The concept of chronotypes and its clinical importance for depressive disorders

Chronotype influences on posttraumatic stress disorder induced by the twin earthquakes in Turkey: A cross-sectional study among medical students

This study aimed to investigate the correlation between chronotypes and posttraumatic stress disorder (PTSD) symptoms in medical students affected by earthquakes in Kahramanmaraş, Turkey, while elucidating if the PTSD manifestation varies among different chronotypes four months post-disaster. The study encompassed 193 medical students, subjected to the sociodemographic data form, the Morningness-Eveningness Questionnaire (MEQ) and the PTSD Checklist for DSM-5 (PCL-5). The results indicated that students identified as "evening types" reported significantly elevated PCL-5 scores (p < 0.001) relative to "morning" and "intermediate" types. According to PCL-5 scores, 43.5% of the participants exhibited PTSD, with a higher occurrence among the evening types. Multivariable linear regression analysis revealed that lower MEQ scores independently correlated with elevated PTSD symptoms (β = -0.1389 [95% CI = -0.273 - -0.0048], p = 0.042), suggesting the potential of eveningness as a risk factor for PTSD post-disaster. These findings could enhance our understanding of PTSD, aid the development of preventive strategies, and underscore the importance of considering chronotypes. Further expansive, population-based studies with a longitudinal design are necessary to better understand the relationship between PTSD and the circadian system.

Chronotype Profile, Stress, Depression Level, and Temporomandibular Symptoms in Students with Type D Personality

Background: Despite a growing interest in the types of human circadian activity, different chronotypes and personality-related issues have been rarely studied. It has already been emphasized that ‘stress personality’ is considered a risk factor for certain psychosomatic diseases and may be a temporomandibular disorders (TMDs) predictor. Therefore, an attempt has been made to analyze the chronotypes, stress levels, stress factors, and the occurrence of depression and TMDs in students with type D personalities. People with this personality trait tend to experience negative emotions more—depression, anxiety, anger, or hostility—yet may have a negative image of themselves and report somatic complaints. Aim: The aim of this study was to analyze the importance of the chronotype profile for the level of stress perceived, as well as for the occurrence of depression and TMDs in people with type D personalities. Material and Methods: The study has been conducted on a group of 220 physical therapy students. The study group G1 consisted of 110 participants with type D personalities, the control group G2 consisted of the same number of participants without the stress personality. All participants have been analyzed for the chronotype (MEQ), stress perception (PSS10), the occurrence of depression (Beck scale-BDI), the occurrence of TMDs symptoms and have completed the stress factor assessment questionnaire during the study, followed by DS14 questionnaire—a tool for assessing the prevalence of type D personality. Results: In students with type D personalities (G1), the definitely evening and evening chronotypes have been significantly more predominant than in the control group (G2). A significantly higher number of stressors and TMDs symptoms have been observed in the respondents from the G1 group than in the control group (<0.001). Univariate logistic regression analysis showed that type D personality was strongly associated with a more frequent occurrence of all TMD symptoms. Additionally, a significant influence of the evening chronotype on the occurrence of type D personality was observed. Among the potential confounding variables, female gender and a mild and moderate degree of depression have an impact on the occurrence of type D personality (p < 0.05). In the multivariate model, adjusted with the above-mentioned factors, an increased risk of the type D personality trait was found. Conclusion: The evening chronotype and type D personality may imply greater feelings of stress, greater depression, and more frequent symptoms of TMDs in young adults.

Circadian preference and its relationship with possible sleep and awake bruxism in adults assisted by the public health system

Modern lifestyle and social demands induce changes in sleep routines that may not meet individual circadian preferences (chronotype). Such changes may be associated with the development of unhealthy lifestyles and the emergence of diseases relevant to public health services, such as obesity, hypertension, and diabetes mellitus, as well as sleep bruxism (SB) and awake bruxism (AB). The present study aimed to assess the relationship between the evening, morning or intermediate chronotypes with the report of possible SB and AB in adult individuals assisted by the Family Health Strategy (FHS). The selection of participants was performed through probabilistic cluster analysis. The sample size (n = 384) was calculated to include a representative sample of the 52,628 adults registered in the FHS of a countryside city located in the Southeast Region of Brazil. The Morningness-Eveningness Questionnaire (MEQ) was used to determine the chronotype, and Questionnaire-Based Self-Reported Bruxism was used for identifying possible SB and AB. The following clinical and social-behavioral variables were also evaluated: age, sex, BMI, income, physical activity, schooling, alcohol consumption and smoking, chronic diseases and depression. Two logistic regression models were used: one for SB and one for AB. Possible SB was associated with female sex, lack of physical activity and income above 2 minimum wages. Regarding chronotype, a 19% reduction in the chance of possible SB was observed in morning individuals compared to evening individuals (p = .017). Possible AB was associated with younger individuals, smoking and depression. In conclusion, compared with the evening circadian preference, the morning circadian preference was associated with greater protection against possible SB in an adult population assisted by the FHS.

A chrononutrition perspective of diet quality and eating behaviors of Brazilian adolescents in associated with sleep duration

It is well recognized that sleep and food intake exhibit 24-h patterns and disturbances of these patterns can lead to health problems. Cross-sectional and prospective studies suggest that diet quality and eating behaviors are negatively affected by short sleep duration. Adolescence is a particularly vulnerable period for the emergence of inadequate sleep and diet patterns. The aim of the study was to investigate associations, from a chrononutrition perspective, of diet quality, nutrients intake, and eating behaviors (eating frequency, eating period, and time-interval between eating occasions) in relation to sleep duration among a multi-ethnic cohort of Brazilian adolescents. Data were collected by the 2015 ISA-Capital survey, a population-based cross-sectional study comprising 419 adolescents of both sexes (12-19 years old) of São Paulo, Brazil. Demographic, socioeconomic, anthropometric, and lifestyle, including sleep duration, data were obtained from an interviewer-administered structured questionnaire. Dietary data were obtained by 24-h dietary recall (24-HDR), and diet quality was assessed by the Brazilian Healthy Eating Index - Revised (BHEI-R), validated for the Brazilian population. The independent associations between sleep duration categories (i.e., <8 h as short sleep and 8-10 h as adequate sleep), and dietary variables were assessed after adjustments for covariates. Multiple linear, logistic, and Poison regression models were used, depending on the variable. Diet quality, nutrients intake, and eating behaviors differed according to adolescents' sleep duration. Approximately 36% of adolescents were sleep deprived. They presented poorer diet quality (53 points, p = .034) and eating behaviors characterized by lower probability of having lunch (88%, p < .001) and dinner (71%, p < .001) and higher probabilities of eating breakfast (87%, p < .001) and morning snack (26%, p = .001). These adolescents compared to those with adequate sleep duration also had, from snacks and in the 24-h cycle, higher contribution of available carbohydrates (8%, p < .001; 50%, p = .024) and total sugar (6%, p < .001; 21%, p < .001) and added sugar (3%, p < .001; 15%, p < .001). The chrononutrition characteristics of sleep-deprived adolescents were marked by longer eating periods (12 h, p < .001) and time-interval between eating occasions (3 h, p < .001) than adolescents with adequate sleep duration. These differences point to the relevance of the interrelation between sleep and diet, i.e., disruption of circadian cycles and consequent metabolic health problems, to inform public health policies and clinical interventions.

Chronotype, Sleep, and Depressive Symptoms Among Chinese College Students: A Cross-Sectional Study

Objective: To describe the prevalence of chronotype and depressive symptoms among Chinese college students and to examine the association between chronotype and depressive symptoms.

Methods: From April to May 2019, a cross-sectional survey was conducted among 1,179 Chinese college students from 2 universities in Anhui and Jiangxi provinces. A total of 1,135 valid questionnaires were collected, the valid response rate was 98.6%. The questionnaire investigated age, gender, major, height, weight, only child status, living place, self-reported family economy, and self-reported study burden. The chronotype was assessed by the Morning and Evening Questionnaire (MEQ). Depressive symptoms and sleep quality were evaluated by the Patient Health Questionnaire 9 (PHQ-9) and the Pittsburgh Sleep Quality Index (PSQI), respectively. A Chi-square test was used to examine the proportion of depressive symptoms among Chinese college students with different demographic characteristics. The generalized linear model was used to analyze the relationships between chronotype and depressive symptoms.

Results: The proportion of morning types (M-types), neutral types (N-types), and evening types (E-types) of college students were 18.4, 71.1, and 10.5%, respectively. The proportion of mild depression, moderate depression, and moderate to severe depression of participants were 32.4, 6.0, and 4.2%, respectively. Compared to the M-types, after controlled for age, gender, major, sleep quality, self-reported study burden, father's education level, and self-reported family economy, depressive symptoms were positively correlated with E-types (OR = 2.36, 95% CI: 1.49–3.73).

Conclusions: There was a significant association between chronotype and depressive symptoms among Chinese college students. Further longitudinal studies were needed to clarify the causal relationship between chronotype and depressive symptoms.

Sex differences in the association between chronotype and risk of depression

Information on sex differences in the association between chronotype and depression is scarce. We aimed to investigate these differences using data from the Korea National Health and Nutrition Examination Survey in 2016. Chronotypes were categorised based on mid-sleep time on free days corrected by sleep debt accumulated on workdays (MSFsc): early type, < mean MSFsc - 1 standard deviation (SD); intermediate type, between mean MSFsc - 1 SD and MSFsc + 1 SD; and late type, > mean MSFsc + 1 SD. A Patient Health Questionnaire-9 score of ≥ 10 indicated depression. Among 5550 non-shift working adults aged 19-80 years, the prevalence rates of depression in the early, intermediate, and late chronotype groups were 7.4%, 4.5%, and 9.3%, respectively. Women with late chronotype (odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.8-4.7) showed a higher risk of depression than women with intermediate chronotype after adjusting for covariates. Women with early chronotype did not show a significant difference in depression risk (OR = 1.3, 95% CI = 0.9-2.0). In conclusion, late chronotype is associated with an increased risk of depression in women but not in men. Early chronotype is not associated with depression in women or men.

Influence of chronotype on daily mood fluctuations: pilot study in patients with depression

Depression risk is associated with a late chronotype pattern often described as an 'evening chronotype'. Fluctuations in mood over consecutive days have not yet been measured according to chronotype in in-patients with depression. A total of 30 in-patients with depression and 32 healthy controls matched for gender and age completed a chronotype questionnaire and twice-daily ratings on mood for 10 consecutive days (registered in the German Clinical Trials Register: DRKS00010215). The in-patients had Saturdays and Sundays as hospital-leave days. The relationship between chronotype and daily mood was mediated by the weekday-weekend schedule with higher levels of negative affect in the evening-chronotype patient subgroup at weekends. Results are discussed with respect to a probably advantageous standardised clinical setting with early morning routines, especially for patients with evening chronotypes.

Evening preference and poor sleep independently affect attentional-executive functions in patients with depression

Cognitive impairments are well documented in major depressive disorder (MDD), however, they cannot be fully explained by depressive symptom severity. We investigated how diurnal preference and sleep quality affect cognitive function in MDD. In 34 inpatients with current MDD and 29 healthy controls (HC), we obtained diurnal preference (Morningness-Eveningness Questionnaire, MEQ) and subjective sleep quality (Pittsburgh Sleep Quality Index, PSQI). Further, current mood and neuropsychological performance (Trail Making Test, TMT, part A and B) were assessed in the evening and in the following morning. Patients with MDD performed worse than HC on the TMT-B (particularly requiring executive function), but not on the TMT-A (assessing foremost visuomotor processing speed). In general, participants with evening preference (MEQ-score median split) performed poorer on the TMT than participants with morning preference. Subgroup analyses within MDD confirmed the negative effect of evening preference on the TMT. In addition, patients with severely impaired sleep quality (PSQI > 10) performed cognitively worse than patients with normal to moderately impaired sleep quality (PSQI ≤ 10). The results were largely independent of current mood state. Our findings suggest that evening preference and severely impaired sleep quality independently contribute to cognitive impairment in MDD.

Chronotype and Mental Health: Recent Advances

PURPOSE OF REVIEW

Evening chronotype is increasingly recognized as a correlate of, and perhaps a contributor to, mental illness. The current review evaluates recent evidence for the association between chronotype and mental illness and putative mechanisms underlying the association, while highlighting methodological advances and areas of research that are relatively under-examined in the literature.

RECENT FINDINGS

While evening chronotype is most consistently associated with severity of mood disorder symptoms, emerging evidence implicates evening chronotype as a transdiagnostic correlate of substance use severity, anxiety symptoms, attentional difficulties, and maladaptive behaviors such as aggression. Longitudinal studies point to the possibility that evening chronotype precedes problematic substance use, depression, and anxiety. Neural processes related to reward and affective regulation may underlie associations between evening chronotype and illness. The literature on chronotype and mental illness has evolved to (1) include associations with a broader range of psychiatric symptom profiles; (2) explore underlying mechanisms; and (3) expand on earlier research using objective measures and more sophisticated study designs. In addition to further mechanistic research, additional work is needed to examine the stability and key subcomponents of the chronotype construct, as well as more attention to pediatric and special populations. This research is needed to clarify the chronotype-mental health relationship, and to identify how, when, and what aspects of chronotype can be targeted via therapeutic interventions.