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.

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

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

Factors associated with seasonal affective disorders in Lebanese adults.

PURPOSE: Evaluate seasonal affective disorder (SAD) and the possible factors associated with it among Lebanese adults, during winter and summer seasons of 2018 and 2019. DESIGN AND METHODS: Cross-sectional study was conducted in two time intervals. The winter period took place from December 2018 to January 2019, whereas the summer period was from May to June 2019, evaluating the same participants. FINDINGS: Higher winter depression (adjusted odds ratio [ORa] = 1.16), higher winter insomnia (ORa = 1.04) were significantly associated with higher odds of having winter SAD. Higher summer depression (ORa = 1.20) was significantly associated with higher odds of having summer SAD. PRACTICE IMPLICATIONS: A proper recognition of risk factors associated with SAD allows the clinician to effectively differentiate between SAD and nonseasonal depressive symptoms.

Seasonality in Major Depressive Disorder: Effect of Sex and Age.

BACKGROUND: Aside from the concept of seasonal affective disorder, the evidence for a seasonal pattern (SP) of major depressive disorder (MDD) is controversial. Furthermore, the effect of sex and age is still unclear. METHODS: This is a nationwide, registry-based study assessing all inpatient admissions in mental health hospitals due to MDD episodes according to ICD-10 (moderate (F32/33.1), severe (F32/33.2) and severe with psychotic features (F32/33.3)) in Austria across 14 years. Calculations were based on deviations from expected monthly admissions. RESULTS: The sample comprised 231,824 hospitalisations (36.8% men) for MDD. A significant SP (p=0.001) in moderate and severe depressive episodes in both women and men with decreased admission rates in the summer months and December was detected. In psychotic depression a significant SP was only evidenced in women (p = 0.002, men: p = 0.291). Patients older than 55 years had a reduced SP compared to those being younger. LIMITATIONS: Only anonymised admission data of inpatient treatments were available. Hospitalization rates cannot fully be equated to the occurrence of MDD. CONCLUSIONS: The current study indicates a seasonal variation in MDD symptoms that may go beyond seasonal affective disorder. Knowledge about the predictability of depressive symptoms in patients should encourage preventive strategies.

Effect of Hometown Seasonality on Undergraduate Students' Risk of Developing Seasonal Affective Disorder.

Seasonal affective disorder (SAD) is a prevalent and potentially serious medical condition. Young adults are at particularly high risk. However, it is unknown if college students whose hometowns are in geographic areas with less seasonal variability, such as in the state of Hawai'i, are particularly vulnerable if they attend schools in areas with seasonal variability. An adapted version of the Seasonal Patterns Assessment Questionnaire (SPAQ) was administered to students at 3 universities to test this hypothesis. Surveys were administered twice: a baseline (T0) assessment in the fall and a follow-up (T1) assessment in the winter and were administered in the second month of each semester. A linear regression model was constructed to identify potential risk factors for developing seasonal fluctuations in mood (SPAQ scores T1-T0). Study subjects (n=115) from non-seasonal hometowns had a 1.6-point greater increase in SPAQ score than students from seasonal hometowns (-0.26 ± 3.88 vs 1.35 ± 3.03; P =.01). This difference is independent of demographic and lifestyle predictors (linear regression coefficient: ß = 1.73; standard error = 0.68; P =.012). Interestingly, SPAQ score changes of students from seasonal hometowns did not differ significantly from 0 (t = -0.97; P =.33), indicating that they did not generally experience seasonal shifts in depressive symptoms. Students from less seasonal hometowns and counselors at seasonal institutions should be aware that these students could be more at risk of developing depressive symptoms and address these concerns before interfering with students' daily and academic lives.

Seasonal sensitivity and psychiatric morbidity: study about seasonal affective disorder.

BACKGROUND: Seasonal Affective Disorder is a recurrent depressive disorder which usually begins in the fall/winter and enters into remission in the spring/summer, although in some cases may occur in the summer with remission in the autumn-winter. In this study the authors evaluated the association between seasonal changes in mood and behavior with psychiatric disturbance. METHOD: Descriptive, cross-sectional study. Participants, students attending higher education and vocational courses (N = 324), were evaluated with the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Screening Scale for Mental Health (ER80). RESULTS: Among the respondents, 12.7% showed seasonal affective disorder (SAD), 29.0% showed subsyndromal seasonal affective disorder (s-SAD) and 58.3% did not show significant seasonal affective symptomatology. As for psychiatric morbidity, 36.6% of subjects with SAD and 13.8% of those with s-SAD were considered "psychiatric cases" whereas for subjects without SAD this value was only 3.2%. CONCLUSIONS: There is a statistically significant association between psychiatric morbidity and seasonal affective disorder. This association corroborates the importance of the Seasonal Pattern Assessment Questionnaire in screening for seasonal fluctuations in mood and behavior related disorders, and the clinical need for recognition of these conditions, particularly associated suffering and disabilities.

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

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

Bipolar II disorder has the highest prevalence of seasonal affective disorder in early-onset mood disorders: Results from a prospective observational cohort study.

BACKGROUND: Many mood disorder patients experience seasonal changes in varying degrees. Studies on seasonality have shown that bipolar disorder has a higher prevalence rate in such patients; however, there is limited research on seasonality in early-onset mood disorder patients. This study estimated the prevalence of seasonality in early-onset mood disorder patients, and examined the association between seasonality and mood disorders. METHODS: Early-onset mood disorder patients (n = 378; 138 major depressive disorder; 101 bipolar I disorder; 139 bipolar II disorder) of the Mood Disorder Cohort Research Consortium and healthy control subjects (n = 235) were assessed for seasonality with Seasonality Pattern Assessment Questionnaire (SPAQ). RESULTS: A higher global seasonality score, an overall seasonal impairment score, and the prevalence of seasonal affective disorder (SAD) and subsyndromal SAD showed that mood disorder subjects had higher seasonality than the healthy subjects. The former subject group had a significantly higher mean overall seasonal impairment score than the healthy subjects (p < .001); in particular, bipolar II disorder subjects had the highest prevalence of SAD, and the diagnosis of bipolar II disorder had significantly higher odds ratios for SAD when compared to major depression and bipolar I disorder (p < .05). CONCLUSIONS: Early-onset mood disorders, especially bipolar II disorder, were associated with high seasonality. A thorough assessment of seasonality in early-onset mood disorders may be warranted for more personalized treatment and proactive prevention of mood episodes.

Light and Hormones in Seasonal Regulation of Reproduction and Mood.

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

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

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

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.

Seasonal variation in specific depressive symptoms: A population based study.

INTRODUCTION: Depression varies with season in Canadian youth. However, the symptom profile of seasonal depression may differ from that of non-seasonal depression. Here we evaluate which specific symptoms vary by season. METHODS: Using data from the 2015/2016 Canadian Community Health Survey, cross-sectional analysis was conducted. The Patient Health Questionnaire-9 (PHQ-9) was administered to respondents in 8 provinces/territories (n ≈ 53,000), with interviews conducted throughout the year. Seasonal effects were assessed using quadratic terms in a logistic regression model. Guided by previous literature and analysis, analyses were stratified by age into youth (age 12-24) and adult (age 25+) groups. RESULTS: In the youth, 8 items of the PHQ-9 exhibited a significant season variation: lack of interest/pleasure, feeling depressed/down, hypersomnia/insomnia, lacking energy, poor appetite/overeating, feeling bad about yourself/ like a failure, being slow/fidgety, and trouble concentrating. In the adult group, only sleep and poor appetite/overeating exhibited a seasonal effect. Notably, symptoms of self-harm/suicide did not demonstrate seasonality in either group. LIMITATIONS: Due to use of cross-sectional data and a brief symptom rating scale, conventional criteria for Seasonal Affective Disorder or Major Depressive Disorder with seasonal variation could not be applied. Also, treatment status of respondents was not assessed in the survey, therefore possible confounding by this variable could not be assessed. CONCLUSIONS: A seasonal pattern was observed in most symptoms of depression in Canadian youth, whereas in adults, only symptoms related to sleep and appetite disturbance displayed seasonal variation.

The prevalence of seasonal affective disorder among the blind and patients with serious visual impairment.

BACKGROUND: Seasonal affective disorder (SAD) is an interesting disorder in which depression should occur at a particular time of a year, each year and it should disappear at a specific time of the year. While the prevalence of SAD among generally healthy individuals is well known, the information about the prevalence of this disorder among the blind and visually impaired patients is very limited. The aim of the study was to investigate the prevalence of SAD among the blind and people with serious visual impairment in polish population. SUBJECTS AND METHODS: 250 blind or seriously visually impaired individuals and 258 healthy controls were assessed with the usage of Seasonal Pattern Assessment Questionnaire (SPAQ). In research group survey was conducted with the Computer Assisted Telephone Interview (CATI) technique. In control group the questionnaire was distributed via Internet. The results were analysed with the usage statistical package - Statistica 13.1. RESULTS: The results revealed that among people suffering from SAD there is statistically significant difference in SPAQ scores between completely blind and seriously visually impaired people. The study shows that is the control group age is negatively correlated with score in SPAQ score, while in the study group age is positively correlated with SPAQ score. The data show that there is a difference in occurrence of SAD between men and women. CONCLUSION: The study has shown a significant difference in occurrence of SAD between study and control groups. What is more the analysis has indicated major difference in the occurrence of SAD between men and women from the study group. Taking into consideration the fact that this is the second analysis of this type in Europe further investigations are needed.

Second-generation antidepressants for preventing seasonal affective disorder in adults.

BACKGROUND: Seasonal affective disorder (SAD) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring. The prevalence of SAD ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This review - one of four reviews on efficacy and safety of interventions to prevent SAD - focuses on second-generation antidepressants (SGAs). OBJECTIVES: To assess the efficacy and safety of SGAs (in comparison with other SGAs, placebo, light therapy, melatonin or agomelatine, psychological therapies or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD. SEARCH METHODS: We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles. SELECTION CRITERIA: For efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we planned to include non-randomised studies. Eligible studies compared a SGA versus another SGA, placebo, light therapy, psychological therapy, melatonin, agomelatine or lifestyle changes. We also intended to compare SGAs in combination with any of the comparator interventions versus placebo or the same comparator intervention as monotherapy. DATA COLLECTION AND ANALYSIS: Two review authors independently screened abstracts and full-text publications, extracted data and assessed risk of bias of included studies. When data were sufficient, we conducted random-effects (Mantel-Haenszel) meta-analyses. We assessed statistical heterogeneity by calculating the Chi2 statistic and the Cochran Q. We used the I2 statistic to estimate the magnitude of heterogeneity. We assessed publication bias by using funnel plots.We rated the strength of the evidence using the system developed by the GRADE Working Group. MAIN RESULTS: We identified 3745 citations after de-duplication of search results and excluded 3619 records during title and abstract reviews. We assessed 126 full-text papers for inclusion in the review, of which four publications (on three RCTs) providing data from 1100 people met eligibility criteria for this review. All three RCTs had methodological limitations due to high attrition rates.Overall, moderate-quality evidence indicates that bupropion XL is an efficacious intervention for prevention of recurrence of depressive episodes in people with a history of SAD (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.44 to 0.72; 3 RCTs, 1100 participants). However, bupropion XL leads to greater risk of headaches (moderate-quality evidence), insomnia and nausea (both low-quality evidence) when compared with placebo. Numbers needed to treat for additional beneficial outcomes (NNTBs) vary by baseline risks. For a population with a yearly recurrence rate of 30%, the NNTB is 8 (95% CI 6 to 12). For populations with yearly recurrence rates of 50% and 60%, NNTBs are 5 (95% CI 4 to 7) and 4 (95% CI 3 to 6), respectively.We could find no studies on other SGAs and no studies comparing SGAs with other interventions of interest, such as light therapy, psychological therapies, melatonin or agomelatine. AUTHORS' CONCLUSIONS: Available evidence indicates that bupropion XL is an effective intervention for prevention of recurrence of SAD. Nevertheless, even in a high-risk population, three out of four people will not benefit from preventive treatment with bupropion XL and will be at risk for harm. Clinicians need to discuss with patients advantages and disadvantages of preventive SGA treatment, and might want to consider offering other potentially efficacious interventions, which might confer a lower risk of adverse events. Given the lack of comparative evidence, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.Future researchers need to assess the effectiveness and risk of harms of SGAs other than bupropion for prevention of SAD. Investigators also need to compare benefits and harms of pharmacological and non-pharmacological interventions.

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.

Tanning dependence and seasonal affective disorder are frequent among sunbathers but are not associated.

Ultraviolet radiation (UVR) is a known risk factor for skin cancers. Those who are tanning dependent seek out UVR exposure. Many tanners have expressed symptoms of seasonal affective disorder (SAD), but conclusive evidence of a connection with tanning dependence is lacking. We evaluated the frequency of tanning dependence or abuse and symptoms of SAD among Finnish sunbathers and analysed whether phenomena are associated which could indicate a common biological mechanism. Sunbathing related tanning dependence/abuse among Finnish sunbathers were assessed using the Structured Interview for Tanning Abuse and Dependence measure (SITAD), and symptoms of SAD were assessed with the Seasonal Pattern Assessment Questionnaire (SPAQ). Of 229 sunbathers, 8% (n = 18) were classified as tanning-dependent, and 26% (n = 59) were classified as tanning abusers. Additionally, 16% (n = 37) met the criteria for SAD, and 26% (n = 60) met the criteria for subsyndromal seasonal affective disorder (S-SAD), but there was no significant association between tanning dependence or abuse and SAD or S-SAD. Sunbathing dependence or abuse and SAD/S-SAD were frequent among sunbathers, and they may promote sun-seeking risk behaviour. However, within this sample, tanning dependence and SAD/S-SAD were not associated.

Prevalence of seasonal depression in a prospective cohort study.

The prevalence of autumn/winter seasonality in depression has been documented in the longitudinal Zurich cohort study by five comprehensive diagnostic interviews at intervals over more than 20 years (N = 499). Repeated winter major depressive episodes (MDE-unipolar + bipolar) showed a prevalence of 3.44% (5× more women than men), whereas MDE with a single winter episode was much higher (9.96%). A total of 7.52% suffered from autumn/winter seasonality in major and minor depressive mood states. The clinical interviews revealed novel findings: high comorbidity of Social Anxiety Disorder and Agoraphobia within the repeated seasonal MDE group, high incidence of classic diurnal variation of mood (with evening improvement), as well as a high rate of oversensitivity to light, noise, or smell. Nearly twice as many of these individuals as in the other MDE groups manifested the syndrome of atypical depression (DSM-V), which supports the prior description of seasonal affective disorder (SAD) as presenting primarily atypical symptoms (which include hypersomnia and increase in appetite and weight). This long-term database of regular structured interviews provides important confirmation of SAD as a valid diagnosis, predominantly found in women, and with atypical vegetative symptoms.

No evidence of seasonal variation in mild forms of depression.

BACKGROUND AND OBJECTIVES: Seasonal Affective Disorder (SAD) is ubiquitous in popular culture and has influenced psychiatric diagnosis with the inclusion of the seasonal pattern modifier for the Major Depressive Episode in DSM. However, recent research has not supported the association of Major Depressive Episode with seasonal changes. The present study was conducted to determine if a seasonally-related pattern of occurrence of mild variants of depression could be demonstrated in a population-based study. METHODS: This is a cross-sectional U.S. survey of adults who completed the PHQ-8 Depression Scale with mild depression defined using a PHQ-8 cut score and a second model based on the DSM-5 diagnosis, Depression with insufficient symptoms. Regression models were used to determine if either variant of mild depression was related to season, latitude, or measures of daylight hours. RESULTS: Neither measure of mild depression was related to daylight hours or its proxy measures. LIMITATIONS: Screening instruments for depression, even if consistent with DSM-5 diagnostic criteria, do not allow a formal diagnosis of depression or the exclusion of similar-appearing disorders. Current depression symptoms but not duration of depressive episode is measured. CONCLUSIONS: Mild depression is not related to seasonal changes or proxy measures of light exposure. The findings cast doubt on light deficiency as a causal factor of depressive disorders, which underpins the inclusion of the seasonal pattern modifier in DSM-5 and light supplementation as a treatment modality.

The effects of seasonal affective disorder and alcohol abuse on sleep and snoring functions in a population-based study in Finland.

Seasonal affective disorder (SAD) is a recurrent depressive disorder with a seasonal pattern. In addition to some specific symptoms such as sad mood, low energy or carbohydrate craving, this mood disorder is also characterized by the presence of sleeping problems and alcohol disorders. Interestingly, there is a strong link between alcohol use and sleeping deficits. Although previous studies have focused extensively on the sleep patterns in SAD patients and patients with alcohol use disorder (AUD), no research has yet been conducted on subjects with comorbid SAD and AUD. The aim of this study was to examine the differences in sleep functioning between subjects with SAD, AUD and SAD+AUD. A total of 4554 Finnish subjects from the population-based Health 2011 survey were interviewed, and of these 2430 individuals completed all the questionnaires. We selected those participants who fulfilled the criteria for SAD (n = 298), AUD (n = 359), SAD+AUD (n = 69), controls 1 (no current alcohol use, n = 226) and controls 2 (current alcohol use but not AUD, n = 1445). Controls with a history of alcohol abuse were excluded (n = 33). All the participants completed the EuroQoL five-dimensions questionnaire (EQ-5), the Seasonal Pattern Assessment Questionnaire (SPAQ), the Alcohol Use Disorders Identification Test (AUDIT) and several questions about sleeping, based on the Basic Nordic Sleep Questionnaire (BNSQ). Our results showed that those subjects with SAD+AUD reported the highest levels of subjective sleeping problems compared to controls, SAD and AUD. These findings suggest the relevance of examining the comorbidity of SAD and AUD when studying sleep functioning in these groups of patients.