Lifestyle modification as intervention for seasonal affective disorder: A systematic review

Bright light therapy (BLT) and pharmacological therapies currently represent the first line treatments for patients with seasonal affective disorder (SAD). Lifestyle modifications offer a diverse field of additional intervention options. Since it is unclear, if lifestyle modifications are effective in SAD patients, this systematic review aims to synthesize the current evidence on their effectiveness and safety. We systematically searched for randomized controlled trials (RCTs) assessing lifestyle modifications (nutrition, exercise, staying outdoors, sleep, social aspects, mindfulness methods) in SAD patients. We defined the primary outcome as the post-therapeutic extent of depressive symptoms, measured by validated psychiatric symptom scales. Due to the insufficient number of studies and the high heterogeneity of the interventions we were not able to calculate a meta-analysis. We identified 6 studies from the following areas of lifestyle modification: diet, exercise, staying outdoors, sleep and music therapy. All studies showed improvements of depression scores in the intervention as well as in the control groups. The risk of bias was rated as high for all studies and the certainty of evidence was rated as very low. The results point towards the possible effectiveness of the interventions examined, but due to the small number of studies found, too small sample sizes and methodological limitations, we cannot draw a valid conclusion about the effectiveness of lifestyle-modifying measures in SAD patients. Larger, high-quality RCTs are needed to make evidence-based recommendations and thus to expand the range of therapeutic options for SAD.

Treatment measures for seasonal affective disorder: A network meta-analysis

OBJECTIVE

The purpose of this study was to assess the potential effectiveness of several mainstream therapies, including phototherapy, antidepressants, cognitive-behavioral therapy, and negative ion generators, in the treatment of Seasonal Affective Disorder (SAD).

METHODS

A systematic search of PubMed, Embase, Cochrane, and WOS databases was conducted from January 1975 to December 3, 2022. Randomized controlled trials meeting predefined selection criteria for the treatment of SAD using mainstream therapeutic approaches were identified. After reviewing abstracts, data were synthesized and categorized based on the type of intervention and the targeted disorder.

RESULTS

A total of 21 randomized controlled trials, involving 1037 participants, were included. The standardized mean difference of depression scores and corresponding 95 % confidence intervals were calculated to assess the efficacy of phototherapy for Seasonal Affective Disorder. The meta-analysis revealed that phototherapy was significantly more effective than other intervention groups or control therapies, with an effect size of 4.64(2.38,7.03). Subgroup analysis demonstrated that no factors could explain the significant heterogeneity observed. Phototherapy exhibited statistically significant mild to moderate therapeutic effects in alleviating depressive symptoms and can be considered as a clinical therapy for treating Seasonal Affective Disorder. However, the quality of evidence remains low, and further well-designed, larger sample size, and high-quality studies are needed to confirm the efficacy of phototherapy in treating Seasonal Affective Disorder.

CONCLUSION

In conclusion, our systematic review and meta-analysis indicate that bright light therapy is a promising first-line non-pharmacological treatment for Seasonal Affective Disorder (SAD), showing significant improvement in mood symptoms compared to placebo. The findings support the use of bright light therapy as an effective and well-tolerated intervention for SAD. However, further large-scale, multicenter randomized controlled trials with long-term follow-up are needed to assess the long-term efficacy and safety of different treatment approaches for SAD.

Prospectively assessed summer mood status in major depression, recurrent with seasonal pattern: Evidence for SAD's construct validity

OBJECTIVE

Seasonal patterns are often undetectable in population-based depression studies, calling into question the existence of winter seasonal affective disorder (SAD). If SAD has construct validity, individuals with SAD should show spontaneous depression remission in the summer. Data are sparse on prospectively assessed summer mood status in confirmed SAD patients.

METHOD

We conducted prospective summer followup of community adults who, the winter before, were diagnosed with Major Depression, Recurrent with Seasonal Pattern on the Structured Clinical Interview for DSM-IV Axis I Disorders, developed a current SAD episode on the Structured Interview Guide for the Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD), and enrolled in a clinical trial comparing group cognitive-behavioral therapy for SAD and light therapy. In July/August after treatment, 143/153 (93.5 %) participants provided data on the SIGH-SAD, the Beck Depression Inventory-Second Edition, and the Longitudinal Interval Followup Evaluation (LIFE).

RESULTS

Summer mean depression scores were in the normal range, with the substantial majority in remission across different measures. On the LIFE, 113/143 (79.0 %) experienced complete summer remission, 19/143 (13.3 %) experienced partial summer remission, and 11/143 (7.7 %) had major depression in the summer. Depression scores were significantly lower at summer than post-treatment in both treatments, indicating incomplete treatment response.

LIMITATIONS

This was a single-site study with a relatively homogeneous sample.

CONCLUSIONS

Supporting construct validity for SAD, the substantial majority experienced complete summer remission, with a minority in partial remission and a very small minority in episode. Both treatments left residual symptoms at treatment endpoint compared to summer.

Seasonal pattern and depression outcomes from repetitive transcranial magnetic stimulation

Individuals with major depressive disorder (MDD) may exhibit a seasonal pattern. The impact of a seasonal pattern in depressive symptoms on rTMS outcomes is unexplored. A retrospective analysis was performed on patients with MDD receiving open-label high frequency rTMS to the left dorsolateral prefrontal cortex. Having a seasonal pattern was defined as scoring ≥ 12 on the Personal Inventory for Depression and Seasonal Affective Disorder (PIDS). Primary outcomes included improvement in the Hamilton Depression Rating Scale (HAMD) and remission. Secondary analyses included the use of the self-rated Quick Inventory of Depressive Symptomatology (QIDS) to assess for changes in atypical neurovegetative symptoms. Multiple linear regression, multiple logistic regression, and linear mixed effects analyses were performed. 46 % (58/127) of the sample had a seasonal pattern. Seasonal pattern did not significantly influence improvement in HAMD (PIDS < 12, 7.8, SD 5.9; PIDS ≥ 12, 10.4, SD 4.9 or remission (PIDS < 12, 30 %; PIDS ≥ 12, 34 %). There were equivalent degrees of improvement in atypical neurovegetative symptoms over time as assessed using the QIDS. Depression with seasonal pattern was found to respond to rTMS treatment similarly to depression without seasonal pattern, suggesting that this may be a viable treatment for this group.

Predictors of cognitive behavioral therapy for insomnia (CBT-I) effects in insomnia with major depressive episode

Insomnia plays a critical role in the onset and maintenance of Major Depressive Episode (MDE). Cognitive behavioral therapy for insomnia (CBT-I) can successfully improve the sleep of patients with insomnia and MDE. Nonetheless, the factors influencing CBT-I's effects in MDE remain uncertain. This study aimed to identify predictors of insomnia improvement following CBT-I, as well as predictors of insomnia response, remission in patients with MDE and specific insomnia subtypes. Initially, we compared a 4-session weekly CBT-I treatment to baseline sleep education (SE) in a control group. This confirmed CBT-I's positive effects and the need to explore predictive factors. Notably, treatment-resistant depression (TRD) predicted reduced insomnia severity with CBT-I. Patients exhibiting seasonal fluctuations in depressive symptoms and sleep patterns throughout the year, or having daytime dysfunction, experienced enhanced CBT-I efficacy, especially for early awakenings insomnia. Conversely, shorter sleep duration predicted a less favorable response to CBT-I, less improvement in daytime dysfunction and sleep disturbance worries. Additionally, MDE with suicide attempts predicted a poorer improvement of daytime dysfunction. Further research is essential to comprehensively grasp the mechanisms behind CBT-I's heightened effectiveness in MDE patients with TRD and seasonal fluctuations.

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.

Light Therapy for Adolescent Depression: A Scoping Review

PURPOSE

Depressive disorders in adolescents are a major health concern associated with developmental, social, and educational impairment. Bright Light Therapy (BLT) is a feasible and effective treatment for depressive disorders in adults, but few controlled trials have been conducted with children or adolescents. This scoping review focuses on the current state of knowledge for BLT in the treatment of adolescent depression. We reviewed the literature for novel data and methodologic approaches using BLT and pediatric and young adult populations.

RECENT FINDINGS

BLT is a tolerable treatment with few side effects. However, there is a marked lack of well-powered studies to support BLT as a treatment for depressive disorders in adolescent populations. Given evidence of tolerability and positive treatment effect on depression in the adult literature, research is needed to establish the efficacy, feasibility, and acceptability of BLT in adolescents.

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.

Elucidating treatment targets and mediators within a confirmatory efficacy trial: study protocol for a randomized controlled trial of cognitive-behavioral therapy vs. light therapy for winter depression

Background

This study is a confirmatory efficacy trial of two treatments for winter seasonal affective disorder (SAD): SAD-tailored group cognitive-behavioral therapy (CBT-SAD) and light therapy (LT). In our previous efficacy trial, post-treatment outcomes for CBT-SAD and LT were very similar, but CBT-SAD was associated with fewer depression recurrences two winters later than LT (27.3% in CBT-SAD vs. 45.6% in LT). CBT-SAD engaged and altered a specific mechanism of action, seasonal beliefs, which mediated CBT-SAD’s acute antidepressant effects and CBT-SAD’s enduring benefit over LT. Seasonal beliefs are theoretically distinct from LT’s assumed target and mechanism: correction of circadian phase. This study applies the experimental therapeutics approach to determine how each treatment works when it is effective and to identify the best candidates for each. Biomarkers of LT’s target and effect include circadian phase angle difference and the post-illumination pupil response. Biomarkers of CBT-SAD’s target and effect include decreased pupillary and sustained frontal gamma-band EEG responses to seasonal words, which are hypothesized as biomarkers of seasonal beliefs, reflecting less engagement with seasonal stimuli following CBT-SAD. In addition to determining change mechanisms, this study tests the efficacy of a “switch” decision rule upon recurrence to inform clinical decision-making in practice.

Methods

Adults with SAD (target N = 160) will be randomzied to 6-weeks of CBT-SAD or LT in winter 1; followed in winter 2; and, if a depression recurrence occurs, offered cross-over into the alternate treatment (i.e., switch from LT➔CBT-SAD or CBT-SAD➔LT). All subjects will be followed in winter 3. Biomarker assessments occur at pre-, mid-, and post-treatment in winter 1, at winter 2 follow-up (and again at mid-/post-treatment for those crossed-over), and at winter 3 follow-up. Primary efficacy analyses will test superiority of CBT-SAD over LT on depression recurrence status (the primary outcome). Mediation analyses will use parallel process latent growth curve modeling.

Discussion

Consistent with the National Institute of Mental Health’s priorities for demonstrating target engagement at the level of Research Domain Criteria-relevant biomarkers, this work aims to confirm the targets and mechanisms of LT and CBT-SAD to maximize the impact of future dissemination efforts.

Trial registration

ClinicalTrials.gov identifier: NCT03691792. Registered on October 2, 2018. 

Body mass index and atypical balance as predictors of winter depression remission in cognitive-behavioral therapy and light therapy

BACKGROUND

Efficacious treatments for winter seasonal affective disorder (SAD) include light therapy (LT) and cognitive-behavioral therapy (CBT-SAD); however, baseline characteristics may differentially predict treatment outcomes. This study investigated body mass index (BMI) and atypical balance (the proportion of atypical depression symptoms), as predictors of depression remission.

METHODS

The parent study randomized 177 adults diagnosed with Major Depression, Recurrent with Seasonal Pattern to 6-weeks of CBT-SAD (n = 88) or LT (n = 89) and followed participants one and two winters later. At baseline, BMI was measured and atypical balance was derived using the Structured Interview Guide for the Hamilton Rating Scale for Depression-Seasonal Affective Disorder Version (SIGH-SAD) as 8-item atypical subscale score/total SIGH-SAD score × 100. Depression remission was defined using standard SIGH-SAD cutpoints. Hierarchical logistic regressions tested the main effects of treatment modality, BMI, and atypical balance and their interactive effects on depression remission at post-treatment and follow-ups.

RESULTS

The BMI × treatment and atypical balance × treatment interactions significantly predicted depression remission at second winter follow-up. The probability of remission was higher in CBT-SAD than LT at BMI ≤ 26.1 and atypical balance ≤ 40.3%. This predictive relationship survived when adjusting atypical balance for BMI, but not vice-versa.

LIMITATIONS

Participants were predominantly White and older. BMI does not account for muscle mass or fat distribution.

CONCLUSIONS

BMI and atypical balance prescriptively predicted higher likelihood of depression remission two winters following CBT-SAD but not LT. This work informs clinical decision-making and precision medicine efforts.

Polysomnography in seasonal affective disorder: A systematic review and meta-analysis

BACKGROUND

. Although sleep disturbances are ubiquitous in depression, studies assessing sleep architecture lead to conflicting results, possibly because of the heterogeneity in this disorder. We aimed to focus on Seasonal Affective Disorder (SAD), which is directly associated with circadian and sleep homeostasis impairments.

METHODS

. A systematic search was conducted in July 2019. Original papers reporting data about night sleep architecture using polysomnography (PSG), in SAD or remitted-SAD and controls, were included.

RESULTS

. Seven studies were retained and included 183 individuals, including 109 patients with SAD and 74 healthy controls. The random-effects meta-analysis showed that rapid eye movement sleep (REM) was significantly increased in SAD compared to controls (REM amount: SMD=1[0.11,1.88], p = 0.027; REM percentage: SMD=0.71[0.02,1.40], p = 0.045). Remitted SAD patients, compared to controls, also had a significantly increased REM sleep (REM amount: SMD=1.84[0.78,2.90], p<0.001; REM percentage: SMD=1.27[0.51,2.03], p = 0.001) and a significantly decreased REM latency (SMD=-0.93[-1.73,-0.13], p = 0.022). No differences were observed for total sleep time, sleep efficiency, and slow-wave-sleep.

LIMITATIONS

. Most studies had small sample size, with no placebo group and with open designs.

CONCLUSIONS

. REM sleep amount and latency appear altered both during the acute and remitted phase of SAD, representing trait markers with interesting diagnosis and therapeutic implications.

Bimodal effects of sunlight on major depressive disorder

BACKGROUND

Seasonal patterns in the effect of sunlight on depression, where depression decreases when sunlight increases, have been observed in previous studies. In this study, we demonstrate a bimodal effect of sunlight on depression - short-term increases in sunlight increase depression and long-term increases in sunlight decrease depression. The analysis showed that the significant effect of sunlight is temporary and appears only when seasonal changes are severe within a given year.

METHODS

We analyzed approximately 530,000 cases where patients visited hospital for depression in Korea from January 1 to December 31, 2016. We measured the daily average amount of sunlight and daily sunlight for the 30 days previous to the day of measurement using data from 96 weather stations. To analyze the effect of sunlight, several climatic variables and local dummies were added to the negative binomial model, and the period in which the effect of sunlight was significant was derived as a term of the interaction between the month variable and sunlight.

RESULTS

When the average effects of climatic factors such as temperature, precipitation, and humidity were removed, the number of cases of depression increased when the daily average amount of sunlight increased [IRR = 1.024 (95% CI: 1.009 to 1.039)]; this effect was significant only in January and May. The number of cases of depression decreased with higher daily average sunlight for the previous 30 days increasing [IRR = 0.917 (95% CI: 0.892 to 0.944)], and this effect was significant only in January, March, and May.

CONCLUSIONS

The effect of sunlight on depression appears in both the short and long terms, but the effect is significant only for limited periods. The data examined in this study supports a pattern where short-term daily sunlight increases depression and daily sunlight for the previous 30 days decreases depression.

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.

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.

Ethics analysis of light and vitamin D therapies for seasonal affective disorder

OBJECTIVE

The aim of this ethics analysis was to highlight the overt and covert value issues with regard to two health technologies (light therapy and vitamin D therapy), the health technology assessment (HTA) and the disease of seasonal affective disorder (SAD). The present ethics analysis served as a chapter of a full HTA report that aimed to assist decision makers concerning the two technologies.

METHOD

First, we used the revised Socratic approach of Hofmann et al. to build overarching topics of ethical issues, and then, we conducted a hand search and a comprehensive systematic literature search on between 12 and 14 February 2019 in seven databases.

RESULTS

The concrete ethical issues found concerned vulnerability of the target population and the imperative to treat depressive symptoms for the sake of preventing future harm. Further disease-related ethical issues concerned the questionable nature of SAD as a disease, autonomy, authenticity, and capacity for decision making of SAD patients, and the potential stigma related to the underdiagnosis of SAD, which is contrasted with the concern over unnecessary medicalization. Regarding the interventions and comparators, the ethical issues found concerned their benefit-harm ratios and the question of social inequality. The ethical issues related to the assessment process relate to the choice of comparators and the input data for the selected health economic studies.

CONCLUSIONS

The concrete ethical issues related to the interventions, the disease, and the assessment process itself were made overt in this ethics analysis. The ethics analysis provided an (additional) value context for making future decisions regarding light and vitamin D therapies.

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).

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.

Converging evidence that short-active photoperiod increases acetylcholine signaling in the hippocampus

Seasonal variations in environmental light influence switches between moods in seasonal affective disorder (SAD) and bipolar disorder (BD), with depression arising during short active (SA) winter periods. Light-induced changes in behavior are also seen in healthy animals and are intensified in mice with reduced dopamine transporter expression. Specifically, decreasing the nocturnal active period (SA) of mice increases punishment perseveration and forced swim test (FST) immobility. Elevating acetylcholine with the acetylcholinesterase inhibitor physostigmine induces depression symptoms in people and increases FST immobility in mice. We used SA photoperiods and physostigmine to elevate acetylcholine prior to testing in a probabilistic learning task and the FST, including reversing subsequent deficits with nicotinic and scopolamine antagonists and targeted hippocampal adeno-associated viral administration. We confirmed that physostigmine also increases punishment sensitivity in a probabilistic learning paradigm. In addition, muscarinic and nicotinic receptor blockade attenuated both physostigmine-induced and SA-induced phenotypes. Finally, viral-mediated hippocampal expression of human AChE used to lower ACh levels blocked SA-induced elevation of FST immobility. These results indicate that increased hippocampal acetylcholine neurotransmission is necessary for the expression of SA exposure-induced behaviors. Furthermore, these studies support the potential for cholinergic treatments in depression. Taken together, these results provide evidence for hippocampal cholinergic mechanisms in contributing to seasonally depressed affective states induced by short day lengths.

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.

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.

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.

Seasonal variation in antidepressant prescriptions, environmental light and web queries for seasonal affective disorder

The state of an individual's mental health depends on many factors. Determination of the importance of any particular factor within a population needs access to unbiased data. We used publicly available data-sets to investigate, at a population level, how surrogates of mental health covary with light exposure. We found strong seasonal patterns of antidepressant prescriptions, which show stronger correlations with day length than levels of solar energy. Levels of depression in a population can therefore be determined by proxy indicators such as web query logs. Furthermore, these proxies for depression correlate with day length rather than solar energy.Declaration of interestNone.

Light as a modulator of emotion and cognition: Lessons learned from studying a diurnal rodent

Light profoundly affects the behavior and physiology of almost all animals, including humans. One such effect in humans is that the level of illumination during the day positively contributes to affective well-being and cognitive function. However, the neural mechanisms underlying the effects of daytime light intensity on affect and cognition are poorly understood. One barrier for progress in this area is that almost all laboratory animal models studied are nocturnal. There are substantial differences in how light affects nocturnal and diurnal species, e.g., light induces sleep in nocturnal mammals but wakefulness in diurnal ones, like humans. Therefore, the mechanisms through which light modulates affect and cognition must differ between the chronotypes. To further understand the neural pathways mediating how ambient light modulates affect and cognition, our recent work has developed a diurnal rodent model, the Nile grass rat (Arvicanthis niloticus), in which daytime light intensity is chronically manipulated in grass rats housed under the same 12:12 hour light/dark cycle. This simulates lighting conditions during summer-like bright sunny days vs. winter-like dim cloudy days. Our work has revealed that chronic dim daylight intensity results in higher depression- and anxiety-like behaviors, as well as impaired spatial learning and memory. Furthermore, we have found that hypothalamic orexin is a mediator of these effects. A better understanding of how changes in daytime light intensity impinge upon the neural substrates involved in affect and cognition will lead to novel preventive and therapeutic strategies for seasonal affective disorder, as well as for non-seasonal emotional or cognitive impairments associated with light deficiency.

Seasonality of antidepressant prescriptions and sick leaves

The aim of the present study was to estimate the number of patients with a seasonal prescription pattern of antidepressants, which might be taken as a surrogate marker for medicated patients with seasonal affective disorder (SAD). Furthermore, we examined the time course of sick leaves for patients with seasonal and non-seasonal prescriptions of antidepressants. A retrospective analysis of prescription data of all patients insured by the Sickness Fund Burgenland (BGKK) between 2005 and 2016 was performed. Patients with treatment initiation of an antidepressant in the last and first quarter of the year for at least two consecutive years were selected (SAD-med). Patients with continuation treatment in the third quarter and patients with initiation of antidepressant medication in the second and third quarter of the year were excluded. The mean yearly prescription rate for antidepressants was 9.6% in the insured population. 3.0% of patients treated with antidepressants and 0.9% of insured cases satisfied the definition of SAD-med. The mean number of yearly sick leave days was similar for SAD-med patients and those with non-seasonal prescriptions. Time series analysis showed that sick leaves in SAD-med were influenced by seasonal fluctuations for several years after the first antidepressant prescription. Our study sheds light on antidepressant prescription and sick leave patterns in the general population. Compared to the prevalence of SAD, the estimated rate of SAD-med is substantial. Sick leaves appear to be closely linked to antidepressant prescriptions, and show a characteristic time course before and after the initial prescription.

Sensory processing sensitivity and its association with seasonal affective disorder

It has been hypothesized that an increased sensitivity to the surroundings, can leave some individuals vulnerable to experience the environmental stress of winter more overwhelming, thus leading to a greater risk of Seasonal Affective Disorder (SAD). However, the association between trait Sensory Processing Sensitivity (SPS) and SAD is not known. We therefore aimed to investigate: 1)cross-seasonal group differences in trait SPS, in 31 individuals with SAD compared to 30 age-, gender- and education-matched healthy controls, and 2)the association between trait SPS in remitted phase (summer) and depression severity in symptomatic phase (winter) in individuals with SAD. All participants completed the Highly Sensitive Person Scale, as a measure of SPS, and the Major Depression Inventory in summer and in winter, using a longitudinal and seasonally counterbalanced design. In both remitted and symptomatic phase, individuals with SAD exhibited higher trait SPS compared to healthy controls, which for individuals with SAD was heightened during depression in winter. Notably, when averaged across season, about 25% of the individuals with SAD display high-sensitivity whereas this is only the case for 5% of the healthy controls. In addition, higher trait SPS in summer was associated with more severe SAD symptoms in winter. Our findings suggest that those with SAD are more likely to score high on SPS and that high SPS may be a vulnerability marker related to more severe SAD symptomatology.

Depressive mood and circadian rhythms disturbances as outcomes of seasonal affective disorder treatment: A systematic review

BACKGROUND

The present systematic review was aimed at critically summarizing the evidence about interventions focused on circadian rhythms and mood symptoms in seasonal affective disorder (SAD).

METHODS

A systematic search of the electronic databases PUBMED, PsycINFO and Web of Science was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Original papers reporting data about the effects of treatments on both mood and circadian rhythms disturbances in SAD patients were considered for inclusion. The quality of the evidence provided by the eligible studies was assessed using the Revised Cochrane Risk of Bias Tool (RoB 2.0) and the Cochrane Risk of Bias in Non-Randomized Studies of Interventions Tool (ROBINS-I).

RESULTS

Forty papers were deemed eligible for the systematic review. The evidence of treatment outcomes referring to circadian disturbances was not robust. Despite this, bright light therapy (BLT) demonstrates to phase-advance delayed rhythms and to improve sleep-wake disorders. As for mood symptoms, both BLT and selective serotonin reuptake inhibitors (SSRIs) show evidence of efficacy. The possible connection between improvements of mood symptoms and changes in circadian outcomes seems controversial.

LIMITATIONS

The included studies presented considerable methodological heterogeneity, small sample sizes and non-optimal sample selection.

CONCLUSIONS

The effectiveness of BLT in depressive symptoms and circadian disturbances of SAD was outlined by the present systematic review. The evidence about other biological and pharmacological treatments, although promising, should be replicated. A multifactorial etiopathogenesis could explain the heterogeneous clinical presentations of SAD and the complex link between mood and circadian 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.

Seasonality of depressive symptoms during pregnancy

Various risk factors have been identified for antepartum depression. This study evaluated seasonal influences on antepartum depressive symptoms. Data of 2,438 pregnant women on current depressive symptoms was obtained from a large-scale cross-sectional study in The Netherlands. Most women were screened during the first trimester. Depressive symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS) and dichotomized using ≥ 9 as cut-off score. The seasonal relationship between antepartum depressive symptoms and the month of assessment was estimated by fitting a sinusoidal curve to the data. A total of 323 women (13.2%) scored above cut-off. In the full sample, we found no significant evidence for seasonal influences on depressive symptoms after adjusting for confounders. Additionally, we found that the seasonal influence was obscured by the modification of the effect by current treatment status. In women untreated for psychiatric complaints, we found a minimum of depressive symptomatology in September and a maximum in March. In women treated for psychiatric complaints we found a minimum of depressive symptomatology in December and a maximum in June. Thus, the effects of seasonality are apparent, but opposite in treated and untreated women. However, health professionals should be aware of depressive symptoms the whole year through.

Seasonality-resilient individuals downregulate their cerebral 5-HT transporter binding in winter - A longitudinal combined 11C-DASB and 11C-SB207145 PET study

We have recently shown that the emergence and severity of seasonal affective disorder (SAD) symptoms in the winter is associated with an increase in cerebral serotonin (5-HT) transporter (SERT) binding. Intriguingly, we also found that individuals resilient to SAD downregulate their cerebral SERT binding in the winter. In the present paper, we provide an analysis of the SERT- and 5-HT dynamics as indexed by 5-HT₄ receptor (5-HT4R) binding related to successful stress coping. We included 46 ¹¹C-DASB positron emission tomography (PET) scans (N = 23, 13 women, age: 26 ± 6 years) and 14 ¹¹C-SB207145 PET scans (7 participants, 3 women, age: 25 ± 3 years) from 23 SAD-resilient Danes. Data was collected longitudinally in summer and winter. We found that compared to the summer, raphe nuclei and global brain SERT binding decreased significantly in the winter (p_raphe = 0.003 and p_global = 0.003) and the two measures were positively correlated across seasons (summer: R² = 0.33, p = .004, winter: R² = 0.24, p = .018). A voxel-based analysis revealed prominent changes in SERT in clusters covering both angular gyri (0.0005 < p_corrected < 0.0016), prefrontal cortices (0.00087 < p_corrected < 0.0039) and the posterior temporal and adjacent occipital cortices (0.0001 < p_corrected < 0.0066). We did not observe changes in 5-HT4R binding, suggesting that 5-HT levels remained stable across seasons. We conclude that resilience to SAD is associated with a global downregulation of SERT levels in winter which serves to keep 5-HT levels across seasons.

A cross-sectional study of retrospectively reported seasonality in native and non-native residents of Chukotka and Turkmenistan

Seasonality represents a response of human mood, physiology, and behavior to annual variations in natural and social environment. A strong seasonal response is expected in non-native than native residents of such regions as Turkmenistan that is characterized by high air temperature in summer and Chukotka that is characterized by high-amplitude annual variation in both air temperature and day length. Seasonality was retrospectively reported by 732 residents of these regions. Self-reports on sleep-wake traits and mental and physical health were analyzed as possible confounding variables. The expectation of stronger seasonality in non-native residents was confirmed only for Chukotka samples. However, the native-non-native seasonality differences in this region paralleled the differences in several health scores, while native-non-native health difference in Turkmenistan was found to be non-significant. Given the possible role of such confounding factor as poor health in producing higher self-reported seasonality scores, caution must be taken when the conclusion is drawn from the results suggesting a reduced degree and severity of seasonality in native residents of Chukotka as compared to other native and non-native residents of the two regions.

The effects of low-intensity narrow-band blue-light treatment compared to bright white-light treatment in seasonal affective disorder

BACKGROUND

Ever since a new photoreceptor was discovered with a highest sensitivity to 470-490 nm blue light, it has been speculated that blue light has some advantages in the treatment of Seasonal Affective Disorder (SAD) over more traditional treatments. In this study we compared the effects of exposure to narrow-band blue light (BLUE) to those of broad-wavelength white light (BLT) in the treatment of SAD.

METHODS

In a 15-day design, 45 patients suffering from SAD completed 30-min sessions of light treatment on 5 consecutive days. 21 subjects received white-light treatment (BLT, broad-wavelength without UV, 10 000 lx, irradiance 31.7 W/m²), 24 subjects received narrow-band blue light (BLUE, 100 lx, irradiance 1.0 W/m²). All participants completed weekly questionnaires concerning mood and energy levels, and were also assessed by means of the SIGH-SAD, which is the primary outcome measure.

RESULTS

On day 15, SIGH-SAD ratings were significantly lower than on day 1 (BLT 73.2%, effect size 3.37; BLUE 67%, effect size 2.63), which outcomes were not statistically significant different between both conditions.

LIMITATIONS

Small sample size.

CONCLUSIONS

Light treatment is an effective treatment for SAD. The use of narrow-band blue light is equally effective as a treatment using bright white-light.

Chronotype and Psychiatric Disorders

PURPOSE OF REVIEW

Chronotype, reflecting interindividual differences in daily activity patterns and sleep-wake cycles, is intrinsically connected with well-being. Research indicates increased risk of many adverse mental health outcomes for evening-type individuals. Here, we provide an overview of the current evidence available on the relationship between chronotype and psychiatric disorders.

RECENT FINDINGS

The association between eveningness and depression is well established cross-sectionally, with preliminary support from longitudinal studies. The mechanisms underlying this relationship warrant further research; deficient cognitive-emotional processes have recently been implicated. Eveningness is associated with unhealthy lifestyle habits, and the propensity of evening types to addiction has been recognized. Chronotype may also be implicated in disordered eating.

SUMMARY

Eveningness is associated with depression-including seasonal affective disorder (SAD)-and substance dependence, while support for a relation with anxiety disorders and psychosis is lacking. In bipolar disorder, chronotype is linked to depression but not mania. Eveningness is also related to sleep disturbances and poor lifestyle habits, which may increase risk for psychiatric disorders.

Associations of depression and seasonality with morning-evening preference: Comparison of contributions of its morning and evening components

Despite predominance of positive findings on associations of morning-evening preference with seasonality and depression, it remains to be clarified whether morning and evening components of this preference equally contribute to these associations and whether these associations persist after accounting for confounding variables. Data on retrospectively reported seasonal changes in well-being, mood, and behaviors were collected from 2398 residents of West Siberia, South and North Yakutia, Chukotka, Alaska, and Turkmenistan. Other self-reports included mental and physical health, sleep duration, and adaptabilities of the sleep-wake cycle. Depression was found to be linked to morning rather than evening component of morning-evening preference, i.e., morning lateness. Morning lateness was also linked to retrospectively reported degree of seasonal changes rather than to severity of problems associated with such changes. Variation in morning-evening preference explained not more than 2% and 4% of the total variation in depression and seasonality, respectively. The associations became even weaker but remained significant after accounting for other differences between respondents, such as their gender, age, physical health, and adaptability of their sleep-wake cycle. These results have practical relevance for understanding of the roles playing by morning earliness and insensitivity to seasonal changes in the environment to protection against different mood disorders.

Amygdala response to emotional faces in seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is characterized by seasonally recurring depression. Heightened amygdala activation to aversive stimuli is associated with major depressive disorder but its relation to SAD is unclear. We evaluated seasonal variation in amygdala activation in SAD and healthy controls (HC) using a longitudinal design targeting the asymptomatic/symptomatic phases of SAD. We hypothesized increased amygdala activation to aversive stimuli in the winter in SAD individuals (season-by-group interaction).

METHODS

Seventeen SAD individuals and 15 HCs completed an implicit emotional faces BOLD-fMRI paradigm during summer and winter. We computed amygdala activation (SPM5) to an aversive contrast (angry & fearful minus neutral) and angry, fearful and neutral faces, separately. Season-by-group and main effects were evaluated using Generalized Least Squares. In SAD individuals, we correlated change in symptom severity, assessed with The Hamilton Rating Scale for Depression - Seasonal Affective Disorder version (SIGH-SAD), with change in amygdala activation.

RESULTS

We found no season-by-group, season or group effect on our aversive contrast. Independent of season, SAD individuals showed significantly lower amygdala activation to all faces compared to healthy controls, with no evidence for a season-by-group interaction. Seasonal change in amygdala activation was unrelated to change in SIGH-SAD.

LIMITATIONS

Small sample size, lack of positive valence stimuli.

CONCLUSIONS

Amygdala activation to aversive faces is not increased in symptomatic SAD individuals. Instead, we observed decreased amygdala activation across faces, independent of season. Our findings suggest that amygdala activation to angry, fearful and neutral faces is altered in SAD individuals, independent of the presence of depressive symptoms.

Association of G-Protein β3 Subunit C825T Polymorphism with Seasonal Variations in Mood and Behavior

OBJECTIVE

Seasonal affective disorder and seasonal changes in mood and behavior are associated with several genes that regulate circadian rhythms. In this study, we investigated the relationship between the C825T polymorphism of the G-protein β3 subunit and seasonal variations in mood and behavior in a young healthy Korean population.

METHODS

A total of 507 young Korean participants were recruited through a newspaper advertisement, and their seasonality was evaluated by the Korean version of the Seasonal Pattern Assessment Questionnaire to assess the global seasonality score (GSS). We analyzed the CC, CT, and TT genotypes and their association with the GSS score and subscales.

RESULTS

T allele carriers of the GNB3 C825T polymorphism were more likely to score higher on body weight and GSS. In the female group, the T allele carriers obtained significantly high total GSS and its subscale scores for mood, body weight, energy level, and appetite; however, differences in genotypes and allele carriers were also observed in the male participants.

CONCLUSION

These results suggested that GNB3 C825T polymorphism plays a role in seasonal variations in mood, body weight, energy level, and appetite in a Korean population, particularly in females.

Prediction of outcome of bright light treatment in patients with seasonal affective disorder: Discarding the early response, confirming a higher atypical balance, and uncovering a higher body mass index at baseline as predictors of endpoint outcome

BACKGROUND

We tested the hypothesis that the early improvement in mood after the first hour of bright light treatment compared to control dim-red light would predict the outcome at six weeks of bright light treatment for depressed mood in patients with Seasonal Affective Disorder (SAD). We also analyzed the value of Body Mass Index (BMI) and atypical symptoms of depression at baseline in predicting treatment outcome.

METHODS

Seventy-eight adult participants were enrolled. The first treatment was controlled crossover, with randomized order, and included one hour of active bright light treatment and one hour of control dim-red light, with one-hour washout. Depression was measured on the Structured Interview Guide for the Hamilton Rating Scale for Depression-SAD version (SIGH-SAD). The predictive association of depression scores changes after the first session. BMI and atypical score balance with treatment outcomes at endpoint were assessed using multivariable linear and logistic regressions.

RESULTS

No significant prediction by changes in depression scores after the first session was found. However, higher atypical balance scores and BMI positively predicted treatment outcome.

LIMITATIONS

Absence of a control intervention for the six-weeks of treatment (only the first session in the laboratory was controlled). Exclusion of patients with comorbid substance abuse, suicidality and bipolar I disorder, and patients on antidepressant medications, reducing the generalizability of the study.

CONCLUSION

Prediction of outcome by early response to light treatment was not replicated, and the previously reported prediction of baseline atypical balance was confirmed. BMI, a parameter routinely calculated in primary care, was identified as a novel predictor, and calls for replication and then exploration of possible mediating mechanisms.

Meteorological analysis of symptom data for people with seasonal affective disorder

It is thought that variation in natural light levels affect people with Seasonal Affective Disorder (SAD). Several meteorological factors related to luminance can be forecast but little is known about which factors are most indicative of worsening SAD symptoms. The aim of this meteorological analysis is to determine which factors are linked to SAD symptoms. The symptoms of 291 individuals with SAD in and near Groningen have been evaluated over the period 2003-2009. Meteorological factors linked to periods of low natural light (sunshine, global radiation, horizontal visibility, cloud cover and mist) and others (temperature, humidity and pressure) were obtained from weather observation stations. A Bayesian zero adjusted auto-correlated multilevel Poisson model was carried out to assess which variables influence the SAD symptom score BDI-II. The outcome of the study suggests that the variable sunshine duration, for both the current and previous week, and global radiation for the previous week, are significantly linked to SAD symptoms.

Premenstrual mood and empathy after a single light therapy session

To examine whether acute changes in cognitive empathy might mediate the impact of light therapy on mood, we assessed the effects of a single light-therapy session on mood and cognitive empathy in 48 premenstrual women, including 17 who met Premenstrual Symptoms Screening Tool criteria for moderate-to-severe premenstrual syndrome / premenstrual dysphoric disorder (PMS/PMDD). Using a participant-blind between-groups design, 23 women underwent 30min of morning light therapy (5,000lx; blue-enriched polychromatic light, 17,000K) while 25 women had a sham session (200lx, polychromatic light, 5,000K). We administered the Positive Affect and Negative Affect Schedule and the Affect Grid right before and after the intervention, and 60min later upon completion of a computerized empathic accuracy task. There were no significant effects of light condition on cognitive empathy as assessed using the computer task. Nonetheless, bright light reduced negative affect, specifically in women not using hormonal contraceptives. No effects of bright light on mood were observed in women who were using contraceptives. If a single light-therapy session does not alter cognitive empathy, then cognitive empathy may not mediate the impact of light therapy on mood in premenstrual women.

Dopamine and light: effects on facial emotion recognition

Bright light can affect mood states and social behaviours. Here, we tested potential interacting effects of light and dopamine on facial emotion recognition. Participants were 32 women with subsyndromal seasonal affective disorder tested in either a bright (3000 lux) or dim light (10 lux) environment. Each participant completed two test days, one following the ingestion of a phenylalanine/tyrosine-deficient mixture and one with a nutritionally balanced control mixture, both administered double blind in a randomised order. Approximately four hours post-ingestion participants completed a self-report measure of mood followed by a facial emotion recognition task. All testing took place between November and March when seasonal symptoms would be present. Following acute phenylalanine/tyrosine depletion (APTD), compared to the nutritionally balanced control mixture, participants in the dim light condition were more accurate at recognising sad faces, less likely to misclassify them, and faster at responding to them, effects that were independent of changes in mood. Effects of APTD on responses to sad faces in the bright light group were less consistent. There were no APTD effects on responses to other emotions, with one exception: a significant light × mixture interaction was seen for the reaction time to fear, but the pattern of effect was not predicted a priori or seen on other measures. Together, the results suggest that the processing of sad emotional stimuli might be greater when dopamine transmission is low. Bright light exposure, used for the treatment of both seasonal and non-seasonal mood disorders, might produce some of its benefits by preventing this effect.

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.

Is There a Relationship between Vegetarianism and Seasonal Affective Disorder? A Pilot Study

BACKGROUND AND AIM

Seasonal patterns of food intake are found in healthy individuals and particularly in patients with seasonal affective disorder (SAD). One nutritional choice is a vegetarian diet.

METHODS

In a Finnish population study, FINRISK 2012, information about diet and SAD was collected. In a Dutch outpatient clinic, SAD patients were asked if they were vegetarian.

RESULTS

The percentage of SAD patients among Finnish vegetarians was 4 times higher than in the normal population. The percentage of vegetarians among the SAD patients in a Dutch outpatient clinic was 3 times higher than in the normal population. In the Dutch population, the seasonal loss of energy, in particular, is related to vegetarianism.

CONCLUSION

These findings suggest a possible link between vegetarianism and SAD.

Investigation of an Immediate Effect of Bright Light on Oxygen Consumption, Heart Rate, Cortisol, and α-Amylase in Seasonal Affective Disorder Subjects and Healthy Controls

BACKGROUND

Body (fat) mass has been shown to decrease following bright light treatment for overweight women, irrespective of their seasonal (light) dependence. It is not known if this is due to an (immediate) increase of metabolism.

METHODS

Ten women with seasonal affective disorder (SAD) and 10 non-SAD women matched by age, body mass index, and menopausal status participated in a laboratory study in the morning, twice within 1-5 days. During one session, bright light (4,300 lx) was presented for 30 min, and during the other session, red light (250 lx "placebo") was used. After an initial 15 min of sitting quietly in an experimental chamber, 10-min measurements were done before, at the end, and 15 min after light exposure; the subjects remained seated for 80 min in total. The measurements included 5-min oxyspirography (oxygen consumption, carbon dioxide emission, and heart rate), saliva sampling for the estimation of cortisol and α-amylase concentrations, and self-rating of mood, energy, and sleepiness.

RESULTS

There was no light-specific effect on the measured variables, except that sleepiness was reduced more with bright light than with red light in the combined group. α-Amylase values were lower in the SAD patients than in the non-SAD controls.

CONCLUSIONS

Morning artificial bright light, in comparison with dim red light, had no immediate effect on metabolism and resting sympathetic tone, though subjective sleepiness decreased more with bright light. SAD patients have low salivary α-amylase levels, indicating lower sympathetic tone.

Use of Light Therapy by Office-Based Physicians

BACKGROUND

Light therapy (LT) is a non-pharmacological biological treatment that has been used in psychiatry since the 1980s. Previous research has investigated the usage of LT in hospitals. The aim of this study was to examine the pattern of use of LT by office-based physicians.

METHODS

A questionnaire was sent by mail to 400 randomly selected doctors in Austria. We made sure that the sample was equally representative of general practitioners (GPs) and psychiatrists, public health service doctors and private doctors, physicians in cities and in the country as well as male and female doctors. Non-responders were asked by phone and e-mail to answer the questionnaire. We achieved a response rate of 27.7%.

RESULTS

LT was generally recommended by 67.3% of all physicians (91.6% of the psychiatrists but only 46.6% of the GPs). The recommended location of treatment was patients' homes in 90%. Physicians were asked whether they considered LT to be an appropriate treatment for various disorders. There were affirmative answers from: 94.2% for seasonal affective disorder (SAD), 93.3% for sub-syndromal SAD, 60.6% for non-seasonal recurrent major depressive disorder, 35.6% for jet lag syndrome, 35.6% for chronobiological problems with shift work, 22.1% for insomnia, 13.5% for premenstrual dysphoric disorder, and 10.6% for behavioural problems with Alzheimer's disease.

CONCLUSIONS

Our results indicate that LT is regularly recommended by office-based physicians, especially psychiatrists. However, there is potential for greater application of LT in indications other than depressive disorder. The results found here are comparable to previous findings in psychiatric hospitals.

Plasma Phosphatidylethanolamine and Triacylglycerol Fatty Acid Concentrations are Altered in Major Depressive Disorder Patients with Seasonal Pattern

Disturbances in peripheral and brain lipid metabolism, including the omega-3 fatty acid docosahexaenoic acid (DHA), have been reported in major depressive disorder (MDD). However, these changes have yet to be confirmed in MDD with seasonal pattern (MDD-s), a subtype of recurrent MDD. The present exploratory study quantified plasma plasmalogen and diacyl-phospholipid species, and fatty acids within total phospholipids, cholesteryl esters, triacylglycerols and free fatty acids in non-medicated MDD-s participants (n = 9) during euthymia in summer or fall, and during depression in winter in order to screen for potential high sensitivity lipid biomarkers. Triacylglycerol alpha-linolenic acid concentration was significantly decreased, and myristoleic acid concentration was significantly increased, during winter depression compared to summer-fall euthymia. 1-stearyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine, a diacyl-phospholipid containing stearic acid and DHA, was significantly decreased in winter depression. Concentrations of cholesteryl ester oleic acid and several polyunsaturated fatty acids between summer/fall and winter increased in proportion to the increase in depressive symptoms. The observed changes in lipid metabolic pathways in winter-type MDD-s offer new promise for lipid biomarker development.

Seasonality in mood and behaviours of Japanese residents in high-latitude regions: transnational cross-sectional study

BACKGROUND

Daylight hours in high-latitude regions tend to be longer than those in Japan in summer, and shorter than those in Japan in winter. For example, daylight hours in London in winter are one-third those of Tokyo. Therefore, this study investigated and compared seasonal changes in mood and behaviours of Japanese individuals living in and outside Japan.

METHODS

Surveys were conducted with Japanese residents in summer and winter in the UK (n = 106), Nordic countries (n = 40), Southeast Asia (n = 50), and Japan (n = 96). First, summer and winter General Health Questionnaire-28 (GHQ28) scores of each regional group were analysed. Subsequently, month-wise differences in mood and behaviours were compared across the four geographical regions.

RESULTS

Summer and winter GHQ28 scores of participants living in the UK and Nordic countries differed significantly, while no seasonal differences were observed for residents in Japan and Southeast Asia. Further, in the UK and Nordic countries, summer was associated with better mood and more activity, while winter was linked to lowered mood and reduced activity.

CONCLUSION

The results indicate that Japanese living in the UK and Nordic countries (high-latitude regions) experience seasonal fluctuations in depressive symptoms that may be linked to drastic seasonal environmental changes. Observed over a 12-month period, their mood and behaviour declined in winter and improved in summer. Therefore, considering the prevalence of overseas stressors that differ from those in their home country, it is necessary to investigate the effectiveness of support systems that help migrants adapt to seasonal changes in high-latitude regions.

ADHD, circadian rhythms and seasonality

OBJECTIVE

We evaluated whether the association between Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Seasonal Affective Disorder (SAD) was mediated by the circadian rhythm.

METHOD

Data of 2239 persons from the Netherlands Study of Depression and Anxiety (NESDA) were used. Two groups were compared: with clinically significant ADHD symptoms (N = 175) and with No ADHD symptoms (N = 2064). Sleep parameters were sleep-onset and offset times, mid sleep and sleep duration from the Munich Chronotype Questionnaire. We identified the prevalence of probable SAD and subsyndromal SAD using the Seasonal Pattern Assessment Questionnaire (SPAQ). Clinically significant ADHD symptoms were identified by using a T score>65 on the Conners Adult ADHD Rating Scale.

RESULTS

The prevalence of probable SAD was estimated at 9.9% in the ADHD group (vs. 3.3% in the No ADHD group) and of probable s-SAD at 12.5% in the ADHD group (vs 4.6% in the No ADHD group). Regression analyses showed consistently significant associations between ADHD symptoms and probable SAD, even after adjustment for current depression and anxiety, age, sex, education, use of antidepressants and benzodiazepines (B = 1.81, p < 0.001). Late self-reported sleep onset was an important mediator in the significant relationship between ADHD symptoms and probable SAD, even after correction for confounders (total model effects: B = 0.14, p ≤ 0.001).

CONCLUSION

Both seasonal and circadian rhythm disturbances are significantly associated with ADHD symptoms. Delayed sleep onset time in ADHD may explain the increase in SAD symptoms. Treating patients with SAD for possible ADHD and delayed sleep onset time may reduce symptom severity in these complex patients.

The relation between chronotype and treatment outcome with light therapy on a fixed time schedule

BACKGROUND

Seasonal affective disorder (SAD) is characterized by recurrent episodes of major depression in a seasonal pattern. The therapy of choice is light therapy (LT). It is suggested that LT should be administered relative to the chronotype of the patient, with the optimal timing earlier for morning than for evening types. This study aims to retrospectively investigate the relation between chronotype and the effect of LT on a fixed time in the morning in a population of SAD patients.

METHODS

Data from four different studies conducted at the University Center of Psychiatry in Groningen, the Netherlands was used. Data from 132 patients was used (103 women). Depression score was determined by a structured interview (SIGH-SAD) prior to LT and after LT. Prior to LT morningness/eveningness preference of the patient was determined by the 'Morningness/Eveningness Questionnaire' (MEQ). All patients received LT at 8:00 AM at the clinic, independent of chronotype.

RESULTS

Patients had an average MEQ score of 51.5±8.2. There was no significant relationship between MEQ score and therapy success as measured with the SIGH-SAD (F2,129=0.05, ns). When patients were divided by chronotype (ranging from definite morning to moderate evening) no significant relation between MEQ score and therapy success was found (F2,129=0.02, ns).

LIMITATIONS

Retrospective design.

CONCLUSIONS

The lack of a significant relationship between chronotype, as measured with the MEQ, and therapy success with LT at a fixed timepoint may indicate that the anti-depressive effect of morning light in SAD patients is not explained by a phase shift of the biological clock.

Bright-light intervention induces a dose-dependent increase in striatal response to risk in healthy volunteers

Bright-light interventions have successfully been used to reduce depression symptoms in patients with seasonal affective disorder, a depressive disorder most frequently occurring during seasons with reduced daylight availability. Yet, little is known about how light exposure impacts human brain function, for instance on risk taking, a process affected in depressive disorders. Here we examined the modulatory effects of bright-light exposure on brain activity during a risk-taking task. Thirty-two healthy male volunteers living in the greater Copenhagen area received 3weeks of bright-light intervention during the winter season. Adopting a double-blinded dose-response design, bright-light was applied for 30minutes continuously every morning. The individual dose varied between 100 and 11.000lx. Whole-brain functional MRI was performed before and after bright-light intervention to probe how the intervention modifies risk-taking related neural activity during a two-choice gambling task. We also assessed whether inter-individual differences in the serotonin transporter-linked polymorphic region (5-HTTLPR) genotype influenced the effects of bright-light intervention on risk processing. Bright-light intervention led to a dose-dependent increase in risk-taking in the L_A/L_A group relative to the non-L_A/L_A group. Further, bright-light intervention enhanced risk-related activity in ventral striatum and head of caudate nucleus in proportion with the individual bright-light dose. The augmentation effect of light exposure on striatal risk processing was not influenced by the 5-HTTLPR-genotype. This study provides novel evidence that in healthy non-depressive individuals bright-light intervention increases striatal processing to risk in a dose-dependent fashion. The findings provide converging evidence that risk processing is sensitive to bright-light exposure during winter.

Epidemiology and socioeconomic impact of seasonal affective disorder in Austria

BACKGROUND

Seasonal affective disorder (SAD) is a subtype of recurrent depressive or bipolar disorder that is characterized by regular onset and remission of affective episodes at the same time of the year. The aim of the present study was to provide epidemiological data and data on the socioeconomic impact of SAD in the general population of Austria.

METHODS

We conducted a computer-assisted telephone interview in 910 randomly selected subjects (577 females and 333 males) using the Seasonal Health Questionnaire (SHQ), the Seasonal Pattern Assessment Questionnaire (SPAQ), and the Sheehan Disability Scale (SDS). Telephone numbers were randomly drawn from all Austrian telephone books and transformed using the random last digits method. The last birthday method was employed to choose the target person for the interviews.

RESULTS

Out of our subjects, 2.5% fulfilled criteria for the seasonal pattern specifier according to DSM-5 and 2.4% (95% CI=1.4-3.5%) were diagnosed with SAD. When applying the ICD-10 criteria 1.9% (95% CI=0.9-2.8%) fulfilled SAD diagnostic criteria. The prevalence of fall-winter depression according to the Kasper-Rosenthal criteria was determined to be 3.5%. The criteria was fulfilled by 15.1% for subsyndromal SAD (s-SAD). We did not find any statistically significant gender differences in prevalence rates. When using the DSM-5 as a gold standard for the diagnosis of SAD, diagnosis derived from the SPAQ yielded a sensitivity of 31.8% and a specificity of 97.2%. Subjects with SAD had significantly higher scores on the SDS and higher rates of sick leave and days with reduced productivity than healthy subjects.

CONCLUSIONS

Prevalence estimates for SAD with the SHQ are lower than with the SPAQ. Our data are indicative of the substantial burden of disease and the socioeconomic impact of SAD. This epidemiological data shows a lack of gender differences in SAD prevalence. The higher rates of females in clinical SAD samples might, at least in part, be explained by lower help seeking behaviour in males.