Epidemiological findings of seasonal changes in mood and behavior. A telephone survey of Montgomery County, Maryland

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.

Daily Self-Monitoring and Feedback of Circadian Rhythm Measures in Major Depression and Bipolar Disorder Using Wearable Devices and Smartphones-The Circadian Rhythm for Mood (CRM®) Trial Protocol: A Randomized Sham Controlled Double-Blind Trial

The circadian rhythm for mood (CRM) is a digital therapeutic, which aims to prevent mood episode and improve clinical course in patients with major mood disorders. Developed on the circadian rhythm hypothesis of mood disorder, CRM predicts the impending risk of mood episode with its built-in algorithm, utilizing wearable devices data and daily self-reports, and provides personalized feedback. In a pilot study of the CRM, the users experienced less frequent and shorter duration of mood episodes than the non-users. To investigate the efficacy of the upgraded CRM, a double-blind, randomized, sham-controlled, parallel-group trial is designed. Patients aged between 19 and 70, diagnosed with bipolar I disorder, bipolar II disorder, or major depressive disorder, in a euthymic state for more than two months, can participate. During this 12-month trial, participants are assessed for episode recurrence every three months, and the efficacy of the CRM as a potential digital therapeutic is evaluated. Trial registration: ClinicalTrials.gov Identifier: NCT05400785.

Bright Light Therapy as Add-On to Inpatient Treatment in Youth With Moderate to Severe Depression: A Randomized Clinical Trial

Importance

Major depressive disorder is one of the most common mental disorders among adolescents, entailing severe, long-term psychosocial impairment and a high risk of chronicity. In view of the large number of patients requiring treatment, along with insufficient treatment responses with small effect sizes, innovative adjunctive treatment strategies are urgently needed.

Objective

To investigate whether the effect of adolescent psychiatric inpatient treatment as usual for major depressive disorder can be enhanced by simultaneous use of morning bright light therapy.

Design, Setting, and Participants

This was a double-blind, placebo-controlled randomized parallel-group trial with enrollment between March 2018 and November 2020 and follow-up completed in May 2021. The study took place among inpatients at 4 university hospitals for child and adolescent psychiatry across Germany. Of 248 eligible youth aged 12 to 18 years fulfilling ICD-10 criteria for major depressive disorder, 227 were randomized to bright light therapy (n = 116) or placebo red light (n = 111); 151 participants completed the study.

Interventions

Up to 20 sessions of either morning bright light therapy with an intensity of 10 000 lux or placebo red light (100 lux) in addition to multimodal inpatient treatment as usual over 4 weeks.

Main Outcomes and Measures

The primary outcome was the change in Beck Depression Inventory-II (BDI-II) score from baseline to posttreatment in the intention-to-treat sample.

Results

Among the 224 patients included in the intention-to-treat analyses (192 girls and 32 boys; mean [SD] age, 15.5 [1.4] years), the mean (SD) BDI-II score at baseline was 37.3 (8.7). BDI-II scores were significantly reduced after 4 weeks (postassessment) by a mean of -7.5 (95% CI, -9.0 to -6.0; Hedges g = 0.71). Bright light therapy had no impact on this change (no significant group × time effect). Loss to follow-up was 31% (n = 69) at 16 weeks and 49% (n = 110) at 28 weeks. There were 10 serious adverse events throughout the whole trial, which were not considered related to study treatment.

Conclusions and Relevance

The findings in this study did not indicate superiority of bright light therapy over placebo red light therapy in a large sample of adolescent inpatients with moderate or severe major depressive disorder. Both groups benefited equally from treatment as usual, showing relevant symptom reduction.

Trial Registration

German Clinical Trials Register: DRKS00013188.

Evaluation of the effects of blue-enriched white light on cognitive performance, arousal, and overall appreciation of lighting

Introduction

Light's non-visual effects on the biological clock, cognitive performance, alertness, and mental health are getting more recognized. These are primarily driven by blue light, which triggers specific retinal cells containing melanopsin. Traditionally, research on light has relied on correlated color temperature (CCT) as a metric of its biological influence, given that bluer light corresponds to higher Kelvin values. However, CCT proves to be an inadequate proxy of light's biological effects. A more precise metric is melanopic Equivalent Daylight Illuminance (mel-EDI), which aligns with melanopsin spectrum. Studies have reported positive cognitive impacts of blue-enriched white light. It's unclear if the mixed results are due to different mel-EDI levels since this factor wasn't assessed.

Method

Given recent recommendations from experts to aim for at least 250 mel-EDI exposure daily for cognitive benefits, our aim was to assess if a 50-minute exposure to LED light with 250 mel-EDI could enhance concentration and alertness, without affecting visual performance or comfort compared to conventional lighting producing around 150 mel-EDI. To ensure mel-EDI's impact, photopic lux levels were kept constant across conditions. Conditions were counterbalanced, parameters included subjective sleepiness (KSS; Karolinska Sleepiness Scale), concentration (d2-R test), visual performance (FrACT; Freiburg Visual Acuity and Contrast Test), general appreciation (VAS; Visual Analogous Scale), preferences and comfort (modified OLS; Office Lighting Survey).

Results

The experimental light significantly reduced sleepiness (p = 0.03, Cohen's d = 0.42) and also decreased contrast sensitivity (p = 0.01, Cohen's d = 0.50). The conventional light was found to be more comfortable (p = 0.002, Cohen's d = 0.62), cheerful (p = 0.02, Cohen's d = 0.46) and pleasant (p = 0.005, Cohen's d = 0.55) while the experimental light was perceived as brighter (p = 0.004, Cohen's d = 0.58) and tended to be more stimulating (p = 0.10). Notably, there was a preference for conventional lighting (p = 0.004, Cohen's d=0.56) and concentration was equally improved in both conditions.

Discussion

Despite the lack of further improvement in concentration from exposure to blue-enriched light, given the observed benefits in terms of vigilance, further research over an extended period would be justified. These findings could subsequently motivate cognitive optimization through lighting for workers that would benefit from artificial lighting such as in northern regions.

Seasonal patterns in Chinese population: Validating the seasonal pattern assessment questionnaire and exploring associations with psychiatric diagnoses and biological rhythms

Seasonal patterns (SP) exert a notable influence on the course and prognosis of patients with affective disorders, serving as a specifier in diagnosis. However, there is limited exploration of seasonality among psychotic patients, and the distinctions in seasonality among psychiatric patients remain unclear. In this study, we enrolled 198 psychiatric patients with anxiety and depressive disorders (A&D), bipolar disorder (BD), and schizophrenia (SZ), as well as healthy college students. Online questionnaires, including the Seasonal Pattern Assessment Questionnaire (SPAQ) for seasonality, the Morningness and Eveningness Questionnaire-5 (MEQ-5) for chronotypes, and the Pittsburgh Sleep Quality Index (PSQI), were administered. The validity and reliability of the Chinese version of the SPAQ were thoroughly analyzed, revealing a Cronbach's alpha of 0.896 with a two-factor structure. Results indicated that higher seasonality was correlated with poorer sleep quality and a more delayed chronotype (p < 0.05). Significant monthly variations were particularly evident in BD, specifically in mood, appetite, weight, social activities, and sleep dimensions (p < 0.001). In summary, the Chinese version of SPAQ is validated, demonstrating moderate correlations between seasonality, chronotype, and sleep quality. BD patients exhibited the strongest seasonality, while mood disorder patients displayed more delayed chronotypes than SZ.

Body Uneasiness, Body Figure Perception, and Body Weight: Factor Structure and Longitudinal Measurement Invariance of a Set of Attitudinal and Perceptual Body Image Assessment Tools in Adolescents

Body image is a multifaceted construct that includes attitudinal and perceptual components, but its attention has mainly been focused on the facet of body dissatisfaction. The present longitudinal study extended the validation of a multifacet attitudinal questionnaire, the Body Uneasiness Test (BUT), against perceptions of body shape and weight. A convenient sample of adolescents took part in a 2-year unbalanced panel study (5 waves). The participants completed the BUT questionnaire and selected their perceived actual, ideal, and reflected body figures along the Contour Drawing Rating Scale; ideal/actual and ideal/normative body mass index discrepancies were also included. After replicating the expected five-factor structure of the BUT items, results from confirmatory factor analysis revealed that the five BUT scales loaded on an attitudinal dimension, whereas the perceived body figures and the discrepancy indices were on a perceptive domain. Such a two-domain structure of body image measures showed gender and seasonal (1-year) measurement invariance, whereas longitudinal 6-month and 18-month invariance partially failed. Overall, the present findings support the validity of the Body Uneasiness Test in adolescence, further demonstrating a preliminary multidimensional structure of body image onto which attitudinal and perceptual body image-related measures were projected.

Seasonal changes in positive airway pressure adherence

Through their effects on sleep duration, bedroom environments, and pollen allergies, seasonal variations may impact positive airway pressure (PAP) adherence. We analyzed daily PAP telemonitoring data from 25,846 adults (median age 64 years, 67.8% male) treated with PAP for at least 4 months [mean (standard deviation, SD) duration of PAP: 5.5 years (SD 4.1)] to examine seasonal changes in PAP adherence, leaks, and residual apnea-hypopnea index. We demonstrate a significant decrease in PAP adherence in June compared to January (mean (SD): 0.37 (1.54) h/night) that achieved the minimal clinically important difference (MCID) of 30 min in 13.9% of adults. Furthermore, we provide novel data supporting the association of rising temperatures with seasonal changes in PAP use. Indeed, the most pronounced decline in PAP adherence was observed during the hottest days, while PAP adherence was only slightly reduced during the coolest days of June. Clinicians should be aware of seasonal changes in PAP adherence that are likely to be exacerbated by climate change.

Homo temporus: Seasonal Cycles as a Fundamental Source of Variation in Human Psychology

Many animal species exhibit seasonal changes in their physiology and behavior. Yet despite ample evidence that humans are also responsive to seasons, the impact of seasonal changes on human psychology is underappreciated relative to other sources of variation (e.g., personality, culture, development). This is unfortunate because seasonal variation has potentially profound conceptual, empirical, methodological, and practical implications. Here, we encourage a more systematic and comprehensive collective effort to document and understand the many ways in which seasons influence human psychology. We provide an illustrative summary of empirical evidence showing that seasons impact a wide range of affective, cognitive, and behavioral phenomena. We then articulate a conceptual framework that outlines a set of causal mechanisms through which seasons can influence human psychology-mechanisms that reflect seasonal changes not only in meteorological variables but also in ecological and sociocultural variables. This framework may be useful for integrating many different seasonal effects that have already been empirically documented and for generating new hypotheses about additional seasonal effects that have not yet received empirical attention. The article closes with a section that provides practical suggestions to facilitate greater appreciation for, and systematic study of, seasons as a fundamental source of variation in human psychology.

Emotional Bias among Individuals at Risk for Seasonal Affective Disorder-An EEG Study during Remission in Summer

Emotional bias in attention and memory is well researched in depression. Patients with depression prioritize processing of negative information over positive input. While there is evidence that emotional bias exists in seasonal affective disorder (SAD) during winter, it is unclear whether such altered cognition exists also during summer. Moreover, it is unclear whether such bias affects attention, memory, or both. In this study, we investigated 110 individuals in summer, 34 of whom reported suffering from low mood during winter, according to the seasonal pattern assessment questionnaire. While the electroencephalogram was recorded, participants learned 60 emotional pictures and subsequently were asked to recognize them in an old/new task. There were no clear group differences in behavioral measures, and no brain response differences in frontal alpha power during learning. During recognition, at 100-300 ms post stimulus individuals with higher seasonality scores exhibited larger alpha power in response to negative as compared to neutral stimuli, while individuals with low seasonality scores exhibited larger alpha power in response to positive as compared to neutral stimuli. While we cannot draw conclusions whether this is an effect of attention or memory, the finding suggests that early cognitive processes are altered already during summer in individuals with increased likelihood to experience SAD during winter. Our data provide evidence for an all-year-round cognitive vulnerability in this population.

Seasonal Variation in the Responsiveness of the Melanopsin System to Evening Light: Why We Should Report Season When Collecting Data in Human Sleep and Circadian Studies

It is well known that variations in light exposure during the day affect light sensitivity in the evening. More daylight reduces sensitivity, and less daylight increases it. On average days, we spend less time outdoors in winter and receive far less light than in summer. Therefore, it could be relevant when collecting research data on the non-image forming (NIF) effects of light on circadian rhythms and sleep. In fact, studies conducted only in winter may result in more pronounced NIF effects than in summer. Here, we systematically collected information on the extent to which studies on the NIF effects of evening light include information on season and/or light history. We found that more studies were conducted in winter than in summer and that reporting when a study was conducted or measuring individual light history is not currently a standard in sleep and circadian research. In addition, we sought to evaluate seasonal variations in a previously published dataset of 72 participants investigating circadian and sleep effects of evening light exposure in a laboratory protocol where daytime light history was not controlled. In this study, we selectively modulated melanopic irradiance at four different light levels (<90 lx). Here, we aimed to retrospectively evaluate seasonal variations in the responsiveness of the melanopsin system by combining all data sets in an exploratory manner. Our analyses suggest that light sensitivity is indeed reduced in summer compared to winter. Thus, to increase the reproducibility of NIF effects on sleep and circadian measures, we recommend an assessment of the light history and encourage standardization of reporting guidelines on the seasonal distribution of measurements.

Seasonal variations of functional connectivity of human brains

Seasonal variations have long been observed in various aspects of human life. While there is an abundance of research that has characterized seasonality effects in, for example, cognition, mood, and behavior, including studies of underlying biophysical mechanisms, direct measurements of seasonal variations of brain functional activities have not gained wide attention. We have quantified seasonal effects on functional connectivity as derived from MRI scans. A cohort of healthy human subjects was divided into four groups based on the seasons of their scanning dates as documented in the image database of the Human Connectome Project. Sinusoidal functions were used as regressors to determine whether there were significant seasonal variations in measures of brain activities. We began with the analysis of seasonal variations of the fractional amplitudes of low frequency fluctuations of regional functional signals, followed by the seasonal variations of functional connectivity in both global- and network-level. Furthermore, relevant environmental factors, including average temperature and daylength, were found to be significantly associated with brain functional activities, which may explain how the observed seasonal fluctuations arise. Finally, topological properties of the brain functional network also showed significant variations across seasons. All the observations accumulated revealed seasonality effects of human brain activities in a resting-state, which may have important practical implications for neuroimaging research.

Mediating role of weight concerns in the relationship between seasonality and eating behavior among community-dwelling older adults: A path analysis

BACKGROUND

Weight concerns are common among older adults, and it is unclear how they may impact the relationship between seasonality and eating behaviors, which can contribute to various health-related issues.

AIM

This study investigated the mediating role of weight concerns in the relationship between seasonality and eating behavior among community-dwelling older adults.

METHOD

A descriptive correlational analytical design was used on 200 randomly chosen participants who completed the Personal Inventory for Depression and Seasonal Affective Disorder Self-Assessment Version, the Adult Eating Behavior Questionnaire, and the Weight Concern Subscale. A path analysis was conducted to test the hypothesized model.

RESULTS

The study findings indicated that most older adults reported moderate-to-severe seasonal variations, moderate enjoyment of food, emotional overeating, emotional undereating, and food fussiness. Weight concern partially mediated the relationship between seasonality and eating behavior.

CONCLUSION

By understanding the complex interplay between these factors, weight concerns may play an essential role in mediating the effects of seasonal changes on eating behavior, while seasonal winter symptoms may directly impact eating behavior. These results have potential implications for nurses' efforts to develop interventions to promote healthy eating behaviors and manage weight concerns during seasonal variations, especially in the winter.

The underexplored presence of seasonal affective disorder in the southern hemisphere: A narrative review of the Australian literature

BACKGROUND

Seasonal Affective Disorder (SAD) is well documented in the medical literature, particularly in more northern latitudes in agreement with proposed hypotheses for SAD's pathophysiology. However, in the southern latitudes SAD's presence remains underexplored. The second largest country in the southern hemisphere is Australia. Australia has wide ranging geographical and climatic differences that are expected to support SAD's presence. The aim of this study is therefore, to establish an evidence base for SAD in Australia.

METHODS

PubMed and Google Scholar were searched for published peer-review studies focussed on, or related to SAD, winter depression or seasonal variation in mood in Australia. There were no time-period restrictions.

RESULTS

Thirteen studies were identified. Studies explored the presence/nature of SAD, contributing factors, autonomic activity, treatment, and the validity of the Seasonal Pattern Assessment Questionnaire in the Australian population. An association between changes in mood and behaviour and seasonal occurrence was clearly identified, with SAD's presence varying by location. The highest percentage of study participants with SAD in a single location was observed in Tasmania, Australia's most southern state. The findings and interpretations of the studies included in this review are subject to the number of locations assessed, the number of studies undertaken at each location and individual study limitations.

CONCLUSIONS

Ascertaining information on the prevalence and correlates of SAD in the southern hemisphere, particularly in high-risk locations could contribute to clinical literacy into the syndrome, support management practices, and promote the early identification and treatment of the disorder.

Validation of the Short Form of the Mood Instability Questionnaire-Trait (MIQ-T-SF) in the Korean General Population

OBJECTIVE

Mood instability (MI) is a clinically significant trait associated with psychiatric disorders. However, there are no concise measurements to evaluate MI. The initial Mood Instability Questionnaire-Trait (MIQ-T) was developed to fill this gap. The current study aimed to create a short form of MIQ-T (MIQ-T-SF) that measures MI with high validity and reliability in the Korean general population.

METHODS

Of the 59 items in the MIQ-T, 17 items were chosen for the MIQ-T-SF following the factor analysis process. In total, 540 participants completed the MIQ-T-SF. Cronbach's alpha and McDonald's omega were used to evaluate reliability. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to determine construct validity. Concurrent validity was confirmed via comparisons with Personality Assessment Inventory-Borderline Features Scale. Measurement invariance across gender and age groups was confirmed before analyzing differences in scores using Kruskal-Wallis test.

RESULTS

The MIQ-T-SF displayed expected correlations and high internal consistency (α=0.71-0.90, Ωt=0.72-0.92). Using EFA and CFA, a five-factor structure was confirmed. Measurement invariance was supported, and gender differences were observed.

CONCLUSION

The MIQ-T-SF is an accurate and reliable method to detect MI in the Korean general population. The study's results offer new perspectives for future studies on MI.

The influence of season on glutamate and GABA levels in the healthy human brain investigated by magnetic resonance spectroscopy imaging

Seasonal changes in neurotransmitter systems have been demonstrated in imaging studies and are especially noticeable in diseased states such as seasonal affective disorder (SAD). These modulatory neurotransmitters, such as serotonin, are influencing glutamatergic and GABAergic neurotransmission. Furthermore, central components of the circadian pacemaker are regulated by GABA (the suprachiasmatic nucleus) or glutamate (e.g., the retinohypothalamic tract). Therefore, we explored seasonal differences in the GABAergic and glutamatergic system in 159 healthy individuals using magnetic resonance spectroscopy imaging with a GABA-edited 3D-MEGA-LASER sequence at 3T. We quantified GABA+/tCr, GABA+/Glx, and Glx/tCr ratios (GABA+, GABA+ macromolecules; Glx, glutamate + glutamine; tCr, total creatine) in five different subcortical brain regions. Differences between time periods throughout the year, seasonal patterns, and stationarity were tested using ANCOVA models, curve fitting approaches, and unit root and stationarity tests, respectively. Finally, Spearman correlation analyses between neurotransmitter ratios within each brain region and cumulated daylight and global radiation were performed. No seasonal or monthly differences, seasonal patterns, nor significant correlations could be shown in any region or ratio. Unit root and stationarity tests showed stable patterns of GABA+/tCr, GABA+/Glx, and Glx/tCr levels throughout the year, except for hippocampal Glx/tCr. Our results indicate that neurotransmitter levels of glutamate and GABA in healthy individuals are stable throughout the year. Hence, despite the important correction for age and gender in the analyses of MRS derived GABA and glutamate, a correction for seasonality in future studies does not seem necessary. Future investigations in SAD and other psychiatric patients will be of high interest.

Seasonality of brain function: role in psychiatric disorders

Seasonality patterns are reported in various psychiatric disorders. The current paper summarizes findings on brain adaptations associated with seasonal changes, factors that contribute to individual differences and their implications for psychiatric disorders. Changes in circadian rhythms are likely to prominently mediate these seasonal effects since light strongly entrains the internal clock modifying brain function. Inability of circadian rhythms to accommodate to seasonal changes might increase the risk for mood and behavior problems as well as worse clinical outcomes in psychiatric disorders. Understanding the mechanisms that account for inter-individual variations in seasonality is relevant to the development of individualized prevention and treatment for psychiatric disorders. Despite promising findings, seasonal effects are still understudied and only controlled as a covariate in most brain research. Rigorous neuroimaging studies with thoughtful experimental designs, powered sample sizes and high temporal resolution alongside deep characterization of the environment are needed to better understand the seasonal adaptions of the human brain as a function of age, sex, and geographic latitude and to investigate the mechanisms underlying the alterations in seasonal adaptation in psychiatric disorders.

Seasonality of human sleep: Polysomnographic data of a neuropsychiatric sleep clinic

While short-term effects of artificial light on human sleep are increasingly being studied, reports on long-term effects induced by season are scarce. Assessments of subjective sleep length over the year suggest a substantially longer sleep period during winter. Our retrospective study aimed to investigate seasonal variation in objective sleep measures in a cohort of patients living in an urban environment. In 2019, three-night polysomnography was performed on 292 patients with neuropsychiatric sleep disturbances. Measures of the diagnostic second nights were averaged per month and analyzed over the year. Patients were advised to sleep "as usual" including timing, except alarm clocks were not allowed. Exclusion criteria: administration of psychotropic agents known to influence sleep (N = 96), REM-sleep latency > 120 min (N = 5), technical failure (N = 3). Included were 188 patients: [46.6 ± 15.9 years (mean ± SD); range 17-81 years; 52% female]; most common sleep-related diagnoses: insomnia (N = 108), depression (N = 59) and sleep-related breathing disorders (N = 52). Analyses showed: 1. total sleep time (TST) longer during winter than summer (up to 60 min; not significant); 2. REM-sleep latency shorter during autumn than spring (about 25 min, p = 0.010); 3. REM-sleep longer during winter than spring (about 30 min, p = 0.009, 5% of TST, p = 0.011); 4. slow-wave-sleep stable winter to summer (about 60-70 min) with 30-50 min shorter during autumn (only significant as % of TST, 10% decrease, p = 0.017). Data suggest seasonal variation in sleep architecture even when living in an urban environment in patients with disturbed sleep. If replicated in a healthy population, this would provide first evidence for a need to adjust sleep habits to season.

Declarative Memory Impairment and Emotional Bias in Recurrent Depression with a Seasonal Pattern: The Interplay between Emotion and Cognition in Seasonal Affective Disorder

Seasonal Affective Disorder (SAD) is a subtype of Major Depressive Disorder (MDD) with a seasonal pattern. Although it is a pathological condition limited to specific seasons of the year, during the symptomatic period, patients may experience a significant impairment of well-being and daily quality of life as a result of the depressed mood, associated with other symptoms defined as atypical of MDD. While extensive evidence of memory deficits has been found in MDD, explicit memory impairments in SAD are insufficiently studied. This study aims to investigate the cognitive processing of emotional stimuli in women with SAD, in particular the interplay between emotions and declarative memory. One hundred and twenty young women, screened from an initial number of 1125 university students, were divided into two groups, an experimental one that included 60 medically untreated women affected by “winter type SAD” and a control group of 60 non-SAD women. Different subjects were randomly submitted to two types of audio−visual stories, neutral or arousal, and then their memory performances were analyzed by means of a free-recall test and a recognition memory test. In both the free-recall test (p < 0.008) and in the recognition memory test (p < 0.002), the SAD group showed impaired memory performances. Taken together, our novel key findings suggest that SAD is characterized by impairment in declarative memory and attentional bias for emotional negative stimuli.

Seasonality contributes to depressive, anxiety and alcohol use disorders in the Finnish general adult population

BACKGROUND

Earlier evidence suggests that the seasonal changes in mood and behavior are associated with mental disorders, especially with mood disorders. However, the extent of these associations has not been analyzed by using large samples of the general population.

METHODS

A random sample of adults, aged 29 to 97 years and representative of the general population living in Finland, attended a nationwide health examination survey. Mental disorders were assessed with the Munich version of the Composite International Diagnostic Interview (M-CIDI, n = 4554). Of them, the seasonal variations in mood and behavior (seasonality) were assessed with the six items of the Global Seasonality Score (GSS, n = 4004) as well as with the experienced problem due to these variations.

RESULTS

After adjusting for age, gender, level of education, and region of residence, the GSS was associated with depressive, anxiety and alcohol use disorders (all p < 0.001). Of the GSS items, mood was associated with depressive disorders (p < 0.001), anxiety disorders (p = 0.003) and alcohol use disorders (p = 0.008), whereas appetite was associated only with depressive disorders (p = 0.012), and energy level only with anxiety disorders (p = 0.025).

LIMITATIONS

This cross-sectional study was based on self-reported data on the seasonal pattern.

CONCLUSIONS

Seasonality had significant associations with depressive, anxiety and alcohol use disorders among the general adult population. This needs attention in clinical practice.

EEG-responses to mood induction interact with seasonality and age

The EEG is suggested as a potential diagnostic and prognostic biomarker for seasonal affective disorder (SAD). As a pre-clinical form of SAD, seasonality is operationalized as seasonal variation in mood, appetite, weight, sleep, energy, and socializing. Importantly, both EEG biomarkers and seasonality interact with age. Inducing sad mood to assess cognitive vulnerability was suggested to improve the predictive value of summer assessments for winter depression. However, no EEG studies have been conducted on induced sad mood in relation to seasonality, and no studies so far have controlled for age. We recorded EEG and calculated bandpower in 114 participants during rest and during induced sad mood in summer. Participants were grouped by age and based on a seasonality score as obtained with the seasonal pattern assessment questionnaire (SPAQ). Participants with high seasonality scores showed significantly larger changes in EEG power from rest to sad mood induction, specifically in the alpha frequency range (p = 0.027), compared to participants with low seasonality scores. Furthermore, seasonality interacted significantly with age (p < 0.001), with lower activity in individuals with high seasonality scores that were older than 50 years but the opposite pattern in individuals up to 50 years. Effects of sad mood induction on brain activity are related to seasonality and can therefore be consider as potential predicting biomarkers for SAD. Future studies should control for age as a confounding factor, and more studies are needed to elaborate on the characteristics of EEG biomarkers in participants above 50 years.

Seasonal changes in mood and behavior contribute to suicidality and worthlessness in a population-based study

Limited evidence suggests that the seasonal changes in mood and behavior may associate with suicidality and the feelings of worthlessness, but these associations have not been analyzed in large population-based data. A random sample of adults (n = 4069), representative of the general population living in Finland, attended a nationwide health examination survey. Seasonal variations (seasonality) in mood and behavior were analyzed with the six items of global seasonality score (GSS) and the experienced problem due to these variations. Their impact on suicidality as well as on the feelings of worthlessness were analyzed using logistic regression models. After adjusting for age and gender, the GSS, each of its six items and the experienced problem due to the seasonal variations in mood and behavior all showed separately a significant association with suicidality as well as with worthlessness. After further adjustment for the education level and region of residence, the GSS, its mood item and the experienced problem remained significantly associated with both suicidality and worthlessness. Seasonal variations in mood and behavior have a significant association with both suicidality and worthlessness.

Amygdala and subregion volumes are associated with photoperiod and seasonal depressive symptoms: A cross-sectional study in the UK Biobank cohort

Although seasonal changes in amygdala volume have been demonstrated in animals, seasonal differences in human amygdala subregion volumes have yet to be investigated. Amygdala volume has also been linked to depressed mood. Therefore, we hypothesised that differences in photoperiod would predict differences in amygdala or subregion volumes and that this association would be linked to depressed mood. 10,033 participants ranging in age from 45 to 79 years were scanned by MRI in a single location. Amygdala subregion volumes were obtained using automated processing and segmentation algorithms. A mediation analysis tested whether amygdala volume mediated the relationship between photoperiod and mood. Photoperiod was positively associated with total amygdala volume (p < .001). Multivariate (GLM) analyses revealed significant effects of photoperiod across all amygdala subregion volumes for both hemispheres (p < .001). Post hoc univariate regression analyses revealed significant associations of photoperiod with each amygdala subregion volume (p < .001). PLS showed the highest loadings of amygdala subregions in lateral nucleus, ABN, basal nucleus, CAT, PLN, AAA, central nucleus, cortical nucleus and medial nucleus for left hemisphere and ABN, lateral nucleus, CAT, PLN, cortical nucleus, AAA, central nucleus and medial nucleus for right hemisphere. There were no significant associations between photoperiod and mood nor between mood scores and amygdala volumes, and due to the lack of these associations, the mediation hypothesis was not supported. This study is the first to demonstrate an association between photoperiod and amygdala volume. These findings add to the evidence supporting the role of photoperiod on brain structural plasticity.

Seasonality in Major Depressive Disorder: Effect of Sex and Age

BACKGROUND

Aside from the concept of seasonal affective disorder, the evidence for a seasonal pattern (SP) of major depressive disorder (MDD) is controversial. Furthermore, the effect of sex and age is still unclear.

METHODS

This is a nationwide, registry-based study assessing all inpatient admissions in mental health hospitals due to MDD episodes according to ICD-10 (moderate (F32/33.1), severe (F32/33.2) and severe with psychotic features (F32/33.3)) in Austria across 14 years. Calculations were based on deviations from expected monthly admissions.

RESULTS

The sample comprised 231,824 hospitalisations (36.8% men) for MDD. A significant SP (p=0.001) in moderate and severe depressive episodes in both women and men with decreased admission rates in the summer months and December was detected. In psychotic depression a significant SP was only evidenced in women (p = 0.002, men: p = 0.291). Patients older than 55 years had a reduced SP compared to those being younger.

LIMITATIONS

Only anonymised admission data of inpatient treatments were available. Hospitalization rates cannot fully be equated to the occurrence of MDD.

CONCLUSIONS

The current study indicates a seasonal variation in MDD symptoms that may go beyond seasonal affective disorder. Knowledge about the predictability of depressive symptoms in patients should encourage preventive strategies.

Seasonal affective disorder and engagement in physical activities among adults in Alaska

Seasonal affective disorder (SAD) is a type of depression in which symptoms occur during a particular season. While physical activity has been shown to improve symptoms for depression in general populations, the relationships between physical activity and experiences of seasonality and SAD remain underexplored. We conducted a survey with adult members of a recreational gym in Fairbanks, Alaska. The survey collected self-report data on sociodemographics, health behaviours, and elements of the Seasonal Pattern Assessment Questionnaire (SPAQ). Results indicate that 18.68% of our study participants meet the criteria for winter-pattern SAD and 43.96% meet the criteria for subsyndromal SAD ("winter blues"). We conducted two regressions to understand experiences of SAD and predictors of seasonality more generally. Gender was a significant predictor of SAD, with women more likely than men to experience SAD (p = .04). Being social at the gym, whether going to the gym with others or participating in activities with others, was associated with higher seasonality than being independent at the gym (p = .03). Younger age was also associated with higher seasonality (p < .001). This study contributes new insights about the relationship between engagement in physical activities and experiences of seasonality among adults in a northern latitude.

Running on Empty: Of Hypopinealism and Human Seasonality

The pineal hormone melatonin is the natural transducer of the environmental light-dark signal to the body. Although the responsiveness to photoperiod is well-conserved in humans, only about 25 percent of the human population experiences seasonal changes in behavior. As a consequence, humans seem to have adapted-at least partly-to the seasonal changes in day length. The aim of the study was to demonstrate that the individual melatonin deficit marker DOC (degree of pineal calcification) is related to variation of seasonal phenomena in humans. Out of 3,011 patients in which cranial computer tomography (cCT) was performed for diagnostic reasons, 97 consecutive "healthy" subjects (43 female, 54 male; age 18-68 yrs, mean ± SD: 35.0 ± 13.1) were included. Exclusion criteria were pathological finding in cCT, acute/chronic illness including alcohol/drug abuse, shift work, and medication, which are known to influence melatonin excretion. The degree of pineal calcification (DOC) was semiquantitatively determined using the previously validated method. The Seasonal Pattern Assessment Questionnaire (SPAQ) was performed in a telephone interview. Twenty-six subjects fulfilled the criteria for seasonal affective disorder (SAD) or subsyndromal (S) SAD. Seasonality was more pronounced in women than in men (SPAQ seasonality score: 7.8 ± 4.0 vs. 4.9 ± 4.5; p = 0.001) and negatively and significantly associated with age (r = -0.178; p = 0.04). The subjective sleep length significantly varied between seasons (one-way repeated measures ANOVA: F = 45.75; p < 0.0001), with sleep during winter being 53 min (±70 min) longer than during summer. Controlling for age, the total seasonality score was negatively and significantly associated with DOC (r₉₄ = -0.214; p = 0.036). Data confirm earlier studies with respect to distribution of seasonality with sex and age. The survival of seasonality in the sleep length of people living in an urban environment underlines functionality of the circadian timing system in modern societies. Moreover, data confirm for the first time that diminished experience of seasonality in behavior is associated with a reduced individual capacity to produce melatonin.

Energy intake and season interact to influence physiological stress load among midlife women

Allostatic load (AL) is an index that measures physiologic stress associated with chronic disease risk. One factor that may influence overall physiologic stress load and AL is energy consumption, but whether this association differs across different seasons is unknown. We tested whether energy consumption interacted with the season to influence AL in 52 mid-life (40-60 years) women from the Life in All Seasons Study. Women completed an online 24-h recall every 10 days and had components of allostatic load measured seasonally. Women were from the greater Grand Forks, ND catchment area and were followed for one year between July 2012 and July 2014. We found a significant (p = 0.01) interaction between season and energy consumption on AL. Further inspection showed that, during the summer and winter seasons, the average allostatic load rose with relatively higher energy consumption. We also observed a linear and positive association between AL and energy intake in summer (β = 0.0013 ± 0.0004; p = 0.001; r² = 0.14) and winter (β = 0.0011 ± 0.0004; p = 0.007; r² = 0.10), but not in fall or spring. These results suggest that factors associated with distinct times of the year promote or prevent the effects of higher energy consumption on physiological stress load. Since allostatic load is linked to elevated disease risk, our results provide additional information that may help to explain seasonal differences in disease risk of some women.

Winter-summer difference in post-awakening salivary α-amylase and sleepiness depending on sleep and melatonin

Winter and summer seasons are contrasted by light/dark conditions at temperate latitudes, and the negative influence of this contrast on circadian health is yet to be quantified. This field study (performed in Novosibirsk, 55°N, no daylight saving time transitions) aimed to compare post-awakening arousal state in summer and winter in subjects (N=45) on a fixed 5-workday schedule (waken up by alarm at either ∼6 am or ∼7 am). Their circadian status (by 24-h melatonin profiles) and sleep (by log data) have been previously reported. Salivary α-amylase levels (a biomarker of the sympathetic nervous system activity, or stress) and subjective sleepiness were measured immediately after awakening on Friday, at minute 0 (supine), 10, 20, and 30 (not supine). α-Amylase levels were found to be higher in winter, along with a blunted α-amylase awakening response (AAR; a decline from minute 0 to minute 10 value). Both effects were attributable mainly to the 7am group. Sleepiness levels also increased in winter, mainly due to the seasonally dependent subjects, and predictably associated with shorter, later sleep, and later melatonin circadian phase. The sleepiness and α-amylase changes did not correlate. The seasonal change in α-amylase was positively associated with the change in the amount of melatonin secreted, probably reflecting the parallelism in the noradrenergic neural control of both α-amylase and melatonin secretion. Together, higher post-awakening salivary α-amylase levels (indicating stress) and subjective sleepiness levels (indicating greater sleep need) in winter compared to summer point to a less healthy state in winter.

Light therapy for seasonal affective disorder in visual impairment and blindness - a pilot study

OBJECTIVE

Seasonal and non-seasonal depression are prevalent conditions in visual impairment (VI). We assessed the effects and side effects of light therapy in persons with severe VI/blindness who experienced recurrent depressive symptoms in winter corresponding to seasonal affective disorder (SAD) or subsyndromal SAD (sSAD).

RESULTS

We included 18 persons (11 with severe VI, 3 with light perception and 4 with no light perception) who met screening criteria for sSAD/SAD in a single-arm, assessor-blinded trial of 6 weeks light therapy. In the 12 persons who completed the 6 weeks of treatment, the post-treatment depression score was reduced (p < 0.001), and subjective wellbeing (p = 0.01) and sleep quality were improved (p = 0.03). In 6/12 participants (50%), the post-treatment depression score was below the cut-off set for remission. In four participants with VI, side effects (glare or transiently altered visual function) led to dropout or exclusion.

CONCLUSION

Light therapy was associated with a reduction in depressive symptoms in persons with severe VI/blindness. Eye safety remains a concern in persons with residual sight.

Seasonal sensitivity and psychiatric morbidity: study about seasonal affective disorder

BACKGROUND

Seasonal Affective Disorder is a recurrent depressive disorder which usually begins in the fall/winter and enters into remission in the spring/summer, although in some cases may occur in the summer with remission in the autumn-winter. In this study the authors evaluated the association between seasonal changes in mood and behavior with psychiatric disturbance.

METHOD

Descriptive, cross-sectional study. Participants, students attending higher education and vocational courses (N = 324), were evaluated with the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Screening Scale for Mental Health (ER80).

RESULTS

Among the respondents, 12.7% showed seasonal affective disorder (SAD), 29.0% showed subsyndromal seasonal affective disorder (s-SAD) and 58.3% did not show significant seasonal affective symptomatology. As for psychiatric morbidity, 36.6% of subjects with SAD and 13.8% of those with s-SAD were considered "psychiatric cases" whereas for subjects without SAD this value was only 3.2%.

CONCLUSIONS

There is a statistically significant association between psychiatric morbidity and seasonal affective disorder. This association corroborates the importance of the Seasonal Pattern Assessment Questionnaire in screening for seasonal fluctuations in mood and behavior related disorders, and the clinical need for recognition of these conditions, particularly associated suffering and disabilities.

Seasonal variation in neurohormones, mood and sleep in patients with primary open angle glaucoma - implications of the ipRGC-system

Primary open angle glaucoma is associated with an increased risk of mood and sleep disorders. These adversities have been suggested to relate to a disrupted function of the intrinsically photosensitive retinal ganglion cells (ipRGCs). The ipRGCs are key components in the nonvisual photoreceptive system that mediates light effects on mood, sleep and circadian rhythm. We assessed the diurnal hormone levels, pupillary responses and mood and sleep under seasons with different photoperiods in 24 patients with glaucoma and 24 age- and sex-matched healthy controls to investigate responses to naturalistic seasonal changes in daylight. The patients had moderate-to-advanced glaucoma with substantial visual field defects and reductions in the ipRGC-mediated pupillary responses (p < .001). In winter, compared with summer, patients with glaucoma had higher daytime melatonin concentration (p < .001) and lower nighttime cortisol (p = .002). In winter, the daytime melatonin level was inversely correlated with the ipRGC-mediated pupillary responses in the control group (p = .04). In the control group, there were no significant changes in hormone levels between seasons or any correlations between neurohormone levels and the ipRGC-mediated responses. The two groups showed a similar response to season with lower depression scores in summer compared with winter. In between-group comparison, the nocturnal melatonin level (area under curve from 20:00 h to 08:00 h) in summer was lower in glaucoma compared with controls (p = .03). In winter, nocturnal cortisol (at 04:00 h) was lower (p = .004) and daytime cortisol (12:00 h and 16:00 h) was higher (p = .007) in glaucoma compared with controls. In conclusion, we found that patients with glaucoma displayed a seasonal variation in diurnal hormone levels that was not present in healthy controls. Such neurohormonal changes may contribute to the increased risk of mood and sleep disorders seen in patients with glaucoma.

Childhood maltreatment reports in adult seasonal affective disorder: Associations with sleep disturbances, maladaptive cognitions, and brooding

BACKGROUND

Although childhood maltreatment has been studied in multiple psychopathologies, its role in Seasonal Affective Disorder (SAD) is unknown. The current study examined possible mediators of the relationship between retrospectively-reported childhood maltreatment and adult SAD symptom severity during a major depressive episode in winter.

METHODS

Participants (N = 113), ages 18 to 65, completed measures of childhood maltreatment, SAD severity, sleep disturbances, ruminative brooding, and maladaptive cognitions. Mediation analyses testing the relationship between childhood maltreatment and SAD symptom severity via sleep and cognitive factors were conducted using PROCESS (Hayes, 2012).

RESULTS

Mediation analyses suggested that insomnia, hypersomnia, brooding, and seasonal maladaptive beliefs may account for the association between childhood maltreatment and SAD symptom severity.

LIMITATIONS

Analyses were cross-sectional and should be interpreted with caution. Participants completed self-report childhood trauma measure retrospectively as adults.

CONCLUSION

The present study is the first to examine childhood maltreatment in SAD, a disorder commonly viewed with circadian etiology. Covariance between childhood maltreatment and SAD symptom severity is indirectly explained by sleep difficulties, cognitive factors, and brooding, which may suggest therapeutic targets if replicated in longitudinal or experimental manipulations of sleep and cognition.

Association between the Arylalkylamine N-Acetyltransferase (AANAT) Gene and Seasonality in Patients with Bipolar Disorder

OBJECTIVE

Bipolar disorder (BD) is complex genetic disorder. Therefore, approaches using clinical phenotypes such as biological rhythm disruption could be an alternative. In this study, we explored the relationship between melatonin pathway genes with circadian and seasonal rhythms of BD.

METHODS

We recruited clinically stable patients with BD (n=324). We measured the seasonal variation of mood and behavior (seasonality), and circadian preference, on a lifetime basis. We analyzed 34 variants in four genes (MTNR1a, MTNR1b, AANAT, ASMT) involved in the melatonin pathway.

RESULTS

Four variants were nominally associated with seasonality and circadian preference. After multiple test corrections, the rs116879618 in AANAT remained significantly associated with seasonality (corrected p=0.0151). When analyzing additional variants of AANAT through imputation, the rs117849139, rs77121614 and rs28936679 (corrected p=0.0086, 0.0154, and 0.0092) also showed a significant association with seasonality.

CONCLUSION

This is the first study reporting the relationship between variants of AANAT and seasonality in patients with BD. Since AANAT controls the level of melatonin production in accordance with light and darkness, this study suggests that melatonin may be involved in the pathogenesis of BD, which frequently shows a seasonality of behaviors and symptom manifestations.

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.

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.

The effect of age and chronotype on seasonality, sleep problems, and mood

Seasonal affective disorder has been associated with sleep problems, young age, and an evening chronotype. A chronotype refers to an individual's preference in the timing of their sleep-wake cycle, as well as the time during the sleep-wake cycle when a person is most alert and energetic. Seasonality refers to season-dependent fluctuations in sleep length, social activity, mood, weight, appetite, and energy level. Evening chronotype is more common in young adults and morning chronotype more common in the elderly. This study aimed to estimate the differential contribution of chronotype and age on seasonality. A sample of n=410 participants were included in the study. The age groups showed significantly different results according to sleep parameters, depression, anxiety, stress, seasonality, and chronotype. The oldest group (>59 years) showed the lowest scores on all of these scales. According to a path analysis, chronotype and age predict propensity for seasonality. However, sleep problems were linked to chronotype but not to age. Older adults seem to be more resistant to seasonal changes that are perceived as a problem than young and middle aged adults. Future studies would benefit from considering cultural aspects and examine seasonality, chronotype, depression, and insomnia in longitudinal designs.

Perceived Psychological Feelings Make Important Contributions to the Symptoms of Common Mental Disorders of Medical Staff During the COVID-19

OBJECTIVE

Lack of information about mental health status among medical staff during the epidemic of COVID-19 in China is one of the major barriers to psychological interventions. This paper aims to evaluate the contributions of perceived psychological feelings to the symptoms of common mental disorders among medical staff during the epidemic of COVID-19 in China.

METHOD

A large sample of medical staff based on a non-probability sampling design was collected from February 17 to 24, 2020. The symptoms of common mental disorders were screened based on self-reported instruments to evaluate psychological distress, anxious symptoms, and depressive symptoms during the past week. Perceived psychological feelings were based on self-report. Logistic regressions and elastic net regularizations were used to evaluate the independent effect of the psychological feelings controlled by hospitals and participants characteristics.

RESULTS

Totally 4,677 medical staff completed the survey. The prevalence of psychological distress, anxious symptoms, and depressive symptoms were 15.9% (95% CI 14.8-16.9), 16.0% (95% CI 15.0-17.1), and 34.6% (95% CI 33.2-35.9). Feelings of having adequate personal protective equipment, receiving enough emotional supports from both family members and colleagues were significantly associated with fewer symptoms of common mental disorders, while the feelings of overloaded work and insufficient rest times contributed to more psychological problems.

CONCLUSIONS

Psychological feelings make important contributions to the symptoms of common mental disorders of medical staff during the epidemic of COVID-19. Strategies of psychological aids or interventions could be developed based on these feelings.

Seasonality and personality: a prospective investigation of Five Factor Model correlates of mood seasonality

The aim of the present study was to explore winter pattern seasonality of mood by investigating its Five Factor Model (FFM) correlates. The study was an advance on existing research in that seasonality was measured not as a retrospective self‐description of mood variation, but as a prospective pattern of current mood states in winter and summer (across two years). Based on contemporary theorizing about the structure and function of mood, Positive Affect (PA) was the mood construct selected for measurement. A seasonality score was calculated for each participant as the difference between summer mood levels and winter mood levels. The NEO‐FFI was administered at all four waves. Three hundred and three respondents from a random community sample in Melbourne, Australia, provided complete data. Regression analyses found that the adaptive trait Openness to Experience (O) was specifically associated with the tendency towards lowered mood in winter relative to summer. The vulnerability trait Neuroticism (N) was not a directional predictor of winter pattern seasonality, but was the sole predictor of absolute seasonality score. Findings are discussed in terms of two affective processes that may be involved in mood variation across the seasonal time frame: adaptive environmental sensitivity and endogenous mood variability. Copyright © 2002 John Wiley & Sons, Ltd.

Self-reported seasonality is strongly associated with chronotype and weakly associated with latitude

The aim of this study was to investigate the association between self-reported seasonality, i.e., seasonal variations in mood and related behavior, and chronotype, and between self-reported seasonality and home address' latitude. Data were collected from an online questionnaire with 45,338 participants. Seasonality and chronotype were measured with the Global Seasonality Score (GSS) and the Composite Scale of Morningness, respectively. The participants were categorized into extreme morning types, moderate morning types, intermediate types, moderate evening types, and extreme evening types. Furthermore, participants were categorized depending on home address' latitude. Data were analyzed with chi-square tests and logistic regression analyses adjusting for sex, age, marital status, level of education, and children living at home. Results showed that high seasonality (GSS 11+) was found in 20.9%. The prevalence dose-dependency ranged from 12.2% in extreme morning types to 42.6% in extreme evening types (adjusted OR = 4.21, CI = 3.27-5.41). The prevalence was higher in participants living in North-Norway (latitude from 65 to 71⁰N) versus South-Norway (latitude from 58 to 65⁰N) (23.8% versus 20.7%; adjusted OR = 1.18, CI = 1.08-1.28). When comparing the northernmost (69-71⁰N) to the southernmost (58-59⁰N) counties of Norway, the association was stronger (24.9% versus 18.7%; adjusted OR = 1.37, CI = 1.20-1.56). Among the adjusting variables, high seasonality was associated with female sex, younger age, being unmarried, low level of education, and not having children living at home. In conclusion, about one in five Norwegians reported high seasonality. High seasonality was strongly associated with late chronotype (being an evening type) and weakly associated with living in the north (high latitude).

Sleep in the land of the midnight sun and polar night: The Tromsø study

While some diseases and human behaviors fluctuate consistently with season, the extent of seasonal variations in sleep, especially at high latitudes, is less consistent. We used data from a geographic region (69º North) with extremely large seasonal differences in daylight that had the participants blinded for the current study's hypotheses. Data were derived from the Tromsø Study (2015-2016), an ongoing population-based study in Northern Norway comprising citizens aged 40 years and older (n = 21,083, participation = 64.7%). The sleep parameters included bedtime, rise time, sleep onset latency (SOL), and total sleep time. Insomnia was defined according to recent diagnostic criteria (International Classification of Sleep Disorders; ICSD-3). We found some evidence of monthly or seasonal variation in sleep problems. Insomnia was most common during the winter months among men, but not women. No seasonal or monthly effects were observed for sleep duration. SOL was slightly longer during the winter months, but the differences were small and hardly of any clinical relevance. The small or non-existing seasonal variation in sleep and sleep difficulties indicate that extreme seasonal variation in daylight is of little influence on sleep status. The city of Tromsø is a modern city with considerable level of artificial light, which may contribute to the observed rather stabile sleep patterns throughout the year.

Seasonality of mood and affect in a large general population sample

Mood and behaviour are thought to be under considerable influence of the seasons, but evidence is not unequivocal. The purpose of this study was to investigate whether mood and affect are related to the seasons, and what is the role of neuroticism in this association. In a national internet-based crowdsourcing project in the Dutch general population, individuals were invited to assess themselves on several domains of mental health. ANCOVA was used to test for differences between the seasons in mean scores on the Positive and Negative Affect Schedule (PANAS) and Quick Inventory of Depressive Symptomatology (QIDS). Within-subject seasonal differences were tested as well, in a subgroup that completed the PANAS twice. The role of neuroticism as a potential moderator of seasonality was examined. Participants (n = 5,282) scored significantly higher on positive affect (PANAS) and lower on depressive symptoms (QIDS) in spring compared to summer, autumn and winter. They also scored significantly lower on negative affect in spring compared to autumn. Effect sizes were small or very small. Neuroticism moderated the effect of the seasons, with only participants higher on neuroticism showing seasonality. There was no within-subject seasonal effect for participants who completed the questionnaires twice (n = 503), nor was neuroticism a significant moderator of this within-subjects effect. The findings of this study in a general population sample participating in an online crowdsourcing study do not support the widespread belief that seasons influence mood to a great extent. For, as far as the seasons did influence mood, this only applied to highly neurotic participants and not to low-neurotic participants. The underlying mechanism of cognitive attribution may explain the perceived relation between seasonality and neuroticism.

Seasonality of plasma tryptophan and kynurenine in pregnant mothers with a history of seasonal affective disorder: Vulnerability or adaptation?

Objectives: Maternal-foetal tryptophan metabolism plays multiple roles in neurodevelopment and immunomodulation across pregnancy. Tryptophan and the immune system are both influenced by the seasons of the year. We thus compared tryptophan and kynurenine levels in subgroups of pregnant women defined by maternal seasonality and season-of-conception (SoC).Methods: Maternal plasma samples taken at 9-15 and 23-29 weeks of pregnancy were analysed in 47 women with historical full or sub-syndromal Seasonal Affective Disorder (SAD) and 144 pregnant controls. Repeated measure ANCOVAs compared tryptophan and kynurenine levels in the two study groups over the two pregnancy sampling times, using SoC as a moderator.Results: Significant differences in both plasma tryptophan and kynurenine were found across the eight subgroups defined by maternal seasonality and SoC. These results were independent of the state of depression.Conclusions: Pregnant women with a history of full or sub-syndromal SAD exhibited a different pattern of plasma tryptophan and kynurenine across the seasons compared to control mothers, independent of current mood state. Follow-up of the children will determine the implications of these findings for neurodevelopment and psychiatric risk. Maternal seasonality and SoC may be important considerations when studying tryptophan and its metabolites in human pregnancy and foetal brain development.

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.

Cross-sectional and within-subject seasonality and regularity of hospitalizations: A population study in mood disorders and schizophrenia

BACKGROUND

Seasonal peaks in hospitalizations for mood disorders and schizophrenia are well recognized and often replicated. The within-subject tendency to experience illness episodes in the same season, that is, seasonal course, is much less established, as certain individuals may temporarily meet criteria for seasonal course purely by chance.

AIMS

In this population, prospective cohort study, we investigated whether between and within-subject seasonal patterns of hospitalizations occurred more frequently than would be expected by chance.

METHODS

Using a compulsory, standardized national register of hospitalizations, we analyzed all admissions for mood disorders and schizophrenia in the Czech Republic between 1994 and 2013. We used bootstrap tests to compare the observed numbers of (a) participants with seasonal/regular course and (b) hospitalizations in individual months against empirical distributions obtained by simulations.

RESULTS

Among 87 184 participants, we found uneven distribution of hospitalizations, with hospitalization peaks for depression in April and November (X² (11) = 363.66, P < .001), for mania in August (X² (11) = 50.36, P < .001) and for schizophrenia in June (X² (11) = 70.34, P < .001). Significantly more participants than would be expected by chance, had two subsequent rehospitalizations in the same 90 days in different years (7.36%, bootstrap P < .01) or after a regular, but non-seasonal interval (6.07%, bootstrap P < .001). The proportion of participants with two consecutive hospitalizations in the same season was below chance level (7.06%).

CONCLUSIONS

Psychiatric hospitalizations were unevenly distributed throughout the year (cross-sectional seasonality), with evidence for regularity, but not seasonality of hospitalizations within subjects. Our data do not support the validity of seasonal pattern specifier. Season may be a general risk factor, which increases the risk of hospitalizations across psychiatric participants.

Differential illness intrusiveness associated with sleep-promoting medications

Differences in daytime sleepiness, lifestyle disruptions, and emotional distress were compared across nine groups taking sleep-promoting substances. Groups included individuals taking zopiclone (n = 274), amitriptyline (n = 107), lorazepam (n = 258), oxazepam (n= 141), diphenhydramine HCl (n = 99), triazolam(n = 137), long acting benzodiazepines (n = 120), temazepam (n = 176), and miscellaneous other medications (n = 286). Data were gathered by self-report, using standardized instruments in a mail-back questionnaire procedure. Respondents included the first 1,598 participants enrolled in a Canadian multicentre project, including six sites attached to academic psychiatric units. Results indicated that quality of life effects differed across groups in both daytime sleepiness and lifestyle disruptions (illness intrusiveness), but not in depressive symptoms. Daytime sleepiness was significantly higher among people taking diphenhydramine HCl as compared to temazepam, zopiclone, lorazepam, and oxazepam. Illness intrusiveness was significantly higher among patients taking amitriptyline as compared to those taking triazolam, oxazepam, long-acting benzodiazepines, and zopiclone. It may be useful to inform patients of differences in psychosocial outcomes when prescribing hypnotic medications.

Mood and behavior seasonality in glaucoma; assessing correlations between seasonality and structure and function of the retinal ganglion cells

Aim

In glaucoma, depression and disturbed sleep has been associated with degeneration of the intrinsically photosensitive retinal ganglion cells, that mediate non-image forming effects of light such as regulation of circadian rhythm, alertness and mood. In this study we assessed associations between seasonal mood and behavior variation and retinal ganglion cell damage in outpatients with glaucoma.

Methods

The seasonal pattern assessment questionnaire was administered to outpatients with glaucoma. Data on visual field defects identified by autoperimetry and retinal nerve fiber layer thickness visualized by ocular coherence tomography were collected from patient charts. The correlations between seasonality and retinal damage were tested and the adjusted effects of retinal function on seasonality were evaluated in a linear regression model.

Results

In total, 113 persons completed the questionnaire. Of these, 4% fulfilled the criteria for seasonal affective disorder (SAD) and 8% for subsyndromal seasonal affective disorder (sSAD). Mean global seasonal score was 4.3. There were no significant correlations between seasonality and either visual field or retinal nerve fiber layer thickness. In the adjusted analysis there were trends toward differential effects of visual field on seasonality in subgroups with different sex and type of glaucoma.

Conclusion

There were no strong associations between seasonality and visual field or retinal nerve fiber layer thickness. Sex, age and glaucoma subtype may modify light effects on complex regulatory systems.

Seasonal affective disorder and seasonal changes in weight and sleep duration are inversely associated with plasma adiponectin levels

Overlapping pathways between mood and metabolic regulation have increasingly been reported. Although impaired regulation of adiponectin, a major metabolism-regulating hormone, has been implicated in major depressive disorder, its role in seasonal changes in mood and seasonal affective disorder-winter type (SAD), a disorder characterized by onset of mood impairment and metabolic dysregulation (e.g., carbohydrate craving and weight gain) in fall/winter and spontaneous alleviation in spring/summer, has not been previously studied. We studied a convenience sample of 636 Old Order Amish (mean (± SD), 53.6 (±14.8) years; 50.1% males), a population with self-imposed restriction on network electric light at home, and low prevalence of total SAD (t-SAD = syndromal + subsyndromal). We calculated the global seasonality score (GSS), estimated SAD and subsyndromal-SAD after obtaining Seasonal Pattern Assessment Questionnaires (SPAQs), and measured overnight fasting plasma adiponectin levels. We then tested associations between plasma adiponectin levels and GSS, t-SAD, winter-summer difference in self-reported sleep duration, and self-reported seasonal weight change, by using analysis of co-variance (ANCOVA) and linear regression analysis after adjusting for age, gender, and BMI. Participants with t-SAD (N = 14; 2.2%) had significantly lower plasma adiponectin levels (mean ± SEM, 8.76 ± 1.56 μg/mL) than those without t-SAD (mean ± SEM, 11.93 ± 0.22 μg/mL) (p = 0.035). In addition, there was significant negative association between adiponectin levels and winter-summer difference in self-reported sleep duration (p = 0.025) and between adiponectin levels and self-reported seasonal change in weight (p = 0.006). There was no significant association between GSS and adiponectin levels (p = 0.88). To our knowledge, this is the first study testing the association of SAD with adiponectin levels. Replication and extension of our findings longitudinally and, then, interventionally, may implicate low adiponectin as a novel target for therapeutic intervention in SAD.

Suppression of voluntary ethanol intake in mice under constant light and constant darkness

Seasonal variations in photoperiod are associated with alterations in human mood and behavior. Similarly, manipulation of the environmental lighting regimen can exert pronounced effects on affective behavior in experimental animals. These observations may be due, in part, to light-induced alterations in circadian rhythms, but it seems likely that other, non-circadian factors also contribute. Several studies have shown that voluntary alcohol (ethanol) consumption can be affected by lighting conditions in rodents, suggesting that photoperiodic variation may account for seasonal and geographic patterns of human alcohol consumption. Nevertheless, the existing animal data are somewhat inconsistent, and little work in this area has been performed in mice. In the present study, we monitored circadian activity rhythms and voluntary ethanol consumption under standard 12:12 light-dark (LD) cycles, and in constant light (LL) and constant darkness (DD). Experiment 1 employed male C3H/He inbred mice, while Experiment 2 employed males and females from a genetically heterogeneous line (WSC). Relative to LD conditions, ethanol intake and ethanol preference were reduced under both LL and DD in both experiments. Because similar effects were seen in both LL and DD, neither circadian disruption nor a classical photoperiodic mechanism are likely to account fully for these findings. Instead, we suggest that the absence of circadian entrainment may function as a mild stressor, resulting in reduced ethanol consumption.

The Relationship of Sleep Duration with Ethnicity and Chronic Disease in a Canadian General Population Cohort

STUDY OBJECTIVES

Sleep duration is an important marker of sleep quality and overall sleep health. Both too little and too much sleep are associated with poorer health outcomes. We hypothesized that ethnicity-specific differences in sleep duration exist.

METHODS

This cross-sectional study utilized questionnaire data from the Ontario Health Study (OHS), a multi-ethnic population-based cohort of Canadian adult residents aged 18 to 99 years, who provided medical, socio-demographic, and sleep information. Generalised linear models were used to investigate the association of sleep duration with ethnicity.

RESULTS

The study sample consisted of 143,307 adults (60.4% women). The sample was multi-ethnic, including self-identified Aboriginal, Arab, Black, Chinese, Filipino, Hispanic, Japanese, Korean, Mixed (>1 ethnicity), South Asian, South-East Asian, West Asian, and White ethnicities. Univariate analyses found that mean sleep duration compared to the White reference group (7.34 hours) was shorter in the Filipino (6.93 hours, 25 min less), Black (6.96 hours, 23 min less), Japanese (7.02 hours, 19 min less), Chinese (7.23 hours, 7 min less), and Mixed (7.27 hours, 4 min less) groups (all P<0.001). Mean sleep duration was shorter in men (7.25 hours) compared to women (7.37 hours) in the cohort as a whole (P<0.001), and in all ethnic groups (P<0.001). Multivariate analyses, adjusted for a wide range of potential risk factors, and analysis of sleep duration as a categorical variable ("short", "average", and "long" sleepers) confirmed these relationships. Both sleep duration and ethnicity were independent significant predictors of a range of physician-diagnosed morbidities including diabetes, stroke, and depression.

CONCLUSION

Important differences exist in sleep duration between ethnic groups and may contribute to observed health disparities. Our results highlight the need for ethnicity-specific targeted education on the importance of prioritizing sleep for good health, and the need to account appropriately for ethnicity in future epidemiological, clinical, and translational research into sleep and related conditions.