Winter Seasonal Affective Disorder Research Articles

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

ObjectiveSeasonal 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. MethodWe 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). ResultsSummer 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. LimitationsThis was a single-site study with a relatively homogeneous sample. ConclusionsSupporting 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.

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

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

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

BackgroundThis 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.MethodsAdults 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.DiscussionConsistent 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 registrationClinicalTrials.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

BackgroundEfficacious 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. MethodsThe 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. ResultsThe 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. LimitationsParticipants were predominantly White and older. BMI does not account for muscle mass or fat distribution. ConclusionsBMI 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.

Factors associated with seasonal affective disorders in Lebanese adults.

Evaluate seasonal affective disorder (SAD) and the possible factors associated with it among Lebanese adults, during winter and summer seasons of 2018 and 2019. 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. 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. A proper recognition of risk factors associated with SAD allows the clinician to effectively differentiate between SAD and nonseasonal depressive symptoms.

Predictive validity of the Seasonal Beliefs Questionnaire for discriminating between seasonal and nonseasonal major depressive disorder.

The Seasonal Beliefs Questionnaire (SBQ) is a 26-item self-report measure of a winter seasonal affective disorder (SAD)-specific cognitive vulnerability consisting of maladaptive thoughts about the seasons, light availability, and weather conditions. In a known groups comparison, currently depressed adults with SAD had significantly higher SBQ scores than currently depressed adults with nonseasonal major depressive disorder (MDD) and healthy controls, and the MDD group had significantly higher SBQ scores than controls. Using that database, this study explored the predictive validity of using an SBQ cutoff score to differentiate SAD from MDD. Receiver operator characteristic curve analyses used SBQ total score to predict SAD versus MDD, SAD versus control, and MDD versus control status. The SBQ subscale combined score, derived from multivariable logistic regression with SBQ subscales, was examined as an alternative predictor. SBQ total score with a cutpoint of 132 had good predictive ability for distinguishing SAD from MDD (C-statistic = .792, sensitivity = .798, specificity = .794). The SBQ subscale combination score slightly improved predictive ability for the SAD/MDD distinction (C-statistic = .813), with better sensitivity (.930) but worse specificity (.571). In contrast, the score on a generic measure of depressogenic cognitive vulnerability, the Dysfunctional Attitudes Scale, was poor for differentiating SAD from MDD. SBQ total score was excellent in discriminating SAD cases from controls with a cutpoint of 121 (C-statistic = .962, sensitivity = .939, specificity .873), but had poor sensitivity for discriminating MDD cases from controls. Results support using the SBQ to screen for probable SAD in practice settings. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The Symptom Structure of Seasonal Affective Disorder: Integrating Results from Factor and Network Analyses in the Context of the Dual Vulnerability Model

Research on seasonal affective disorder (SAD) has produced several etiological models of SAD symptomatology, including a common cause model that conceptualizes symptoms as the result of a single underlying disease process and the Dual Vulnerability Model (Young et al., Journal of Affective Disorders, 22, 191–197 1991) which posits that cognitive/affective symptoms of depression are responses to vegetative symptoms (fatigue, hypersomnia, increased appetite) in individuals with a cognitive vulnerability to these seasonal changes. This study used exploratory factor analysis and network analyses to examine 22 symptoms of winter SAD in 177 adults at the start of a randomized SAD treatment trial (Rohan et al., American Journal of Psychiatry, 172, 862–9 2015). The factor analysis supported a novel four-factor model that included Negative Cognition, Loss of Vitality, Increased Appetite/Weight and Dysregulation across symptom domains. The results of the network model of interacting symptoms paralleled those of the factor analysis in producing four clusters of inter-correlated symptoms. A directed acyclic graph was constructed to model possible causal relations between symptom factors/clusters. Results suggest that vegetative symptoms (Loss of Vitality and Appetite/Weight) contribute to Dysregulation and that Loss of Vitality and Dysregulation contribute to Negative Cognition, supporting the overall structure of the Dual Vulnerability Model but with greater symptom differentiation. Findings have implications for how SAD should be researched (e.g., clusters vs. diagnosis or individual symptoms), opportunities for intervention, and the expected course of onset and remission.

Detecting Critical Decision Points during Cognitive-Behavioral Therapy and Light Therapy for Winter Depression Nonremission and Recurrence.

Using data from a clinical trial comparing cognitive-behavioral therapy (CBT-SAD) and light therapy (LT) for winter seasonal affective disorder (SAD; N = 177), we explored critical decision points, or treatment weeks, that predict likelihood of nonremission at post-treatment and depression recurrence following treatment. In receiver operator characteristic (ROC) curve analyses, we used weekly Structured Clinical Interview for the Hamilton Rating Scale for Depression-SAD Version (SIGH-SAD) scores during treatment to predict nonremission at post-treatment (Week 6) and recurrence one winter later (Winter 1), two winters later (Winter 2), and any recurrence. Although several C-statistics of ≥ .70 were found, only Week 4 SIGH-SAD scores in CBT-SAD for nonremission had enough predictive ability to inform clinical decision-making (C-statistic = .80; sensitivity = .91; specificity = .68). Week 4 of CBT-SAD may be a critical time point to identify likely nonremitters who need tailoring of intervention, based on SIGH-SAD cutpoint score ≥ 13. This study illustrates how clinical trial data can inform detecting optimal decision points in treatment for identifying patients unlikely to remit, a critical first step to developing adaptive treatment strategies using decision rules to operationalize when and for whom treatment should change to maximize clinical benefit.

Applying experimental therapeutics to examine cognitive and chronological vulnerabilities as mediators of acute outcomes in cognitive-behavioral therapy and light therapy for winter depression.

We applied the experimental therapeutics approach to test whether acute treatment outcomes for winter seasonal affective disorder (SAD) are mediated by a cognitive mechanism in cognitive-behavioral therapy (CBT-SAD) versus a chronobiologic mechanism in light therapy (LT). Currently depressed adults with major depression, recurrent with seasonal pattern (N = 177; 83.6% female, 92.1% non-Hispanic White, M age = 45.6) were randomized to 6 weeks of LT or group CBT-SAD. SAD symptoms were assessed weekly on the Structured Clinical Interview for the Hamilton Rating Scale for Depression-SAD Version. At pre-, mid-, and posttreatment, participants completed measures of general depressogenic cognitions (Dysfunctional Attitudes Scale; DAS); SAD-specific negative cognitions (Seasonal Beliefs Questionnaire; SBQ); chronotype (Morningness-Eveningness Questionnaire; MEQ); and depressive symptoms (Beck Depression Inventory-Second Edition). Parallel-process growth models showed evidence for hypothesized mechanisms. For SAD-specific negative cognitions (SBQ), both symptom measures showed (1) an effect of treatment group on the slope of the mediator, with CBT-SAD demonstrating greater decreases, and (2) an effect of the slope of the mediator on the slope of the outcome. These effects held for the SBQ but not the broader measure of depressogenic cognitions (DAS). For the chronotype measure (MEQ), treatment assignment affected change, whereby LT was associated with reduced "eveningness," but this was unrelated to change in symptoms. CBT-SAD promoted decreases in SAD-specific negative cognitions, and these changes were related to decreases in symptoms. Consistent with the theory that LT corrects misaligned circadian rhythms, LT reduced eveningness, but this did not correspond to symptom improvement. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Cognitive Vulnerabilities as Prognostic Predictors of Acute and Follow-up Outcomes in Seasonal Affective Disorder Treatment with Light Therapy or Cognitive-Behavioral Therapy.

First-line treatments for winter seasonal affective disorder include light therapy and cognitive-behavioral therapy; however, it is unclear whether particular patient profiles respond differentially to each treatment type. This study examined baseline patient cognitive and chronobiological vulnerabilities as prognostic and prescriptive predictors of acute and follow-up treatment outcomes. 177 adults with seasonal affective disorder were randomized to 6-weeks of either light therapy or cognitive-behavioral therapy. Participants completed baseline measures of cognitive vulnerabilities (Dysfunctional Attitudes Scale; Ruminative Response Scale; Seasonal Belief Questionnaire) and chronobiological vulnerability (Morningness-Eveningness Questionnaire). Depression was assessed at pre- and post-treatment and at follow-ups one and two winters later. Pre-treatment depression severity correlated significantly with each cognitive vulnerability measure, and significantly predicted future depression. After controlling for pre-treatment depression, higher scores on the Morningness-Eveningness Questionnaire were prognostic of lower depression at treatment endpoint, but no cognitive vulnerability emerged as a prognostic or prescriptive predictor of outcome. Greater morningness was associated with less severe post-treatment depression in both cognitive-behavior therapy and light therapy. No cognitive vulnerability emerged as a prognostic or prescriptive predictor, perhaps because they correlated with pre-treatment depression severity, a robust predictor of outcome. Future research should test alternative cognitive constructs.

T79. Mood Worsening on Hot Days and High Pollen Days in the Old Order Amish With Summer Type SAD

Summer type Seasonal Affective Disorder (S-SAD) is the less common subtype of seasonal affective disorder (SAD). Although winter SAD is reportedly triggered by shortened day-length and reduced sunlight exposure, evidence regarding triggers of S-SAD is scarce. Previous studies have implicated seasonal changes in heat. Yet another factor present in spring/summer is airborne pollen, reported to be associated with seasonal exacerbation of depression and timing of suicidal behavior. This study explores the relationship of mood worsening with pollen in Old Order Amish (OOA) with S-SAD. OOA have increased exposure to the macro-climate in the summer by not using air conditioning. We hypothesized that those with S-SAD will have significantly higher mood worsening on high pollen days relative to those without S-SAD.

Cerebrospinal Fluid Hypocretin-1 (Orexin-A) Level Fluctuates with Season and Correlates with Day Length.

The hypocretin/orexin neuropeptides (hcrt) are key players in the control of sleep and wakefulness evidenced by the fact that lack of hcrt leads to the sleep disorder Narcolepsy Type 1. Sleep disturbances are common in mood disorders, and hcrt has been suggested to be poorly regulated in depressed subjects. To study seasonal variation in hcrt levels, we obtained data on hcrt-1 levels in the cerebrospinal fluid (CSF) from 227 human individuals evaluated for central hypersomnias at a Danish sleep center. The samples were taken over a 4 year timespan, and obtained in the morning hours, thus avoiding impact of the diurnal hcrt variation. Hcrt-1 concentration was determined in a standardized radioimmunoassay. Using biometric data and sleep parameters, a multivariate regression analysis was performed. We found that the average monthly CSF hcrt-1 levels varied significantly across the seasons following a sine wave with its peak in the summer (June—July). The amplitude was 19.9 pg hcrt/mL [12.8–26.9] corresponding to a 10.6% increase in midsummer compared to winter. Factors found to significantly predict the hcrt-1 values were day length, presence of snow, and proximity to the Christmas holiday season. The hcrt-1 values from January were much higher than predicted from the model, suggestive of additional factors influencing the CSF hcrt-1 levels such as social interaction. This study provides evidence that human CSF hcrt-1 levels vary with season, correlating with day length. This finding could have implications for the understanding of winter tiredness, fatigue, and seasonal affective disorder. This is the first time a seasonal variation of hcrt-1 levels has been shown, demonstrating that the hcrt system is, like other neurotransmitter systems, subjected to long term modulation.

Outcomes One and Two Winters Following Cognitive-Behavioral Therapy or Light Therapy for Seasonal Affective Disorder.

The central public health challenge for winter seasonal affective disorder (SAD) is recurrence prevention. Preliminary studies suggest better long-term outcomes following cognitive-behavioral therapy tailored for SAD (CBT-SAD) than light therapy. The present study is a large, randomized head-to-head comparison of these treatments on outcomes one and two winters after acute treatment. Community adults with major depression, recurrent with seasonal pattern (N=177) were followed one and two winters after a randomized trial of 6 weeks of CBT-SAD (N=88) or light therapy (N=89). Prospective follow-up visits occurred in January or February of each year, and major depression status was assessed by telephone in October and December of the first year. The primary outcome was winter depression recurrence status on the Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorder Version (SIGH-SAD). Other outcomes were depression severity on the SIGH-SAD and the Beck Depression Inventory-Second Edition (BDI-II), remission status based on severity cutoff scores, and major depression status from tracking calls. The treatments did not differ on any outcome during the first year of follow-up. At the second winter, CBT-SAD was associated with a smaller proportion of SIGH-SAD recurrences (27.3% compared with 45.6%), less severe symptoms on both measures, and a larger proportion of remissions defined as a BDI-II score ≤8 (68.3% compared with 44.5%) compared with light therapy. Nonrecurrence at the next winter was more highly associated with nonrecurrence at the second winter among CBT-SAD participants (relative risk=5.12) compared with light therapy participants (relative risk=1.92). CBT-SAD was superior to light therapy two winters following acute treatment, suggesting greater durability for CBT-SAD.

CBT vs. Light Therapy for Seasonal Affective Disorder

Bright light therapy can improve winter seasonal affective disorder (SAD), but only in some patients. To examine an alternative treatment,

Ethnic differences in seasonal affective disorder and associated factors among five immigrant groups in Norway

BackgroundResearch studies on seasonal affective disorder (SAD) among immigrant populations are scarce. The objective of this article was to explore the associated risk and protective factors on prevalence of winter SAD (W-SAD), sub syndromal SAD (S-SAD) and Summer-SAD among five immigrant groups living in Oslo, Norway. MethodsThe Oslo Immigrants Health study (innvandrer HUBRO, 2002), is a large cross sectional epidemiological survey conducted among five of the largest immigrant groups living in Oslo. 1047 subjects were included in the analysis out of 3019 who participated in the survey. Mailed questionnaire which included selected items of the seasonal pattern assessment questionnaire (SPAQ), Hopkins symptom check list (HSCL) and other variables were used in the analysis. ResultsThe lowest levels of W-SAD were found among Sri Lankan men and women and the highest among Iranians. W-SAD was significantly associated with country of birth, younger age, smoking, presence of mental distress, frequent visits to general practitioner or psychiatrist, self reported poor health and presence of chronic disorders. S-SAD was significantly associated with country of birth, smoking and higher levels of alcohol consumption. LimitationsSPAQ was not culturally validated. Poor response rate (39.7%) can also be considered as a limitation. ConclusionsEthnic differences in W-SAD and S-SAD were observed. Sri Lankans had the lowest levels of W-SAD. However, there is a need for culturally validated instruments and further research must focus on exploring protective factors for SAD.

Reading increases ocular illuminance during light treatment

Bright-light treatment is a safe and effective treatment for the management of winter seasonal affective disorder (SAD). In a recent study, we found that the relative duration of reading was positively associated with likelihood of remission after six weeks of light treatment. Two technicians measured the illuminance of a light box with a light meter directed towards the center of reading material that was placed on a table in front of the light box. The measurement was also performed after reading material was removed. The two measurements were performed in a randomized order. Friedman analysis of variance with Wilcoxon post-hoc tests were used to compare illuminance with vs. without reading. The presence of the reading material increased illuminance by 470.93 lux (95% CI 300.10-641.75), p<0.0001. This is a technical report done under conditions intended to mimic those of typical ambulatory light treatment as much as possible. As reading materials reflect light from the light box, reading during light therapy increases ocular illuminance. If confirmed by future studies using continuous recordings in randomized design, instructing SAD patients to read during light therapy may contribute to a more complete response to light treatment. The downside of specific relevance for students, is that reading, in particular, with bright light in the late evening/early night may induce or worsen circadian phase delay, adversely affecting health and functioning.

Seasonality of mood and behavior in the Old Order Amish

Background/ObjectiveWe examined seasonality and winter seasonal affective disorder (SAD) in the Old Order Amish of Lancaster County, Pennsylvania, a unique population that prohibits use of network electric light in their homes. MethodsWe estimated SAD using the seasonal pattern assessment questionnaire (SPAQ) in 1306 Amish adults and compared the frequencies of SAD and total SAD (i.e., presence of either SAD or subsyndromal-SAD) between men and women, young and old, and awareness of (ever vs. never heard about) SAD. Heritability of global seasonality score (GSS) was estimated using the maximum likelihood method, including a household effect to capture shared environmental effects. ResultsThe mean (±SD) GSS was 4.36 (±3.38). Prevalence was 0.84% (95% CI: 0.36–1.58) for SAD and 2.59% (95% CI: 1.69–3.73) for total SAD. Heritability of GSS was 0.14±0.06 (SE) (p=0.002) after adjusting for age, gender, and household effects. LimitationsLimitations include likely overestimation of the rates of SAD by SPAQ, possible selection bias and recall bias, and limited generalizability of the study. ConclusionsIn the Amish, GSS and SAD prevalence were lower than observed in earlier SPAQ-based studies in other predominantly Caucasian populations. Low heritability of SAD suggests dominant environmental effects. The effects of awareness, age and gender on SAD risk were similar as in previous studies. Identifying factors of resilience to SAD in the face of seasonal changes in the Amish could suggest novel preventative and therapeutic approaches to reduce the impact of SAD in the general population.

Seasonal symptoms in bipolar and primary care patients

There is evidence of seasonality in bipolar affective disorder (BAD) and the preponderance of atypical symptoms in bipolar depressive episodes is also seen in winter type Seasonal Affective Disorder. Differences in seasonal symptoms between BAD and appropriate comparison populations have been scrutinised only in small studies. Symptoms described on the Seasonal Pattern Assessment Questionnaire (SPAQ) were compared between 183 patients with BAD and 468 patients consulting their general practitioners. Statistical analyses were adjusted for differing age and gender distributions between the two groups. Compared with the general practice patients, subjects with BAD reported greater seasonal fluctuations in mood (p=0.003). On one measure BAD subjects reported increased seasonal changes in social activity (p<0.001) and greater weight fluctuation over the year (p=0.001). The most striking differences were in sleep patterns; BAD subjects slept significantly more throughout the year, and slept for a mean of 1.8h more in winter than in summer (versus a 1.0h difference in the general practice group, p<0.001). Against 20% of the general practice group, 46% of BAD patients rated seasonal changes in well-being to be at least a moderate problem. The SPAQ was designed as a screening instrument for Seasonal Affective Disorder, not for studies of this nature. Some of the reported differences, notably in social activity and weight changes, may reflect secondary psychosocial effects of BAD. Seasonal changes, most notably winter hypersomnia, should be identified in patients with BAD. These symptoms may respond to treatments such as light therapy that are used in recurrent winter depression.

Seasonality and winter-type seasonal depression are associated with the rs731779 polymorphism of the serotonin-2A receptor gene

Seasonal Affective Disorder (SAD), seasonality and increased sensitivity to the fluctuation of seasons in biological and psychological parameters can manifest to varying degrees across a normal population. The serotonin-2A (5-HT2A) receptor gene has long been suggested as a candidate for the genetic basis of this phenomenon. We hypothesized that functional sequence variation in this gene could contribute to seasonality and the development of winter- and/or summer-type seasonal depression. Seasonality was measured by the self-rating Global Seasonality Score (GSS) of the Seasonal Pattern Assessment Questionnaire, and SAD by the Seasonal Health Questionnaire (SHQ). We analysed associations between GSS or SAD scores and 5-HTR2A receptor gene polymorphisms rs731779, rs985934 and rs6311, in 609 individuals. People carrying the GG genotype of rs731779 were six times more likely to manifest winter or summer SAD compared to GT or TT genotypes (OR = 6.47), and the chance of having winter-type SAD was almost nine-fold (OR = 8.7) with the GG genotype. GG subjects of rs731779 also scored significantly higher on the GSS scale compared to carriers of the T allele. In the haplotype analysis subjects carrying the G allele of rs731779 scored higher on the GSS scale, while the presence of the T allele leads to lower scores. These results suggest that variations in the 5-HTR2A gene play a significant role in the development of seasonality and especially in winter-type SAD. The fact that the above polymorphism showed association not only with clinical SAD but also seasonality symptoms in a general population provides evidence for the spectrum nature of this connection.

Biological and Psychological Mechanisms of Seasonal Affective Disorder: A Review and Integration

This article: (1) describes and reviews evidence for hypothesized biological and psychological mechanisms of winter seasonal affective disorder (SAD), (2) advocates for an integrative approach to studying SAD etiology that incorporates both biological and psychological mechanisms, and (3) delineates areas for future research from an integrative perspective. Exciting progress has been made within sub-paradigms testing candidate biological mechanisms (i.e., biological rhythm abnormalities, retinal subsensitivity to light, neurotransmitter alterations, and genetic variations) and psychological mechanisms (i.e., maladaptive cognitions and behaviors) of SAD. However, research from an integrative biological/ psychological perspective is currently lacking. In contrast to a continued exclusive focus on micro-models, we argue that an integrative approach would maximize the capacity to predict and understand the onset, maintenance, and course of SAD. An integrative approach also provides a comprehensive theoretical framework for developing strategies to effectively treat acute SAD, maintain acute treatment gains throughout the winter, and prevent future episodes of this highly recurrent form of depression. Keywords: Seasonal affective disorder, etiology, integrative approach