24-h Monitoring of plasma norepinephrine, MHPG, cortisol, growth hormone and prolactin in depression

The Dual Faces of Oestrogen: The Impact of Exogenous Oestrogen on the Physiological and Pathophysiological Functions of Tissues and Organs

Oestrogen plays a crucial physiological role in both women and men. It regulates reproductive functions and maintains various non-reproductive tissues through its receptors, such as oestrogen receptor 1/oestrogen receptor α (ESR1/Erα), oestrogen receptor 2/oestrogen receptor β (ESR2/Erβ), and G protein-coupled oestrogen receptor 1 (GPER). This hormone is essential for the proper functioning of women's ovaries and uterus. Oestrogen supports testicular function and spermatogenesis in men and contributes to bone density, cardiovascular health, and metabolic processes in both sexes. Nuclear receptors Er-α and Er-β belong to the group of transcription activators that stimulate cell proliferation. In the environment, compounds similar in structure to the oestrogens compete with endogenous hormones for binding sites to receptors and to disrupt homeostasis. The lack of balance in oestrogen levels can lead to infertility, cancer, immunological disorders, and other conditions. Exogenous endocrine-active compounds, such as bisphenol A (BPA), phthalates, and organic phosphoric acid esters, can disrupt signalling pathways responsible for cell division and apoptosis processes. The metabolism of oestrogen and its structurally similar compounds can produce carcinogenic substances. It can also stimulate the growth of cancer cells by regulating genes crucial for cell proliferation and cell cycle progression, with long-term elevated levels linked to hormone-dependent cancers such as breast cancer. Oestrogens can also affect markers of immunological activation and contribute to the development of autoimmune diseases. Hormone replacement therapy, oral contraception, in vitro fertilisation stimulation, and hormonal stimulation of transgender people can increase the risk of breast cancer. Cortisol, similar in structure to oestrogen, can serve as a biomarker associated with the risk of developing breast cancer. The aim of this review is to analyse the sources of oestrogens and their effects on the endogenous and exogenous process of homeostasis.

Circadian rhythms and mood disorders: Time to see the light

The importance of time is ever prevalent in our world, and disruptions to the normal light/dark and sleep/wake cycle have now become the norm rather than the exception for a large part of it. All mood disorders, including seasonal affective disorder (SAD), major depressive disorder (MDD), and bipolar disorder (BD), are strongly associated with abnormal sleep and circadian rhythms in a variety of physiological processes. Environmental disruptions to normal sleep/wake patterns, light/dark changes, and seasonal changes can precipitate episodes. Moreover, treatments that target the circadian system have proven to be therapeutic in certain cases. This review will summarize much of our current knowledge of how these disorders associate with specific circadian phenotypes, as well as the neuronal mechanisms that link the circadian clock with mood regulation. We also discuss what has been learned from therapies that target circadian rhythms and how we may use current knowledge to develop more individually designed treatments.

Unraveling the interplay of circadian rhythm and sleep deprivation on mood: A Real-World Study on first-year physicians

The interplay between circadian rhythms, time awake, and mood remains poorly understood in the real-world. Individuals in high-stress occupations with irregular schedules or nighttime shifts are particularly vulnerable to depression and other mood disorders. Advances in wearable technology have provided the opportunity to study these interactions outside of a controlled laboratory environment. Here, we examine the effects of circadian rhythms and time awake on mood in first-year physicians using wearables. Continuous heart rate, step count, sleep data, and daily mood scores were collected from 2,602 medical interns across 168,311 days of Fitbit data. Circadian time and time awake were extracted from minute-by-minute wearable heart rate and motion measurements. Linear mixed modeling determined the relationship between mood, circadian rhythm, and time awake. In this cohort, mood was modulated by circadian timekeeping (p<0.001). Furthermore, we show that increasing time awake both deteriorates mood (p<0.001) and amplifies mood's circadian rhythm nonlinearly. These findings demonstrate the contributions of both circadian rhythms and sleep deprivation to underlying mood and show how these factors can be studied in real-world settings using Fitbits. They underscore the promising opportunity to harness wearables in deploying chronotherapies for psychiatric illness.

Administration Time and Dietary Patterns Modified the Effect of Inulin on CUMS-Induced Anxiety and Depression

SCOPE

Prebiotics exert anxiolytic and antidepressant effects through the microbiota-gut-brain axis in animal models. However, the influence of prebiotic administration time and dietary pattern on stress-induced anxiety and depression is unclear. In this study, whether administration time can modify the effect of inulin on mental disorders within normal and high-fat diets are investigated.

METHODS AND RESULTS

Mice subjected to chronic unpredicted mild stress (CUMS) are administered with inulin in the morning (7:30-8:00 am) or evening (7:30-8:00 pm) for 12 weeks. Behavior, intestinal microbiome, cecal short-chain fatty acids, neuroinflammatory responses, and neurotransmitters are measured. A high-fat diet aggravated neuroinflammation and is more likely to induce anxiety and depression-like behavior (p < 0.05). Morning inulin treatment improves the exploratory behavior and sucrose preference better (p < 0.05). Both inulin treatments decrease the neuroinflammatory response (p < 0.05), with a more evident trend for the evening administration. Furthermore, morning administration tends to affect the brain-derived neurotrophic factor and neurotransmitters.

CONCLUSION

Administration time and dietary patterns seem to modify the effect of inulin on anxiety and depression. These results provide a basis for assessing the interaction of administration time and dietary patterns, providing guidance for the precise regulation of dietary prebiotics in neuropsychiatric disorders.

Digital Biomarkers for Depression Screening With Wearable Devices: Cross-sectional Study With Machine Learning Modeling

Background

Depression is a prevalent mental disorder that is undiagnosed and untreated in half of all cases. Wearable activity trackers collect fine-grained sensor data characterizing the behavior and physiology of users (ie, digital biomarkers), which could be used for timely, unobtrusive, and scalable depression screening.

Objective

The aim of this study was to examine the predictive ability of digital biomarkers, based on sensor data from consumer-grade wearables, to detect risk of depression in a working population.

Methods

This was a cross-sectional study of 290 healthy working adults. Participants wore Fitbit Charge 2 devices for 14 consecutive days and completed a health survey, including screening for depressive symptoms using the 9-item Patient Health Questionnaire (PHQ-9), at baseline and 2 weeks later. We extracted a range of known and novel digital biomarkers characterizing physical activity, sleep patterns, and circadian rhythms from wearables using steps, heart rate, energy expenditure, and sleep data. Associations between severity of depressive symptoms and digital biomarkers were examined with Spearman correlation and multiple regression analyses adjusted for potential confounders, including sociodemographic characteristics, alcohol consumption, smoking, self-rated health, subjective sleep characteristics, and loneliness. Supervised machine learning with statistically selected digital biomarkers was used to predict risk of depression (ie, symptom severity and screening status). We used varying cutoff scores from an acceptable PHQ-9 score range to define the depression group and different subsamples for classification, while the set of statistically selected digital biomarkers remained the same. For the performance evaluation, we used k-fold cross-validation and obtained accuracy measures from the holdout folds.

Results

A total of 267 participants were included in the analysis. The mean age of the participants was 33 (SD 8.6, range 21-64) years. Out of 267 participants, there was a mild female bias displayed (n=170, 63.7%). The majority of the participants were Chinese (n=211, 79.0%), single (n=163, 61.0%), and had a university degree (n=238, 89.1%). We found that a greater severity of depressive symptoms was robustly associated with greater variation of nighttime heart rate between 2 AM and 4 AM and between 4 AM and 6 AM; it was also associated with lower regularity of weekday circadian rhythms based on steps and estimated with nonparametric measures of interdaily stability and autocorrelation as well as fewer steps-based daily peaks. Despite several reliable associations, our evidence showed limited ability of digital biomarkers to detect depression in the whole sample of working adults. However, in balanced and contrasted subsamples comprised of depressed and healthy participants with no risk of depression (ie, no or minimal depressive symptoms), the model achieved an accuracy of 80%, a sensitivity of 82%, and a specificity of 78% in detecting subjects at high risk of depression.

Conclusions

Digital biomarkers that have been discovered and are based on behavioral and physiological data from consumer wearables could detect increased risk of depression and have the potential to assist in depression screening, yet current evidence shows limited predictive ability. Machine learning models combining these digital biomarkers could discriminate between individuals with a high risk of depression and individuals with no risk.

Plasma prolactin is higher in major depressive disorder and females, and associated with anxiety, hostility, somatization, psychotic symptoms and heart rate

Background

Major Depressive Disorder (MDD) is linked to poor physical health including an increased risk of developing cardiometabolic disease (CMD), yet the underlying physiology of this relationship is not clear. One pathophysiological mechanism that may underlie this relationship is neuroendocrine dysregulation, including that of the hormone prolactin. Prolactin has a role in the regulation of stress, and it is linked to anxiety, hostility, and weight gain, which are all implicated in MDD and increased CMD risk. However, little research has examined plasma prolactin in association with psychological symptoms of MDD or biometric indices of CMD risk. Method: Plasma samples of 120 participants (n ​= ​60 meeting DSM-5 criteria for MDD and n ​= ​60 control; age and sex matched) were analysed to assess prolactin concentration. Biometric data (BMI, waist circumference, blood pressure and heart rate) were collected, and participants completed the Brief Symptom Inventory (BSI) and Depression Anxiety Stress Scale (DASS).

Results

Plasma prolactin was higher in participants with MDD versus controls (8.79 ​± ​5.16 ​ng/mL and 7.03 ​± ​4.78 ​ng/mL, respectively; F ​= ​4.528, p ​= ​0.035) and among females versus males (9.14 ​± ​5.57 ​ng/mL and 6.31 ​± ​3.70 ​ng/mL, respectively; F ​= ​9.157, p ​= ​0.003). Prolactin was correlated with several psychological symptoms including anxiety, hostility and somatization, and with heart rate, but not with any other biometric measures.

Conclusions

The results of this study indicate that neuroendocrine dysregulation in MDD may extend to the hormone prolactin, with prolactin being specifically associated with a subset of related psychometric and cardiovascular measures.

•

Plasma prolactin is higher in major depressive disorder group than in controls.

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Plasma prolactin is significantly higher in females versus males.

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Prolactin is significantly correlated with heart rate.

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Prolactin is correlated with paranoid ideation, anxiety, hostility, somatization.

Chronobiologic parameter changes in patients with major depressive disorder and sleep disturbance treated with adjunctive brexpiprazole: An open-label, flexible-dose, exploratory substudy

BACKGROUND

Circadian rhythm disturbances have been reported in patients with major depressive disorder (MDD). Among these is an increased phase angle between peak cortisol concentration and dim-light melatonin onset (DLMO). The aim of this study was to evaluate changes in chronobiologic parameters of sleep in patients with MDD receiving adjunctive brexpiprazole.

METHODS

This was an interventional, multicenter, open-label, flexible-dose, exploratory study in patients with MDD and inadequate response to antidepressant treatment who were experiencing sleep disturbances. Patients received adjunctive brexpiprazole 2-3 mg/day for 8 weeks. Outcome measures included cortisol and melatonin levels, used to calculate phase angle, and the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN).

RESULTS

The mean (standard error) phase angle between peak cortisol and DLMO increased by 108 (61) minutes from baseline to Week 8 (n = 9). BRIAN Total score changed (improved) by -14.6 (4.6) points from baseline to Week 8 (n = 9). Change in phase angle and BRIAN Total score showed a moderate-to-high correlation (Pearson coefficient: 0.68; 95% confidence limits: 0.04, 0.93; p = 0.040).

LIMITATIONS

This study is limited by its small sample size, and its single-arm, open-label design.

CONCLUSIONS

The findings provide a preliminary indication that the phase angle between peak cortisol and DLMO is of interest as a potential biomarker for depression and therapeutic response. Adjunctive brexpiprazole may represent a strategy for correcting circadian dysfunction in patients with MDD and inadequate response to antidepressant treatment. ClinicalTrials.gov identifier: NCT01942733.

Newly identified sleep-wake and circadian circuits as potential therapeutic targets

Optogenetics and chemogenetics are powerful tools, allowing the specific activation or inhibition of targeted neuronal subpopulations. Application of these techniques to sleep and circadian research has resulted in the unveiling of several neuronal populations that are involved in sleep-wake control, and allowed a comprehensive interrogation of the circuitry through which these nodes are coordinated to orchestrate the sleep-wake cycle. In this review, we discuss six recently described sleep-wake and circadian circuits that show promise as therapeutic targets for sleep medicine. The parafacial zone (PZ) and the ventral tegmental area (VTA) are potential druggable targets for the treatment of insomnia. The brainstem circuit underlying rapid eye movement sleep behavior disorder (RBD) offers new possibilities for treating RBD and neurodegenerative synucleinopathies, whereas the parabrachial nucleus, as a nexus linking arousal state control and breathing, is a promising target for developing treatments for sleep apnea. Therapies that act upon the hypothalamic circuitry underlying the circadian regulation of aggression or the photic regulation of arousal and mood pathway carry enormous potential for helping to reduce the socioeconomic burden of neuropsychiatric and neurodegenerative disorders on society. Intriguingly, the development of chemogenetics as a therapeutic strategy is now well underway and such an approach has the capacity to lead to more focused and less invasive therapies for treating sleep-wake disorders and related comorbidities.

Agomelatine treatment corrects impaired sleep-wake cycle and sleep architecture and increases MT1 receptor as well as BDNF expression in the hippocampus during the subjective light phase of rats exposed to chronic constant light

RATIONALE

Exposure to chronic constant light (CCL) has a detrimental impact on circadian rhythms of motor activity and sleep/wake cycles. Agomelatine is an atypical antidepressant showing a chronotropic activity.

OBJECTIVES

In this study, we explored the role of melatonin (MT) receptors and brain-derived neurotrophic factor (BDNF) in the brain in the mechanism underlying the effects of agomelatine on diurnal variations of motor activity, sleep/wake cycle, and sleep architecture in a rat model of CCL.

METHODS

In Experiment #1, home cage activity was monitored automatically with cameras for a period of 24 h. The diurnal rhythm of MT_1, MT₂ receptors, and BDNF expression in the hippocampus and frontal cortex (FC), was tested using the ELISA test. In Experiment #2, rats were equipped with electroencephalographic (EEG) and electromyographic (EMG) electrodes and recordings were made under basal conditions (12:12 LD cycle + vehicle), LL + vehicle and LL + agomelatine (40 mg/kg/day for 21 days).

RESULTS

The rats exposed to CCL showed an impaired diurnal rhythm of motor activity and sleep/wake cycle with reduced NREM sleep and delta power and increased REM sleep and theta power. The duration and number of episodes of the wake were diminished during the subjective dark phase in this group. The circadian rhythm of MT₁ and MT₂ receptors and their expression did not change in the hippocampus and FC under CCL exposure, while the BDNF levels in the hippocampus decreased during the subjective light phase. Agomelatine restored the diurnal rhythm of motor activity, disturbed sleep/wake cycle, and sleep architecture, which effect was accompanied by an increase in MT₁ receptor and BDNF expression in the hippocampus at 10:00 in CCL rats.

CONCLUSIONS

These findings support the value of agomelatine as an antidepressant that can adjust circadian homeostasis of motor activity and sleep/wake cycle in a CCL model.

Circadian regulation of depression: A role for serotonin

Synchronizing circadian (24 h) rhythms in physiology and behavior with the environmental light-dark cycle is critical for maintaining optimal health. Dysregulation of the circadian system increases susceptibility to numerous pathological conditions including major depressive disorder. Stress is a common etiological factor in the development of depression and the circadian system is highly interconnected to stress-sensitive neurotransmitter systems such as the serotonin (5-hydroxytryptamine, 5-HT) system. Thus, here we propose that stress-induced perturbation of the 5-HT system disrupts circadian processes and increases susceptibility to depression. In this review, we first provide an overview of the basic components of the circadian system. Next, we discuss evidence that circadian dysfunction is associated with changes in mood in humans and rodent models. Finally, we provide evidence that 5-HT is a critical factor linking dysregulation of the circadian system and mood. Determining how these two systems interact may provide novel therapeutic targets for depression.

Molecular basis for the association between depression and circadian rhythm

Depression is a life-threatening psychiatric disorder and a major public health concern worldwide with an incidence of 5% and a lifetime prevalence of 15%–20%. It is related with the social disability, decreased quality of life, and a high incidence of suicide. Along with increased depressive cases, health care cost in treating patients suffering from depression has also surged. Previous evidence have reported that depressed patients often exhibit altered circadian rhythms. Circadian rhythm involves physical, mental, and behavioral changes in a daily cycle, and is controlled by the suprachiasmatic nucleus of the hypothalamus in responding to light and darkness in an environment. Circadian rhythm disturbance in depressive patients causes early morning waking, sleep disturbances, diurnal mood variation, changes of the mean core temperature, endocrine release, and metabolic functions. Many medical interventions have been used to treat depression; however, several adverse effects are noted. This article reviews the types, causes of depression, mechanism of circadian rhythm, and the relationship between circadian rhythm disturbance with depression. Pharmaceutical and alternative interventions used to treat depressed patients are also discussed.

Depressive symptoms among metabolically healthy and unhealthy overweight/obese individuals: a comparative study

Background: Although a growing body of evidence suggests an association between obesity and depressive disorder, the association remains inconclusive. Metabolically healthy obese (MHO) phenotype, defined by favorable lipid profile, and normal insulin sensitivity, blood pressure, may be considered as a possible explanation for these inconsistencies. Accordingly, this study aimed to compare depression score among metabolic unhealthy obese (MUO) and age- and sex-matched healthy controls.

Methods: In this comparative study including 157 Iranian adults, we assigned participants into three groups (non-obese metabolic healthy group, MHO and MUO) according to the BMI cutoff and MetS criteria. Depressive symptoms were assessed by Beck Depression Inventory. Analysis was done using SPSS version 14.0. All variables are expressed as means ± SD. One-way ANOVA and multiple linear regression were used for data analysis.

Results: After adjustment for sex, marital status and educational level, MUO participants had significantly higher Beck depression score (P= 0.036) compared to MHO and non-obese metabolic healthy groups. After adjustment for demographic variables, there was a significant association between waist circumference (β = 0.142, p=0.023), BMI (β= 0.347, p= 0.037), FBS (β= 0.096, p< 0.001), and the number of MetS components (β= 1.71, p= 0.002) with depression score.

Conclusion: MHO was a benign phenotype in relation to depression.

Pathophysiology of Depression: Molecular Regulation of Melatonin Homeostasis - Current Status

Circadian rhythm alterations resulting in disturbed sleep and disturbed melatonin secretion are flagship features of depression. Melatonin, known as a hormone of darkness, is secreted by the pineal gland located near to the center of the brain between the two hemispheres. Melatonin has an antidepressant effect by maintaining the body's circadian rhythm, by regulating the pattern of expression of the clock genes in the suprachiasmatic nucleus (SCN) and modifying the key genes of serotoninergic neurotransmission that are linked with a depressive mood. Melatonin is produced via the metabolism of serotonin in two steps which are catalyzed by serotonin N-acetyltransferase (SNAT) and acetylserotonin-O-methyltransferase (ASMT). Serotonin, SNAT, and ASMT are key melatonin level regulation factors. Melatonin acts mainly on the MT1 and MT2 receptors, which are present in the SCN, to regulate physiological and neuroendocrine functions including circadian entrainment, referred to as a chronobiotic effect. Although melatonin has been known about and refereed to for almost 50 years, the relationship between melatonin and depression is still not clear. In this review, we summarize current knowledge about the genetic and epigenetic regulation of enzymes involved in melatonin synthesis and metabolism as potential features of depression pathophysiology and treatment. Confirmation that melatonin metabolism in peripheral blood partially reflects a disorder in the brain could be a breakthrough in the standardization of measurements of melatonin level for the development of treatment standards, finding new therapeutic targets, and elaborating simple noninvasive clinical tests.

Agomelatine treatment corrects symptoms of depression and anxiety by restoring the disrupted melatonin circadian rhythms of rats exposed to chronic constant light

Desynchronization of circadian rhythms is a hallmark of depression. The antidepressant agomelatine, which is an MT₁/MT₂ melatonin receptor agonist/5-HT_2C serotonin receptor antagonist has advantages compared to the selective serotonin reuptake inhibitors as a circadian phase-shifting agent. The present study was designed to explore whether agomelatine is able to have an antidepressant effect on rats exposed to chronic constant light (CCL) for 6 weeks. Focus is also placed on whether this activity affects diurnal rhythms of depressive-like symptoms and is associated with restoration of impaired circadian rhythms in plasma melatonin and corticosterone. We report that CCL induced a depressive-like symptoms associated with decreased grooming in the splash test during the subjective light/inactive phase. Anhedonia-like deficit in the saccharine preference test and increased immobility in the forced swimming test were both detected during the subjective dark/active phase. The disturbed emotional fluctuations due to CCL were corrected by agomelatine treatment (40 mg/kg, i.p. for 3 weeks). Agomelatine also restored novelty-induced hypophagia, which reflects an anxiety state, during the subjective Light and Dark phase, respectively, in rats exposed to CCL. Parallel to the observed positive influence on behavior, this melatonin analogue restored impaired circadian patterns of plasma melatonin but not that of corticosterone. These findings demonstrated the antidepressant-like effect of agomelatine in rats exposed to CCL possibly exerted via correction of melatonin rhythms and are suggestive of the therapeutic potential of this drug in a subpopulation of people characterized by a melatonin deficit.

Relationship Between the Cortisol-Estradiol Phase Difference and Affect in Women

Affective disorders impact women's health, with a lifetime prevalence of over twelve per cent. They have been correlated with reproductive cycle factors, under the regulation of hormonal circadian rhythms. In affective disorders, circadian rhythms may become desynchronized. The circadian rhythms of cortisol and estradiol may play a role in affective disorders. The purpose of this study was to explore the temporal relationship between the rhythms of cortisol and estradiol and its relationship to affect. It was hypothesized that a cortisol-estradiol phase difference (PD) exists that correlates with optimal affect. A small scale, comparative, correlational design was used to test the hypothesis. Twenty-three women were recruited from an urban university. Salivary samples were collected over a twenty-four-hour period and fitted to a cosinor model. Subjective measures of affect were collected. Relationships between the cortisol-estradiol PD and affect were evaluated using a second-degree polynomial equation. Results demonstrated a significant correlation in affect measures (p < 0.05). An optimal PD was identified for affect to be 3.6 hours. The phase relationship between cortisol and estradiol may play a role in the development of alterations in affective disorders.

New directions for the treatment of depression: Targeting the photic regulation of arousal and mood (PRAM) pathway

Both preclinical and clinical studies demonstrate that depression is strongly associated with reduced light availability, which in turn contributes to decreased function of brain regions that control mood. Here, we review findings that support a critical pathway for the control of mood that depends upon ambient light. We put forward a novel hypothesis, functionally linking retina to locus coeruleus (LC) in depression, and discuss the role of norepinephrine in affective disease. Finally, we discuss how utilizing the chemogenetic tool Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to precisely control this retina-LC circuit may be used as a novel therapeutic to treat depression.

Metabolically healthy obesity and depressive symptoms: 16-year follow-up of the Gazel cohort study

Aims

The health correlates of the metabolically healthy obese (MHO) phenotype, particularly in relation to depressive symptoms remains unclear. Accordingly, we examined the risk of depressive symptoms in this phenotype using a 16-year follow-up prospective study.

Methods

A sample of 14 475 participants (75% men), aged 44–59 years in 1996, was drawn from the Gazel cohort. Obesity was defined as body mass index (BMI) ≥ 30 kg/m² and metabolic health as having none of the self-reported following cardiovascular risk factors: hypertension, type 2 diabetes and dyslipidemia. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression (CES-D) scale in 1996, 1999, 2002, 2005, 2008 and 2012. Generalized Estimating Equations (GEE) were used to estimate the risk of depressive symptoms during a follow-up of 16 years.

Results

In multivariate analyses, metabolically unhealthy normal weight [Odds Ratio (OR) = 1.37; 95% Confidence Interval (CI): 1.25–1.51], overweight [1.44 (1.31–1.59)] and obese [1.30 (1.10–1.54)] but not MHO participants [1.04 (0.81–1.32)] had higher risk of depressive symptoms at the start of follow-up compared to metabolically healthy normal weight individuals. Depressive symptoms decreased over time in metabolically healthy normal weight individuals [0.52 (0.50–0.55)], this decrease was less marked only in metabolically unhealthy obese participants [1.22 (1.07–1.40)]. Compared to MHO participants, metabolically unhealthy obese individuals were at increased risk of depression at the start of follow-up, but with a similar reduction of this risk over time.

Conclusion

Poor metabolic health, irrespective of BMI was associated with greater depressive symptoms at the start of follow-up, whereas a poorer course of depressive symptoms over time was observed only in those with both obesity and poor metabolic health.

The Association of Work Characteristics With Ovarian Cancer Risk and Mortality

OBJECTIVE

Ovarian cancer (OvCA) is a leading cause of cancer death for women. Depression and social isolation have been associated with a higher OvCA risk and poorer survival, but other forms of chronic psychosocial stress, including work-related characteristics, remain understudied.

METHODS

Women from three prospective cohorts (Nurses' Health Study: n = 31,754; Nurses' Health Study II: n = 74,260; Northern Sweden Health and Disease Study: nnested case-control study = 196) completed a job questionnaire, assessing demand and control at work, social support provided by coworkers and supervisor, and job security. Multivariate Cox and conditional logistic regression models estimated hazard ratios (Nurses' Health Study/Nurses' Health Study II) and odd ratios (Northern Sweden Health and Disease Study) of OvCA risk and mortality among cases. Random coefficient models were used for meta-analyses.

RESULTS

There were 396 OvCA cases and 186 deaths during follow-up. Overall, job strain, strain chronicity, social support, and job security were not significantly associated with OvCA risk (e.g., pooled relative risk [RR]high demand/low control = 1.06, confidence interval [CI] = 0.72-1.55) or mortality (e.g., pooled RRhigh demand/low control = 1.08, CI = 0.64-1.82). When considered individually, compared with low levels, only moderate levels of demand were associated with a reduced OvCA risk (pooled RR = 0.66, CI = 0.49-0.90). Social support provided by the coworker or the supervisor did not moderate the association of job strain with either OvCA risk or overall mortality.

CONCLUSIONS

We did not observe clear associations between work characteristics and OvCA incidence or mortality, but further research with diverse populations is warranted.

Suicide behavior as a quantitative trait and its genetic background

INTRODUCTION

Studies have not given yet a clear answer what is the genetic background of suicidal predisposition. The associations between polymorphisms of the TPH1 and 5-HTTLPR genes and violent suicidal behavior was revealed with the least inconsistencies.

METHOD

We selected 10 "strong candidate genes" and 35 SNPs, SLC6A4 and ACP1 for replication study. We searched associations between precisely described suicidal phenotype in 825 affective patients and polymorphisms of selected neurobiological pathways genes as well as their interactions that constitute suicidal risk.

RESULTS

The results confirm the role of TPH1, TPH2, 5HT2A, CRHR1 and ACP1 variants in the risk of suicidal behavior.

LIMITATIONS

In our study we analyzed limited number of candidate genes and only one of them is linked to lithium mechanism of action. We had no data on pharmacological treatment of investigated patients and its relation to the time of suicide attempt.

CONCLUSION

Our results indicate that polymorphisms of various signaling pathways are involved in the pathogenesis of suicidal behavior. Non-genetic factors are also involved in the risk of suicidal attempts.

Depressive symptoms and obesity: instrumental variable analysis using mother-offspring pairs in the 1970 British Cohort Study

BACKGROUND

The extent to which depression and obesity are causally related remains to be determined. We used intergenerational data on mother-offspring pairs in an instrumental variable analysis to examine the longitudinal association between adolescent depressive symptoms and body mass index (BMI) in adulthood.

METHODS

A total of 4733 mother-offspring pairs were identified from the 1970 British Cohort Study. Mothers completed the Malaise Inventory to assess depressive symptoms on three occasions across their offsprings' childhood/adolescence (aged 5, 10 and 16 years). Height and weight were recorded in mother and offspring (aged 16 years). Measures of height, weight and the Malaise Inventory were repeated in the participant at the age of 42 years.

RESULTS

Maternal malaise score was associated with offspring malaise score, thus confirming the validity of the chosen instrumental variable. A higher mother's malaise score was associated with higher offspring BMI at follow-up (B=0.043; 95% confidence interval (CI): 0.013, 0.072). There was a higher risk of adulthood offspring obesity in mothers with two or three episodes of depression compared with one or none (odds ratio, 1.42; 95% CI: 1.14, 1.76). The maternal malaise-offspring BMI association remained (P=0.003) after adjustment for offspring malaise score, suggesting that maternal mental health influences offspring obesity through mechanisms other than depression. Results from standard and instrumental variable analyses did not support a causal pathway in a direction from BMI to depression.

CONCLUSIONS

Our data support a causal pathway linking adolescent depressive symptoms to adiposity in adulthood over 26 years follow-up. The reverse direction, that is, adiposity to depression, was not supported.

MicroRNAs as biomarkers for major depression: a role for let-7b and let-7c

There is a growing emphasis in the field of psychiatry on the need to identify candidate biomarkers to aid in diagnosis and clinical management of depression, particularly with respect to predicting response to specific therapeutic strategies. MicroRNAs are small nucleotide sequences with the ability to regulate gene expression at the transcriptomic level and emerging evidence from a range of studies has highlighted their biomarker potential. Here we compared healthy controls (n=20) with patients diagnosed with major depression (n=40) and who were treatment-resistant to identify peripheral microRNA biomarkers, which could be used for diagnosis and to predict response to electroconvulsive therapy (ECT) and ketamine (KET) infusions, treatments that have previously shown to be effective in treatment-resistant depression (TRD). At baseline and after treatment, blood samples were taken and symptom severity scores rated using the Hamilton Depression Rating Scale (HDRS). Samples were analyzed for microRNA expression using microarray and validated using quantitative PCR. As expected, both treatments reduced HDRS scores. Compared with controls, the baseline expression of the microRNA let-7b was less by ~40% in TRD patients compared with controls. The baseline expression of let-7c was also lower by ~50% in TRD patients who received ECT. Bioinformatic analysis revealed that let-7b and let-7c regulates the expression of 27 genes in the PI3k-Akt-mTOR signaling pathway, which has previously been reported to be dysfunctional in depression. The expression of miR-16, miR-182, miR-451 and miR-223 were similar to that in controls. Baseline microRNA expression could not predict treatment response and microRNAs were unaffected by treatment. Taken together, we have identified let-7b and let-7c as candidate biomarkers of major depression.

[Experience of the antidepressive therapy with valdoxan (agomelatine) in a psychogeriatric unit of the psychiatric hospital]

OBJECTIVE

To assess therapeutic efficacy, tolerability and safety of valdoxan (agomelatine) in the treatment of depression in elderly inpatients of the psychiatric hospital.

MATERIAL AND METHODS

The study included 20 patients, aged 60 years and older, with depression of varying severity. Patients received valdoxan in standard doses 25-50 mg/day during 42 days.

RESULTS

Valdoxan showed a good balanced profile (in terms of indicators of depression, anxiety and anhedonia) of therapeutic response and tolerability in inpatients with mild to moderate depression. The use of valdoxan led to a significant reduction of depressive disorders and anxiety already in the early period of treatment. The severity of anhedonia decreased to the 14th day of treatment. A significant improvement in cognitive functioning of patients was noted to the end of treatment.

CONCLUSION

Valdoxan can be recommended for treatment of mild and moderate depression in inpatients of psychiatric hospitals.

Latent activity rhythm disturbance sub-groups and longitudinal change in depression symptoms among older men

Activity rhythm disturbances and depression often co-occur among older adults. However, little is known about how activity rhythm disturbances themselves co-occur, or how disturbances to multiple aspects of the activity rhythm relate to depression over time. In this study, we performed a Latent Class Analysis to derive sub-groups of older men [total n = 2933, mean age = 76.28, standard deviation (SD) = 5.48] who shared similar patterns of activity rhythm disturbances (defined as extreme values of modeled activity rhythm parameters). We found eight sub-groups with distinct combinations of activity rhythm disturbances: one had all normative activity rhythm parameters (32.09%), one had only lower activity (10.06%), three had earlier activity (totaling 26.96%) and three had later activity (totaling 30.89%). Groups with similar timing were distinguished depending on whether the relative length of the active period was shorter and/or if the activity rhythm had lesser amplitude/robustness. We next examined whether the derived activity rhythm sub-groups were associated with different rates of change in depression symptom levels over an average of 5.5 (0.52 SD) follow-up years. The sub-group with lower activity only had faster increases in depressive symptoms over time (compared with the group with normative rhythm parameters), but this association was accounted for by adjustments for concurrently assessed health status covariates. Independent of these covariates, we found that four activity rhythm disturbance sub-groups experienced faster depressive symptom increases (compared with the normative sub-group): These included all three sub-groups that had later activity timing and one sub-group that had earlier activity timing plus a shorter active period and a dampened rhythm. Low activity rhythm height/robustness with normal timing therefore may mark depression risk that is attributable to co-occurring disease processes; in contrast, having late or combined early/compressed/dampened activity rhythms may independently contribute to depression symptom development. Our findings suggest that activity rhythm-related depression risk is heterogeneous, and may be detected when multiple aspects of rhythm timing are delayed or when early timing is accompanied by compressed/dampened activity rhythms. Future studies should consider how distinct combinations of altered activity rhythm timing and height/robustness develop and conjointly determine health risks. Further research is also needed to determine whether/how activity rhythms can be modified to improve depression outcomes.

Opening the Debate: How to Fulfill the Need for Physicians' Training in Circadian-Related Topics in a Full Medical School Curriculum

BACKGROUND

Circadian rhythms are daily changes in our physiology and behavior that are manifested as patterns of brain wave activity, periodic hormone production, recurring cell regeneration, and other oscillatory biological activities. Their importance to human health is becoming apparent; they are deranged by shift work and jet-lag and in disparate conditions such as insomnia, sleep syndromes, coronary heart attacks, and depression, and are endogenous factors that contribute to cancer development and progression.

DISCUSSION

As evidence of the circadian connection to human health has grown, so has the number of Americans experiencing disruption of circadian rhythms due to the demands of an industrialized society. Today, there is a growing work force that experiences night shift work and time-zone shifts shaping the demands on physicians to best meet the needs of patients exposed to chronic circadian disruptions. The diverse range of illness associated with altered rhythms suggests that physicians in various fields will see its impact in their patients. However, medical education, with an already full curriculum, struggles to address this issue.

SUMMARY

Here, we emphasize the need for incorporating the topic of circadian rhythms in the medical curriculum and propose strategies to accomplish this goal.

Depression and risk of epithelial ovarian cancer: Results from two large prospective cohort studies

OBJECTIVES

While emerging evidence supports a possible link between depression and ovarian cancer progression, no prospective studies have explored the association with ovarian cancer risk.

METHODS

We prospectively followed 77,451 women from the Nurses' Health Study (1992-2010) and 106,452 women from the Nurses' Health Study II (1993-2011). Depression was defined as having one or more of the following: a 5-item Mental Health Index (MHI-5) score≤52, antidepressant use, or physician-diagnosed depression. Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between depression and incident ovarian cancer.

RESULTS

We documented 698 incident cases of epithelial ovarian cancer during follow-up. In multivariable analyses, depression assessed 2-4years before cancer diagnosis was associated with a modestly higher incidence of ovarian cancer (HR=1.30, 95% CI 1.05-1.60). Compared to women with persistent negative depression status, the adjusted HRs were 1.34 (95% CI 1.01-1.76) for women with persistent positive depression status and 1.28 (95% CI 0.88-1.85) for women with worsening depression status over follow-up. The association did not appear to vary by ovarian cancer risk factors or tumor characteristics.

CONCLUSIONS

Our findings suggest that depression may be associated with a modestly increased risk of ovarian cancer. Given the relatively high prevalence of depression in women, future work in larger prospective human studies is needed to confirm our results.

Circadian rest-activity rhythms predict future increases in depressive symptoms among community-dwelling older men

OBJECTIVE

Circadian rest-activity rhythms (CARs) have been cross-sectionally associated with depressive symptoms, although no longitudinal research has examined whether CARs are a risk factor for developing depressive symptoms.

METHODS

We examined associations of CARs (measured with actigraphy over a mean of 4.8 days) with depressive symptoms (measured with the Geriatric Depression Scale) among 2,892 community-dwelling older men (mean age: 76.2 ± 5.5 years) from the MrOS Sleep Study who were without cognitive impairment. Among 2,124 men with minimal (0-2) symptoms at baseline, we assessed associations between CAR parameters and increases to mild (3-5) or clinically significant (≥6) symptoms after an average of 1.2 (±0.32) years.

RESULTS

Cross-sectional associations between rhythm height parameters were independent of chronic diseases, lifestyle, sleep, and self-reported physical activity covariates. For example, men in the lowest mesor quartile had twice the adjusted odds (adjusted odds ratio [AOR]: 2.04, 95% confidence interval [CI]: 1.36-3.04, p = 0.0005) of having prevalent clinically significant symptoms (compared to minimal). Longitudinally, low CAR robustness (being in the lowest quartile of the pseudo-F statistic) was independently associated with increasing odds of developing symptoms (i.e., AOR for having clinically significant depressive symptoms at follow-up = 2.58, 95% CI: 1.11-5.99, p = 0.03).

CONCLUSION

CAR disturbances are indicative of depressive symptomology. Low CAR robustness may independently contribute to the risk of worsening depression symptomology.

Suicidal behavior in the context of disrupted rhythmicity in bipolar disorder--data from an association study of suicide attempts with clock genes

Suicidal behavior exhibits both circadian and annual rhythms. We were seeking an association between selected candidate clock genes and suicidal behavior in bipolar patients. The study included 441 bipolar patients and 422 controls and we genotyped 41 SNPs of the CLOCK, ARNTL, TIMELESS, PER3 genes. The main positive findings built up associations between selected polymorphisms and.

Biological time series analysis using a context free language: applicability to pulsatile hormone data

We present a novel approach for analyzing biological time-series data using a context-free language (CFL) representation that allows the extraction and quantification of important features from the time-series. This representation results in Hierarchically AdaPtive (HAP) analysis, a suite of multiple complementary techniques that enable rapid analysis of data and does not require the user to set parameters. HAP analysis generates hierarchically organized parameter distributions that allow multi-scale components of the time-series to be quantified and includes a data analysis pipeline that applies recursive analyses to generate hierarchically organized results that extend traditional outcome measures such as pharmacokinetics and inter-pulse interval. Pulsicons, a novel text-based time-series representation also derived from the CFL approach, are introduced as an objective qualitative comparison nomenclature. We apply HAP to the analysis of 24 hours of frequently sampled pulsatile cortisol hormone data, which has known analysis challenges, from 14 healthy women. HAP analysis generated results in seconds and produced dozens of figures for each participant. The results quantify the observed qualitative features of cortisol data as a series of pulse clusters, each consisting of one or more embedded pulses, and identify two ultradian phenotypes in this dataset. HAP analysis is designed to be robust to individual differences and to missing data and may be applied to other pulsatile hormones. Future work can extend HAP analysis to other time-series data types, including oscillatory and other periodic physiological signals.

The noradrenaline metabolite MHPG is a candidate biomarker from the manic to the remission state in bipolar disorder I: a clinical naturalistic study

Remission is the primary goal of treatment for bipolar disorder I (BDI). Metabolites of noradrenaline and dopamine, 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA), respectively, are reduced by treatment with antipsychotics, but whether these phenomena are caused by antipsychotics or by the pathophysiology of BDI is not known. Interactions between brain-derived neurotrophic factor (BDNF) and mood disorders have also been suggested. We conducted a multifaceted study in BDI patients to ascertain if biological markers are associated with the manic state. Patients with Young Mania Rating Scale (YMRS) scores >20 participated in the study. Final analyses involved 24 BDI patients (13 men and 11 women). We used YMRS scores to identify mania stages in individual BDI patients (i.e., manic syndrome, response and remission stages). Statistical analyses were done using one-way repeated-measures analyses of variance (rep-ANOVA) throughout manic syndrome, response and remission stages. Plasma concentrations of MHPG and HVA were analyzed by high-performance liquid chromatography with electrochemical detection. Plasma levels of BDNF were measured by sandwich enzyme-linked immunosorbent assay. BDI patients had significantly reduced plasma levels of MHPG throughout manic syndrome, response and remission stages (rep-ANOVA, p = 0.002). Without a case of response state, there was a significant positive correlation between YMRS scores and plasma levels of MHPG (ρ = 0.33, p = 0.033, n = 48). Plasma levels of HVA and BDNF were not significantly altered throughout manic syndrome, response and remission stages. These data suggest that the peripheral level of MHPG (which is associated with noradrenaline levels in the brain) could be used as a biomarker for the manic state in BDI. The MHPG level is likely to reflect the clinical characteristics of the manic syndrome in BDI, and noradrenaline may reflect the pathophysiology from manic to remission states.

Light as a central modulator of circadian rhythms, sleep and affect

Light has profoundly influenced the evolution of life on earth. As widely appreciated, light enables us to generate images of our environment. However, light - through intrinsically photosensitive retinal ganglion cells (ipRGCs) - also influences behaviours that are essential for our health and quality of life but are independent of image formation. These include the synchronization of the circadian clock to the solar day, tracking of seasonal changes and the regulation of sleep. Irregular light environments lead to problems in circadian rhythms and sleep, which eventually cause mood and learning deficits. Recently, it was found that irregular light can also directly affect mood and learning without producing major disruptions in circadian rhythms and sleep. In this Review, we discuss the indirect and direct influence of light on mood and learning, and provide a model for how light, the circadian clock and sleep interact to influence mood and cognitive functions.

Antepartum depression severity is increased during seasonally longer nights: relationship to melatonin and cortisol timing and quantity

Current research suggests that mood varies from season to season in some individuals, in conjunction with light-modulated alterations in chronobiologic indices such as melatonin and cortisol. The primary aim of this study was to evaluate the effects of seasonal variations in darkness on mood in depressed antepartum women, and to determine the relationship of seasonal mood variations to contemporaneous blood melatonin and cortisol measures; a secondary aim was to evaluate the influence of seasonal factors on measures of melancholic versus atypical depressive symptoms. We obtained measures of mood and overnight concentrations of plasma melatonin and serum cortisol in 19 depressed patients (DP) and 12 healthy control (HC) antepartum women, during on-going seasonal variations in daylight/darkness, in a cross-sectional design. Analyses of variance showed that in DP, but not HC, Hamilton Depression Rating Scale (HRSD) scores were significantly higher in women tested during seasonally longer versus shorter nights. This exacerbation of depressive symptoms occurred when the dim light melatonin onset, the melatonin synthesis offset, and the time of maximum cortisol secretion (acrophase) were phase-advanced (temporally shifted earlier), and melatonin quantity was reduced, in DP but not HC. Serum cortisol increased across gestational weeks in both the HC and DP groups, which did not differ significantly in cortisol concentration. Nevertheless, serum cortisol concentration correlated positively with HRSD score in DP but not HC; notably, HC showed neither significant mood changes nor altered melatonin and cortisol timing or quantity in association with seasonal variations. These findings suggest that depression severity during pregnancy may become elevated in association with seasonally related phase advances in melatonin and cortisol timing and reduced melatonin quantity that occur in DP, but not HC. Thus, women who experience antepartum depression may be more susceptible than their nondepressed counterparts to phase alterations in melatonin and cortisol timing during seasonally longer nights. Interventions that phase delay melatonin and/or cortisol timing-for example, increased exposure to bright evening light-might serve as an effective intervention for antepartum depressions whose severity is increased during seasonally longer nights.

Manipulating melatonin in managing mood

OBJECTIVE

Disturbances in circadian rhythms have been associated with major depression and may be an underlying mechanism for the disorder. Resynchronisation of circadian rhythms may provide a new approach to treatment, especially by manipulating melatonin secretion. Melatonin is secreted at night and is a stable marker of circadian rhythms. The timing of its secretion can be changed by exogenous melatonin, agonism of specific melatonin receptors in the suprachiasmatic nucleus, its suppression by light and by sleep deprivation.

METHOD

As part of a series of papers ['Chronobiology of mood disorders' Malhi & Kuiper. Acta Psychiatr Scand 2013;128 (Suppl. 444): 2-15; and 'Getting depression clinical practice guidelines right: time for change?' Kuiper et al. Acta Psychiatr Scand 2013;128 (Suppl. 444): 24-30.] addressing chronobiology, in this article, we conducted a selective review of studies that have examined the antidepressant effects of exogenous melatonin, light therapy, sleep deprivation and melatonin receptor agonists.

RESULTS

Antidepressant effects were identified for bright light therapy, especially for seasonal affective disorder; sleep deprivation, although its antidepressant effect is time limited; and for the novel antidepressant agomelatine with agonistic properties for the MT1 and MT2 receptors and antagonism of 5HT2c receptor. The role of melatonin as an antidepressant has yet to be demonstrated.

CONCLUSION

Shifting the circadian secretion of melatonin using the strategies reviewed offers a new approach to treating depression.

Manipulating the sleep-wake cycle and circadian rhythms to improve clinical management of major depression

BACKGROUND

Clinical psychiatry has always been limited by the lack of objective tests to substantiate diagnoses and a lack of specific treatments that target underlying pathophysiology. One area in which these twin failures has been most frustrating is major depression. Due to very considerable progress in the basic and clinical neurosciences of sleep-wake cycles and underlying circadian systems this situation is now rapidly changing.

DISCUSSION

The development of specific behavioral or pharmacological strategies that target these basic regulatory systems is driving renewed clinical interest. Here, we explore the extent to which objective tests of sleep-wake cycles and circadian function - namely, those that measure timing or synchrony of circadian-dependent physiology as well as daytime activity and nighttime sleep patterns - can be used to identify a sub-class of patients with major depression who have disturbed circadian profiles.

SUMMARY

Once this unique pathophysiology is characterized, a highly personalized treatment plan can be proposed and monitored. New treatments will now be designed and old treatments re-evaluated on the basis of their effects on objective measures of sleep-wake cycles, circadian rhythms and related metabolic systems.

Cortisol and depression: three questions for psychiatry

BACKGROUND

Cortisol plays a multifaceted role in major depression disorder (MDD). Diurnal rhythms are disturbed, there is increased resistance to the feedback action of glucocorticoids, excess cortisol may induce MDD, basal levels may be higher and the post-awakening cortisol surge accentuated in those at risk for MDD. Does this suggest new avenues for studying MDD or its clinical management?

METHOD

The relevant literature was reviewed.

RESULTS

Cortisol contributes to genetic variants for the risk for MDD and the way that environmental events amplify risk. The corticoids' influence begins prenatally, but continues into adulthood. The impact of cortisol at each phase depends not only on its interaction with other factors, such as psychological traits and genetic variants, but also on events that have, or have not, occurred previously.

CONCLUSIONS

This review suggests that the time is now right for serious consideration of the role of cortisol in a clinical context. Estimates of cortisol levels and the shape of the diurnal rhythm might well guide the understanding of subtypes of MDD and yield additional indicators for optimal treatment. Patients with disturbed cortisol rhythms might benefit from restitution of those rhythms; they may be distinct from those with more generally elevated levels, who might benefit from cortisol blockade. Higher levels of cortisol are a risk for subsequent depression. Should manipulation of cortisol or its receptors be considered as a preventive measure for some of those at very high risk of future MDD, or to reduce other cortisol-related consequences such as long-term cognitive decline?

Saliva levels of 3-methoxy-4-hydroxyphenylglycol and clinical efficacy of mirtazapine or selective serotonin reuptake inhibitors in patients with major depression

OBJECTIVE

This study compared saliva levels of 3-methoxy-4-hydroxyphenylglycol (sMHPG) in patients with major depressive disorder (MDD) to levels in healthy controls and explored whether sMHPG levels in patients with MDD were a predictive marker for antidepressant efficacy.

METHODS

sMHPG levels were compared in 53 patients with MDD and 275 age-matched healthy controls. Patients' depressive symptoms were assessed by the 17-item Hamilton Rating Scale for Depression at baseline and 4 weeks after treatment with selective serotonin reuptake inhibitors (SSRIs, n = 23) or mirtazapine (n = 30), followed by saliva sampling. The mirtazapine group included nine patients who had been treated with an SSRI for more than 4 weeks without any improvement. sMHPG levels were measured by gas chromatography-mass spectrometry.

RESULTS

sMHPG levels in MDD patients were significantly higher than in controls. The responder rate to drug treatment at 4 weeks was 62% for mirtazapine (13/21), 57% for SSRIs (13/23), and 89% (8/9) for SSRI plus mirtazapine. sMHPG at baseline in 13 responders treated with SSRIs, but not mirtazapine, was significantly higher than that in non-responder group and showed consequent reduction 4 weeks after treatment. The area under the receiver operating characteristic (ROC) curves of sMHPG for discrimination of SSRI responders and non-responders was 0.86 ± 0.10 (95% confidence interval: 0.64-1.0, p = 0.005). In contrast, the ROC curve of sMHPG levels for discrimination of mirtazapine responders and non-responders was not significant. Adjunctive treatment with mirtazapine to SSRI non-responders was effective, regardless of baseline sMHPG levels.

CONCLUSION

sMHPG in patients with MDD was higher than in healthy controls. High baseline sMHPG levels in patients with MDD maybe a predictive marker for SSRI response.

Depression and coronary heart disease

There are exciting findings in the field of depression and coronary heart disease. Whether diagnosed or simply self-reported, depression continues to mark very high risk for a recurrent acute coronary syndrome or for death in patients with coronary heart disease. Many intriguing mechanisms have been posited to be implicated in the association between depression and heart disease, and randomized controlled trials of depression treatment are beginning to delineate the types of depression management strategies that may benefit the many coronary heart disease patients with depression.

Circadian activity of the hypothalamic-pituitary-adrenal axis is differentially affected in the rat chronic mild stress model of depression

The altered activity of the hypothalamic-pituitary-adrenal (HPA) axis is often observed in stress-related disorders. According to the literature, about 60% of patients with major depressive disorder elicit high levels of cortisol. It is still unclear why high cortisol levels are not observed in all patients. In this study, we used the chronic mild stress (CMS) rat model of depression, which is based on continuous exposure to unpredictable stressors, to track longitudinal changes in HPA function using fecal corticosterone metabolites (FCM) as a read out. The dexamethasone suppression test was used to assess negative feedback inhibition of the HPA axis. Our results show (1) a disturbance in diurnal corticosterone rhythm measured as fluctuations of the diurnal FCM peak, (2) differences in corticosterone levels between stress-susceptible and stress-resilient animals, (3) recovery of diurnal corticosterone rhythm after 8 weeks of CMS, and (4) alterations in sensitivity to dexamethasone in negative feedback regulation of corticosterone secretion during the time course of CMS. Thus, a disruption of HPA axis circadian rhythmicity coincides with the initial state in the development of depression-like behavior. This chronobiological abnormality, as well as the hypersecretion of corticosterone, is state, rather than trait, dependent.

Sympathetic nervous activity, depressive symptoms, and metabolic syndrome in black Africans: the sympathetic activity and ambulatory blood pressure in Africans study

The aim of this study was to examine the association between sympathetic nervous activity, depressive symptoms, and metabolic syndrome in a sample of black and Caucasian Africans. The sample consisted of healthy men and women: 194 blacks (aged, mean ± SD, 44.1 ± 7.9 years) and 206 Caucasians (aged, mean ± SD, 44.7 ± 10.8 years). Salivary 3-methoxy-phenylglycol (MHPG) concentration, the major metabolite of norepinephrine, was measured during the Stroop mental challenge. Depressive symptoms were assessed from the 9-item Patient Health Questionnaire. Metabolic syndrome (defined as central obesity plus any other two risk factors including raised serum triglycerides, reduced serum high-density lipoprotein- cholesterol, raised blood pressure, and raised fasting plasma glucose) was prevalent in 43.0% and 36.4% of blacks and Caucasians, respectively. In blacks there was, on average, a 16.4% increase in salivary MHPG concentration following mental stress, although no significant response was observed in Caucasians. The salivary MHPG response in blacks was associated with risk of metabolic syndrome (odds ratio [OR] = 1.11, 95% CI, 1.00-1.24) after adjusting for age, sex, and baseline salivary MHPG concentration. This association was mainly driven by the central obesity component of the metabolic syndrome. The salivary MHPG response was also related to moderate-severe depressive symptoms (OR = 1.16, 95% CI, 1.04-1.30), and further adjustment for depressive symptoms attenuated the association between salivary MHPG response and metabolic syndrome (OR = 1.07, 95% CI, 0.96-1.20). These data indicate an association between sympathetic activity, depressive symptoms, and metabolic syndrome in a sample of black Africans.

Risk of future depression in people who are obese but metabolically healthy: the English longitudinal study of ageing

There is some evidence to suggest that obesity is a risk factor for the development of depression, although this is not a universal finding. This discordance might be ascribed to the existence of a 'healthy obese phenotype'--that is, obesity in the absence of the associated burden of cardiometabolic risk factors. We examined whether the association of obesity with depressive symptoms is dependent on the individual's metabolic health. Participants were 3851 men and women (aged 63.0±8.9 years, 45.1% men) from the English Longitudinal Study of Ageing, a prospective study of community dwelling older adults. Obesity was defined as body mass index ≥30 kg m(-2). Based on blood pressure, high-density lipoprotein cholesterol, triglycerides, glycated haemoglobin and C-reactive protein, participants were classified as 'metabolically healthy' (0 or 1 metabolic abnormality) or 'unhealthy' (≥2 metabolic abnormalities). Depressive symptoms were assessed at baseline and at 2 years follow-up using the 8-item Centre of Epidemiological Studies Depression (CES-D) scale. Obesity prevalence was 27.5%, but 34.3% of this group was categorized as metabolically healthy at baseline. Relative to non-obese healthy participants, after adjustment for baseline CES-D score and other covariates, the metabolically unhealthy obese participants had elevated risk of depressive symptoms at follow-up (odds ratio (OR)=1.50; 95% confidence interval (CI), 1.05-2.15), although the metabolically healthy obese did not (OR=1.38; 95% CI, 0.88-2.17). The association between obesity and risk of depressive symptoms appears to be partly dependent on metabolic health, although further work is required to confirm these findings.

Rapid-acting antidepressant strategies: mechanisms of action

Current antidepressants are ineffective in many depressed patients. Thus there is an urgent need to develop treatment strategies which have significantly faster response, can be sustained and have minimal side-effects. This paper reviews clinical data, potential biomarkers, mechanisms of action and future research directions for two proven strategies that produce marked improvement in severe depressive symptoms within 48 h, ketamine and sleep deprivation therapy (SDT). These treatments provide unequivocal evidence that the depressive process can be rapidly reversed in a subgroup of patients. Seventeen ketamine studies in over 150 patients showed a rapid response. Low-dose intravenous ketamine produced mild psychotomimetic effects but response has not been effectively sustained. SDT has been investigated in over 60 studies with a 40-60% response rate within 48 h. Although SDT is often used in Europe to initiate a rapid response, it is less utilized within the USA, in part, because it has a short duration when administered alone. We review data concerning chronotherapeutic strategies of bright-light therapy (BLT) and sleep-phase advance (SPA) which successfully sustain the antidepressant efficacy of SDT. Evidence is further discussed that a significant group of mood disorders have abnormal circadian rhythms which are known to be controlled by clock genes. It is hypothesized that chronotherapeutic manipulations can reset clock genes and thus, abnormalities in circadian rhythms. Further findings are reviewed that ketamine, in addition to its role as an NMDA antagonist, can also alter circadian rhythms. Thus, ketamine may share a critical mechanism with SDT.

Depressive Symptoms and 24-Hour Ambulatory Blood Pressure in Africans: The SABPA Study

Disturbances in circadian rhythm might play a central role in the neurobiology of depression. We examined the association between depressive symptoms and 24-hour ambulatory BP in a sample of 405 (197 black and 208 Caucasian) urbanized African teachers aged 25 to 60 yrs (mean 44.6 ± 9.6 yrs). Depressive symptoms were assessed using the self-administered 9-item Patient Health Questionnaire (PHQ-9). After adjusting for age, sex, and ethnicity, participants with severe depressive symptoms (PHQ-9 ≥ 15) had higher odds of hypertension defined from ambulatory BP and/or use of antihypertensive medication (odds ratio = 2.19, 95% CI, 1.00–4.90) in comparison to participants with no symptoms. Compared to Caucasians with no depressive symptoms, those with severe symptoms had blunted nocturnal systolic BP drop of 4.7 mmHg (95% CI, −0.5 to 10.0, P = 0.07). In summary, depressive symptoms were associated with the circadian BP profile in black and Caucasian Africans.

Circadian rhythms and treatment implications in depression

In humans almost all physiological and behavioural functions occur on a rhythmic basis. Therefore the possibility that delays, advances or desynchronizations of circadian rhythms may play a role in the pathophysiology of psychiatric disorders is an interesting field of research. In particular mood disorders such as seasonal affective disorder and major depression have been linked to circadian rhythms alterations. Furthermore, the antidepressant efficacy of both pharmacological and non-pharmacological strategies affecting endogenous circadian rhythms, such as new antidepressant medications, light-therapy and sleep deprivation, is consistent with the idea that circadian alterations may represent a core component of depression, at least in a subgroup of depressed patients. This paper briefly describes the molecular and genetic mechanisms regulating the endogenous clock system, and reviews the literature supporting the relationships between depression, antidepressant treatments and changes in circadian rhythms.