The diagnosis, symptomatology, and epidemiology of seasonal affective disorder

Circadian clock gene aryl hydrocarbon receptor nuclear translocator-like polymorphisms are associated with seasonal affective disorder: An Indian family study

BACKGROUND AND AIM

Polymorphisms in aryl hydrocarbon receptor nuclear translocator-like (ARNTL) gene, the key component of circadian clock manifests circadian rhythm abnormalities. As seasonal affective disorder (SAD) is associated with disrupted circadian rhythms, the main objective of this study was to screen an Indian family with SAD for ARNTL gene polymorphisms.

MATERIALS AND METHODS

In this study, 30 members of close-knit family with SAD, 30 age- and sex-matched controls of the same caste with no prior history of psychiatric illness and 30 age- and sex-matched controls belonging to 17 different castes with no prior history of psychiatric illness were genotyped for five different single nucleotide polymorphisms (SNPs) in ARNTL gene by TaqMan allele-specific genotyping assay.

STATISTICAL ANALYSIS

Statistical significance was assessed by more powerful quasi-likelihood score test-XM.

RESULTS

Most of the family members carried the risk alleles and we observed a highly significant SNP rs2279287 (A/G) in ARNTL gene with an allelic frequency of 0.75.

CONCLUSIONS

Polymorphisms in ARNTL gene disrupt circadian rhythms causing SAD and genetic predisposition becomes more deleterious in the presence of adverse environment.

Melatonin and agomelatine for preventing seasonal affective disorder

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 in the United States ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on agomelatine and melatonin as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of agomelatine and melatonin (in comparison with each other, placebo, second-generation antidepressants, light therapy, psychological therapy or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We conducted a search of the Specialised Register of the Cochrane Depression, Anxiety and Neurosis Review Group (CCDANCTR) to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We conducted a grey literature search (e.g. in clinical trial registries) and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we planned to include randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. To examine adverse events, we intended to include non-randomised studies. We planned to include studies that compared agomelatine versus melatonin, or agomelatine or melatonin versus placebo, any second-generation antidepressant (SGA), light therapy, psychological therapies or lifestyle changes. We also intended to compare melatonin or agomelatine in combination with any of the comparator interventions listed above versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors planned to independently extract data and assess risk of bias of included studies. We planned to pool data for meta-analysis when participant groups were similar and when studies assessed the same treatments by using the same comparator and presented similar definitions of outcome measures over a similar duration of treatment; however, we identified no studies for inclusion.

MAIN RESULTS

We identified 2986 citations through electronic searches and reviews of reference lists after de-duplication of search results. We excluded 2895 records during title and abstract review and assessed 91 articles at full-text level for eligibility. We identified no controlled studies on use of melatonin and agomelatine to prevent SAD and to improve patient-centred outcomes among adults with a history of SAD.

AUTHORS' CONCLUSIONS

No available methodologically sound evidence indicates that melatonin or agomelatine is or is not an effective intervention for prevention of SAD and improvement of patient-centred outcomes among adults with a history of SAD. Lack of evidence clearly shows the need for well-conducted, controlled studies on this topic. A well-conducted RCT of melatonin or agomelatine for prevention of SAD would assess the comparative benefits and risks of these interventions against others currently used to treat the disorder.

Psychological therapies for preventing seasonal affective disorder

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 is one of four reviews on the efficacy and safety of interventions to prevent SAD; we focus on psychological therapies as preventive interventions.

OBJECTIVES

To assess the efficacy and safety of psychological therapies (in comparison with no treatment, other types of psychological therapy, second-generation antidepressants (SGAs), light therapy, melatonin or agomelatine or lifestyle interventions) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We conducted a search of the Cochrane Depression, Anxiety and Neurosis Review Group Specialised Register (CCDANCTR) to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We conducted a grey literature search (e.g. in clinical trial registries) and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

To examine efficacy, we planned to include randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. To examine adverse events, we intended to include non-randomised studies. We planned to include studies that compared psychological therapy versus any other type of psychological therapy, placebo, light therapy, SGAs, melatonin, agomelatine or lifestyle changes. We also intended to compare psychological therapy in combination with any of the comparator interventions listed above versus the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors planned to independently extract data and assess risk of bias. We planned to pool data for meta-analysis when participant groups were similar and when studies assessed the same treatments versus the same comparator and provided similar definitions of outcome measures over a similar duration of treatment; however, we included no studies.

MAIN RESULTS

We identified 2986 citations through electronic searches and reviews of reference lists after de-duplication of search results. We excluded 2895 records during title and abstract review and assessed 91 articles at full-text review for eligibility. We found no controlled studies on use of psychological therapy to prevent SAD and improve patient-centred outcomes in adults with a history of SAD.

AUTHORS' CONCLUSIONS

Presently, there is no methodologically sound evidence available to indicate whether psychological therapy is or is not an effective intervention for prevention of SAD and improvement of patient-centred outcomes among adults with a history of SAD. Randomised controlled trials are needed to compare different types of psychological therapies and to compare psychological therapies versus placebo, light therapy, SGAs, melatonin, agomelatine or lifestyle changes for prevention of new depressive episodes in patients with a history of winter-type SAD.

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 second-generation antidepressants (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

A search of the Specialised Register of the Cochrane Depression, Anxiety and Neuorosis Review Group (CCDANCTR) included all years to 11 August 2015. The CCDANCTR contains reports of randomised controlled trials derived from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trials (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (to 26 May 2014). 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 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 an 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 the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications and assigned risk of bias ratings based on the Cochrane 'Risk of bias' tool. We resolved disagreements by consensus or by consultation with a third party. Two review authors independently 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 Chi(2) statistic and the Cochran Q. We used the I(2) statistic to estimate the magnitude of heterogeneity and examined potential sources of heterogeneity using sensitivity analysis or analysis of subgroups. We assessed publication bias by using funnel plots. However, given the small number of component studies in our meta-analyses, these tests have low sensitivity to detect publication bias. We rated the strength of the evidence using the system developed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) Working Group.

MAIN RESULTS

We identified 2986 citations after de-duplication of search results and excluded 2895 records during title and abstract reviews. We assessed 91 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 patients with a history of SAD (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.44 to 0.72; three 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 40% and 50%, NNTBs are 6 (95% CI 5 to 9) and 5 (95% CI 4 to 7), 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, four of five patients 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 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.

Light therapy for preventing seasonal affective disorder

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 light therapy as a preventive intervention. Light therapy is a non-pharmacological treatment that exposes people to artificial light. Mode of delivery (e.g. visors, light boxes) and form of light (e.g. bright white light) vary.

OBJECTIVES

To assess the efficacy and safety of light therapy (in comparison with no treatment, other types of light therapy, second-generation antidepressants, melatonin, agomelatine, psychological therapies, lifestyle interventions and negative ion generators) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

A search of the Specialised Register of the Cochrane Depression, Anxiety and Neuorosis Review Group (CCDANCTR) included all years to 11 August 2015. The CCDANCTR contains reports of relevant randomised controlled trials derived from EMBASE (1974 to date), MEDLINE (1950 to date), PsycINFO (1967 to date) and the Cochrane Central Register of Controlled Trails (CENTRAL). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, The Cochrane Library and the Allied and Complementary Medicine Database (AMED) (to 26 May 2014). We also conducted a grey literature search and handsearched the reference lists of all included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants (SGAs), psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention and compared this with the same comparator intervention as monotherapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications against the inclusion criteria. Two review authors independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 2986 citations after de-duplication of search results. We excluded 2895 records during title and abstract review. We assessed 91 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included randomised controlled trial (RCT) had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, both forms of preventive light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but in this case also the CI was too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28). The quality of evidence for all outcomes was very low. Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as SGA, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for patients with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

The first observation of seasonal affective disorder symptoms in Rhesus macaque

Diurnal animals are a better model for seasonal affective disorder (SAD) than nocturnal ones. Previous work with diurnal rodents demonstrated that short photoperiod conditions brought about depression-like behavior. However, rodents are at a large phylogenetic distance from humans. In contrast, nonhuman primates are closely similar to humans, making them an excellent candidate for SAD model. This study made the first attempt to develop SAD in rhesus macaque (Macaca mulatta) and it was found that short photoperiod conditions could lead monkeys to display depressive-like huddling behavior, less spontaneous locomotion, as well as less reactive locomotion. In addition to these depression-related behavioral changes, the physiological abnormalities that occur in patients with SAD, such as weight loss, anhedonia and hypercortisolism, were also observed in those SAD monkeys. Moreover, antidepressant treatment could reverse all of the depression-related symptoms, including depressive-like huddling behavior, less spontaneous locomotion, less reactive locomotion, weight loss, anhedonia and hypercortisolism. For the first time, this study observed the SAD symptoms in rhesus macaque, which would provide an important platform for the understanding of the etiology of SAD as well as developing novel therapeutic interventions in the future.

Determinants of postnatal depression in rural ghana: findings from the don population based cohort study

BACKGROUND

Risk factors for postnatal depression (PND), one of the most pervasive complications of child bearing, are poorly understood in Africa. A recent systematic review of 31 studies found that the strongest predictors are social and economic disadvantage and gender-based factors; only six of these studies were community based, and almost all were in South Asia.

METHODS

Cohort study nested within 4 weekly surveillance of all women of reproductive age to identify pregnancies and collect data on births and deaths in the Kintampo Health Research Centre study area of Ghana. Women were screened for depression during pregnancy and after birth using the Patient Health Questionnaire to ascertain DSM-IV major or minor depression. Information was collected on determinants relating to the mother, birth, and baby, which were examined using logistic regression; effect sizes reported as relative risks with 95% confidence intervals.

RESULTS

Thirteen thousand nine hundred and twenty nine women were screened both during pregnancy and after birth, of whom 13,360 (95.9%) had complete data on potential determinants. Two hundred and fifty five (3.8%, 95% CI: 3.5%, 4.1%) had PND. Antenatal depression (AND) was the strongest determinant accounting for 34.4% of PND cases. Other determinants were season of delivery, peripartum/postpartum complications, newborn ill health, still birth, or neonatal death. Common determinants were observed for onset and persistent depression.

CONCLUSIONS

Although most AND resolves in this setting, more than a third of women with PND also had AND. Adverse birth- and baby-related outcomes are the other main determinants. We recommend that programs detect and treat depression during pregnancy and provide support to women with adverse birth outcomes.

Graph theory reveals hyper-functionality in visual cortices of Seasonal Affective Disorder patients

OBJECTIVES

Seasonal affective disorder (SAD) is a subtype of recurrent unipolar or bipolar depressive disorder with a higher prevalence in winter than in summer. The biological underpinnings of SAD are so far poorly understood. Studies examining SAD have found disturbances between the molecular and connectivity scales. The aim of the study was to explore changes in functional connectivity typical for SAD.

METHODS

We investigated unmedicated, untreated SAD patients and healthy controls using resting-state functional magnetic resonance imaging (rs-fMRI) utilizing graph theory, a data driven and hypothesis free approach, to model functional networks of the brain.

RESULTS

Comparing whole brain network properties using graph theory we observed globally affected network topologies with increasing pathlength in SAD. Nodal changes, however, were highly restricted to bilateral inferior occipital cortex. Interestingly, we found a lateralization where hyper-connectedness was restricted to right inferior occipital cortex and hyper-efficiency was found in the left inferior occipital cortex. Furthermore, we found these nodes became more "hub like" in patients, suggesting a greater functional role.

CONCLUSIONS

Our work stresses the importance of abnormal intrinsic processing during rest, primarily affecting visual areas and subsequently changing whole brain networks, and thus providing an important hint towards potential future therapeutic approaches.

Frequency and characteristics of individuals with seasonal pattern among depressive patients attending primary care in France

OBJECTIVE

High rates of bipolar disorder (BD) have been found among major depressives with seasonal pattern (SP) consulting in psychiatric departments, as well as among patients seeking primary care. As SP was reported to be common in the latter, the current study was designed to assess (a) the frequency and characteristics of SP among major depressives attending primary care and (b) the prevalence and aspects of BD in this population.

METHODS

Among 400 patients who consulted French general practitioners (GPs) for major depression between February and December 2010, 390 could be included in the study: 167 (42.8%) met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for seasonal pattern [SP(+)], whereas 223 (57.2%) did not meet these criteria [SP(-)]. The two groups were compared on demographic, clinical, family history and temperamental characteristics.

RESULTS

Compared to SP(-), SP(+) patients were more frequently female, married and with a later age at first depressive episode, and showed more atypical vegetative symptoms, comorbid bulimia and stimulant abuse. They also exhibited more lifetime depressive episodes, were more often diagnosed as having BD II and met more often bipolarity specifier criteria, with higher rates of bipolar temperaments and a higher BD family loading. Among SP(+) patients, 68.9% met the bipolarity specifier criteria, whereas 31.1% did not. Seasonality was not influenced by climatic conditions. The following independent variables were associated with SP: BD according to bipolarity specifier, female gender, comorbid bulimia nervosa, hypersomnia, number of depressive episodes and family history of substance abuse.

CONCLUSIONS

Seasonal pattern is frequent among depressive patients attending primary care in France and may be indicative of hidden bipolarity. Given the risks associated with both SP and bipolarity, GPs are likely to have a major role in regard to prevention.

Transcranial bright light treatment via the ear canals in seasonal affective disorder: a randomized, double-blind dose-response study

BACKGROUND

Bright light treatment is effective for seasonal affective disorder (SAD), although the mechanisms of action are still unknown. We investigated whether transcranial bright light via the ear canals has an antidepressant effect in the treatment of SAD.

METHODS

During the four-week study period, 89 patients (67 females; 22 males, aged 22-65, mean ± SD age: 43.2 ± 10.9 years) suffering from SAD were randomized to receive a 12-min daily dose of photic energy of one of three intensities (1 lumen/0.72 mW/cm(2); 4 lumens/2.881 mW/cm(2); 9 lumens/6.482 mW/cm(2)) via the ear canals. The light was produced using light-emitting diodes. The severity of depressive symptoms was assessed with the Hamilton Depression Rating Scale - Seasonal Affective Disorder (SIGH-SAD), the Hamilton Anxiety Rating Scale (HAMA), and the Beck Depression Inventory (BDI). Cognitive performance was measured by the Trail Making Test (TMT). The within-group and between-group changes in these variables throughout the study were analysed with a repeated measures analysis of variance (ANOVA), whereas gender differences at baseline within the light groups were analysed using Student's t-tests.

RESULTS

Patients in all three groups showed significant decreases in their BDI, HAMA, and SIGH-SAD scores. Response rates, i.e., an at least 50% decrease of symptoms as measured by the BDI, were 74%-79% in the three treatment groups. Corresponding variations for the SIGH-SAD and the HAMA were 35-45% and 47-62%, respectively. No intensity-based dose-response relationships in the improvement of anxiety and depressive symptoms or cognitive performance between treatment groups were observed. Approximately one in four patients experienced mild adverse effects, of which the most common were headache, insomnia, and nausea.

CONCLUSIONS

These results suggests that transcranial bright light treatment may have antidepressant and anxiolytic effect in SAD patients, as both self- and psychiatrist-rated depressive and anxiety symptoms decreased in all treatment groups. These improvements are comparable to findings of earlier bright light studies that used conventional devices. The lack of dose response may be due to a saturation effect above a certain light intensity threshold. Further studies on the effects of transcranial bright light with an adequate placebo condition are needed.

TRIAL REGISTRATION

NCT01293409, ClinicalTrials.gov.

Seasonal obsessive-compulsive disorder

A case of obsessive-compulsive disorder (OCD) with seasonal variation in symptoms of 10-years duration is reported because of its rarity. The phenomenology of the observed disorder was obsessions related to dirt and contamination resulting in washing compulsions with onset in October and complete resolution in April-May every year. The patient responded to phototherapy along with exposure and response prevention therapy and pharmacotherapy.

Seasonal affective disorder: is there light at the end of the tunnel?

Seasonal affective disorder, which is underdiagnosed in the primary care setting, is a mood disorder subtype characterized by episodic major depression that typically develops in winter when daylight hours are short. Patients with SAD experience increased morbidity and decreased quality of life. This article focuses on recognition and management of this condition. Light therapy is the preferred treatment for SAD because it is safe and easy to administer; light therapy may be combined with pharmacologic therapy. Cognitive behavioral therapy (CBT) also has a positive therapeutic effect when combined with light therapy and may help prevent SAD in subsequent seasons.

The post illumination pupil response is reduced in seasonal affective disorder

Individuals with seasonal affective disorder (SAD) may have a decreased retinal sensitivity in the non-image forming light-input pathway. We examined the post illumination pupil response (PIPR) among individuals with SAD and healthy controls to identify possible differences in the melanopsin signaling pathway. We also investigated whether melanopsin gene (OPN4) variations would predict variability in the PIPR. Fifteen SAD and 15 control participants (80% women, mean age 36.7 years, S.D.=14.5) were assessed in the fall/winter. Participants were diagnosed based on DSM-IV-TR criteria. Infrared pupillometry was used to measure pupil diameter prior to, during, and after red and blue stimuli. In response to blue light, the SAD group had a reduced PIPR and a lower PIPR percent change relative to controls. The PIPR after the blue stimulus also varied on the basis of OPN4 I394T genotype, but not OPN4 P10L genotype. These findings may indicate that individuals with SAD have a less sensitive light input pathway as measured by the PIPR, leading to differences in neurobiological and behavioral responses such as alertness, circadian photoentrainment, and melatonin release. In addition, this sensitivity may vary based on sequence variations in OPN4, although a larger sample and replication is needed.

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

BACKGROUND

Research 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.

METHODS

The 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.

RESULTS

The 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.

LIMITATIONS

SPAQ was not culturally validated. Poor response rate (39.7%) can also be considered as a limitation.

CONCLUSIONS

Ethnic 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.

Bipolar disorder with seasonal pattern: clinical characteristics and gender influences

Bipolar disorder (BD) has a multifactorial etiology with heterogeneous clinical presentations. Around 25% of BD patients may present with a depressive seasonal pattern (SP). However, there are limited scientific data on the prevalence of SP, its clinical manifestations, and any gender influence. Four hundred and fifty-two BD I and II cases (62% female), recruited from three French university-affiliated psychiatric departments, were assessed for SP. Clinical, treatment, and sociodemographic variables were obtained from structured interviews. One hundred and two (23%) cases met DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) criteria for SP, with similar frequency according to gender. Multivariate analysis showed a significant association between SP and BD II (odds ratio [OR] = 1.99, p = 0.01), lifetime history of rapid cycling (OR = 2.05, p = 0.02), eating disorders (OR = 2.94, p = 0.003), and total number of depressive episodes (OR = 1.13, p = 0.002). Seventy-one percent of cases were correctly classified by this analysis. However, when stratifying the analyses by gender, SP was associated with BD II subtype (OR = 2.89, p = 0.017) and total number of depressive episodes (OR = 1.21, p = 0.0018) in males but with rapid cycling (OR = 3.02, p = 0.0027) and eating disorders (OR = 2.60, p = 0.016) in females. This is the first study to identify different associations between SP and clinical characteristics of BD according to gender. The authors suggest that SP represents a potentially important specifier of BD. These findings indicate that seasonality may reflect increased severity or complexity of disorder.

Sleep disorders and depression: brief review of the literature, case report, and nonpharmacologic interventions for depression

Sleep disorders are so frequently associated with depression that, in the absence of sleep complaints, a diagnosis of depression should be made with caution. Insomnia, in particular, may occur in 60%-80% of depressed patients. Depressive symptoms are important risk factors for insomnia, and depression is considered an important comorbid condition in patients with chronic insomnia of any etiology. In addition, some drugs commonly prescribed for the treatment of depression may worsen insomnia and impair full recovery from the illness. The aim of this paper is to review briefly and discuss the following topics: common sleep disturbances during depression (in particular pavor nocturnus, nightmares, hypersomnia, and insomnia); circadian sleep disturbances; and treatment of depression by manipulation of the sleep-wake rhythm (chronotherapy, light therapy, cycles of sleep, and manipulation of the sleep-wake rhythm itself). Finally, we present a case report of a 65-year-old Caucasian woman suffering from insomnia associated with depression who was successfully treated with sleep deprivation.

Getting depression clinical practice guidelines right: time for change?

OBJECTIVE

As part of a series of papers ['Chronobiology of mood disorders' Malhi & Kuiper. Acta Psychiatr Scand 2013;128(Suppl. 444):2-15; and 'It's time we managed depression: The emerging role of chronobiology' Malhi et al. Acta Psychiatr Scand 2013;128(Suppl. 444):1] examining chronobiology in the context of depression, this article examines recent western clinical practice guidelines (CPGs) for the treatment of depression with respect to the recommendations they make, in particular as regards chronobiological treatments, and briefly considers the implications of their methodology and approach.

METHOD

Five international treatment guidelines, which had been published in the past 5 years, were identified, representing North American and European views. Chosen guidelines were reviewed by the authors, and the relevant recommendations were distributed for discussion and subsequent synthesis.

RESULTS

Most current guidelines do not address chronobiology in detail. Chronotherapeutic recommendations are tentative, although agomelatine is considered as an option for major depression and bright light therapy for seasonal affective disorder. Sleep deprivation is not routinely recommended.

CONCLUSION

Recommendations are limited by the lack of reliable therapeutic markers for chronotherapeutics. Current evidence supports use of light therapy in seasonal depression, but in non-seasonal depression there is insufficient evidence to support reliance on chronotherapeutics over existing treatment modalities.

Test-retest reliability of the Seasonal Pattern Assessment Questionnaire in Old Order Amish

BACKGROUND

Research on test-retest reliability of the Season Pattern Assessment Questionnaire (SPAQ) is sparse, and to date, has not been done with subgroups such as the Old Order Amish.

METHODS

We examined the test-retest reliability of the SPAQ in a sample of Old Order Amish. A total of 68 Old Order Amish participants completed the SPAQ twice, with 4 months between administrations. Quantitative data analyses were carried out to determine respective strengths of test-restest reliability for two variables [i.e., Global Seasonality Score (GSS), and Problem Rating Score (PRS)].

RESULTS AND CONCLUSIONS

Results revealed the test-retest reliability of the SPAQ in this population to be strong within the respective variables (GSS, α= 0.87; and PRS, α= 0.79) using Cronbach's alpha.

Influence of seasonal variation in mood and behavior on cognitive test performance among young adults

BACKGROUND

Seasonal variations in mood and behavior are common among the general population and may have a deteriorating effect on cognitive functions.

AIMS

In this study the effect of seasonal affective disorder (SAD-like symptoms) on cognitive test performance were evaluated in more detail.

METHODS

The data were derived from the study Mental Health in Early Adulthood in Finland. Participants (n = 481) filled in a modified Seasonal Pattern Assessment Questionnaire (SPAQ) and performed cognitive tests in verbal and visual skills, attention and general intelligence.

RESULTS

SAD-like symptoms, especially regarding the seasonal variations in weight and appetite, had a significant effect on working memory (Digit Span Backward, P = 0.008) and auditory attention and short-term memory (Digit Span Forward, P = 0.004). The seasonal variations in sleep duration and mood had an effect on auditory attention and short-term memory (Digit Span Forward, P = 0.02 and P = 0.0002, respectively). The seasonal variations in social activity and energy level had no effect.

CONCLUSIONS

Seasonal changes in mood, appetite and weight have an impairing effect on auditory attention and processing speed. If performance tests are not to repeated in different seasons, attention needs to be given to the most appropriate season in which to test.

Mental health and employment: The SAD story

This paper explores the relationship between health-related quality of life (HRQOL) measures and employment status in light of a constructed index related to Seasonal Affective Disorder that depends only on latitude and day of year. In models including demographic covariates and indicators for state, year, and quarter, more hours of darkness is associated with poorer HRQOL, which in turn is associated with a lower likelihood of employment. The relationships between the darkness index and HRQOL measures are stronger overall for women than for men. Inclusion of both the darkness index and the HRQOL measures in models of employment status determinants provides some evidence that the former operates through the latter in predicting a lower likelihood of employment. When specifying the darkness index as an instrument for HRQOL, each additional day of poor mental health per month leads to a 0.76 percentage point increase in the probability of unemployment among women.

Relationship between the number of outpatient visits for hypotension in the springtime in Japan, extracted from clinical electronic records, and global solar radiation levels

Hypotension is commonly reported in springtime when health changes, such as autonomic imbalance, are common and its symptoms may cause difficulties in daily activities. In this study, medical data from 101 outpatient clinic attendees (mean age 43.9 years; 16 males) making their first visit for hypotension symptoms, were compared with meteorological data from the clinic's location. The main symptom of hypotension was giddiness on standing. The most common coexisting conditions were gastrointestinal; e.g. gastro-oesophageal reflux disorder and irritable bowel syndrome. The 7-day moving average of total global solar radiation correlated significantly with the 7-day moving average of the number of patients with hypotension. Discriminant analysis revealed an increase in hypotension consultations in the total global solar radiation moving average range 11-19 MJ/m(2), consistent with the local spring season. Guidance--such as wearing compression stockings during springtime--may help to reduce the occurrence of clinical hypotension in susceptible patients.

Can transcranial brain-targeted bright light treatment via ear canals be effective in relieving symptoms in seasonal affective disorder? A pilot study

Bright light therapy (BLT) is widely accepted as first-line treatment of seasonal affective disorder (SAD). However, the mechanism of action of BLT is still widely unknown. On the other hand, in mammals, light penetrates the skull bone and reaches the brain, and extra ocular transcranial phototransduction has physiological influences such as changed reproductive cycles and increased brain serotonin levels. Therefore, we challenged the existing conceptual framework that light therapy would only be mediated through the eyes. Consequently, we run a pilot study on the putative effect of transcranial bright light in the treatment of SAD. The light was produced using light-emitting diodes (LEDs), which were attached to earplugs. The amount of photic energy was 6.0-8.5 lumens in both ear canals, and the length of treatment was 8 or 12 min five times a week during a four-week study period. Subjects were recruited through advertisements in the city of Oulu, Finland (latitude 65°01'N) during 14 January 2009-03 February 2009. The final patient series consisted of 13 (aged 37.1 ± 7.2 years) physically healthy indoor workers suffering from SAD according to DSM-IV-TR criteria. Severity of depressive symptoms was assessed using the 17-item Hamilton Depression Rating Scale (HAMD-17) and Beck Depression Inventory (BDI)-21. Furthermore, severity of anxiety symptoms was measured by the 14-item Hamilton Anxiety Rating Scale (HAMA). The HAMD-17 mean sum score at screening was 23.1 ± 1.6. Ten out of 13 SAD patients (76.9%) achieved full remission (i.e., HAMD-17 sum score ≤ 7), and 92.3% (12/13) at least 50% reduction in HAMD-17 sum scores at "Week 4". By using a mixed regression model of repeated measures (AR-1) controlling for age, gender, and HAMD-17 mean sum score at screening, significant differences were found comparing the HAMD-17 mean sum scores of "Week 0" with the corresponding scores at the "Week 3" (t=-2.05, p=0.045) and "Week 4" visit (t=-2.77, p=0.008). Correspondingly, significant differences were found comparing the BDI-21 mean sum scores (15.2 ± 6.7) of "Week 0" with the corresponding scores at the "Week 3" (t=-2.37, p=0.021) and "Week 4" visit (t=-3.65, p<0.001). The HAMA mean sum score at screening was 20.5 ± 5.4. During the study period, 12 out of 13 (92.3%) patients achieved at least 50% reduction in their HAMA sum scores, and in 10 out of 13 patients (76.9%), the HAMA sum score was <7. In conclusion, it is hard to believe that our findings could be explained solely by placebo effect. Consequently, the basic assumptions underlying extraocular photoreception in humans deserve to be reconsidered. Given that a proper placebo treatment can be implemented via ear canals, further investigations with randomized placebo-controlled and/or dose-finding study designs regarding the extraocular transcranial bright light in the treatment of SAD are called for.

Mood disorders, circadian rhythms, melatonin and melatonin agonists

Recent advances in the understanding of circadian rhythms have led to an interest in the treatment of major depressive disorder with chronobiotic agents. Many tissues have autonomous circadian rhythms, which are orchestrated by the master clock, situated in the suprachiasmatic nucleus (SNC). Melatonin (N-acetyl-5-hydroxytryptamine) is secreted from the pineal gland during darkness. Melatonin acts mainly on MT1 and MT2 receptors, which are present in the SNC, regulating physiological and neuroendocrine functions, including circadian entrainment, referred to as the chronobiotic effet. Circadian rhythms has been shown to be either misaligned or phase shifted or decreased in amplitude in both acute episodes and relapse of major depressive disorder (MDD) and bipolar disorder. Manipulation of circadian rhythms either using physical treatments (such as high intensity light) or behavioral therapy has shown promise in improving symptoms. Pharmacotherapy using melatonin and pure melatonin receptor agonists, while improving sleep, has not been shown to improve symptoms of depression. A novel antidepressant, agomelatine, combines 5HT2c antagonist and melatonin agonist action, and has shown promise in both acute treatment of MDD and in preventing relapse.

Abnormal hypothalamic response to light in seasonal affective disorder

BACKGROUND

Vulnerability to the reduction in natural light associated with fall/winter is generally accepted as the main trigger of seasonal affective disorder (SAD), whereas light therapy is a treatment of choice of the disorder. However, the relationship between exposure to light and mood regulation remains unclear. As compared with green light, blue light was shown to acutely modulate emotion brain processing in healthy individuals. Here, we investigated the impact of light on emotion brain processing in patients with SAD and healthy control subjects and its relationship with retinal light sensitivity.

METHODS

Fourteen symptomatic untreated patients with SAD (34.5 ± 8.2 years; 9 women) and 16 healthy control subjects (32.3 ± 7.7 years; 11 women) performed an auditory emotional task in functional magnetic resonance imaging during the fall/winter season, while being exposed to alternating blue and green monochromatic light. Scotopic and photopic retinal light sensitivities were then evaluated with electroretinography.

RESULTS

Blue light enhanced responses to auditory emotional stimuli in the posterior hypothalamus in patients with SAD, whereas green light decreased these responses. These effects of blue and green light were not observed in healthy control subjects, despite similar retinal sensitivity in SAD and control subjects.

CONCLUSIONS

These results point to the posterior hypothalamus as the neurobiological substrate involved in specific aspects of SAD, including a distinctive response to light and altered emotional responses.

Estimation of effective day length at any light intensity using solar radiation data

The influence of day length on living creatures differs with the photosensitivity of the creature; however, the possible sunshine duration (N₀) might be an inadequate index of the photoperiod for creatures with low light sensitivity. To address this issue, the authors tried to estimate the effective day length, i.e., the duration of the photoperiod that exceeds a certain threshold of light intensity. Continual global solar radiation observation data were gathered from the baseline surface radiation network (BSRN) of 18 sites from 2004 to 2007 and were converted to illuminance data using a luminous efficiency model. The monthly average of daily photoperiods exceeding each defined intensity (1 lx, 300 lx, … 20,000 lx) were calculated [defined as Ne_(lux)]. The relationships between the monthly average of global solar radiation (Rs), N₀, and Ne_(lux) were investigated. At low light intensity (<500 lx), Ne_(lux) were almost the same as N₀. At high light intensity (>10,000 lx), Ne_(lux) and Rs showed a logarithmic relationship. Using these relationships, empirical models were derived to estimate the effective day length at different light intensities. According to the validation of the model, the effective day length for any light intensity could be estimated with an accuracy of less than 11% of the mean absolute percentage error (MAPE) in the estimation of the monthly base photoperiod. Recently, a number of studies have provided support for a link between day length and some diseases. Our results will be useful in further assessing the relationships between day length and these diseases.

Circadian rhythms and depression: human psychopathology and animal models

Most organisms (including humans) developed daily rhythms in almost every aspect of their body. It is not surprising that rhythms are also related to affect in health and disease. In the present review we present data that demonstrate the evidence for significant interactions between circadian rhythms and affect from both human studies and animal models research. A number of lines of evidence obtained from human and from animal models research clearly demonstrate relationships between depression and circadian rhythms including (1) daily patterns of depression; (2) seasonal affective disorder; (3) connections between circadian clock genes and depression; (4) relationship between sleep disorders and depression; (5) the antidepressant effect of sleep deprivation; (6) the antidepressant effect of bright light exposure; and (7) the effects of antidepressant drugs on sleep and circadian rhythms. The integration of data suggests that the relationships between the circadian system and depression are well established but the underlying biology of the interactions is far from being understood. We suggest that an important factor hindering research into the underlying mechanisms is the lack of good animal models and we propose that additional efforts in that area should be made. One step in that direction could be the attempt to develop models utilizing diurnal animals which might have a better homology to humans with regard to their circadian rhythms. This article is part of a Special Issue entitled 'Anxiety and Depression'.

Seasonal symptoms in bipolar and primary care patients

BACKGROUND

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.

METHODS

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.

RESULTS

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.

LIMITATIONS

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.

CONCLUSIONS

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.

Insights on unemployment, unemployment insurance, and mental health

This paper contributes to the growing literature on the relationship between business cycles and mental health. It is one of the first applications in the economics literature to incorporate data on web searches from Google Insights for Search, and these unique data allow the opportunity to estimate the association between weekly unemployment insurance (UI) claims, in addition to monthly unemployment rates, and search indexes for "depression" and "anxiety". Results from state fixed effects models yield (1) a positive relationship between the unemployment rate and the depression search index and (2) a negative relationship between initial UI claims on the one hand and the depression and anxiety search indexes on the other. A lag analysis also shows that an extended period of higher levels of continued UI claims is associated with a higher depression search index.

Improvement in Fatigue, Sleepiness, and Health-Related Quality of Life with Bright Light Treatment in Persons with Seasonal Affective Disorder and Subsyndromal SAD

Objective. To investigate the effects of bright light treatment for secondary outcome measures and to explore and validate empirically derived subgroups and treatment effects in subgroups. Methods. A descriptive design. A sample of forty-nine persons (mean age of 45.8) with clinically assessed seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD) participated in a two-group clinical trial evaluating the effects of treatment with bright light therapy. A person-oriented cluster analysis was applied to study treatment effects in subgroups. Results. For the merged group, sleepiness (Epworth Sleepiness Scale), fatigue (fatigue questionnaire), and health-related quality of life (SF-36) were improved at posttreatment, and results were maintained at the one-month followup. Three distinct subgroups had a high level of fatigue in common, while the level of excessive daytime sleepiness and depressed mood differed between the subgroups. Over time, all subgroups improved following ten days treatment in a light room. Conclusion. Fatigue, excessive daytime sleepiness, and health-related quality of life improve in a similar way as depressed mood following treatment with bright light. The treatment was effective irrespective of the severity of the disorder, that is, for persons with SAD and subsyndromal SAD.

Does the weather make us sad? Meteorological determinants of mood and depression in the general population

It is a common and well-spread belief that people feel more depressed when the weather is bad. However, whether meteorological factors such as temperature, sunshine and rainfall can actually account for variations in the prevalence of depression in the general population has yet to be investigated. We aimed to assess the influence of weather conditions on the seasonal variation of depression observed in the general population. We used data from a large-scale depression-screening programme in the south of the Netherlands. Seasonal prevalence of DSM-IV classified major depression and sad mood in a sample of 14,478 participants from the general population was calculated, and linked to mean daily temperature, duration of sunshine and duration of rainfall in logistic regression analyses. The prevalence of major depression and sad mood showed seasonal variation, with peaks in the summer and fall. Weather conditions were not associated with mood, and did not explain the seasonal variation we found. We conclude that, contrary to popular belief, weather conditions and sad mood or depression do not seem to be associated. Future studies might use daily measures of well-being as outcome.

Darkness reduces BDNF expression in the visual cortex and induces repressive chromatin remodeling at the BDNF gene in both hippocampus and visual cortex

Neuronal activity regulates the expression of brain-derived neurotrophic factor (BDNF) in brain. In darkness, reduced neuronal activity in the visual cortex markedly decreases total BDNF transcription level in adult rats. Epigenetic mechanisms are crucially involved in the regulation of gene expression in response to environmental stimuli. In this study, we examined the effect of 1 week of light deprivation (LD) on the activity-dependent changes in BDNF expression from different promoters in the visual cortex and hippocampus. We analyzed the correlation between the chromatin state of Bdnf promoters, exon-specific transcripts levels, and total protein levels in light-deprived rats and in rats reared under normal light-dark cycle. We found that 1 week of LD significantly reduced Bdnf mRNA and protein in the visual cortex but not in the hippocampus. However, epigenetic analysis revealed that LD increased histone-3 methylation and DNA methylation at the Bdnf promoter IV in both the visual cortex and hippocampus. These data highlight the spatial differences in signaling pathways that lead to the BDNF expression in response to diminished ambient light.

Coming to grips with complex disorders: genetic risk prediction in bipolar disorder using panels of genes identified through convergent functional genomics

We previously proposed and provided proof of principle for the use of a complementary approach, convergent functional genomics (CFG), combining gene expression and genetic data, from human and animal model studies, as a way of mining the existing GWAS datasets for signals that are there already, but did not reach significance using a genetics-only approach [Le-Niculescu et al., 2009b]. CFG provides a fit-to-disease prioritization of genes that leads to generalizability in independent cohorts, and counterbalances the fit-to-cohort prioritization inherent in classic genetic-only approaches, which have been plagued by poor reproducibility across cohorts. We have now extended our previous work to include more datasets of GWAS, and more recent evidence from other lines of work. In essence our analysis is the most comprehensive integration of genetics and functional genomics to date in the field of bipolar disorder. Biological pathway analyses identified top canonical pathways, and epistatic interaction testing inside these pathways has identified genes that merit future follow-up as direct interactors (intra-pathway epistasis, INPEP). Moreover, we have put together a panel of best P-value single nucleotide polymorphisms (SNPs), based on the top candidate genes we identified. We have developed a genetic risk prediction score (GRPS) based on our panel, and demonstrate how in two independent test cohorts the GRPS differentiates between subjects with bipolar disorder and normal controls, in both European-American and African-American populations. Lastly, we describe a prototype of how such testing could be used to categorize disease risk in individuals and aid personalized medicine approaches, in psychiatry and beyond.

ARNTL (BMAL1) and NPAS2 gene variants contribute to fertility and seasonality

BACKGROUND

Circadian clocks guide the metabolic, cell-division, sleep-wake, circadian and seasonal cycles. Abnormalities in these clocks may be a health hazard. Circadian clock gene polymorphisms have been linked to sleep, mood and metabolic disorders. Our study aimed to examine polymorphisms in four key circadian clock genes in relation to seasonal variation, reproduction and well-being in a sample that was representative of the general population, aged 30 and over, living in Finland.

METHODOLOGY/PRINCIPAL FINDINGS

Single-nucleotide polymorphisms in the ARNTL, ARNTL2, CLOCK and NPAS2 genes were genotyped in 511 individuals. 19 variants were analyzed in relation to 31 phenotypes that were assessed in a health interview and examination study. With respect to reproduction, women with ARNTL rs2278749 TT genotype had more miscarriages and pregnancies, while NPAS2 rs11673746 T carriers had fewer miscarriages. NPAS2 rs2305160 A allele carriers had lower Global Seasonality Scores, a sum score of six items i.e. seasonal variation of sleep length, social activity, mood, weight, appetite and energy level. Furthermore, carriers of A allele at NPAS2 rs6725296 had greater loadings on the metabolic factor (weight and appetite) of the global seasonality score, whereas individuals with ARNTL rs6290035 TT genotype experienced less seasonal variation of energy level.

CONCLUSIONS/SIGNIFICANCE

ARNTL and NPAS2 gene variants were associated with reproduction and with seasonal variation. Earlier findings have linked ARNTL to infertility in mice, but this is the first time when any polymorphism of these genes is linked to fertility in humans.

Seasonal trends in depressive problems among United States children and adolescents: a representative population survey

This study examined season-of-assessment differences in parent and child reports of depressive problems on well-validated instruments in 2009 U.S. children and adolescents, aged 6 to 18 years, from a nationally representative population survey. A parent completed the Child Behavior Checklist (CBCL) for each participant and 1226 of the 11-18-year-olds completed the Youth Self-Report (YSR). Outcome measures were CBCL and YSR withdrawn/depressed syndrome scale scores and rates of clinically elevated scores. Overall fall/winter versus spring/summer differences were not found on the CBCL or YSR for depressive problem severity or rates of depressive problems. Age, sex, and latitude were examined as potential moderators of the association between season-of-assessment and the outcomes. Of these, the effect of season-of-assessment on CBCL depressive problem severity depended upon age. Parents of 16-18-year-old adolescents rated depressive problems as significantly more severe in fall and winter than in spring and summer. Parents also rated depressive problems as significantly more severe in 16-18-year-olds than in 6-15-year-olds, but only when assessed in the fall and winter. There were no season-of-assessment differences among 6-15-year-old children and adolescents. The overall lack of season-of-assessment differences and the finding of age as a moderator on only one of four outcomes suggest minimal seasonality effects.

Convergent functional genomics of genome-wide association data for bipolar disorder: comprehensive identification of candidate genes, pathways and mechanisms

Given the mounting convergent evidence implicating many more genes in complex disorders such as bipolar disorder than the small number identified unambiguously by the first-generation Genome-Wide Association studies (GWAS) to date, there is a strong need for improvements in methodology. One strategy is to include in the next generation GWAS larger numbers of subjects, and/or to pool independent studies into meta-analyses. We propose and provide proof of principle for the use of a complementary approach, convergent functional genomics (CFG), as a way of mining the existing GWAS datasets for signals that are there already, but did not reach significance using a genetics-only approach. With the CFG approach, the integration of genetics with genomics, of human and animal model data, and of multiple independent lines of evidence converging on the same genes offers a way of extracting signal from noise and prioritizing candidates. In essence our analysis is the most comprehensive integration of genetics and functional genomics to date in the field of bipolar disorder, yielding a series of novel (such as Klf12, Aldh1a1, A2bp1, Ak3l1, Rorb, Rora) and previously known (such as Bdnf, Arntl, Gsk3b, Disc1, Nrg1, Htr2a) candidate genes, blood biomarkers, as well as a comprehensive identification of pathways and mechanisms. These become prime targets for hypothesis driven follow-up studies, new drug development and personalized medicine approaches.