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.

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.

The Efficacy of Light Therapy in the Treatment of Seasonal Affective Disorder: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Bright light therapy (BLT) has been used as a treatment for seasonal affective disorder (SAD) for over 30 years. This meta-analysis was aimed to assess the efficacy of BLT in the treatment of SAD in adults.

METHOD

We performed a systematic literature search including randomized, single- or double-blind clinical trials investigating BLT (≥1,000 lx, light box or light visor) against dim light (≤400 lx) or sham/low-density negative ion generators as placebo. Only first-period data were used from crossover trials. The primary outcome was the post-treatment depression score measured by validated scales, and the secondary outcome was the rate of response to treatment.

RESULTS

A total of 19 studies finally met our predefined inclusion criteria. BLT was superior over placebo with a standardized mean difference of -0.37 (95% CI: -0.63 to -0.12) for depression ratings (18 studies, 610 patients) and a risk ratio of 1.42 (95% CI: 1.08-1.85) for response to active treatment (16 studies, 559 patients). We found no evidence for a publication bias, but moderate heterogeneity of the studies and a moderate-to-high risk of bias.

CONCLUSIONS

BLT can be regarded as an effective treatment for SAD, but the available evidence stems from methodologically heterogeneous studies with small-to-medium sample sizes, necessitating larger high-quality clinical trials.

Treating winter depressive episodes in bipolar disorder: an open trial of light therapy

BACKGROUND

Light therapy has been used to treat winter depression in bipolar disorder, although the dose, duration, and timing of treatment have differed. The present study is an open trial of light therapy for depressive episodes in autumn/winter using a Dutch protocol specific for patients with a bipolar disorder.

METHODS

Data were collected for the seasons September-April 2017-2018 and September-April 2018-2019. In total, 58 patients received light therapy for a minimum of 7 days and a maximum of 21 days; there was a follow-up measurement after two weeks. Outcomes were quick inventory of depressive symptomatology (QIDS) scores and side effects.

RESULTS

QIDS scores were significantly lower at the last day of therapy (B = - 6.00, p < 0.001) and 2 weeks after the end of treatment (B = - 6.55, p < 0.001) compared with pre-intervention. Remission (QIDS ≤ 5) was reached in 55% of the treatments and response (50% symptom reduction) in 57% of the treatments. Side effects were mild; two hypomanic periods occurred.

CONCLUSIONS

The Dutch light therapy protocol for patients with a bipolar disorder may be effective in treating a seasonal depression and side effects are mild. Light therapy deserves a prominent place in the treatment because effects may be large and quick.

Has the sun set for seasonal affective disorder and HPA axis studies? A systematic review and future prospects

OBJECTIVE

Seasonal Affective Disorder (SAD) is a form of cyclic mood disorder that tends to manifest as winter depression. SAD has anecdotally been described as a hypocortisolemic condition. However, there are no systematic reviews on SAD and Hypothalamic-Pituitary-Adrenal (HPA) axis function. This review intends to summarize these findings.

METHODS

Using the PRISMA (2009) guideline recommendations we searched for relevant articles indexed in databases including MEDLINE, EMBASE, PsycINFO, and PsychArticles. The following keywords were used: "Seasonal affective disorder", OR "Winter Depression", OR "Seasonal depression" associated with: "HPA Axis" OR "cortisol" OR "CRH" OR "ACTH".

RESULTS

Thirteen papers were included for qualitative analysis. Studies used both heterogeneous methods and populations. The best evidence comes from a recent study showing that SAD patients tend to demonstrate an attenuated Cortisol Awakening Response (CAR) in winter, but not in summer, compared to controls. Dexamethasone Suppression Test (DST) studies suggest SAD patients have normal suppression of the HPA axis.

CONCLUSION

There is still insufficient evidence to classify SAD as a hypocortisolemic condition when compared to controls. Heterogeneous methods and samples did not allow replication of results. We discuss the limitations of these studies and provide new methods and targets to probe HPA axis function in this population. SAD can provide a unique window of opportunity to study HPA axis in affective disorders, since it is highly predictable and can be followed before, during and after episodes subsides.

Seasonal variation in symptoms of depression: A Canadian population based study

BACKGROUND

There is no consensus as to whether depressive symptoms vary by season. Using data from the Canadian Community Health Survey (CCHS), the purpose of this study was to evaluate seasonal variation in depressive symptoms in the Canadian household population.

METHODS

A cross-sectional analysis of data from the CCHS in 2015 and 2016 was used. Mean Patient Health Questionnaire-9 (PHQ-9) scores, and categories defined by 5+ or 10+ cut-points were used for analysis. Seasonal effects were assessed using quadratic terms in regression models, generalized linear models were used for this purpose. Models were stratified by youth ages 12-24 (rounded n ≈ 8000) and adults ages 25+ (rounded n ≈ 45,000).

RESULTS

Significant seasonal variation was observed for youth (age 12-24) for mean PHQ-9 scores and proportion with scores of 5+. There was evidence of effect modification by age. The youth group had stronger seasonal effects compared to respondents age 25+. Seasonal effect was highly significant for mean PHQ-9 scores (p = 0.009) and 5+ (p = 0.001), but not for 10+ (p = 0.481).

LIMITATIONS

Use of cross-sectional data limits the capacity to generalize results to the classic definition of Seasonal Affective Disorder. Data surrounding respondent's anti-depressant use was unavailable.

CONCLUSIONS

Seasonal variation in depressive symptoms is evident in the Canadian population. Higher levels of symptoms were reported in winter months compared to summer months. The seasonal trend is most pronounced in youth specifically those who reported at least mild depressive symptoms, but not in respondents reporting moderate to severe symptoms.

Implementing prevention of seasonal affective disorder from patients' and physicians' perspectives - a qualitative study

BACKGROUND

Seasonal affective disorder (SAD) is a seasonally recurrent type of major depression that has detrimental effects on patients' lives during winter. Little is known about how it affects patients during summer and about patients' and physicians' perspectives on preventive SAD treatment. The aim of our study was to explore how SAD patients experience summers, what type of preventive treatment patients implement, which preventive treatment methods, if any, physicians recommend, and what factors facilitate or hinder implementation/recommendation of SAD prevention.

METHODS

We conducted 15 semi-structured interviews, ten with adult patients with a history of SAD and five with physicians. Transcripts were analyzed by two researchers using an inductive thematic analysis approach.

RESULTS

One group of patients was able to enjoy summer and ignore thoughts of the upcoming winter. The other group feared the impending depressive episode in winter, and this fear negatively impacted these patients' well-being during the summer. Preventive treatment was a relevant issue for all patients, and all but one person implemented SAD prevention during summer. We identified six factors that influenced patient use of preventive treatment of SAD. Four factors occur on an individual level (knowledge about disease and preventive treatment options, experience with treatment in acute phase, acceptability of intervention, willingness to take responsibility for oneself), one on an interpersonal level (social and work environment), and one on a structural level (healthcare system). All psychiatrists recommended some kind of preventive intervention, most commonly, lifestyle changes. Four factors influenced psychiatrists in recommending prevention of SAD (patient expectations, disease history and stability, risk/benefit ratio, lack of evidence).

CONCLUSIONS

Success in the implementation of SAD prevention does not solely depend on the willingness of the patients, but is also influenced by external factors. Raising awareness of SAD among general practitioners and low-level access to mental-health support could help patients find appropriate help sooner. To better guide the optimal treatment choice, comparative effectiveness research on treatments to prevent a new onset in patients with a history of SAD and clinical practice guidelines on SAD are needed.

Pharmacotherapy and nutritional supplements for seasonal affective disorders: a systematic review

INTRODUCTION

A seasonal affective disorder (SAD) is a subtype of unipolar and bipolar major depressive disorders. It is characterized by its annual recurrence of depressive episodes at a particular season, mostly seen in winter and is responsible for 10-20% of the prevalence of major depressive disorders. Some pathophysiological hypotheses, such as the phase delay and the monoamine depletion hypotheses, have been postulated but the exact cause has not been fully unraveled yet. Studies on treatment for SAD in the last decade are lacking. To tackle this chronic disease, attention needs to be drawn to the gaps in this research field.

AREAS COVERED

In this systematic review, the authors give a broad overview of the pharmacological therapy available for SAD. Also, nutritional substances fitting well with the postulated hypotheses are reviewed for the treatment and prevention of SAD. There is a specific focus on the quality of the currently performed studies.

EXPERT OPINION

Light therapy and fluoxetine are the only proven and effective acute treatment options for SAD, while bupropion is the only registered drug for prevention of SAD. This area of research is in dire need of valid large-scale and sufficiently reproducible randomized control trials.

Prevention of seasonal affective disorder in daily clinical practice: results of a survey in German-speaking countries

BACKGROUND

Seasonal affective disorder (SAD) is a seasonally recurrent type of major depression. This predictable aspect makes it promising for preventive treatment. However, evidence for the efficacy and harm of preventive treatment of SAD is scarce, as are recommendations from clinical practice guidelines. The aim of this study was to assess the current use of preventive treatment of SAD in clinical practice in German-speaking countries for the first time.

METHODS

We conducted a postal and web-based survey sent to the heads of all psychiatric institutions listed in the inventory "Deutsches Krankenhaus Adressbuch, 2015" that contains all psychiatric hospitals in Germany, Austria, and Switzerland.

RESULTS

One hundred institutions (out of 533 institutions, 19%), which treated in total more than 3100 SAD patients in the years 2014/2015, responded. Of those, 81 reported recommending preventive treatment to patients with a history of SAD. There was no consensus on the optimal starting point for preventive treatment. Most of the institutions that implemented prevention of SAD, recommended lifestyle changes (85%), antidepressants (84%), psychotherapy (73%), and light therapy (72%) to their patients. The situation was similar in northern and southern regions.

CONCLUSIONS

Most hospitals recommended the use of preventive treatment to SAD patients, although evidence on efficacy and harm is limited. A wide variety of interventions were recommended, although guidelines only include recommendations for acute treatment. To assist psychiatrists and patients in future decision making, controlled studies on preventive treatment for SAD that compare different interventions with one another are needed.

Changes in winter depression phenotype correlate with white blood cell gene expression profiles: a combined metagene and gene ontology approach

In the present study we evaluate the feasibility of gene expression in white blood cells as a peripheral marker for winter depression. Sixteen patients with winter type seasonal affective disorder were included in the study. Blood was taken by venous puncture at three time points; in winter prior and following bright light therapy and in summer. RNA was isolated, converted into cRNA, amplified and hybridized on Illumina® gene expression arrays. The raw optical array data were quantile normalized and thereafter analyzed using a metagene approach, based on previously published Affymetrix gene array data. The raw data were also subjected to a secondary analysis focusing on circadian genes and genes involved in serotonergic neurotransmission. Differences between the conditions were analyzed, using analysis of variance on the principal components of the metagene score matrix. After correction for multiple testing no statistically significant differences were found. Another approach uses the correlation between metagene factor weights and the actual expression values, averaged over conditions. When comparing the correlations of winter vs. summer and bright light therapy vs. summer significant changes for several metagenes were found. Subsequent gene ontology analyses (DAVID and GeneTrail) of 5 major metagenes suggest an interaction between brain and white blood cells. The hypothesis driven analysis with a smaller group of genes failed to demonstrate any significant effects. The results from the combined metagene and gene ontology analyses support the idea of communication between brain and white blood cells. Future studies will need a much larger sample size to obtain information at the level of single genes.

Intensity and pleasantness of sucrose taste in patients with winter depression

OBJECTIVES

Increased consumption of carbohydrates and craving for sweets are considered core features of winter depression. Unfortunately, little is known about neural and behavioral correlates of these symptoms. The primary aim of the present study was to evaluate taste responses to sucrose solutions in depressed patients with seasonal affective disorder (SAD).

METHODS

Intensity and pleasantness ratings of sucrose solutions, electrogustometric thresholds, and taste identification abilities were assessed in depressed patients with SAD and non-seasonal affective disorder (non-SAD), and in non-depressed controls.

RESULTS

Electrogustometric thresholds and identification abilities did not differ between the study groups. There were no differences between the groups in intensity or pleasantness ratings of sucrose solutions (1-30%). The proportion of 'sweet likers', i.e. subjects rating the highest sucrose concentration as most pleasant, was similar in the controls, SAD, and non-SAD patients.

DISCUSSION

The present results suggest that: (i) winter depression is not associated with major alterations in gustatory function; and (ii) sweet craving and increased consumption of carbohydrates in patients with winter depression is not secondary to altered responses to sweet tastants. More studies are needed to characterize hedonic responses of patients with SAD to other sweet and non-sweet foods.

Photoperiodic responses of depression-like behavior, the brain serotonergic system, and peripheral metabolism in laboratory mice

Seasonal affective disorder (SAD) is characterized by depression during specific seasons, generally winter. The pathophysiological mechanisms underlying SAD remain elusive due to a limited number of animal models with high availability and validity. Here we show that laboratory C57BL/6J mice display photoperiodic changes in depression-like behavior and brain serotonin content. C57BL/6J mice maintained under short-day conditions, as compared to those under long-day conditions, demonstrated prolonged immobility times in the forced swimming test with lower brain levels of serotonin and its precursor l-tryptophan. Furthermore, photoperiod altered multiple parameters reflective of peripheral metabolism, including the ratio of plasma l-tryptophan to the sum of other large neutral amino acids that compete for transport across the blood-brain barrier, responses of circulating glucose and insulin to glucose load, sucrose intake under restricted feeding condition, and sensitivity of the brain serotonergic system to peripherally administered glucose. These data suggest that the mechanisms underlying SAD involve the brain-peripheral tissue network, and C57BL/6J mice can serve as a powerful tool for investigating the link between seasons and mood.