Psychometric properties of the German version of the Composite Scale of Morningness

Investigating non-inferiority of internet-delivered versus face-to-face cognitive behavioural therapy for insomnia (CBT-I): a randomised controlled trial (iSleep well)

BACKGROUND

Insomnia is a highly prevalent disorder associated with numerous adverse health outcomes. Cognitive behavioural therapy for insomnia (CBT-I) is recommended as first-line treatment by clinical guidelines but is accessible to only a minority of patients suffering from insomnia. Internet-delivered CBT-I (iCBT-I) could contribute to the widespread dissemination of this first-line treatment. As there is insufficient evidence regarding non-inferiority, this study directly aims to compare therapist-guided internet-delivered versus face-to-face CBT-I in terms of insomnia severity post-treatment. Furthermore, a health-economic evaluation will be conducted, and potential benefits and disadvantages of therapist-guided iCBT-I will be examined.

METHODS

This study protocol describes a randomised controlled two-arm parallel-group non-inferiority trial comparing therapist-guided iCBT-I with face-to-face CBT-I in routine clinical care. A total of 422 patients with insomnia disorder will be randomised and treated at 16 study centres throughout Germany. Outcomes will be assessed at baseline, 10 weeks after randomisation (post), and 6 months after randomisation (follow-up). The primary outcome is insomnia severity measured using the Insomnia Severity Index. Secondary outcomes include depression-related symptoms, quality of life, fatigue, physical activity, daylight exposure, adverse events related to treatment, and a health-economic evaluation. Finally, potential moderator variables and several descriptive and exploratory outcomes will be assessed (e.g. benefits and disadvantages of internet-delivered treatment).

DISCUSSION

The widespread implementation of CBT-I is a significant healthcare challenge. The non-inferiority of therapist-guided iCBT-I versus face-to-face CBT-I will be investigated in an adequately powered sample in routine clinical care, with the same therapeutic content and same level of therapist qualifications provided with both interventions. If this trial demonstrates the non-inferiority of therapist-guided iCBT-I, healthcare providers may be more confident recommending this treatment to their patients, contributing to the wider dissemination of CBT-I.

TRIAL REGISTRATION

Trial registration number in the German Clinical Trials Register: DRKS00028153 ( https://drks.de/search/de/trial/DRKS00028153 ). Registered on 16th May 2023.

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.

Beyond sleep: A multidimensional model of chronotype

Chronotype can be defined as an expression or proxy for circadian rhythms of varied mechanisms, for example in body temperature, cortisol secretion, cognitive functions, eating and sleeping patterns. It is influenced by a range of internal (e.g., genetics) and external factors (e.g., light exposure), and has implications for health and well-being. Here, we present a critical review and synthesis of existing models of chronotype. Our observations reveal that most existing models and, as a consequence, associated measures of chronotype have focused solely or primarily on the sleep dimension, and typically have not incorporated social and environmental influences on chronotype. We propose a multidimensional model of chronotype, integrating individual (biological and psychological), environmental and social factors that appear to interact to determine an individual's true chronotype with potential feedback loops between these factors. This model could be beneficial not only from a basic science perspective but also in the context of understanding health and clinical implications of certain chronotypes as well as designing preventive and therapeutic approaches for related illnesses.

[Personal factors influencing daytime sleepiness]

Hintergrund und Zielsetzung

Während der ersten Coronawelle kam das öffentliche Leben weitgehend zum Erliegen. Viele Beschäftigte haben zum Schutz vor Ansteckung im Homeoffice gearbeitet. Mit der vorliegenden Befragung wurden Veränderungen im Schlafverhalten und der Tagesmüdigkeit bei Personen untersucht, die coronabedingt ins Homeoffice gewechselt hatten.

Methode

Büroangestellte wurden online zu ihrem Chronotyp, ihren üblichen Schlafenszeiten und dem Auftreten von Tagesmüdigkeit befragt. Die Datenerhebung fand zwischen dem 15.07. und 07.08.2020 statt. Zur Chronotypermittlung wurde die Composite Scale of Morningness (CSM) in der deutschsprachigen Version verwendet. Der Zusammenhang von Alter, Geschlecht, Chronotyp, Schlafqualität und Schlafdauer mit der selbst eingeschätzten Tagesmüdigkeit wurde mittels multivariabler logistischer Regression untersucht.

Ergebnisse

Die Daten von n = 228 Personen konnten ausgewertet werden. Unter Homeoffice-Bedingungen verlängerte sich die Schlafdauer. Der Anteil an Personen mit einer „Zeit-im-Bett“ von weniger als 7,5 h verringerte sich von 57 % auf 33 %, und der Anteil mit mehr als 8 h „Zeit-im-Bett“ erhöhte sich von 43 % vor Pandemiebeginn auf 67 % beim Arbeiten im Homeoffice. Der Anteil an Personen, die sich bei der Arbeit immer oder häufig müde fühlten, verringerte sich von 47 % vor Pandemiebeginn mit Präsenzpflicht im Büro auf 15 % unter Lockdown-Bedingungen beim Arbeiten im Homeoffice. Der Chronotyp zeigte einen signifikanten Einfluss auf die Tagesmüdigkeit an Büroarbeitstagen, nicht aber beim Arbeiten im Homeoffice unter Lockdownbedingungen.

Diskussion

Die längere Schlafdauer und die höhere Zufriedenheit mit der eigenen Schlafqualität könnten die Verringerung im Auftreten von Tagesmüdigkeit erklären. Späte Chronotypen scheinen besonders vom Arbeiten im Homeoffice zu profitieren. Ein flexibler Arbeitsbeginn unter Einbeziehung des Chronotyps sowie Maßnahmen für gesundheitsförderlichen Schlaf könnten die Tagesmüdigkeit verringern und dadurch die Gesundheit und Arbeitssicherheit verbessern.

Validity of chronotype questionnaires in adolescents: Correlations with actigraphy

There are only a few validated chronotype and morningness-eveningness questionnaires for adolescents. We evaluated three such questionnaires, namely Morningness-Eveningness Stability Scale improved; reduced Morningness-Eveningness Questionnaire for Children and Adolescents; and Composite Scale of Morningness in adolescents against actigraphy. Fifty-five healthy 13- to 16-year-old adolescents completed the Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, Composite Scale of Morningness, and Pediatric Daytime Sleepiness Scale, and provided a 7-day actigraphy and sleep diary recording about their sleep-wake patterns. We examined the correlations between sleep-wake and activity parameters, and the questionnaires. The influence of age and sex on chronotype classification was studied using uni- and multivariate analyses. All three chronotype questionnaires showed good internal consistency and convergent validity. Spearman correlations reflected less daytime sleepiness, earlier sleep times, midpoints of sleep, and acrophase in morning-oriented participants. Evening-oriented participants had more sleepiness and later respective sleep-wake times. Chronotype classification differed significantly between questionnaires. The Composite Scale of Morningness classified more participants as morning types when compared with the reduced Morningness-Eveningness Questionnaire for Children and Adolescents (12 versus 7, respectively), and fewer adolescents as evening types (5 versus 9, respectively). Age and sex had no significant influence on questionnaire scores. The Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, and Composite Scale of Morningness are valid instruments to determine circadian preference in adolescents; however, chronotype classification from the Composite Scale of Morningness and reduced Morningness-Eveningness Questionnaire for Children and Adolescents cannot be used interchangeably.

Well‐being and sleep in stressful times of the COVID‐19 pandemic: Relations to worrying and different coping strategies

The present study examined the relationships between emotional well-being (positive and negative affect), sleep-related variables (sleep quality, sleep duration, and change in sleep quality and duration compared to weeks before lockdown), and worrying about coronavirus disease (COVID-19) challenges during the beginning of the outbreak in Europe. In addition, four different coping strategies were investigated. The study was conducted in Germany with data from 665 participants (53.8% female; 18-73 years), who completed an online questionnaire in April 2020. The results revealed that COVID-19 worry was associated with impaired well-being and sleep. Meaning- and problem-focused coping were the most frequently used coping strategies, and showed positive associations with well-being and sleep. Social and avoidance coping were associated with decreased well-being and worse sleep outcomes. Three coping strategies showed moderating effects. People who worried more showed higher levels of positive affect when they used problem-focused coping compared to those who did not. Similarly, highly worried participants showed lower levels of negative affect when they reported using meaning-focused coping more often. In contrast, social coping increased the risk of high negative affect levels in worried participants. In conclusion, problem-focused and meaning-focused coping strategies seemed to be most effective in coping with COVID-19 challenges.

The difference in sleep, depression, anxiety, and Internet addiction between Korean adolescents with different circadian preference

OBJECTIVES

Compared to adults, adolescents tend to prefer evening times developmentally. The orientation toward evening times is associated with behavioral and emotional problems. Thus, this study examined the association of circadian preference with sleep-related variables, depression, anxiety, and Internet addiction in Korean adolescents.

MATERIALS AND METHODS

Participants completed the questionnaires measuring sleep pattern, sleep problem, depression, anxiety, and Internet addiction.

RESULTS

Among 765 students (age range: 13-17 years), 211 students (N _male= 134) were allocated into morning types (MT) and 258 adolescents (N _male= 147) were allocated into evening types (ET) based on scores of the Morningness-Eveningness Scale. Adolescents without circadian preference (N = 296) were defined as neither type (NT). ET, compared to MT and NT, woke up later in the weekend, showed delays in bedtimes, and spent shorter time sleeping. They also reported a higher level of daytime sleepiness, insomnia, and depression than NT. However, the group difference in wake time on school days was not significant, and adolescents showed mild insomnia regardless of their circadian preference. Although smartphone using time in the weekend was significantly different between groups, group difference in Internet addiction was significant only when gender was adjusted.

CONCLUSION

Circadian preference was associated with sleep patterns and sleep problems in Korean adolescents. ET showed significantly different sleep patterns compared to MT and NT. ET not only reported a higher level of daytime sleepiness and insomnia but also more depressive symptoms compared to NT. These findings suggest that the uniqueness of adolescence and environmental factors seemed to influence the association of circadian preference with mental problem.

Composite Scale of Morningness: Psychometric properties, validity with Munich ChronoType Questionnaire and age/sex differences in Poland

The present study aimed at testing psychometric properties of the Composite Scale of Morningness (CSM) and validating it with mid sleep on free days (MSF) derived from the Munich ChronoType Questionnaire (MCTQ) in Poland, along with analyzing age and sex differences in the CSM and MSF. A sample of 952 Polish residents (62.6% females) aged between 13 and 46 was tested. Additionally, a sample of 33 university students were given MCTQ and filled in a sleep diary for 8 days. MSF derived from MCTQ was related to the one from sleep diary (r = .44). The study revealed good reliability of the CSM (α = .84) and its validity: greater morningness preference was associated with earlier MSF from MCTQ (r = –.52). CSM scores were distributed over its full range, with a mean of 34, and did not differ between sexes, although females were earlier than males by 23 minutes in MSF. Regarding age, eveningness estimated with both CSM and MSF was greatest in subjects aged 16–18 years, and a shift toward eveningness during puberty and a shift back toward morningness in older age was observed. The Polish version of the CSM consisted of two components of morningness. Cutoff scores were: for evening types (lower 10%) 24 or less, for morning types (upper 10%) 43 or more. The Polish CSM presents good psychometric properties, which are similar to those reported in other language versions, and also presents sex/age patterns similar to those found previously.

From Lark to Owl: developmental changes in morningness-eveningness from new-borns to early adulthood

Morningness-eveningness or chronotype changes significantly throughout the life span. This has been reported for the transition during adolescence in some studies, and to a lesser extent in early adulthood. Primary and pre-school children have been under investigation in fewer studies. This is the first comprehensive study covering the age range from very young children until early adulthood (0-30 years) based on the same measurement instrument. Here, we show that the turn towards eveningness starts at an early age in German children. Based on 26,214 cross-sectional data, we further show that at the end of adolescence, morningness-eveningness does not significantly change during early adulthood. Sex differences arise during puberty and remain until 30 years. The breaking point for the turn towards morningness is 15.7 years in girls and 17.2 boys. At the age of 0-1 years, there are about 70% morning types, and about 1% evening types, while at the age of 16 years, only 5% are morning types and 19% are evening types.

Psychometric properties of Persian version of Composite Scale of Morningness

BACKGROUND

Morningness-eveningness preference is commonly measured by questionnaires such as the Composite Scale of Morningness (CSM). The purpose of this study is to assess the Persian translation of the CSM and explore its psychometric properties.

METHOD

Participants consisted of 288 students at the University of Bojnord, Iran. Of the participants selected, 47.6% were female, 52.4% were male, and all were aged between 18 and 24 (20.09±1.32). Participants were selected using the stratified random sampling method. The scale was translated into Persian using the parallel translation method. SPSS-22 and AMOS-22 were used for analyses.

RESULTS

Mean CSM scores were 31.43±6.32 in a range of 14-50. Internal reliability, as measured by Cronbach's α, was 0.790, which fits well with previous studies undertaken in many countries. The factor analysis revealed a two-factor structure based on parallel analysis: one factor was labeled as "morning affect" and the other as "self-assessment/activity planning." Also, the confirmatory factor analysis supported the two-factor model fit. Construct validity was also evaluated by the MEQ with the results showing that correlations were comparable to other studies (r=0.76). Results did not show any significant correlation between age (r=0.041; P=0.487) and the CSM scores. According to the results of the t-test, women and men were not significantly different in terms of the CSM scores (t=-0.264; P=0.792).

CONCLUSIONS

The Persian version of the CSM is freely available and can be adopted for behavioral research related to sleep and circadian function and also applied to other Persian-speaking populations.

Cross-cultural validity of Morningness-Eveningness Stability Scale improved (MESSi) in Iran, Spain and Germany

Morningness-Eveningness Stability Scale improved (MESSi) is a newly constructed measure to assess circadian types and amplitude. In this study, we applied this measure to participants from three different countries: Germany, Spain and Iran. Confirmatory factorial analysis (CFA) of MESSi displayed mediocre fit in the three countries. Comparing increasingly stringent models using multigroup confirmatory factor analyses indicated at least partial measurement invariance (metric invariance) by country for Morning Affect and Distinctness subscales. Age was positively related to Morning Affect (MA), and negatively related to Eveningness (EV) and Distinctness (DI). Men reported higher MA than women, whereas women reported higher DI than men. Regarding country effect, Iranian participants reported highest MA compared to Spaniards and Germans, whereas Germans reported higher DI compared to Iranians and Spaniards. As a conclusion, our study corroborated the validity and reliability of MESSi across three different countries with different geographical and cultural characteristics.

Morningness-eveningness in a large sample of German adolescents and adults

People differ in their sleep-wake behavior. This individual difference is conceptualized in different aspects, such as wake up times, bed times, times of peak performance, as well as in morning affect. A total of 14,987 visitors of an exhibition in the LWL State Museum of Natural History, Münster (Germany), did the survey on chronotype and gave their consent that these data can be used for a scientific study. Age groups were coded into 5-year bins. Mean age (mean ± SD) was 28.2 ± 17.5 years. There were 8075 females (54%) and 6912 males in the sample. The German version of the rMEQ (reduced Morningness-Eveningness-Questionnaire) was used for data collection. The data showed clear age effects. Younger children are more morning oriented and become rapidly evening oriented during puberty, while the more attenuated turn towards morningness occurs from the age of 20 years. Then between the ages 25 to 30 morningness-eveningness remained rather stable. Significant gender differences existed in the reproductive age, i.e., the age groups 20 to 50 (corresponding to the age 16–50 years). In other age groups, no gender differences could be detected. Seasonal effects were also found. Chronotype score was lowest during the summer months (and more evening oriented). Based on the single item analysis of the five questions of the rMEQ, we found age group differences in all items. Gender differences occurred in all items except item 1, which deals with the preferred wake-up time. Men always scored significantly lower (i.e. more evening oriented) than women except in item 2 (tiredness after awakening). Seasonal effects were only significant in item 3, which is related to preferred bed times. People showed a later bed time preference during summer. The classification of chronotypes according to the cut-off scores provided by Adan and Almirall (1991) and by using the 20/80 percentile provided identical cut-off scores (values of 11 and below for evening types and 18 and above for morning types).

Smartphone addiction proneness in relation to sleep and morningness-eveningness in German adolescents

Background Mobile phones are an important part of adolescents' life. In this study, the relationships among smartphone addiction, age, gender, and chronotype of German adolescents were examined. Materials and methods Two studies focused on two different measures of smartphone addiction. The Smartphone Addiction Proneness Scale (SAPS) was applied to 342 younger adolescents (13.39 ± 1.77; 176 boys, 165 girls, and 1 not indicated) in Study 1 and the Smartphone Addiction Scale was applied to 208 older adolescents (17.07 ± 4.28; 146 girls and 62 boys) in Study 2, both samples in southwest Germany. In addition, a demographic questionnaire and the Composite Scale of Morningness (CSM) and sleep measures were implemented. Results The most remarkable result of this study was that morningness-eveningness (as measured by CSM scores) is an important predictor for smartphone addiction; even stronger than sleep duration. Evening oriented adolescents scored higher on both smartphone addiction scales. In addition, gender is an important predictor for smartphone addiction and girls are more prone to become addicted. In addition, while sleep duration on weekdays negatively predicted SAPS, age, sleep duration on weekends, and midpoint of sleep on weekdays and weekends did not predicted smartphone addiction in both scales. The analysis of covariance revealed statistically significant effects of the covariates gender and age in both studies, as well as the main effect of chronotype. According to the t-test results, girls had higher scores than boys in smartphone addiction. Conclusion Evening types and girls are more prone to become smartphone addicted.

Chronotype, Light Exposure, Sleep, and Daytime Functioning in High School Students Attending Morning or Afternoon School Shifts

Adolescent maturation is associated with delays of the endogenous circadian phase. Consequently, early school schedules may lead to a mismatch between internal and external time, which can be detrimental to adolescent sleep and health. In parallel, chronotype is known to play a role in adolescent health; evening chronotype adolescents are at higher risk for sleep problems and lower academic achievement. In the summer of 2008, Kénogami High School (Saguenay, Canada) was destroyed by fire. Kénogami students were subsequently relocated to Arvida High School (situated 5.3 km away) for the 2008-2009 academic year. A dual school schedule was implemented, with Arvida students attending a morning schedule (0740-1305 h) and Kénogami students an afternoon schedule (1325-1845 h). This study aimed to investigate the effects of such school schedules and chronotype on sleep, light exposure, and daytime functioning. Twenty-four morning and 33 afternoon schedule students wore an actigraph during 7 days to measure sleep and light exposure. Academic achievement was obtained from school. Subjects completed validated questionnaires on daytime sleepiness, psychological distress, social rhythms, school satisfaction, alcohol, and chronotype. Overall, afternoon schedule students had longer sleep duration, lower sleepiness, and lower light exposure than morning schedule students. Evening chronotypes (E-types) reported higher levels of sleepiness than morning chronotypes (M-types) in both morning and afternoon schedules. Furthermore, M-types attending the morning schedule reported higher sleepiness than M-types attending the afternoon schedule. No difference was found between morning and afternoon schedule students with regard to academic achievement, psychological distress, social rhythms, school satisfaction, and alcohol consumption. However, in both schedules, M-type had more regular social rhythms and lower alcohol consumption. In summary, this study emphasizes that an early school schedule is associated with detrimental effects in terms of sleep deprivation and daytime sleepiness, even for M-types. Furthermore, irrespective of school schedule, E-type adolescents face an increased risk for poor daytime functioning.

Arabic versions of the sleep timing questionnaire and the composite scale of morningness

OBJECTIVES

To develop Arabic versions of English language questionnaires to estimate morningness/eveningness and sleep variables.

METHODS

We translated the Composite scale of morningness (CSM) and the sleep timing questionnaire (STQ) [with added siesta questions] into Arabic; the Arabic versions were then back translated. The revised Arabic and the original English versions were next administered to bi-lingual Egyptians using a crossover design (n=25). The Arabic versions of both scales were subsequently administered to an independent Egyptian sample (n=79) and the siesta variables examined in relation to the CSM.

RESULTS

Satisfactory correlations were present between the English and Arabic versions for total CSM scores (Spearman's ρ=0.90, p<0.001). All but one of the STQ variables were significantly correlated (Spearman's ρ=0.45-0.88, p≤0.05). In the Arabic version, the frequency of siesta naps per week was significantly correlated with the total CSM score, with evening types taking more naps (Spearman's ρ=-0.23, p≤0.05).

CONCLUSIONS

Arabic versions of the STQ and CSM have been developed in Egypt, and are freely available. They can be used for behavioral research related to sleep and circadian function and can be adapted for use in other Arab speaking populations.

Do different circadian typology measures modulate their relationship with personality? A test using the Alternative Five Factor Model

The relationship between personality and circadian typology shows some inconsistent results and it has been hypothesized that the model used to measure personality might have a moderating effect on this relationship. However, it has never been explored if this inconsistency was dependent on the questionnaire used to measure differences in circadian rhythms as well. We explored this issue in a sample of 564 university students (32% men; 19-40 years) using the Zuckerman-Kuhlman Personality Questionnaire, which is based on an evolutionary-biological approach, in combination with the Composite Scale of Morningness (CSM) and the reduced Morningness-Eveningness Questionnaire (rMEQ). Both questionnaires detected differences between circadian typologies in Sociability (highest in evening types; ET) and Impulsive Sensation-Seeking scales (highest in ET), while the CSM also detected differences in Activity (lowest in ET) and Aggression-Hostility (highest in ET). Further, both questionnaires detected differences between circadian typologies in the subscales General Activity (morning types [MT] higher than ET), Impulsivity (ET highest) and Sensation-Seeking (highest in ET). Differences between circadian typologies/groups in the subscales Parties (highest in ET) and Isolation Intolerance (lowest in MT) were only detected by the rMEQ. The CSM clearly separated evening types from neither and morning types while the rMEQ showed that neither types are not intermediate but closer to evening types in General Activity and Isolation Intolerance, and closer to morning types in Impulsive Sensation-Seeking, Parties, Impulsivity and Sensation Seeking. The obtained results indicate that the relationship between circadian typology and personality may be dependent on the instrument used to assess circadian typology. This fact may help to explain some of the conflicting data available on the relationship between these two concepts.

Psychometric Properties of the Turkish Version of the Composite Scale of Morningness

The Composite Scale of Morningness is widely used and translated into several languages. The aim of the study was to present psychometric properties of Turkish version of CSM based on a sample of high school and university students. A total of 543 high school and 650 university students have participated in to the study. The internal consistency coefficient was found to be .73 (high school) and .80 (university). The test-retest reliability of the scale was .89 in high school sample and .84 in university sample. The mean CMS scores did not differ by gender in both samples. Exploratory and confirmatory factor analysis revealed that the scale is valid. As an external validation, morningness was associated with MEQ scores, sleep length, mid-point of sleep, rising and retiring time. The data obtained in the study suggested that the Turkish version of the CSM is a reliable and valid instrument to assess circadian preference in both high school and university samples.

Sleep disorders, medical conditions, and road accident risk

Sleep disorders and various common acute and chronic medical conditions directly or indirectly affect the quality and quantity of one's sleep or otherwise cause excessive daytime fatigue. This article reviews the potential contribution of several prevalent medical conditions - allergic rhinitis, asthma, chronic obstructive pulmonary disease, rheumatoid arthritis/osteoarthritis - and chronic fatigue syndrome and clinical sleep disorders - insomnia, obstructive sleep apnea, narcolepsy, periodic limb movement of sleep, and restless legs syndrome - to the risk for drowsy-driving road crashes. It also explores the literature on the cost-benefit of preventive interventions, using obstructive sleep apnea as an example. Although numerous investigations have addressed the impact of sleep and medical disorders on quality of life, few have specifically addressed their potential deleterious effect on driving performance and road incidents. Moreover, since past studies have focused on the survivors of driver crashes, they may be biased. Representative population-based prospective multidisciplinary studies are urgently required to clarify the role of the fatigue associated with common ailments and medications on traffic crash risk of both commercial and non-commercial drivers and to comprehensively assess the cost-effectiveness of intervention strategies.

Morningness-Eveningness and Eating Disorders in a Sample of Adolescent Girls

Eating disorders and morningness-eveningness preferences are presumed to be associated with each other. We tested this hypothesis in an adolescent population using a questionnaire for morningness (CSM) and three scales of the EDI-2: drive for thinness, bulimic behavior, and body dissatisfaction. After controlling for age and BMI, we found a positive association between eveningness and all three scales; evening-oriented girls reported higher values in eating disorders. There was a positive correlation between body dissatisfaction and drive for thinness on the one side and bedtimes during the week and on the weekend on the other, again supporting the view that eveningness and eating disorders are associated. The association between circadian preference and eating disorders thus emerges already in adolescence.