in our sample. The number of children in the household was a significant factor predicting sleep timing. Participants with children living in the same household slept longer and sleep onset was later.

Conclusion

In terms of sleep behaviour and, consequently, sleep health, participants benefited from the transition to home office. They were able to adapt their waking and working hours better to their biological rhythm, which reduced social jetlag.

Associations of chronotype, Big Five, and emotional competences with perceived stress in university students

This study aimed to investigate the associations between individual difference factors (chronotype, Big Five, emotional competences) and perceived stress in French university students. In total, 362 students agreed to take part (M _age = 20.19 ± 1.75 years). Participants completed the Caen Chronotype Questionnaire, Big Five Inventory, the Profile of Emotional Competences, and the Perceived Stress Scale. Results showed that chronotype amplitude (+), eveningness chronotype (+), neuroticism (+), conscientiousness (-), and intrapersonal emotional competences (-) were important for perceived stress. These findings have theoretical and practical implications in terms of identifying students who might benefit most from stress management interventions.

Weak Associations of Morningness-Eveningness and Stability with Skin Temperature and Cortisol Levels

Differences in daytime preferences can be described on the dimension of morningness-eveningness (continuous) or circadian typology (categorical) and are associated with our physiological functioning, which is reflected in body temperature and cortisol levels in the morning. The purpose of the present study was to explore the relationship between morningness-eveningness, stability and physiological markers (body temperature and cortisol) based on a three-dimensional conceptualization of morningness-eveningness using the Morningness-Eveningness-Stability Scale improved (MESSi). In contrast to previously used unidimensional measures, the MESSi determines circadian typology and its amplitude in three dimensions: Morning affect (MA), Eveningness (EV) and Stability/Distinctness (DI). Furthermore, the differences of the cortisol levels between weekday and weekend were examined. The sample (N = 42) consisted of extreme chronotypes (age 18–54 years; M = 24.8 years, SD = 5.83; 22 morning types [5 men and 17 women] and 20 evening types [8 men and 12 women]). The participants were asked to measure their skin temperature for one week and sample four saliva probes for cortisol determination. Morning types showed a better fit in the actual temperature data to the approximating data as compared to Evening types and showed a higher overall temperature. The Stability/Distinctness (DI) component of the MESSi was negatively correlated with the nadir. Morning types also showed higher cortisol levels than Evening types immediately after awakening. The cortisol levels were higher on a weekday compared to the weekend. To conclude, the present findings demonstrate that the skin temperature is weakly associated with morningness-eveningness and the stability of the circadian phase.

Reproductive Success, Relationship Orientation, and Sexual Behavior in Heterosexuals: Relationship With Chronotype, Sleep, and Sex

Following previous studies, chronotype was related to sexual attitudes and behavior. Evening people tend to be more promiscuous and follow short-term mating strategies and extra-pair matings (EPM), which might lead to a higher reproductive success. In this study, one aim was to assess reproductive success directly by asking for children, and, second, to obtain a higher sample size for the analysis of sexual behavior and chronotype than in previous studies. N = 1,843 heterosexual persons (551 men, 1,288 women, 4 without data) responded to our online survey. Five hundred fifty-nine persons were single and 1,281 in a relationship; 203 reported having children (1.9 ± 0.81). Age was positively related and age at first intercourse was negatively related to the number of children. People being later chronotypes had fewer children, and shorter sleep duration was linked with more children. Extroversion was correlated with number of children, as was the long-term relationship orientation. Sociosexual orientation and EPM were unrelated to number of children. Age at first intercourse was earlier in evening people, and unrestricted sociosexuality was higher in late chronotypes. Morning orientation correlated with long-term relationship orientation and eveningness with short-term relationship orientation. Number of sexual partners was lower in morning people. Men were more evening oriented, later chronotypes, and slept shorter. There were no differences in sociosexual behavior, but men were less restricted in attitude and desire. Men scored higher on short-term relationship orientation and women higher on long-term relationship orientation. This study confirmed previous results about chronotype and sexual behavior but provided the first evidence that morningness was related to higher reproductive success.

Factorial Structure of the Morningness-Eveningness-Stability-Scale (MESSi) and Sex and Age Invariance

Assessing morningness-eveningness preferences (chronotype), an individual characteristic that is mirrored in daily mental and physiological fluctuations, is crucial given their overarching influence in a variety of domains. The current work aimed to investigate the best factor structure of an instrument recently presented to asses this characteristic: the Morningness-Eveningness-Stability-Scale improved (MESSi). For the first time, the originally proposed three-factor structure was pitched against a uni- and a two-factor solution. Another novelty was to establish that the best-fitting model would be invariant in relation to sex and age, two variables that influence chronotype. A Confirmatory Factor Analyses on the data obtained from a sample of 2096 German adults (age: 18–76; M = 25.5, SD = 7.64) revealed that the originally proposed three-factor structure of the MESSi – Morning Affect, Eveningness, and Distinctness – was the only one to achieve acceptable fit indicators. Furthermore, each scale obtained good internal consistency. In order to assess age invariance, following the literature on development and chronotype, our sample was divided into three age groups: 18–21 years, 22–31 years, and 32 years or older. Full measurement invariance of the three-factor model was found for sex and age. Regarding differences between sexes, females did not differ significantly from males in Morning Affect, but scored significantly lower on Eveningness and higher on Distinctness; this last result has been consistent across validation studies of the MESSi. With respect to age differences, the oldest group scored lower on Eveningness and Distinctness in comparison with the other two age-groups; the intermediate group (age: 22–31) scored lower on Morning Affect when compared to both the younger and older age groups. Additionally, both Eveningness and Distinctness were negatively correlated with age. This latter relation has been consistently reported in other validation studies. Our results reinforce the idea that the MESSi assesses three different components of chronotype in a reliable manner and that this instrument can be used to explore sex and age differences.

Morningness-eveningness and social anxiety symptoms: the influence of depression symptoms on the indirect effect through punishment sensitivity and experiential avoidance

Social anxiety has recently been linked to morningness-eveningness; however, the psychological mechanisms underlying this relationship are not well known. As such, the purpose of the current study is to propose a model by which morningness-eveningness is related to social anxiety symptoms through punishment sensitivity and experiential avoidance within an adult American, community sample recruited via Amazon's Mechanical Turk (MTurk). It was hypothesized that experiential avoidance and punishment sensitivity would be associated with increased social anxiety symptoms and that morningness-eveningness would be negatively related to social anxiety symptoms. Furthermore, eveningness was hypothesized to be associated with increased punishment sensitivity and in turn, greater experiential avoidance. Lastly, the relationship between morningness-eveningness and social anxiety was hypothesized to be mediated by punishment sensitivity among the group with high depression levels, but not among the group with lesser depression symptoms. The results indicated that eveningness was related to social anxiety symptoms through experiential avoidance, and that depression symptoms influenced the relationship between morningness-eveningness and punishment sensitivity such that, in those high in depression symptoms, there was a significant association between eveningness and punishment sensitivity, but not among those with lower depression levels. The study findings build upon existing chronobiological research and addresses inconsistencies in previous literature.