Seasonality in affective disorders

Non-human primate seasonal transcriptome atlas reveals seasonal changes in physiology and diseases

The metabolic, immune, and endocrine systems show profound seasonal changes in animals, including humans. In addition, morbidity from cardiovascular and psychiatric diseases is more severe and mortality rate is higher in winter. However, their molecular mechanisms remain unknown. Here we report the seasonal transcriptome of 80 tissues collected over 1 year from male and female rhesus macaques kept in a semi-natural outdoor environment. We find seasonal changes in plasma metabolites and hormones. Transcriptome analysis identifies sex differences in seasonally oscillating genes (SOGs) in all tissues studied, and we generate the web database 'Non-Human Primate Seasonal Transcriptome Atlas (NHPSTA).' Transcriptional regulatory network analysis, siRNA knockdown, and mutant mouse analyses reveal regulation of SOGs by GA-binding protein (GABP). We also demonstrate seasonal oscillations in the expression of disease risk factor genes and drug interacting genes. NHPSTA provides a molecular resource for seasonally regulated physiology and targets for therapeutic interventions for seasonally regulated diseases.

Seasonal, weekly, and individual variations in long-term use of wearable medical devices for diabetes management

Wearable medical-grade devices are transforming the standard of care for prevalent chronic conditions like diabetes. Yet, adoption and long-term use remain a challenge for many people. In this study, we investigate patterns of consistent versus disrupted use of continuous glucose monitors (CGMs) through analysis of more than 118,000 days of data, with over 22 million blood glucose samples, from 108 young adults with type 1 diabetes (average: 3 years of CGM data per person). In this population, we found more consistent CGM use at the start and end of the year (e.g., January, December), and more disrupted CGM use in the middle of the year/warmer months (i.e., May to July). We also found more consistent CGM use on weekdays (Monday to Thursday) and during waking hours (6AM - 6PM), but more disrupted CGM use on weekends (Friday to Sunday) and during evening/night hours (7PM - 5AM). Only 52.7% of participants (57 out of 108) had consistent and sustained CGM use over the years (i.e., over 70% daily wear time for more than 70% of their data duration). From semi-structured interviews, we unpack factors contributing to sustained CGM use (e.g., easier and better blood glucose management) and factors contributing to disrupted CGM use (e.g., changes in insurance coverage, issues with sensor adhesiveness/lifespan, and college/life transitions). We leverage insights from this study to elicit implications for next-generation technology and interventions that can circumvent seasonal and other factors that disrupt sustained use of wearable medical devices for the goal of improving health outcomes.

The role of circadian clock gene Arntl in the winter depression-like behavior in melatonin-proficient female CBA/N mice

Seasonal affective disorder (SAD), also known as winter depression, is a subtype of depression typically manifesting in winter. Typical symptoms of SAD, such as an increased need for sleep and carbohydrate cravings associated with increased appetite and weight, are distinct from those of major depression, and the underlying mechanisms of SAD remain unclear. Although laboratory mice are generally considered non-seasonal animals, we observed depression-like behaviors in melatonin-proficient female CBA/N mice maintained under winter-mimicking conditions. Transcriptome analysis of the brains of CBA/N mice maintained under winter- and summer-mimicking conditions revealed changes in the expression of circadian clock genes, including Arntl (also known as Bmal1). We generated Arntl-deficient, melatonin-proficient CBA/N mice using the speed congenic method to examine the role of Arntl in depressive behavior. The tail suspension test in these mice revealed a depressive phenotype. These results suggested that the circadian clock gene Arntl may be involved in winter depression-like behavior.

The role of affective temperaments as a factor of vulnerability to seasonal affective disorder

BACKGROUND

Growing evidence suggests the relevance of affective temperaments in the development of mood disorders. This study aims to assess their potential role as a vulnerability factor for seasonal affective disorder (SAD) and subsyndromal SAD (S-SAD) in a sample of young individuals without a history of clinical diagnosis.

METHODS

Eight hundred and forty-six university students were enrolled in a cross-sectional study. Participants were evaluated for exclusion and inclusion criteria and divided into Control, S-SAD, and SAD groups. They filled out two self-administered questionnaires to assess the degree of seasonality problems and the predominant type of affective temperaments, the Seasonal Pattern Assessment Questionnaire (SPAQ), and the Temperament Evaluation Instrument of Memphis, Pisa, Paris, and San Diego-Auto-questionnaire version scale (briefTEMPS-M version). We conducted a multinomial logistic regression model to explore the relationship between affective temperaments and seasonality.

RESULTS

Our results evidenced that cyclothymic [χ2 (2) = 33.486, p < 0.001] and anxious [χ2 (2) = 86.991, p < 0.001] temperaments were significant predictors in the model, suggesting that individuals with cyclothymic and anxious temperaments are at increased risk of developing SAD, due to heightened seasonal changes in mood and behavior. In contrast, people with hyperthymic temperament appear less susceptible to experiencing seasonal problems.

LIMITATIONS

The homogeneity of the sample; only retrospective self-reported data were considered; measures of temperament and seasonality were simultaneously assessed.

CONCLUSIONS

Understanding which affective temperaments may constitute a potential predisposing factor for vulnerability to seasonal changes can aid in better assessing SAD and predicting its outcome.

Usability and feasibility of an online intervention for older adults to support changes to routines and the home ('Light, activity and sleep in my daily life')

BACKGROUND

Indoor lighting, exposure to outdoor daylight, physical activity and sleep interact to influence functioning, mood and cicadian rhythm. Older adults (≥ 65 years), who often spend more time at home, are less physically active and experience more sleep problems, could benefit from strategies to support behavioural change and self-managed modifications in the home. The study's primary objective was to assess the usability and feasibility of the 'Light, activity and sleep in my daily life' intervention, delivered as a web-based course.

METHODS

This 9-week intervention was delivered in a municipality in Sweden (55.70° N). Participants were eight healthy women (age 71-84), community-living in one-person households. We recruited through municipal staff and posters at senior citizen meeting points. Both qualitative and quantitative data were collected before and after the intervention. The outcome measures were intervention usability (ease of use, usefulness) and study feasibility (e.g., recruitment procedure, online engagement). Measures also included changes to routines and self-managed home adjustments to determine whether the participants applied what they had learnt.

RESULTS

All participants completed the intervention. Time logged in varied between 25 min and 3 h (M = 1 h 50 min) per week. Seven participants' system usability scores were between 90 and 100 ('Excellent') out of 100. When interviewed, participants reported overall high satisfaction with what they had learnt. Six participants were particularly satisfied with the modules targeting light. Seven participants made changes to their lighting or darkness conditions, such as replaced bulbs with either 3-step dimming or higher colour temperature LEDs (samples were included in the intervention test kit). One suggestion to improve the online delivery was to enable participants to add text comments to the weekly evaluation form.

CONCLUSIONS

The web-based intervention was feasible to deliver but time for recruitment should be extended and advertisement in the local newspaper should be considered. Participants' computer proficiency and access to the internet at home will be critical in a future study with a larger sample. Only minor changes to the online content of the intervention are needed based on participants' feedback. The intervention will be possible to evaluate in a future pilot study.

The Usage of a Chat-Based Help Service for Young People: A Nationwide Descriptive Study

Adolescents with subclinical depression are at high risk of developing mental disorders. Early interventions are effective but expensive. Affordable and accessible mental health services are needed. This multimethod study obtained its sample from the database of the Finnish national chat room service and describes the usage of the service among young people in Finland. All chats between 1.1-31.12.2018 were extracted and analysed using quantitative and qualitative methods. The usage frequency was analysed with descriptive statistics, while the specific content of the chat topics was first categorised with content analysis and then quantified and analysed using descriptive statistics. The association between the demographic characteristics and the usage were analysed. A total of 839 young people used chat room services. The great majority of the chat users were girls, and half were 12-14 years old. The use of the chat room varied in terms of the number of words and the duration of the chat discussions. Based on the chat room topics, young people had complex life situations with psychological distress, difficulties related to their social living environment, or they were involved in risky behaviour. The gender and the age of the users influenced their chat room usage. The results of this study can be used in the development of mental health services for young people.

A translationally informed approach to vital signs for psychiatry: a preliminary proof of concept

The nature of data obtainable from the commercial smartphone - bolstered by a translational model emphasizing the impact of social and physical zeitgebers on circadian rhythms and mood - offers the possibility of scalable and objective vital signs for major depression. Our objective was to explore associations between passively sensed behavioral smartphone data and repeatedly measured depressive symptoms to suggest which features could eventually lead towards vital signs for depression. We collected continuous behavioral data and bi-weekly depressive symptoms (PHQ-8) from 131 psychiatric outpatients with a lifetime DSM-5 diagnosis of depression and/or anxiety over a 16-week period. Using linear mixed-effects models, we related depressive symptoms to concurrent passively sensed behavioral summary features (mean and variability of sleep, activity, and social engagement metrics), considering both between- and within-person associations. Individuals with more variable wake-up times across the study reported higher depressive symptoms relative to individuals with less variable wake-up times (B [95% CI] = 1.53 [0.13, 2.93]). On a given week, having a lower step count (-0.16 [-0.32, -0.01]), slower walking rate (-1.46 [-2.60, -0.32]), lower normalized location entropy (-3.01 [-5.51, -0.52]), more time at home (0.05 [0.00, 0.10]), and lower distances traveled (-0.97 [-1.72, -0.22]), relative to one's own typical levels, were each associated with higher depressive symptoms. With replication in larger samples and a clear understanding of how these components are best combined, a behavioral composite measure of depression could potentially offer the kinds of vital signs for psychiatric medicine that have proven invaluable to assessment and decision-making in physical medicine. Clinical Trials Registration: The data that form the basis of this report were collected as part of clinical trial number NCT03152864.

Biological Sex Influences Daily Locomotor Rhythms in Mice Held Under Different Housing Conditions

Daily rhythms are programmed by a central circadian clock that is modulated by photoperiod. Here, we recorded locomotor activity rhythms in C57Bl/6 or mPer2Luc mice of both sexes held under different housing conditions. First, we confirm that the structure of locomotor activity rhythms differs between male and female mice in both genetic backgrounds. Male mice exhibit a nightly "siesta," whereas female mice fluctuate between nights with and without a nightly siesta, which corresponds with changes in locomotor activity levels, circadian period, and vaginal cytology. The nightly siesta is modulated by the presence of a running wheel in both sexes but is not required for the infradian patterning of locomotor rhythms in females. Finally, photoperiodic changes in locomotor rhythms differed by sex, and females displayed phase-jumping responses earlier than males under a parametric photoentrainment assay simulating increasing day length. Collectively, these results highlight that sex and sex hormones influence daily locomotor rhythms under a variety of different environmental conditions.

Time me by the moon : The evolution and function of lunar timing systems

The moon has significant impact on the timing of organisms. Can the study of molecular timing mechanisms of marine animals and algae help to understand some of the “weird” correlations between human physiological/behavioral rhythms and the lunar cycle?

Putative Pharmacological Depression and Anxiety-Related Targets of Calcitriol Explored by Network Pharmacology and Molecular Docking

Depression and anxiety disorders, prevalent neuropsychiatric conditions that frequently coexist, limit psychosocial functioning and, consequently, the individual's quality of life. Since the pharmacological treatment of these disorders has several limitations, the search for effective and secure antidepressant and anxiolytic compounds is welcome. Vitamin D has been shown to exhibit neuroprotective, antidepressant, and anxiolytic properties. Therefore, this study aimed to explore new molecular targets of calcitriol, the active form of vitamin D, through integrated bioinformatic analysis. Calcitriol targets were predicted in SwissTargetPrediction server (2019 version). The disease targets were collected by the GeneCards database searching the keywords "depression" and "anxiety". Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the intersections of targets. Network analyses were carried out using GeneMania server (2023 version) and Cytoscape (V. 3.9.1.) software. Molecular docking predicted the main targets of the network and Ligplot predicted the main intermolecular interactions. Our study showed that calcitriol may interact with multiple targets. The main targets found are the vitamin D receptor (VDR), histamine H3 receptor (H3R), endocannabinoid receptors 1 and 2 (CB1 and CB2), nuclear receptor NR1H3, patched-1 (PTCH1) protein, opioid receptor NOP, and phosphodiesterase enzymes PDE3A and PDE5A. Considering the role of these targets in the pathophysiology of depression and anxiety, our findings suggest novel putative mechanisms of action of vitamin D as well as new promising molecular targets whose role in these disorders deserves further investigation.

One seasonal clock fits all?

Adaptation of physiology and behavior to seasonal changes in the environment are for many organisms essential for survival. Most of our knowledge about the underlying mechanisms comes from research on photoperiodic regulation of reproduction in plants, insects and mammals. However, even humans, who mostly live in environments with minimal seasonal influences, show annual rhythms in physiology (e.g., immune activity, brain function), behavior (e.g., sleep-wake cycles) and disease prevalence (e.g., infectious diseases). As seasonal variations in environmental conditions may be drastically altered due to climate change, the understanding of the mechanisms underlying seasonal adaptation of physiology and behavior becomes even more relevant. While many species have developed specific solutions for dedicated tasks of photoperiodic regulation, we find a number of common principles and mechanisms when comparing insect and mammalian systems: (1) the circadian system contributes to photoperiodic regulation; (2) similar signaling molecules (VIP and PDF) are used for transferring information from the circadian system to the neuroendocrine system controlling the photoperiodic response; (3) the hormone melatonin participates in seasonal adaptation in insects as well as mammals; and (4) changes in photoperiod affect neurotransmitter function in both animal groups. The few examples of overlap elaborated in this perspective article, as well as the discussion on relevance for humans, should be seen as encouragement to unravel the machinery of seasonal adaptation in a multitude of organisms.

Effects of seasonality in emergency admissions for mental disorders: two years of clinical experience

OBJECTIVES

This retrospective study, conducted in Turin, Italy, between January 2021 and February 2023, investigates the impact of seasonal heatwaves on emergency department (ED) admissions for mental disorders.

METHODS

Through the analysis of data from 2,854 patients, this research found a significant link between the occurrence of heatwaves, especially from June to August, and an elevated rate of ED admissions for psychiatric conditions.

RESULTS

The data indicate a clear seasonal pattern, with admissions peaking during the hot months and diminishing in the colder months. Particularly, the study delineates an enhanced correlation between heatwaves and admissions for severe psychiatric disorders, such as bipolar disorder, major depression, personality disorders, and schizophrenia, accounting for 1,868 of the cases examined. This correlation was most pronounced among individuals aged 50-59 years.

CONCLUSIONS

The results of this study highlight a critical association between the incidence of seasonal heatwaves and an uptick in ED visits for psychiatric disorders, with a distinct impact on severe cases. It underscores the urgency for healthcare systems to anticipate seasonal fluctuations in psychiatric ED admissions and to allocate resources effectively to support patients during peak periods.

Effect of Short Photoperiod on Behavior and Brain Plasticity in Mice Differing in Predisposition to Catalepsy: The Role of BDNF and Serotonin System

Seasonal affective disorder is characterized by depression during fall/winter as a result of shorter daylight. Catalepsy is a syndrome of some grave mental diseases. Both the neurotransmitter serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) are involved in the pathophysiological mechanisms underlying catalepsy and depressive disorders. The aim was to compare the response of behavior and brain plasticity to photoperiod alterations in catalepsy-resistant C57BL/6J and catalepsy-prone CBA/Lac male mice. Mice of both strains were exposed for six weeks to standard-day (14 h light/10 h darkness) or short-day (4 h light/20 h darkness) conditions. Short photoperiod increased depressive-like behavior in both strains. Only treated CBA/Lac mice demonstrated increased cataleptic immobility, decreased brain 5-HT level, and the expression of Tph2 gene encoding the key enzyme for 5-HT biosynthesis. Mice of both strains maintained under short-day conditions, compared to those under standard-day conditions, showed a region-specific decrease in the brain transcription of the Htr1a, Htr4, and Htr7 genes. After a short photoperiod exposure, the mRNA levels of the BDNF-related genes were reduced in CBA/Lac mice and were increased in the C57BL/6J mice. Thus, the predisposition to catalepsy considerably influences the photoperiodic changes in neuroplasticity, wherein both C57BL/6J and CBA/Lac mice can serve as a powerful tool for investigating the link between seasons and mood.

Evaluation of Rhodanine Indolinones as AANAT Inhibitors

Circadian rhythm (CR) dysregulation negatively impacts health and contributes to mental disorders. The role of melatonin, a hormone intricately linked to CR, is still a subject of active study. The enzyme arylalkylamine N-acetyltransferase (AANAT) is responsible for melatonin synthesis, and it is a potential target for disorders that involve abnormally high melatonin levels, such as seasonal affective disorder (SAD). Current AANAT inhibitors suffer from poor cell permeability, selectivity, and/or potency. To address the latter, we have employed an X-ray crystal-based model to guide the modification of a previously described AANAT inhibitor, containing a rhodanine-indolinone core. We made various structural modifications to the core structure, including testing the importance of a carboxylic acid group thought to bind in the CoA site, and we evaluated these changes using MD simulations in conjunction with enzymatic assay data. Additionally, we tested three AANAT inhibitors in a zebrafish locomotion model to determine their effects in vivo. Key discoveries were that potency could be modestly improved by replacing a 5-carbon alkyl chain with rings and that the central rhodanine ring could be replaced by other heterocycles and maintain potency.

Taking biological rhythms into account: From study design to results reporting

Numerous physiological and behavioral processes in living organisms exhibit strong rhythmicity and are regulated within a 24-hour cycle. These include locomotor activity and sleep patterns, feeding-fasting cycles, hormone synthesis, body temperature, and even mood and cognitive abilities, all of which are segregated into different phases throughout the day. These processes are governed by the internal timing system, a hierarchical multi-oscillator structure conserved across all organisms, from bacteria to humans. Circadian rhythms have been seen across multiple taxonomic kingdoms. In mammals, a hierarchical internal timing system is comprised of so-called central and periphereal clocks. Although these rhythms are intrinsic, they are under environmental influences, such as seasonal temperature changes, photoperiod variations, and day-night cycles. Recognizing the existence of biological rhythms and their primary external influences is crucial when designing and reporting experiments. Neglecting these physiological variations may result in inconsistent findings and misinterpretations. Thus, here we propose to incorporate biological rhythms into all stages of human and animal research, including experiment design, analysis, and reporting of findings. We also provide a flowchart to support decision-making during the design process, considering biological rhythmicity, along with a checklist outlining key factors that should be considered and documented throughout the study. This comprehensive approach not only benefits the field of chronobiology but also holds value for various other research disciplines. The insights gained from this study have the potential to enhance the validity, reproducibility, and overall quality of scientific investigations, providing valuable guidance for planning, developing, and communicating scientific studies.

Orphan nuclear receptor nr4a1 regulates winter depression-like behavior in medaka

About 10% of the population suffers from depression in winter at high latitude. Although it has become a serious public health issue, its underlying mechanism remains unknown and new treatments and therapies are required. As an adaptive strategy, many animals also exhibit depression-like behavior in winter. Previously, it has been reported that celastrol, a traditional Chinese medicine, can rescue winter depression-like behavior in medaka, an excellent model of winter depression. Nuclear receptor subfamily 4 group A member 1 (nr4a1, also known as nur77) is a known target of celastrol, and the signaling pathway of nr4a1 was suggested to be inactive in medaka brain during winter, implying the association of nr4a1 and winter depression-like behavior. However, the direct evidence for its involvement in winter depression-like behavior remains unclear. The present study found that nr4a1 was suppressed in the medaka brain under winter conditions. Cytosporone B, nr4a1 chemical activator, reversed winter depression-like behavior under winter conditions. Additionally, nr4a1 mutant fish generated by CRISPR/Cas9 system showed decreased sociability under summer conditions. Therefore, our results demonstrate that the seasonal regulation of nr4a1 regulates winter depression-like behavior and offers potential therapeutic target.

[Study of the photoperiodic dynamics of the peripheral dopamine content in comparison with the thyroid profile in various groups of men from the European North]

BACKGROUND

Knowledge of the physiological mechanisms of adaptation arising in response to changes in photoperiods is especially important for residents of the European North. In the literature, there is practically no information about photoperiodic dynamics of serum dopamine level, despite its significant role in the regulation of the body's activity. The mutual modulating effect of the dopaminergic and thyroid systems is known.

AIM

To show the ratio of dopamine levels and the content of hormones, protines and autoantibodies of the thyroid system, taking into account photoperiod of the year, in practically healthy populations of the European North.

MATERIALS AND METHODS

Healthy male population (20 men) of Arkhangelsk was examined in various photoperiods of the year (80 samples): an increase in the length of daylight hours (March), its maximum duration (June), a decrease (September), and a minimum duration (December). The inhabitants of the settlements and the nomadic aboriginal population (100 men) were examined during 2 photoperiods of the year - March and December. The serum levels of iodothyronines, TSH, TG, antibodies to TPO, antibodies to TG and plasma level of dopamine were determined using ELISA methods.

RESULTS

Residents of Arkhangelsk in June compared to December have higher levels of dopamine (0.502 and 0.365 nmol/l, p=0.01), T3 (1.09 and 0.94 nmol/l, p=0.003), T4 (113.45 and 99.03 nmol/l, p=0.0002). In September, compared with June, a decrease in dopamine (0.235 nmol/l, p=0.0003), T3 (0.92 nmol/l, p=0.004) was recorded with an increase in T4/T3 ratio from 106.54 to 117.89 units (p=0.006). The nomadic aboriginal population in March compared with December showed a tendency to a higher content of dopamine (0.00 and 0.394 nmol/l, p=0.07) with the decrease in fT4 (15.20 and  13.90, p=0.015), fT4/fT3 ratio from 3.13 to 2.28 units (p=0.006). In December, 67% of nomadic population had undetectable dopamine values (0 nmol/l) and 22% - excess dopamine values, in March 27% - excess values.

CONCLUSION

Unidirectional changes in dopamine and thyroid activity in men of the European North were shown with their decrease during periods of decrease and minimum daylight hours and an increase during periods of increase and maximum daylight hours.

Somatostatin regulates central clock function and circadian responses to light

Daily and annual changes in light are processed by central clock circuits that control the timing of behavior and physiology. The suprachiasmatic nucleus (SCN) in the anterior hypothalamus processes daily photic inputs and encodes changes in day length (i.e., photoperiod), but the SCN circuits that regulate circadian and photoperiodic responses to light remain unclear. Somatostatin (SST) expression in the hypothalamus is modulated by photoperiod, but the role of SST in SCN responses to light has not been examined. Our results indicate that SST signaling regulates daily rhythms in behavior and SCN function in a manner influenced by sex. First, we use cell-fate mapping to provide evidence that SST in the SCN is regulated by light via de novo Sst activation. Next, we demonstrate that Sst  -/- mice display enhanced circadian responses to light, with increased behavioral plasticity to photoperiod, jetlag, and constant light conditions. Notably, lack of Sst  -/- eliminated sex differences in photic responses due to increased plasticity in males, suggesting that SST interacts with clock circuits that process light differently in each sex. Sst  -/- mice also displayed an increase in the number of retinorecipient neurons in the SCN core, which express a type of SST receptor capable of resetting the molecular clock. Last, we show that lack of SST signaling modulates central clock function by influencing SCN photoperiodic encoding, network after-effects, and intercellular synchrony in a sex-specific manner. Collectively, these results provide insight into peptide signaling mechanisms that regulate central clock function and its response to light.

Mimicking seasonal changes in light-dark cycle and ambient temperature modulates gut microbiome in mice under the same dietary regimen

To better adapt to seasonal environmental changes, physiological processes and behaviors are regulated seasonally. The gut microbiome interacts with the physiology, behavior, and even the diseases of host animals, including humans and livestock. Seasonal changes in gut microbiome composition have been reported in several species under natural environments. Dietary content significantly affects the composition of the microbiome, and, in the natural environment, the diet varies between different seasons. Therefore, understanding the seasonal regulatory mechanisms of the gut microbiome is important for understanding the seasonal adaptation strategies of animals. Herein, we examined the effects of changing day length and temperature, which mimic summer and winter conditions, on the gut microbiome of laboratory mice. Principal coordinate analysis and analysis of the composition of microbiomes of 16S rRNA sequencing data demonstrated that the microbiomes of the cecum and large intestine showed significant differences between summer and winter mimicking conditions. Similar to previous studies, a daily rhythm was observed in the composition of the microbiome. Furthermore, the phylogenetic investigation of communities by reconstruction of unobserved states predicted seasonal changes in several metabolic pathways. Changing day length and temperature can affect the composition of the gut microbiome without changing dietary contents.

Physical Activity, Seasonal Sensitivity and Psychological Well-Being of People of Different Age Groups Living in Extreme Environments

Physical activity can prevent many organic and mental pathologies. For people living in extreme southern high-latitude environments, weather conditions can affect these activities, altering their psychological well-being and favoring the prevalence of seasonal sensitivity (SS). This study aims to determine the relationships between the practice of physical activity, seasonal sensitivity and well-being in people living in high southern latitudes. A cross-sectional study was conducted, using the Seasonal Pattern Assessment Questionnaire (SPAQ), applying a psychological well-being scale, and determining sports practice according to the recommendations of the World Health Organization (WHO) for the 370 male (n = 209; 55%) and female (n = 173; 45%) participants. The main results indicated that 194 people (52 ± 7.7 years) reported physical activity. High-intensity physical activity practitioners recorded a significantly lower proportion of SS. In terms of psychological well-being, an adverse effect was found between the Seasonal Score Index (SSI) and five subcategories of the Ryff well-being scale. In conclusion, those who perform high-intensity physical activity have a lower SS, and those who have a higher SS have a lower psychological well-being.

Effects of Environmental and Socioeconomic Inequalities on Health Outcomes: A Multi-Region Time-Series Study

The gradual increase in temperatures and changes in relative humidity, added to the aging and socioeconomic conditions of the population, may represent problems for public health, given that future projections predict even more noticeable changes in the climate and the age pyramid, which require analyses at an appropriate spatial scale. To our knowledge, an analysis of the synergic effects of several climatic and socioeconomic conditions on hospital admissions and deaths by cardiorespiratory and mental disorders has not yet been performed in Brazil. Statistical analyses were performed using public time series (1996-2015) of daily health and meteorological data from 16 metropolitan regions (in a subtropical climate zone in South America). Health data were stratified into six groups according to gender and age ranges (40-59; 60-79; and ≥80 years old) for each region. For the regression analysis, two distributions (Poisson and binomial negative) were tested with and without zero adjustments for the complete series and percentiles. Finally, the relative risks were calculated, and the effects based on exposure-response curves were evaluated and compared among regions. The negative binomial distribution fit the data best. High temperatures and low relative humidity were the most relevant risk factors for hospitalizations for cardiovascular diseases (lag = 0), while minimum temperatures were important for respiratory diseases (lag = 2 or 3 days). Temperature extremes, both high and low, were the most important risk factors for mental illnesses at lag 0. Groups with people over 60 years old presented higher risks for cardiovascular and respiratory diseases, while this was observed for the adult group (40-59 years old) in relation to mental disorders. In general, no major differences were found in the results between men and women. However, regions with higher urbanization levels presented risks, mainly for respiratory diseases, while the same was observed for cardiovascular diseases for regions with lower levels of urbanization. The Municipal Human Development Index is an important factor for the occurrence of diseases and deaths for all regions, depending on the evaluated group, representing high risks for health outcomes (the value for hospitalization for cardiovascular diseases was 1.6713 for the female adult group in the metropolitan region Palmas, and the value for hospitalization for respiratory diseases was 1.7274 for the female adult group in the metropolitan region Campo Mourão). In general, less developed regions have less access to adequate health care and better living conditions.

Can Homes Affect Well-Being? A Scoping Review among Housing Conditions, Indoor Environmental Quality, and Mental Health Outcomes

The purpose of the scoping review is to explore the relationship between housing conditions, indoor environmental quality (IEQ), and mental health implications on human well-being. In fact, time spent at home increased due to the recent COVID-19 lockdown period, and social-sanitary emergencies are expected to grow due to the urbanization phenomenon. Thus, the role of the physical environment in which we live, study, and work, has become of crucial importance, as the literature has recently highlighted. This scoping review, conducted on the electronic database Scopus, led to the identification of 366 articles. This, after the screening processes based on the inclusion criteria, led to the final inclusion of 31 papers related specifically to the OECD area. The review allowed the identification of five housing conditions [house type, age, and floor level; housing qualities; household composition; neighborhood; green spaces] that, by influencing the IEQ parameters, had impacts on the mental health outcomes addressed. By synthesizing the contributions of the review, a list of design recommendations has been provided. These will serve as a basis for future researchers, from which to develop measures to reduce inequalities in housing by making them healthier, more resilient, and salutogenic.

The Architecture of Happiness

Happiness is an increasingly prominent topic of interest across academia. However, relatively little attention has been paid to how it is created, especially not in a multidimensional sense. By ‘created’ we do not mean its influencing factors, for which there is extensive research, but how it actually forms in the person. The work that has been done in this arena tends to focus on physiological dynamics, which are certainly part of the puzzle. But they are not the whole picture, with psychological, phenomenological, and socio cultural processes also playing their part. As a result, this paper offers a multidimensional overview of scholarship on the ‘architecture’ of happiness, providing a stimulus for further work into this important topic.

Healthy Lifestyles of University Students, According to Demographics, Nationality, and Study Specialty With Special Reference to Sport Studies

This study compares lifestyles behavior in Italian and Latvian university students, with special reference to sport students, to assess if there are differences for sex, age, university, or studies specialties. An online questionnaire investigating healthy lifestyle habits and 8 wellness dimensions has been compiled by 156 students (43.6% females) from Italy and 105 from Latvia (82.9% females). Answers were collected between April and December 2020. Presence of smokers in our sample is negligible. The questionnaire showed a good internal consistency (Cronbach α = 0.929). On the total group, statistically significant differences were found in all the dimensions regarding age, sex, study specialty and university. Physical activity was associated with healthier lifestyles choices. Geographical differences were found (eating and sleep behaviors, alcohol awareness) as well as socio-economic differences. Female students shown to be more stressed than males. Occupational wellness increased by age. Sport students shown more health awareness. Many of the differences found between males and females in the total group disappeared when comparing only sport students of the two universities.

Web messaging among young people in online services: A descriptive mixed-methods study

Objective

To describe web messaging patterns and the content of web messages among young people in a Finnish national online service.

Methods

A descriptive mixed-method was used. The data consisted of text-based web messaging communication between young people and a counsellor in a nationwide online service between 1 January and 31 December 2018. Web messaging patterns were analysed using descriptive statistics. The content of the messages was analysed with thematic analysis and qualitative results were presented. In addition, the factors associated with messaging patterns and content were analysed.

Results

A total of 1941 messages were sent by 1354 young people. Most of them were between 12 and 17 years old and females. Less than one-fifth of young people had multiple two-way discussions with counsellor. The total period of two-way discussions and the number of words in each message varied widely. The number of words was lower in messages sent by males. The content of the messages was divided into three main themes: interpersonal relationships and environment (Social relationships), oneself (Construction of self), and health-related problems and support received from professionals (Health and wellbeing). The young people’s messages mostly contained topics related to the main theme of ‘Social environment’.

Conclusion

Most young people sent one message only. Messages ranged from simple, single messages to complex texts describing the daily life of young people. Girls were more active in messaging, and they wrote longer texts.

Enlightened: addressing circadian and seasonal changes in photoperiod in animal models of bipolar disorder

Bipolar disorders (BDs) exhibit high heritability and symptoms typically first occur during late adolescence or early adulthood. Affected individuals may experience alternating bouts of mania/hypomania and depression, with euthymic periods of varying lengths interspersed between these extremes of mood. Clinical research studies have consistently demonstrated that BD patients have disturbances in circadian and seasonal rhythms, even when they are free of symptoms. In addition, some BD patients display seasonal patterns in the occurrence of manic/hypomanic and depressive episodes as well as the time of year when symptoms initially occur. Finally, the age of onset of BD symptoms is strongly influenced by the distance one lives from the equator. With few exceptions, animal models useful in the study of BD have not capitalized on these clinical findings regarding seasonal patterns in BD to explore molecular mechanisms associated with the expression of mania- and depression-like behaviors in laboratory animals. In particular, animal models would be especially useful in studying how rates of change in photoperiod that occur during early spring and fall interact with risk genes to increase the occurrence of mania- and depression-like phenotypes, respectively. Another unanswered question relates to the ways in which seasonally relevant changes in photoperiod affect responses to acute and chronic stressors in animal models. Going forward, we suggest ways in which translational research with animal models of BD could be strengthened through carefully controlled manipulations of photoperiod to enhance our understanding of mechanisms underlying seasonal patterns of BD symptoms in humans. In addition, we emphasize the value of incorporating diurnal rodent species as more appropriate animal models to study the effects of seasonal changes in light on symptoms of depression and mania that are characteristic of BD in humans.

Rate of change in solar insolation is a hidden variable that influences seasonal alterations in bipolar disorder

The consensus in the literature is that bipolar disorder is seasonal. We argue that there is finer detail to seasonality and that changes in mood and energy in bipolar disorder are dictated by the rate of change of solar insolation.

Diurnal and seasonal differences in cardiopulmonary response to exercise in morning and evening chronotypes

Circadian clocks regulate multiple physiological domains from molecular to behavioral levels and adjust bodily physiology to seasonal changes in day length. Circadian regulation of cellular bioenergy and immunity in the cardiovascular and muscle systems may underpin the individual diurnal differences in performance capacity during exercise. Several studies have shown diurnal differences in cardiopulmonary parameters at maximal and submaximal workloads in morning and evening circadian human phenotypes. However, the effect of seasons on these changes was not elucidated. In this study, we recruited subjects with Morningness-Eveningness Questionnaire scores corresponding to morning and evening types. Subjects underwent morning (7:00-9:00) and evening (20:00-22:00) maximal workload spiroergometry in both winter and summer seasons. We analyzed their performance time, anaerobic threshold, heart rate, and respiratory parameters. Our results suggest that evening types manifest diurnal variations in physical performance, particularly in winter. They also have slower heart rate recovery than morning types, irrespective of the time of day or season. Compared to winter, the chronotype effect on the magnitude of morning-evening differences in performance time, maximal heart rate, and anaerobic threshold onset was more significant in summer. Our data are in concordance with previous observations and confirm the difference between morning and evening types in the timing of maximum performance capacity.

Confined Students: A Visual-Emotional Analysis of Study and Rest Spaces in the Homes

Confinement was adopted globally as a containment measure to face the COVID pandemic declared by WHO on March 2020. In Spain, the State of Alarm was established for three months. This implied the interruption of educational activities, having a higher incidence for children, since teaching would not be resumed until the following academic year, in September. This, together with the confusing initial information about COVID-19 transmission between children and their families, has made them one of the groups most vulnerable. In this study, a qualitative approach is made to secondary school students (aged 12). They were asked to share their experiences about confinement from the perspective of the home spaces, in relation to two main tasks relevant in this period: the tele-study and their relaxing time and well-being. Using images and narratives with an abstract and emotional description, the response of 46 children was obtained. A sentiment analysis was carried out from their testimonies. Results suggest a greater availability of tele-study spaces with daylighting, mainly in bedrooms, with laptops. For leisure and rest spaces, sofas, beds, and cohabitant gathering were preferred. Written testimonials were mainly positive. Housing features and family cohesion condition their resilience in situations of uncertainty, like confinement.

Validity and Usage of the Seasonal Pattern Assessment Questionnaire (SPAQ) in a French Population of Patients with Depression, Bipolar Disorders and Controls

The Seasonal Pattern Assessment Questionnaire (SPAQ), by Rosenthal et al. (1984), is by far the most used questionnaire to evaluate seasonal effects on mood and behavior. It includes a general seasonality score (GSS), composed of 6 items, from which cutoffs have been established to screen for seasonal affective disorder (SAD). However, it has never been validated in French and associations with circadian rhythm and symptoms of depression and bipolarity remain unclear. In this study, including 165 subjects (95 controls and 70 patients with depression or bipolar disorder), we confirmed the validity of the French version of the SPAQ, with a two-factor structure (a psychological factor: energy, mood, social activity and sleep length; and a food factor: weight and appetite) and a good fit was observed by all indicators. Mood and social activity dimensions were significantly affected by seasons in the depressed/bipolar group and a stronger global seasonality score (GSS) was associated with more severe phenotypes of depression and mania. Subjects meeting SAD and subsyndromal-SAD criteria also showed a delayed circadian rhythm compared to controls. Simple tools, such as the SPAQ, can aid the identification of significant seasonal changes and have direct implications on therapeutics including the use of bright light therapy in order to enhance personalized treatments, but also to prevent adverse seasonal effects.

From Precision Metapharmacology to Patient Empowerment: Delivery of Self-Care Practices for Epilepsy, Pain, Depression and Cancer Using Digital Health Technologies

To improve long-term outcomes of therapies for chronic diseases, health promotion and lifestyle modifications are the most promising and sustainable strategies. In addition, advances in digital technologies provide new opportunities to address limitations of drug-based treatments, such as medication non-adherence, adverse effects, toxicity, drug resistance, drug shortages, affordability, and accessibility. Pharmaceutical drugs and biologics can be combined with digital health technologies, including mobile medical apps (digital therapeutics), which offer additional clinical benefits and cost-effectiveness. Promises of drug+digital combination therapies are recognized by pharmaceutical and digital health companies, opening opportunities for integrating pharmacotherapies with non-pharmacological interventions (metapharmacology). Herein we present unique features of digital health technologies which can deliver personalized self-care modalities such as breathing exercises, mindfulness meditation, yoga, physical activity, adequate sleep, listening to preferred music, forgiveness and gratitude. Clinical studies reveal how aforementioned complimentary practices may support treatments of epilepsy, chronic pain, depression, cancer, and other chronic diseases. This article also describes how digital therapies delivering “medicinal” self-care and other non-pharmacological interventions can also be personalized by accounting for: 1) genetic risks for comorbidities, 2) adverse childhood experiences, 3) increased risks for viral infections such as seasonal influenza, or COVID-19, and 4) just-in-time stressful and traumatic circumstances. Development and implementation of personalized pharmacological-behavioral combination therapies (precision metapharmacology) require aligning priorities of key stakeholders including patients, research communities, healthcare industry, regulatory and funding agencies. In conclusion, digital technologies enable integration of pharmacotherapies with self-care, lifestyle interventions and patient empowerment, while concurrently advancing patient-centered care, integrative medicine and digital health ecosystems.

Beneficial Effects of Early Time-Restricted Feeding on Metabolic Diseases: Importance of Aligning Food Habits with the Circadian Clock

The importance of metabolic health is a major societal concern due to the increasing prevalence of metabolic diseases such as obesity, diabetes, and various cardiovascular diseases. The circadian clock is clearly implicated in the development of these metabolic diseases. Indeed, it regulates physiological processes by hormone modulation, thus helping the body to perform them at the ideal time of day. Since the industrial revolution, the actions and rhythms of everyday life have been modified and are characterized by changes in sleep pattern, work schedules, and eating habits. These modifications have in turn lead to night shift, social jetlag, late-night eating, and meal skipping, a group of customs that causes circadian rhythm disruption and leads to an increase in metabolic risks. Intermittent fasting, especially the time-restricted eating, proposes a solution: restraining the feeding window from 6 to 10 h per day to match it with the circadian clock. This approach seems to improve metabolic health markers and could be a therapeutic solution to fight against metabolic diseases. This review summarizes the importance of matching life habits with circadian rhythms for metabolic health and assesses the advantages and limits of the application of time-restricted fasting with the objective of treating and preventing metabolic diseases.

Nighttime Light Hurts Mammalian Physiology: What Diurnal Rodent Models Are Telling Us

Natural sunlight permits organisms to synchronize their physiology to the external world. However, in current times, natural sunlight has been replaced by artificial light in both day and nighttime. While in the daytime, indoor artificial light is of lower intensity than natural sunlight, leading to a weak entrainment signal for our internal biological clock, at night the exposure to artificial light perturbs the body clock and sleep. Although electric light at night allows us "to live in darkness", our current lifestyle facilitates nighttime exposure to light by the use, or abuse, of electronic devices (e.g., smartphones). The chronic exposure to light at nighttime has been correlated to mood alterations, metabolic dysfunctions, and poor cognition. To decipher the brain mechanisms underlying these alterations, fundamental research has been conducted using animal models, principally of nocturnal nature (e.g., mice). Nevertheless, because of the diurnal nature of human physiology, it is also important to find and propose diurnal animal models for the study of the light effects in circadian biology. The present review provides an overview of the effects of light at nighttime on physiology and behavior in diurnal mammals, including humans. Knowing how the brain reacts to artificial light exposure, using diurnal rodent models, is fundamental for the development of new strategies in human health based in circadian biology.

Relation between Mood and the Host-Microbiome Co-Metabolite 3-Indoxylsulfate: Results from the Observational Prospective NutriNet-Santé Study

Gut microbiota metabolizes tryptophan into indole, which can influence brain and behavior. Indeed, some oxidized derivatives of indole, formed in the liver, have neuroactive properties, and indole overproduction by the gut microbiota induces an anxio-depressive phenotype in rodents. The aim of this study was to investigate in humans whether there was a relationship between recurrent depressive symptoms and indole production by the gut microbiota. A case-control study was conducted in 45–65-year-old women, who were participants in the observational prospective NutriNet-Santé Study. Cases were defined as having two Center for Epidemiological Studies-Depression Scales (CES-D) scores ≥ 23 at a two-year interval (recurrent depressive symptoms, n = 87). Each case was matched with two controls (two CES-D <23; n = 174). Urinary excretion of 3-indoxylsulfate, the major final metabolite of indole, was used as a biomarker of indole production by the gut microbiota. Conditional logistic regression models for paired data showed a positive association between urinary 3-indoxylsulfate concentrations, grouped in tertiles, and recurrent depressive symptoms (odds ratio = 2.46, p for trend = 0.0264 in the final model adjusted for confounding factors). This association suggested that indole production by the gut microbiota may play a role in the onset of mood disorders in humans.

A new approach for seasonal pattern: is it related to bipolarity dimension? Findings from an Italian multicenter study

OBJECTIVE

The aims of this study were to assess the impact of seasonal pattern on several clinical dimensions in inpatients with a current major depressive episode and to evaluate clinical differences between unipolar and bipolar depression according to seasonal pattern.

METHODS

Study participants were 300 patients affected by major depressive disorder (MDD) or bipolar disorder (BD) currently experiencing a major depressive episode (MDE) and were recruited at three University Medical Centres in Italy. All study subjects completed several evaluation scales for depressive and hypomanic symptoms, quality of life and functioning, impulsiveness, and seasonal pattern.

RESULTS

Several differences between BD with and without seasonal pattern, MDD with and without seasonal pattern but in particular between BD and MDD with seasonal pattern were found. Patients with MDE with seasonal pattern had more frequently received a longitudinal diagnosis of BD.

CONCLUSIONS

A large number of patients with BD and seasonal pattern, but also a considerable number of patients with MDD and seasonal pattern, endorsed manic items during a current MDE. Seasonal pattern should be associated with a concept of bipolarity in mood disorders and not only related to bipolar disorder. A correct identification of seasonal patterns may lead to the implementation of personalised pharmacological treatment approaches.KEY POINTSHigh prevalence of mixed features in mood disorders with seasonal pattern, supporting the need for a dimensional approach to major depressive disorder and bipolar disorder.Significant percentage of patients with a primary diagnosis of major depressive disorder had seasonal pattern.Significant percentage of patients with a primary diagnosis of major depressive disorder reported (hypo)manic symptomatology.

Melatonin In Acute Mania Investigation (MIAMI-UK). A randomized controlled trial of add-on melatonin in bipolar disorder

OBJECTIVES

Current options for treating emergent episodes of hypomania and mania in bipolar disorder are limited. Our objective was to compare the effectiveness and safety of add-on melatonin in hypomania or mania over 3 weeks as a well-tolerated therapy.

METHODS

A randomized, double-blind, parallel-group, 3-week comparison of modified release melatonin (n = 21) vs placebo (n = 20) in adult bipolar patients aged 18-65 years. Permuted block randomization was used with participants and investigators masked to treatment allocation. Trial registration is ISRCTN28988273 and EUdraCT2008-000281-23. Approved by the South Central National Research Ethics Service (Oxford REC A) ref: 09/H0604/63.

RESULTS

The trial was negative as there was no significant difference between melatonin and placebo on the primary outcome-mean Young Mania Rating Scale (YMRS) score at Day 21: (mean difference [MD] -1.77 ([95% CI: -6.39 to 2.85]; P = .447). Significantly fewer patients on melatonin scored 10 or more on the Altman Self Rating Mania Scale: (odds ratio [OR] 0.164 [95% CI: 0.0260-1.0002]; P = .05). Quick Inventory of Depression Symptomatology Clinician Version-16 (QIDS-C16) scores were not significantly different. (OR 1.77 [95% CI: 0.43-7.29]; P = .430). The proportion of patients scoring less than or equal to 5 on the self-report QIDS-SR16 at end-point was greater for the melatonin group (OR 8.35 [95% CI: 1.04-67.23]; P = .046).

CONCLUSIONS

In this small trial, melatonin did not effectively treat emerging hypomania or mania as there was no significant difference on the primary outcome. The sample size limitation and secondary outcomes suggest further investigation of melatonin treatment in mood episodes is indicated.

Photoperiodic regulation of dopamine signaling regulates seasonal changes in retinal photosensitivity in mice

At high latitudes, approximately 10% of people suffer from depression during the winter season, a phenomenon known as seasonal affective disorder (SAD). Shortened photoperiod and/or light intensity during winter season are risk factors for SAD, and bright light therapy is an effective treatment. Interestingly, reduced retinal photosensitivity along with the mood is observed in SAD patients in winter. However, the molecular basis underlying seasonal changes in retinal photosensitivity remains unclear, and pharmacological intervention is required. Here we show photoperiodic regulation of dopamine signaling and improvement of short day–attenuated photosensitivity by its pharmacological intervention in mice. Electroretinograms revealed dynamic seasonal changes in retinal photosensitivity. Transcriptome analysis identified short day-mediated suppression of the Th gene, which encodes tyrosine hydroxylase, a rate-limiting enzyme for dopamine biosynthesis. Furthermore, pharmacological intervention in dopamine signaling through activation of the cAMP signaling pathway rescued short day–attenuated photosensitivity, whereas dopamine receptor antagonists decreased photosensitivity under long-day conditions. Our results reveal molecular basis of seasonal changes in retinal photosensitivity in mammals. In addition, our findings provide important insights into the pathogenesis of SAD and offer potential therapeutic interventions.

Electronic Sun Journal Versus Self-report Sun Diary: A Comparison of Recording Personal Sunlight Exposure Methods

This research compared personal sunlight exposure times monitored electronically within suburban Australian environments against self-report paper journals for determining the timing and total duration of individual exposure to daily solar radiation. A total of 90 Electronic Sun Journal (ESJ) daily readings and self-report timing and duration estimates of exposure for weekend and weekdays were compared. A Wilcoxon ranked sign test showed a significant difference (V = 157, P < 0.001) between the duration of exposure recorded electronically and the duration of exposure that was self-reported in a diary. There was also found to be a statistically significant difference between total exposure time measured using both methods for weekends (V = 10, P < 0.001) and weekdays (V = 87, P < 0.001). General trends in outdoor exposure timing confirmed that the most frequent daily exposures received over the weekend occurred between 1 and 2 h earlier than the most frequent exposures received on weekdays. This preliminary research found that exposure durations as recorded by the ESJ were longer on the weekends compared to weekdays (W = 402, P < 0.001) and confirmed that the ESJ is a viable alternative to self-reporting diaries.

Jet Lag Recovery and Memory Functions Are Correlated with Direct Light Effects on Locomotion

Jet lag is a circadian disruption that affects millions of people, resulting, among other things, in extreme sleepiness and memory loss. The hazardous implications of such effects are evident in situations in which focus and attention are required. Remarkably, there is a limited understanding of how jet lag recovery and associated memory loss vary year round under different photoperiods. Here we show, using different cycles representing winter, summer, and equinox in male mice, that jet lag recovery and memory vary significantly with photoperiod changes. We uncover a positive correlation of acute light effects on circadian-driven locomotion (known as negative masking) with photoentrainment speed and memory enhancement during jet lag. Specifically, we show that enhancing or reducing negative masking is correlated with better or worse memory performance, respectively. This study indicates that in addition to timed-light exposure for phase shifting, the negative masking response could also be biologically relevant when designing effective treatments of jet lag.

Hospitalization trends and chronobiology for mental disorders in Spain from 2005 to 2015

Rhythm research has had a long tradition in psychiatry, especially in affective disorders. The study of trends in incidence plays a central role in epidemiology and public health. The aims of this research were to describe the socio-demographic and clinical characteristics of persons admitted for psychiatric hospitalization and their trends and periodicity in cases (global and by groups) in Spain over the 11 year study span. We conducted a cross-sectional study of the hospital discharge database of Castilla y León from 2005 to 2015, selecting hospitalizations for psychiatric reasons. Trends in the rates of hospitalization were studied by joinpoint regression analysis. Time series analysis for periodicities was done by spectral analysis, fast Fourier transform, and cosinor analysis. Some 49501 hospitalizations due to psychiatric disorders, out of 2717192 hospital admissions, took place during the study span. Hospitalizations for psychosis were frequent (15949, 32.2%), while such for eating disorders were infrequent, but showed the highest average stay (28 days) and DRG relative weight (2.41). The general trend was a statistically significant 2% annual increase in psychiatric hospitalizations over the 11 year span; substance abuse was the only exception to this trend. The whole population and the subgroups of psychosis and bipolar disorders showed significant circannual (one-year) variation in admissions. The rhythm percentage of the global group was 11.4%, while the rhythm percentages of the psychosis, bipolar, and eating disorders were 17.1%, 17.5%, and 9.6%, respectively (p < .05).

Light and Hormones in Seasonal Regulation of Reproduction and Mood

Organisms that inhabit the temperate zone exhibit various seasonal adaptive behaviors, including reproduction, hibernation, molting, and migration. Day length, known as photoperiod, is the most noise-free and widely used environmental cue that enables animals to anticipate the oncoming seasons and adapt their physiologies accordingly. Although less clear, some human traits also exhibit seasonality, such as birthrate, mood, cognitive brain responses, and various diseases. However, the molecular basis for human seasonality is poorly understood. Herein, we first review the underlying mechanisms of seasonal adaptive strategies of animals, including seasonal reproduction and stress responses during the breeding season. We then briefly summarize our recent discovery of signaling pathways involved in the winter depression-like phenotype in medaka fish. We believe that exploring the regulation of seasonal traits in animal models will provide insight into human seasonality and aid in the understanding of human diseases such as seasonal affective disorder (SAD).

The Role of Diet, Eating Behavior, and Nutrition Intervention in Seasonal Affective Disorder: A Systematic Review

Background: Seasonal affective disorder (SAD) is a biological and mood disorder with a seasonal pattern. Dietary intervention and nutritional status have been reported to affect SAD severity. The objective of this study was to systematically review the evidence of associations between SAD and diet, eating behavior, and nutrition intervention. Methods: We performed a comprehensive search of MEDLINE, EMBASE, Web of Science, and Google Scholar from inception up to July 1, 2019. Studies that examined diet and eating behaviors in SAD patients and tests of nutrition interventions for SAD were included. Two independent investigators extracted data based on study designs, participants, outcomes, exposures, and association measures. Results: Eleven studies were included: six studies examined distinctive dietary patterns and eating behaviors in SAD patients and five studies explored the efficacy of nutrition interventions for SAD. Vegetarianism and alcoholism were associated with higher SAD prevalence, but normal alcohol intake was not correlated with SAD severity. Compared with non-clinical subjects, SAD patients tended to consume significantly larger dinners and more evening snacks during weekdays and weekends and exhibit a higher frequency of binge eating, external eating, and emotional eating. Additionally, compared to healthy controls, SAD patients presented more cravings for starch-rich food and food with high fiber. However, neither the ingestion of carbohydrate-loaded meals nor Vitamin D/B12 supplementation showed benefit for SAD. Conclusion: Studies suggest that SAD patients may exhibit distinctive diet preferences and eating behaviors, but no current nutrition intervention has demonstrated efficacy for ameliorating SAD symptoms. Further evidence is needed from randomized controlled trials with larger sample sizes and longer durations.

Seasonal variation in gut microbiota composition: cross-sectional evidence from Ukrainian population

BACKGROUND

Gut microbiota composition is known to depend on environmental (diet, day length, infections, xenobiotic exposure) and lifestyle (alcohol/drug intake, physical activity) factors. All these factors fluctuate seasonally, especially in areas with highly variable climatic conditions between seasons. Seasonal microbiota changes were reported in several previous studies. The purpose of our study was to investigate whether there is a seasonal variability in the gut microbiota composition in Ukrainian population. In contrast to previous studies performed on small-size samples using a longitudinal design, we used cross-sectional design with a large sample size (n = 769). Determination of microbial composition at the level of major microbial phyla was performed by qRT-PCR.

RESULTS

The relative abundance of major taxonomic groups of gut microbiota was found to be affected by month of sampling. Actinobacteria were more abundant and Bacteroidetes were less abundant in summer-derived samples compared to those obtained during other seasons, whereas Firmicutes content was seasonally independent. The Firmicutes to Bacteroidetes (F/B) ratio was significantly higher in summer-derived samples than in winter-derived ones. Odds to have F/B > 1 were 3.3 times higher in summer samples and 1.9 times higher in autumn samples than in winter ones; neither age, nor sex were significant confounding factors.

CONCLUSIONS

Seasonality of sampling could influence results of human microbiome research, thereby potentially biasing estimates. This factor must be taken into consideration in further microbiome research.

Seasonal changes in NRF2 antioxidant pathway regulates winter depression-like behavior

At high latitudes, about 10% of the population suffers from depression in winter. Although it has become a serious public health issue, its underlying mechanism remains unknown. Interestingly, animals also show depression-like behavior in winter, and small teleosts have emerged as powerful models for the study of complex brain disorders. Here, we show that medaka exhibit decreased sociability and increased anxiety-like behavior under winter-like conditions. Using metabolomic and transcriptomic analyses, we found changes in multiple signaling pathways involved in depression, including the NRF2 antioxidant pathway. Chemical genomics and targeted mutation of the NRF2 gene revealed that seasonal changes in the NRF2 pathway regulate winter depression-like behavior. This study provides insights into the understanding and treatment of seasonally regulated affective disorders.

Seasonal changes in the environment lead to depression-like behaviors in humans and animals. The underlying mechanisms, however, are unknown. We observed decreased sociability and increased anxiety-like behavior in medaka fish exposed to winter-like conditions. Whole brain metabolomic analysis revealed seasonal changes in 68 metabolites, including neurotransmitters and antioxidants associated with depression. Transcriptome analysis identified 3,306 differentially expressed transcripts, including inflammatory markers, melanopsins, and circadian clock genes. Further analyses revealed seasonal changes in multiple signaling pathways implicated in depression, including the nuclear factor erythroid-derived 2-like 2 (NRF2) antioxidant pathway. A broad-spectrum chemical screen revealed that celastrol (a traditional Chinese medicine) uniquely reversed winter behavior. NRF2 is a celastrol target expressed in the habenula (HB), known to play a critical role in the pathophysiology of depression. Another NRF2 chemical activator phenocopied these effects, and an NRF2 mutant showed decreased sociability. Our study provides important insights into winter depression and offers potential therapeutic targets involving NRF2.

Brainstem volume mediates seasonal variation in depressive symptoms: A cross sectional study in the UK Biobank cohort

Seasonal differences in mood and depressive symptoms affect a large percentage of the general population, with seasonal affective disorder (SAD) representing the most common presentation. SAD affects up to 3% of the world’s population, and it tends to be more predominant in females than males. The brainstem has been shown to be affected by photoperiodic changes, and that longer photoperiods are associated with higher neuronal density and decreased depressive-like behaviours. We predict that longer photoperiod days are associated with larger brainstem volumes and lower depressive scores, and that brainstem volume mediates the seasonality of depressive symptoms. Participants (N = 9289, 51.8% females and 48.1% males) ranging in age from 44 to 79 years were scanned by MRI at a single location. Photoperiod was found to be negatively correlated with low mood and anhedonia in females while photoperiod was found to be positively correlated with brainstem volumes. In females, whole brainstem, pons and medulla volumes individually mediated the relationship between photoperiod and both anhedonia and low mood, while midbrain volume mediated the relationship between photoperiod and anhedonia. No mediation effects were seen in males. Our study extends the understanding of the neurobiological factors that contribute to the pathophysiology of seasonal mood variations.

Shallow metabolic depression and human spaceflight: a feasible first step

Synthetic torpor is an induced state of deep metabolic depression (MD) in an organism that does not naturally employ regulated and reversible MD. If applied to spaceflight crewmembers, this metabolic state may theoretically mitigate numerous biological and logistical challenges of human spaceflight. These benefits have been the focus of numerous recent articles where, invariably, they are discussed in the context of hypothetical deep MD states in which the metabolism of crewmembers is profoundly depressed relative to basal rates. However, inducing these deep MD states in humans, particularly humans aboard spacecraft, is currently impossible. Here, we discuss shallow MD as a feasible first step toward synthetic torpor during spaceflight and summarize perspectives following a recent NASA-hosted workshop. We discuss methods to safely induce shallow MD (e.g., sleep and slow wave enhancement via acoustic and photoperiod stimulation; moderate sedation via dexmedetomidine), which we define as an ~20% depression of metabolic rate relative to basal levels. We also discuss different modes of shallow MD application (e.g., habitual versus targeted, whereby shallow MD is induced routinely throughout a mission or only under certain circumstances, respectively) and different spaceflight scenarios that would benefit from its use. Finally, we propose a multistep development plan toward the application of synthetic torpor to human spaceflight, highlighting shallow MD's role. As space agencies develop missions to send humans further into space than ever before, shallow MD has the potential to confer health benefits for crewmembers, reduce demands on spacecraft capacities, and serve as a testbed for deeper MD technologies.