The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects.

BACKGROUND: The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. METHODS: This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured. RESULTS: IL-6 levels showed a positive correlation with light exposure (r = 0.257; p < 0.001) and a negative correlation with the mid-sleep phase on work-free days (r = -0.177; p = 0.028). Multiple linear regression analysis showed that only the length of light exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037). CONCLUSIONS: The amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time.

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.

Effects of lighting patterns in pubertal development and metabolism of female wistar rats.

Modern lifestyle is characterized by constant exposure to artificial light, which is associated with alterations in biological rhythms, abnormalities to reproductive cycles and metabolic changes. In this study, we aimed to evaluate the effects of four different lighting patterns on puberty timing and on possible metabolic changes in female Wistar rats. Additionally, we developed a machine learning algorithm to automatically classify the stages of the estrous cycle. Adult Wistar rats mated during a week at a photoperiod station where they were exposed to combined red-green-blue lights (RGB) during the photoperiod that varied its spectral composition (i.e., variable color temperature) during the day (RGB-v; N = 14), RGB during the photoperiod with a fixed light color temperature (RGB-f; N = 13) during the whole photoperiod; constant darkness (DD; N = 13) and constant fixed light (LL; N = 15). Experiments were performed only on female litters from postnatal day (PND) 22 to 50. Body weight, puberty onset, estrous cyclicity and serum metabolic parameters were measured. We also collected pictures of vaginal smears to create a dataset of 15,936 images to construct an automatic classifier based on convolutional neural networks. No significant differences were found in the age of vaginal opening; however, the RGB-v group showed a significantly lower number of complete and consecutives cycles. Also, the RGB-f group showed the first complete estrous cycle significantly earlier than the RGB-v group. Female rats housed in LL condition presented significantly lower mean body weight from PND 33 to PDN 47 compared to the other groups. Furthermore, higher levels of plasma triglycerides were found in the DD group compared to RGB-f and RGB-v. HDL levels were significantly lower in RGB-v compared to RGB-f and LL groups. Total cholesterol was significantly lower in RGB-v compared to all groups. Visceral fat was significantly higher in RGB-f compared to the LL group. These results suggest that both changes in photoperiod and lighting quality affect pubertal development and alter lipid profiles and visceral fat accumulation.

Sleep disturbances, circadian activity, and nocturnal light exposure characterize high risk for and current depression in adolescence.

STUDY OBJECTIVES: Major depressive disorder (MDD) in adolescence is associated with irregularities in circadian rhythms and sleep. The characterization of such impairment may be critical to design effective interventions to prevent development of depression among adolescents. This study aimed to examine self-reported and actimetry-based circadian rhythms and sleep-wake behavior associated with current MDD and high risk (HR) for MDD among adolescents. METHODS: Ninety-six adolescents who took part in the IDEA-RiSCo study were recruited using an empirically developed depression-risk stratification method: 26 classified as low risk (LR), 31 as HR, and 39 as a current depressive episode (MDD). We collected self-report data on insomnia, chronotype, sleep schedule, sleep hygiene as well as objective data on sleep, rest-activity, and light exposure rhythms using actimetry for 10 days. RESULTS: Adolescents with MDD exhibited more severe insomnia, shorter sleep duration, higher social jetlag (SJL), lower relative amplitude (RA) of activity, and higher exposure to artificial light at night (ALAN) compared with the other groups. They also presented poorer sleep hygiene compared with the LR group. The HR group also showed higher insomnia, lower RA, higher exposure to ALAN, and higher SJL compared with the LR group. CONCLUSIONS: HR adolescents shared sleep and rhythm alterations with the MDD group, which may constitute early signs of depression, suggesting that preventive strategies targeting sleep should be examined in future studies. Furthermore, we highlight that actimetry-based parameters of motor activity (particularly RA) and light exposure are promising constructs to be explored as tools for assessment of depression in adolescence.

6­Sulfatoxymelatonin as a predictor of clinical outcome in depressive patients.

OBJECTIVES: This study established the value of the 6­sulfatoxymelatonin (aMT6s) urine concentration as a predictor of the therapeutic response to noradrenaline reuptake inhibitors in depressive patients. METHODS: Twenty-two women aged 18-60 years were selected. Depressive symptoms were assessed by using the Hamilton Depression Scale. Urine samples were collected at 0600-1200 h, 1200-1800 h, 1800-2400 h, and 2400-0600 h intervals, 1 day before and 1 day after starting on the nortriptyline treatment. Urine aMT6s concentration was analyzed by a one-way analysis of variance/Bonferroni test. Spearman's rank correlation coefficient was used to analyze the correlation between depressive symptoms after 2 weeks of antidepressant treatment and the increase in aMT6s urine concentration. RESULTS: Higher and lower size effect groups were compared by independent Student's t-tests. At baseline, the 2400­ to 0600­h interval differed from all other intervals presenting a significantly higher aMT6s urine concentration. A significant difference in aMT6s urine concentrations was found 1 day after treatment in all four intervals. Higher size effect group had lower levels of depressive symptoms 2 weeks after the treatment. A positive correlation between depressive symptoms and the delta of aMT6s in the 2400-0600 h interval was observed. CONCLUSION: Our results reinforce the hypothesis that aMT6s excretion is a predictor of clinical outcome in depression, especially in regard to noradrenaline reuptake inhibitors.

Morningness-eveningness, use of stimulants, and minor psychiatric disorders among undergraduate students.

Morningness-eveningness dimension in humans have been indicated to influence social behavior and individual health. The aim of the present study was to investigate the association of the morningness-eveningness dimension with behavioral and health aspects in a sample of undergraduate students. We assessed demographic data; the Pittsburgh Sleep Quality Index was used to evaluate sleep quality; the Morningness/Eveningness Questionnaire to determine morningness-eveningness, and the Self-Reporting Questionnaire to assess minor psychiatric disorders. A total of 372 students (66.7% females), on average 21.6 years old, participated in this study. Among them, 92.2% did not smoke, 58.9% engaged in physical activities, and 19.7% were night-shift workers. In regard to morningness-eveningness, 55.9% of the participants were intermediate between evening (39.5%) and morning (4.6%) types. Poor sleep quality (OR = 1.89), minor psychiatric disorders (OR = 1.92), and tobacco consumption (OR = 3.65) predominated among evening types. Evening types were predominantly males (OR = 1.72). This study suggests that evening types are more vulnerable to sleep and psychiatric disturbances, and tend to smoke more than morning types.

Prevalence of psychiatric comorbidities in temporal lobe epilepsy: the value of structured psychiatric interviews.

BACKGROUND: Although many studies have demonstrated a high prevalence of psychiatric disorders in epileptic patients, most have used unstructured psychiatric interviews for diagnosis, which may lead to significant differences in results. Here we present a study evaluating the prevalence of major psychiatric comorbidities in a cohort of South Brazilian patients with temporal lobe epilepsy using a structured clinical interview. METHODS: Neuropsychiatric symptoms were analyzed in 98 patients (39 men and 59 women) with temporal lobe epilepsy. Patient mean age was 43 years old, and mean duration of epilepsy was 25 years. Patients were diagnosed according to the ILAE Classification of Epileptic Syndromes using clinical, EEG, and neuroimaging criteria. All patients participated in the Structured Clinical Interview for DSM-IV (SCID). RESULTS: Fifty-three patients (54.1%) presented major psychiatric comorbidities. Mood disorders were observed in 42 patients (42.9%), the most common being neuropsychiatric disorders. Anxiety disorders were the second most frequent disorders, observed in 18 patients (18.4%). Psychotic disorders and substance abuse were each observed in six patients (6.1%). There were no clinical variables regarding epilepsy characteristics (age of onset, duration, response to antiepileptic drugs) and no MRI features associated with psychiatric disorders. A seven-fold increased risk of mood disorders was identified in patients with inter-ictal EEG abnormalities associated with the left hemisphere. CONCLUSION: Relative to previous reports, we identify a high prevalence of psychiatric disorders in TLE patients, although our data is similar to that observed in other studies which have used similar structured interviews in populations of epileptic patients attending tertiary centres. The wide variation in percentages is probably attributable to the different patient groups investigated and to the even greater variety of diagnostic methods. Structured psychiatric interviews may contribute to a better evaluation of the true prevalence of psychiatric comorbidities in temporal lobe epilepsy.

[Translation and adaptation of the Brazilian version of the Night Eating Questionnaire]. / Tradução e adaptação da versão brasileira do Night Eating Questionnaire.

The goal of this study was to translate and adapt the Night Eating Questionnaire to Portuguese and assess the reliability of the Portuguese-language version. The study included two phases. The first consisted of: (1) translation into Portuguese; (2) back-translation into English; (3) correction and semantic adaptation; (4) content validation; and (5) assessment of the understanding of the questionnaire by means of 10 cm Visual Analogue Scales with 30 adult users of a nutritional support clinic. In the second phase, the questionnaire's reliability was assessed in 100 subjects with similar demographic characteristics to the first sample. In the fifth step, understanding of the instrument assessed by the visual analogue scales was 8.20+/-1.55 cm. The instrument showed satisfactory internal consistency, with an overall Cronbach alpha of 0.78. The Portuguese version proved to be easily understandable, with good semantic validation and consistency, suggesting that the questionnaire may be a good instrument for screening the night eating syndrome. However, other psychometric characteristics of this instrument need to be assessed in samples with different social and educational levels.

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.

Nocturnal motor activity and light exposure: Objective actigraphy-based marks of melancholic and non-melancholic depressive disorder. Brief report.

Differentiation of melancholic (MEL) and non-melancholic (N-MEL) depression results from subjective assessment of psychomotor disturbance, which obscures their accurate diagnosis. CORE instrument assigned participants with severe or refractory depression to MEL or N-MEL group. Participants underwent 7 days of actigraphy. Data was fitted to a cosinusoidal curve corresponding to a 24-h rhythm. Nocturnal activity was significantly higher in N-MEL. ROC curve shows that average night activity discriminate participants with 71% sensitivity and 100% specificity (area under the curve = 0.84). Actigraphy contribute to the objective differentiation of depression subtypes, and have implications for research on their neurobiology and clinical management.

Translation and adaptation of the indoor environmental quality questionnaire to Brazilian portuguese

Introduction: Indoor environmental quality (IEQ) impacts well-being, performance, and mental and physical health. A questionnaire for assessing occupants' perception of IEQ was developed in English. This study aimed to translate this instrument into Brazilian Portuguese and adapt it to the Brazilian population.Methods: The translation and adaptation process consisted of forward translation, reconciliation, back translation, back translation review, harmonization, two cognitive debriefings, and finalization.Results: The final translated version included new questions and changed the scale to a visual-analog format. The clarity assessment showed that, after cognitive debriefings, all questions displayed satisfactory scores, with the majority rated higher than 9 on a 0-10 scale.Conclusions: The Brazilian Portuguese version of the IEQ questionnaire is a simple tool that can be employed in biomedical and building research to investigate the association of perceived IEQ with health-related parameters, as well as in architecture, engineering, and management projects. As a next step, a psychometric validation of the instrument will be performed.

Biological adaptability under seasonal variation of light/dark cycles.

3A substantial amount of experimental models designed to understand rhythms entrainment and the effects of different regimens of light exposure on health have been proposed. However, many of them do not relate to what occurs in real life. Our objective was to evaluate the influence of "seasonal-like" variation in light/dark cycles on biological rhythms. Twenty adult male Wistar rats were assigned to three groups: control (CT), kept in 12:12 light/dark (LD) cycle; long photoperiod/short photoperiod (LP/SP), kept in 16.5:7.5 LD cycle for 18 days (phase A), then 17 days of gradual reductions in light time (phase B), then 18 days of shorter exposure (7.5:16.5 LD cycle, phase C); short photoperiod/long photoperiod (SP/LP) group, with same modifications as the LP/SP group, but in reverse order, starting phase A in 7.5:16.5 LD cycle. Activity and temperature were recorded constantly, and melatonin and cortisol concentrations were measured twice. Activity and temperature acrophases of all groups changed according to light. The correlation between activity and temperature was, overall, significantly lower for SP/LP group compared with LP/SP and CT groups. Regarding melatonin concentration, LP/SP group showed significant positive correlation between phase A and C (p = 0.018). Animals changed temperature and activity according to photoperiod and demonstrated better adaptability in transitioning from long to short photoperiod. Since this model imitates seasonal variation in light in a species that is largely used in behavioral experiments, it reveals promising methods to improve the reliability of experimental models and of further environmental health research.

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.

Cohesion and adaptability among individuals under treatment for infertility.

The objective of this study was to evaluate cohesion and adaptability as relationship patterns of individuals in the presence or absence of infertility. Infertile subjects (20 men and 26 women, age 29.9 yr., SD = 3.8), and 100 fertile individuals (52 men and 48 women, age 29.5 yr., SD = 3.6) were included in this cross-sectional study conducted in Brazil. Subjects were married for the first time and had no children. The pattern of relationship (cohesion and adaptability) was assessed on the Family Adaptability and Cohesion Evaluation Scale (FACES III). Subjects were also interviewed and the interviews tape-recorded and analyzed by independent and blinded senior psychiatrists. The concepts of cohesion and adaptability did not differentiate infertile couples from fertile ones. Further, the recorded interviews also resulted in heterogeneous. nonconcordant judgments. These results lead to two conclusions: that awareness of infertility is not present in the population studied or that it is present but the magnitude of its effect is quite small and that FACES III and the interview focus on adaptability and cohesion are not sensitive enough to measure the difficulties in these couples' relationships. This leads us to reflect on the type of psychiatric support available to infertile couples.

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.

Performance of chronotypes on memory tests during the morning and the evening shifts.

Memory consists of several phases or processes that can be influenced by many factors, including the individual's circadian rhythm and the time of day at which tests are performed. The present objective was to evaluate the performance on memory tests of different chronotypes during the morning and the evening shifts. Subjects (21 men and 26 women, between the ages of 20 and 35 yr.) were evaluated for memory and metamemory differences in the morning and in the afternoon, using a battery of neuropsychological tests composed of the Word List with Emotional Content, Visual Memory, Scale-Semantic Memory, Digit Span, Word-Pairs Associated, Verbal Fluency Test, and Metamemory questionnaire. In the evening shift, there was a statistical difference among chronotypes on the Word List with Neutral Content and on the Verbal Fluency Test. In the morning, there were no statistically significant differences; however, the morning-type subjects had higher scores on the metamemory tests (p<.01), while the evening-type subjects had higher scores in the afternoon (p<.01). In spite of their perception, on Word-Pairs Associated and Word List with Emotional Content, the subjects, independently of their chronotype, showed better performance by the evening than by the morning shift. These results highlight the importance of controlling the shift of day and chronotype in studies with the objective of exploration of human performance.

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.

The concept of time in the perception of children and adolescents.

INTRODUCTION: Children and adolescents use different markers to elaborate the concept of time, and such markers change along their development. The objective of the present article was to analyze changes in time concepts in different age groups. METHODS: The study included 81 children and adolescents aged 6 to 17 years, attending elementary or high school at a public school in southern Brazil. Participants were asked to provide their definition of time, either orally (children) or in writing (older children and adolescents). RESULTS: Twenty-one words were identified as related with the definition of time. The term "hours" was the most frequently cited (24.7%), followed by "clock" and "family" (11.1% each). Among children aged 6 to 8 years, "family" was the term most frequently mentioned to refer to time. Between 9 to 11 years of age, the notion of time was essentially related to the use of a clock, and in the 12-17-year age group, time was mostly associated with the word "days." The word "family" appears to be a frequent temporal marker in childhood, but loses this function during adolescence, as new social relationships are established. CONCLUSION: The results of this study show that the concept of time varies according to age. Chronobiological studies should therefore take into consideration the temporal perception peculiar to each age group.

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.

Spanish translation of the mood rhythm instrument: a novel approach to mood evaluation

Introduction: The Mood Rhythm Instrument (MRI) is a questionnaire developed to assess the circadian rhythm of mood-related behaviors. The aim of this study was to translate this instrument from Brazilian Portuguese into Spanish. Methods: The translation process consisted of forward translation, adjustment, back translation, back translation review and harmonization. Results: Comparing the initial Spanish translation and the final Spanish version, there were no semantic differences and the items were not changed. Conclusions: The Spanish version of the MRI is ready to be tested in a Spanish population. In the future, assessing and comparing mood-related behaviors in transcultural studies will be possible(AU)