Work routines moderate the association between eveningness and poor psychological well-being.

Well-being is a useful screening method for the detection of mood disorders. Evidence associating psychological well-being with sleep-wake patterns exists, as well as associations with sleep-wake patterns, work-related parameters, and perceived self-efficacy. Despite the growing research regarding the relationship between these factors and mental health, there are few studies that analyze them together. OBJECTIVE: To investigate if the association between sleep-wake patterns and psychological well-being is mediated or moderated by perceived self-efficacy, work flexibility and work routines. MATERIAL AND METHODS: This cohort study was performed in southern Brazil. A sample of 987 individuals was analyzed (66.9% women; mean age = 43.9 years). Work routines parameters and work schedule flexibility were evaluated, most participants were farmers (46%) and most worked 7 days a week (69.1%). Munich Chronotype Questionnaire (MCTQ) was administered for evaluation of sleep-wake patterns, General Self-Efficacy Scale (GSE) for assessment the participants' beliefs about how they coped with daily hassles, and World Health Organization Five-item Well-being Index (WHO-5) for evaluation of psychological well-being levels. Moderation and mediation models were tested. RESULTS: The moderation model showed influences of work end time on the relationship between sleep onset time and psychological well-being (R2 = 0.147; F = 24.16; p<0.001). The final regression model showed an association of psychological well-being with sex (Beta = -0.086; p = 0.004), sleep onset time (Beta = -0.086; p = 0.006), and self-efficacy (Beta = 0.316; p<0.001); the work end time showed association in the interaction with sleep onset time (Beta = -0.075; p = 0.016). CONCLUSION: The findings support the direct association of psychological well-being with sleep-wake patterns and self-efficacy, and show an interaction between work routines and sleep-wake patterns. Our results draw attention to the importance of the interplay between individual and social rhythms in relation to psychological well-being.

The midpoint of sleep on working days: a measure for chronodisruption and its association to individuals' well-being.

There is consistent evidence suggesting a relationship between individuals' sleep-wake rhythms and well-being. The indiscriminate demands from daily working routines, which do not respect this individual physiological rhythm, might be mediating this phenomenon. The aim of the present study was to evaluate the relationship between the characteristics of sleep routines during working days and psychological well-being. This was a cross-sectional study on 825 individuals from rural communities from southern Brazil. The study protocol included a questionnaire on demographic characteristics, working routines, health complaints, and habits; the Munich Chronotype Questionnaire for sleep-wake rhythm and; the WHO-Five well-being index. Since sex has been shown to affect sleep circadian rhythm and well-being, analysis was performed on men and women separately. In the proposed hierarchical regression models, different factors contributed to well-being according to sex. Among men, sleep-wake and work-related variables did not predict well-being scores. Among women, later midpoints of sleep on working days (B = -1.243, SE B = 0.315, ß = -0.220), working more days per week (B = -1.507, SE B = 0.494, ß = 0.150), having longer working journeys (B = -0.293, SE B = 0.105, ß = -0.166), earlier working journey midpoints (B = 0.465, SE B = 0.222, ß = 0.115), and being exposed to less sunlight (B = 0.140, SE B = 0.064, ß = 0.103) predicted worse well-being. For the subgroup of women with days free from work, we have found a correlation between later midpoints of sleep during the week with worse well-being (Pearson's r = -0.159, p = 0.045) while the same relationship was not significantly observed with the midpoint of sleep on non-working days (Pearson's r = -0.153, p = 0.054). Considering WHO-Five as categorical, based on proposed clinical cut-offs, among women working 7-d/week, those with worst well-being (WHO-Five < 13) had the latest midpoint of sleep (F = 4.514, p = 0.012). Thus, the midpoint of sleep on working days represents the interaction between individuals' sleep-wake behavior and working routines. It plays an important role as a stress factor and may be a useful alternative variable related to chronodisruption.

Midpoint of sleep on school days is associated with depression among adolescents.

Depression is a serious and prevalent disease among adolescents. Identifying possible factors involved with its genesis and presentation is an important task for researchers and clinical practitioners. The individual's chronotype and social jetlag have been associated with depression in different populations. However, information on this is lacking among adolescents. The objective of this cross-sectional study was to examine the relationship between chronotype (midpoint of sleep) and social jetlag with the presence of depression symptoms in young students. We assessed 351 students aged 12-21 years old. They answered a questionnaire on demographic characteristics, the Munich Chronotype Questionnaire (MCTQ) and the Beck Depression Inventory (BDI). Demographic characteristics (age, sex and classes' schedule) and circadian rhythmic variables for school and free days (sunlight exposure, sleep duration, midpoint of sleep and social jetlag) were taken as factors and the presence of at least mild depression symptoms as outcome. In univariate analysis, girls (χ(2) = 5.01, p ≤ 0.05) and evening students (χ(2) = 6.63, p ≤ 0.05) were more frequently present among the depressed. Also, the depression group was significantly delayed for both midpoints of sleep during school (t = 2.84, p ≤ 0.01) and free days (t = 2.20, p ≤ 0.05). The two groups did not differ in relation to their social jetlag hours (t = -0.68, p = 0.501) neither subjects with two or more hours of social jetlag were more frequent among the depressed (χ(2) = 1.00, p = 0.317). In multivariate analysis, the model that best explained our outcome (R(2) = 0.058, F = 2.318, p ≤ 0.05) included sex (ß = -0.12, p ≤ 0.05) and the midpoint of sleep on school days (ß = -0.21, p ≤ 0.001) as significant predictor variables. A sleep phase delay (later midpoints of sleep for school and free days) was associated with higher levels of depression. However, we were not able to detect similar relationship with the social jetlag hours. This could be attributed to the fact that our sample showed a smaller amount of social jetlag, possibly because even during free days a social routine, this time parents' rules, limited the observation from what could be a natural tendency to sleep later and over. Yet, even when considering the group with more social jetlag, we did not find an association. Perhaps, this variable will only manifest its effect if it is maintained for longer periods throughout life. Additionally, when considering all the variables together, the midpoint of sleep on school days was pointed as the predictor of greatest weight for depression, together with the factor sex. Young girls, possibly earlier types, who are required to study in the evening have more chances of presenting depression symptoms. This study explicit some peculiar characteristics of the assessment of chronobiological variables in the young, such as the presence of an imposed social routine also during free days. Therefore, the expression of chronotype under the influence of the weekly social schedule (midpoint of sleep on school days) could be a more useful marker to measure the stress produced from the mismatch between external and inner rhythms rather than social jetlag. This also reinforces the importance of reconsidering the weekly routine imposed on young people.

Impact of the time in an animal model of mood disorder.

UNLABELLED: The objective of the study is to evaluate whether intervening and testing in different rest-activity periods of the day would produce different measurements in animal behavior studies. METHODOLOGY: Thirty-five, 60-day-old male Wistar rats were submitted to an inescapable foot shock (IFS) stress model and behavioral tests (Light-Dark Box test). The animals received intervention and were tested in both light and dark phases, resulting in the following groups: control L (tested in the light), control D (tested in the dark), LL (IFS and tested in the light), LD (IFS in the light and tested in the dark), DL (IFS in the dark and tested in the light), and DD (IFS and tested in the dark). RESULTS: The Light-Dark Box test showed that control L was not significantly different from other groups in any of the parameters. However, when comparing control D with the intervention groups, we observed a difference in the mean length of time spent in the light compartment (t=2.56; p=0.045). A significant difference in the number of crossings into the light compartment was only observed between the control D and the LL and LD groups (t=-2.608; p=0.028; t=-2.571; p=0.030, respectively). The latency time for the control D group was significantly lower than that of the DD group (t=-2.556; p=0.043). CONCLUSIONS: These results show that behavior testing during the animal's period of highest activity (dark period) revealed differences caused by the intervention, whereas no differences were apparent when the control group was observed during the day.

World Health Organization 5-item well-being index: validation of the Brazilian Portuguese version.

The psychological well-being dimension and depressive symptoms are both important variables in an individual's health. In this study, we evaluated the World Health Organization 5-item well-being index (WHO-Five) internal and external validities, and accuracy in detecting depression. A total of 1,128 individuals between 18 and 65 years old from a rural Brazilian population were included. Cronbach's alpha and factor analysis were performed for internal validation. Demographic variables means were compared, receiver operating characteristic (ROC) curve was constructed, and sensitivity, specificity and positive and negative predictive values for different cutoff points were calculated for external validation and accuracy in detecting depression. Cronbach's alpha was 0.83, and only one factor was responsible for 59% of common variances, with an eigenvalue of 2.96. Higher WHO-Five scores were associated with being man, from oldest age category and retired. It was also related to better general health self-perception and negative screening in the Beck Depression Inventory (BDI). Based on BDI, the area under the curve was 67.37. A sensitivity of 66/75% and a negative predictive value of 91/92% for cutoffs <19/20 were detected. WHO-Five showed internal and external validities when used to measure the well-being dimension and to be a useful tool for depression screening.

Association of daytime sleepiness and the morningness/eveningness dimension in young adult subjects in Brazil.

Sleepiness is a major public health problem associated with motor vehicle crashes, occupational accidents, decreased productivity, and interpersonal problems. It can be influenced by many factors, including the individual's circadian rhythm. The objective of this study is to assess the correlation between the morningness/eveningness dimension and daytime sleepiness in medical school students. This is a cross-sectional study; 310 subjects (123 women and 187 men, M age 20.5 +/- 1.9 yr.) completed a questionnaire on use of drugs, diagnostic diseases, sleeping habits, the Morningness/Eveningness Questionnaire and the Epworth Sleepiness Scale. The only variable related to daytime sleepiness was the morningness/eveningness dimension (r = -.18, p=.002). Questions with higher coefficients of discrimination between the morning and the evening chronotype were "Lying down to rest in the afternoon when circumstances permit" (.61), "Sitting and reading" (.53), and "As a passenger in a car for an hour without a break" (.53). The implications of the findings are discussed.