Prolonged secretion of cortisol as a possible mechanism underlying stress and depressive behaviour

A Standardized Withania somnifera (Linn.) Root Extract with Piperine Alleviates the Symptoms of Anxiety and Depression by Increasing Serotonin Levels: A Double-Blind, Randomized, Placebo-Controlled Study

Background: Withania somnifera (Linn) or Ashwagandha is used in Ayurveda and other traditional medicine systems as an adaptogen and a neuroprotective supplement. Objective: The effect of Ashwagandha root extract (ARE) standardized for 2.5% full-spectrum withanolides as per The United States Pharmacopeia (USP) protocol with piperine (500 mg with 5 mg of 95% piperine) once a day (12.5 mg withanolides/day) was evaluated in individuals with mild to moderate depression and anxiety. Methods: In a randomized, double-blind placebo-controlled study, for 90 days, 70 participants were randomized to ARE (n = 34) or placebo (n = 36) once daily at night. Mean change in the Hamilton Depression Rating Scale (HDRS) and Hamilton Anxiety Rating Scale (HARS), Groningen Sleep Quality Scale (GSQS), and quality of life (QOL) from screening to days 30, 60, and 90 were evaluated. Safety was evaluated by monitoring any incidence of adverse events and laboratory parameters. Two-way analysis of variance (ANOVA) and repeated-measure ANOVA were used to compare ARE and placebo, and the changes within the group at different time points. Results: Seventy individuals were randomized and all of them completed the study. The HARS, HDRS, GSQS, and QOL scores improved significantly (p < 0.001) in all the participants taking ARE compared to placebo on days 30, 60, and 90. Anxiety and depression improved from baseline to end of the study in both groups, but the quantum of improvement was significantly higher in ARE. Serum levels of serotonin increased in ARE, but showed a decrease in placebo, the difference being statically significant (p < 0.001). Biochemical and hematological parameters remained in the normal range in all participants and ARE was well tolerated during the study. Conclusion: The results of the study suggest that 500 mg of ARE standardized for 2.5% withanolides with 5 mg piperine is beneficial in improving depression, and anxiety, by increasing serum serotonin levels. The trial was registered prospectively with the Clinical Trial Registry of India (CTRI) with the registration number CTRI/2022/05/042640, on May 18, 2022.

Clinical and instrumental features in 82 patients with insufficient sleep syndrome

Insufficient sleep syndrome possibly represents the worldwide leading cause of daytime sleepiness, but remains poorly recognised and studied. The aim of this case series is to comprehensively describe a cohort of patients with insufficient sleep syndrome. Eighty-two patients were studied concerning demographic and socio-economic features, medical, psychiatric and sleep comorbidities, substance use, sleep symptoms, actigraphy, video-polysomnography, multiple sleep latency tests and treatment. The typical patient with insufficient sleep syndrome is a middle-aged adult (with no difference of gender), employed, who has a family, often carrying psychiatric and neurological comorbidities, in particular headache, anxiety and depression. Other sleep disorders, especially mild sleep apnea and bruxism, were common as well. Actigraphy was a valuable tool in the characterisation of insufficient sleep syndrome, showing a sleep restriction during weekdays, associated with a recovery rebound of night sleep during weekends and a high amount of daytime sleep. An over- or underestimation of sleeping was common, concerning both the duration of night sleep and daytime napping. The average daily sleep considering both daytime and night-time, weekdays and weekends corresponds to the recommended minimal normal duration, meaning that the burden of insufficient sleep syndrome could mainly depend on sleep fragmentation and low quality. Sleep efficiency was elevated both in actigraphy and video-polysomnography. Multiple sleep latency tests evidenced a tendency toward sleep-onset rapid eye movement periods. Our study offers a comprehensive characterisation of patients with insufficient sleep syndrome, and clarifies their sleeping pattern, opening avenues for management and treatment of the disorder. Current options seem not adapted, and in our opinion a cognitive-behavioural psychotherapy protocol should be developed.

Dietary acid load in health and disease

Maintaining an appropriate acid-base equilibrium is crucial for human health. A primary influencer of this equilibrium is diet, as foods are metabolized into non-volatile acids or bases. Dietary acid load (DAL) is a measure of the acid load derived from diet, taking into account both the potential renal acid load (PRAL) from food components like protein, potassium, phosphorus, calcium, and magnesium, and the organic acids from foods, which are metabolized to bicarbonate and thus have an alkalinizing effect. Current Western diets are characterized by a high DAL, due to large amounts of animal protein and processed foods. A chronic low-grade metabolic acidosis can occur following a Western diet and is associated with increased morbidity and mortality. Nutritional advice focusing on DAL, rather than macronutrients, is gaining rapid attention as it provides a more holistic approach to managing health. However, current evidence for the role of DAL is mainly associative, and underlying mechanisms are poorly understood. This review focusses on the role of DAL in multiple conditions such as obesity, cardiovascular health, impaired kidney function, and cancer.

Clinical and Laboratory Characteristics of Fatigue-Dominant Long-COVID Subjects: A Cross-Sectional Study

BACKGROUND

Long COVID is defined by persistent symptoms following COVID-19 infection. Approximately 71% of individuals with long COVID experience ongoing fatigue, postexertional malaise, and cognitive impairments, which share pathological similarities with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This similarity has prompted studies to explore the characteristics of long COVID to gain a better understanding of ME/CFS. To gain insights, we investigated the clinical and laboratory characteristics of individuals with fatigue-dominant long COVID.

METHODS

We enrolled 100 subjects (36 males, 64 females) with long COVID who had a higher score than 60 in the modified Korean version of the Chalder Fatigue Scale (mKCFQ11) and higher than 5 in a fatigue-focused visual analogue scale. To investigate fatigue symptoms, the mKCFQ11, the Multidimensional Fatigue Inventory, a visual analogue scale for fatigue and brain fog, along with the Short-Form survey, were employed. We also measured 3 cytokines and cortisol levels for immunological and endocrinological indicators. As a cross-sectional observational study, the data were collected at a single point in time.

RESULTS

The mean scores on the measurements showed severe fatigue, and these scores were significantly correlated, with no differences based on sex, the post-COVID period, or age. Among the laboratory tests, plasma cortisol levels had a significant negative correlation with fatigue scores and a positive correlation with living quality. The negative correlation between cortisol levels and mKCFQ11 scores appeared to be more specific to mental fatigue than physical, which conflicted with other measurements.

CONCLUSION

Our findings provide the first insights into the characteristics of fatigue in individuals with long COVID, particularly in terms of fatigue severity and cortisol levels. These results serve as valuable reference data for clinicians dealing with fatigue symptoms in long-COVID patients and for researchers exploring postviral fatigue symptoms, including ME/CFS, in the future.

Presenilin-2 knock-In mice show severe depressive behavior via DVL3 downregulation

INTRODUCTION

Alzheimer's disease (AD) is the most common form of dementia. Depression is one of the most critical psychiatric complications of AD, and 20%-30% of patients with AD experience symptoms of depression. Phospho-glycogen synthase kinase-3 beta (GSK3β) is known to be associated with AD and depression. Furthermore, the role of disheveled (DVL) is known to regulate GSK3β. Moreover, presenilin-2 (PS2) and DVL have cross-talk with each other. Also, it is widely hypothesized that stress leads to hypersecretion of cortisol and is thus associated with depression. Dickkopf WNT signaling pathway inhibitor-1 (DKK-1) is a crucial factor regulating depression and both amyloid beta (Aβ) and phosphorylation of tau are widely known as a biomarker of AD.

METHODS

To investigate the relationship between AD and depression, and possible pathways connecting the two diseases, we examined memory function and depression-related behavior test results in PS2 knock-in AD mice (PS2 MT). Next, we confirmed that there are relationships between DVL, depression, and cognitive disease through the comparative toxicogenomics database (https://ctdbase.org) and STRING (https://string-db.org) database.

RESULTS

PS2 knock-in mice showed much more severe memory impairment and depression than PS2 wild-type mice (PS2 WT). In AD-related behavioral experiments, PS2 MT mice showed more memory dysfunction compared with PS2 WT group mice. Moreover, Aβ and phosphorylation of tau showed higher expression in PS2 MT mice than in PS2 WT mice. Depression-related behavioral tests showed that PS2 MT mice exhibited more depressive behaviors than PS2 WT mice. Furthermore, both higher cortisol levels and higher expression of DKK-1 were found in PS2 MT mice relative to PS2 WT mice. The results indicated that there is a relationship between DVL and the release of AD-related mediators and expression of the depression-related glucocorticoid receptor and DKK-1. In the PS2 knock-in group, DVL was significantly decreased compared with the PS2 WT group.

CONCLUSION

Depression increases the risk of developing AD and other forms of dementia. Recent evidence indicates that depression symptoms could trigger changes in memory and thinking over time. However, it is recognized that there are no drugs to facilitate a full recovery for both AD and depression. However, our results suggest that AD and depression could be associated, and DVL could be a significant target for the association between AD and depression.

A meta-analysis of the efficacy and safety of the traditional Chinese medicine formula Kaixinsan decoction for depression

BACKGROUND

Kaixinsan (KXS) decoction is a traditional Chinese herbal formulation commonly used to treat depression. This study aimed to evaluate the efficacy and safety of KXS, which is widely used, alone and in combination with other therapies, for the treatment of depression. The main objective was to assess the efficacy and safety of KXS in the treatment of depression as a single agent or in combination with other methods.

METHODS

Randomized controlled trials of KXS in the treatment of depression were systematically searched from several Chinese and English databases with no language restriction. Patients in these studies met the relevant diagnostic criteria for depression. Data on HAMD, SDS, practical situations, and occurrence of side effects in the studies were extracted. Finally, the methodological quality and risk of bias of the included studies were assessed using the Jadad scale and Cochrane bias evaluation tool.

RESULTS

Twelve studies with 1034 patients were included after screening. The Jadad scale and Cochrane bias evaluation tool indicated that the quality of the studies ranged from fair to good, with 41.7% categorized as good and 58.3% as poor. Egger test and funnel plots showed that the publication bias remain low.

CONCLUSION

The results showed that the frequency of side effects in the control group was higher than that in the treatment group, and there was a statistically significant difference. KXS was comparable or superior to antidepressants in treating depression and has fewer side effects. The data analysis showed that effectiveness and other indicators differed significantly by geographic area and dosage form, which has implications for future clinical work.

Chronic stress predisposes to the aggravation of inflammation in autoimmune diseases with focus on rheumatoid arthritis and psoriasis

The global incidence of autoimmune diseases is on the rise, and many healthcare professionals believe that chronic stress plays a prominent role in both the aggravation and remission of these conditions. It is believed that prolonged exposure to stress is associated with neuroimmune axis malfunction, which eventually dysregulates multiple immunological factors as well as deregulates autoimmune responses that play a central role in various autoimmune diseases, including rheumatoid arthritis and psoriasis. Herein, we performed validation of an 8-week long rat model of chronic unpredictable stress (CUS) which consisted of exposing groups of rats to random stressors daily for 8 weeks. Additionally, we developed a novel rat model combining 8-week long random stressor-induced CUS with CIA-triggered arthritis and IMQ-triggered psoriasis and have successfully used both these models to assess the role of chronic stress in the aggravation of arthritis and psoriasis, respectively. Notably, the 8-week CUS protocol extensively aggravated and prolonged both arthritis and psoriasis condition in the rat model by upregulating the release of different pro-inflammatory cytokines, dysregulation of immune cell responses and oxidative stress system, which were all related to severe inflammation. Further, CUS aggravated macroscopic features and the increase in destruction of joint tissue and epidermal thickness induced by CIA and IMQ, respectively, in rats. In conclusion, this study suggests that exposure to an 8-week long CUS paradigm aggravates the distinctive characteristics of rheumatoid arthritis and psoriasis in rats via amplifying the inflammatory circuits and immune cell responses linked to these autoimmune diseases.

Amelioration of modified chronic unpredictable stress using Celastrus paniculatus seed oil alone and in combination with fluoxetine

The various stressors in chronic unpredictable stress (CUS) triggers depressive behavior, impairs learning, and decision-making abilities. The present study investigated the effects of Celastrus paniculatus seed oil (CPSO) alone and in combination with fluoxetine (FLU) in modified CUS (mCUS) induced depression in mice. In this study, adult albino mice were subjected to a modified version of CUS protocol having six different stressors and were applied daily consistently for 15 days. The post-treatment with CPSO (50 and 100 mg/kg) and FLU (10 mg/kg) alone and in combination from day 16th to 36th. Group I: normal control; group II: diseased control (mCUS subjected group); group III: CPSO (50 mg/kg); group IV: CPSO (100 mg/kg); group V: CPSO (50 mg/kg)+FLU (10 mg/kg); group VI: CPSO (100 mg/kg)+FLU (10 mg/kg); group VII: FLU (10 mg/kg); group VIII: FLU (20 mg/kg). During experimentation, various behavioral, biochemical, oxidative stress, inflammatory, and neurotransmitters level were checked. The CUS treated mice exhibited increased escaped latency, decreased number of open arm entries, increased immobility time, decreased percentage of sucrose consumption, and number of the boxes crossed as compared to the normal group. The post-treatment with the CPSO 50 + FLU 10, CPSO 100 + FLU 10, FLU 10 significantly (p < 0.05) attenuated behavioral, biochemical, inflammation, corticosteroid, and neurotransmitters level as compared to CPSO 50, CPSO 100, and FLU 20 alone. CPSO along with FLU appreciably achieved anti-depressant effect via lowering stress, inflammation, corticosteroid level, and restoration of neurotransmitters level in mCUS induced depression mice model.

Risk of dementia and psychiatric or sleep disorders after diagnosis of adrenal adenomas: a population-based cohort study

OBJECTIVE

Adrenal adenomas are commonly encountered in clinical practice. To date, population-based data on their impact on cognition, mental health, and sleep are lacking. We aimed to study possible associations between adrenal adenomas and dementia, psychiatric or sleep disorders.

DESIGN

Population-based cohort study, Olmsted County, MN, 1995-2017.

METHODS

Patients with adrenal adenoma and absent overt hormone excess were age- and sex-matched 1:1 to a referent person without adrenal adenoma. Outcomes were baseline and incident diagnoses of dementia, psychiatric or sleep disorders, assessed using ICD codes.

RESULTS

Of 1004 patients with adrenal adenomas, 582 (58%) were women, and median age at diagnosis was 63 years. At baseline, and after adjusting for age, sex, education, BMI, and tobacco use, patients with adenoma had higher odds of depression (adjusted odds ratio, aOR: 1.3, 95% CI, 1.1-1.6), anxiety (aOR: 1.4, 95% CI, 1.1-1.8), and substance abuse (aOR: 2.4, 95% CI, 1.7-3.4) compared to referents. During a median follow-up of 6.8 years, and after adjusting for age, sex, socioeconomic status, BMI, tobacco, and substance abuse, patients demonstrated a higher risk of psychiatric and sleep disorders [adjusted hazard ratio (95% CI)]: depression [1.7 (1.3-2.2)], anxiety [1.4, CI (1.1-1.7)], insomnia [1.4 (1.0-1.9)], sleep-related breathing disorders [1.5 (1.1-1.9)], hypersomnias [2.1 (1.0-4.2)], parasomnias [2.1 (1.0-4.2)], and sleep-related movement disorders [1.5 (1.0-2.1)], but not dementia.

CONCLUSIONS

Patients with adenomas demonstrate a higher incidence of psychiatric and sleep disorders, possibly due to the underlying subtle increase in cortisol secretion.

Heterogeneous complement and microglia activation mediates stress-induced synapse loss

Spatially heterogeneous synapse loss is a characteristic of many psychiatric and neurological disorders, but the underlying mechanisms are unclear. Here, we show that spatially-restricted complement activation mediates stress-induced heterogeneous microglia activation and synapse loss localized to the upper layers of the mouse medial prefrontal cortex (mPFC). Single cell RNA sequencing also reveals a stress-associated microglia state marked by high expression of the apolipoprotein E gene (ApoE high ) localized to the upper layers of the mPFC. Mice lacking complement component C3 are protected from stress-induced layer-specific synapse loss, and the ApoE high microglia population is markedly reduced in the mPFC of these mice. Furthermore, C3 knockout mice are also resilient to stress-induced anhedonia and working memory behavioral deficits. Our findings suggest that region-specific complement and microglia activation can contribute to the disease-specific spatially restricted patterns of synapse loss and clinical symptoms found in many brain diseases.

Genetic polymorphisms in the serotonin, dopamine and opioid pathways influence social attention in rhesus macaques (Macaca mulatta)

Behaviour has a significant heritable component; however, unpicking the variants of interest in the neural circuits and molecular pathways that underpin these has proven difficult. Here, we present a comprehensive analysis of the relationship between known and new candidate genes from identified pathways and key behaviours for survival in 109 adult rhesus macaques (Macaca mulatta). Eight genes involved in emotion were analysed for variation at a total of nine loci. Genetic data were then correlated with cognitive and observational measures of behaviour associated with wellbeing and survival using MCMC-based Bayesian GLMM in R, to account for relatedness within the macaque population. For four loci the variants genotyped were length polymorphisms (SLC6A4 5-hydroxytryptamine transporter length-polymorphic repeat (5-HTTLPR), SLC6A4 STin polymorphism, Tryptophan 5-hydroxylase 2 (TPH2) and Monoamine oxidase A (MAOA)) whilst for the other five (5-hydroxytryptamine receptor 2A (HTR2A), Dopamine Receptor D4 (DRD4), Oxytocin receptor (OXTR), Arginine vasopressin receptor 1A (AVPR1a), Opioid receptor mu(μ) 1 (OPRM1)) SNPs were analysed. STin genotype, DRD4 haplotype and OXTR haplotype were significantly associated with the cognitive and observational measures of behaviour associated with wellbeing and survival. Genotype for 5-HTTLPR, STin and AVPR1a, and haplotype for HTR2A, DRD4 and OXTR were significantly associated with the duration of behaviours including fear and anxiety. Understanding the biological underpinnings of individual variation in negative emotion (e.g., fear and anxiety), together with their impact on social behaviour (e.g., social attention including vigilance for threat) has application for managing primate populations in the wild and captivity, as well as potential translational application for understanding of the genetic basis of emotions in humans.

Depression and Its Phytopharmacotherapy-A Narrative Review

Depression is a mental health disorder that develops as a result of complex psycho-neuro-immuno-endocrinological disturbances. This disease presents with mood disturbances, persistent sadness, loss of interest and impaired cognition, which causes distress to the patient and significantly affects the ability to function and have a satisfying family, social and professional life. Depression requires comprehensive management, including pharmacological treatment. Because pharmacotherapy of depression is a long-term process associated with the risk of numerous adverse drug effects, much attention is paid to alternative therapy methods, including phytopharmacotherapy, especially in treating mild or moderate depression. Preclinical studies and previous clinical studies confirm the antidepressant activity of active compounds in plants, such as St. John's wort, saffron crocus, lemon balm and lavender, or less known in European ethnopharmacology, roseroot, ginkgo, Korean ginseng, borage, brahmi, mimosa tree and magnolia bark. The active compounds in these plants exert antidepressive effects in similar mechanisms to those found in synthetic antidepressants. The description of phytopharmacodynamics includes inhibiting monoamine reuptake and monoamine oxidase activity and complex, agonistic or antagonistic effects on multiple central nervous system (CNS) receptors. Moreover, it is noteworthy that the anti-inflammatory effect is also important to the antidepressant activity of the plants mentioned above in light of the hypothesis that immunological disorders of the CNS are a significant pathogenetic factor of depression. This narrative review results from a traditional, non-systematic literature review. It briefly discusses the pathophysiology, symptomatology and treatment of depression, with a particular focus on the role of phytopharmacology in its treatment. It provides the mechanisms of action revealed in experimental studies of active ingredients isolated from herbal antidepressants and presents the results of selected clinical studies confirming their antidepressant effectiveness.

Protective effects and mechanisms of the Erzhi formula on glucocorticoid induced primary cortical neuron injury

High concentrations of glucocorticoids (GC) can cross the blood-brain barrier into the brain parenchyma, triggering a stress state that can lead to a range of physiological changes. This study investigated whether Erzhi formula has neuroprotective effects against glucocorticoid damage by establishing a dexamethasone-induced primary cortical neuron injury model in vitro. The results showed that Erzhi formula could reduce dexamethasone-induced apoptosis in primary cultured cortical neurons and improve synaptic damage. Further, network pharmacological analysis revealed that Erzhi formula may exert antidepressant effects by multi-component, multi-target, and multi-pathway characteristics, in which Salidroside, Biochanin-A and other ingredients are key components, HSD11B1, NR3C1, and other proteins are key targets, and steroid metabolism may be a key process in its action. Moreover, our study found that the neuroprotective effect of Erzhi formula might be related to the 11β-HSD1-GC/glucocorticoid receptor (GR) signaling pathway. The Erzhi formula could significantly inhibit the activity of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in vitro using homogeneous time-resolved fluorescence. In addition to providing evidence for the pharmacological effects of the Erzhi formula, the present study lays down the foundation for subsequent experiments.

The Oil Formulation Derived from Moringa Oleifera Seeds Ameliorates Behavioral Abnormalities in Water-immersion Restraint Stress Mouse Model

Purpose

Repeated stress events are well known to be associated with the onset of behavioral abnormalities including depression, anxiety and memory impairment. In spite of the traditional uses of Moringa oleifera (MO), no experimental evidence for its use against chronic stress exists. Here, we investigated whether seed oil from MO (MOO) could improve behavior abnormalities of chronic stress mice induced by water-immersion restraint stress (WIRS) and the underlying mechanism.

Methods

BALB/C male mice at 12 weeks of age were exposed to chronic WIRS for two weeks and divided in to four groups: normal group, WIRS group, WIRS+MOO1 group (treated with MOO at the dose of 1 mL/kg BW), and WIRS+MOO2 group (treated with MOO 2 mL/kg BW). The MOO treatment was given orally for 23 days. On day 24, we checked the behavior parameters, the plasma level of cortisol, acetylcholinesterase (AChE) activity in hippocampus, mRNA expression level of brain-derived neurotrophic factor (BDNF) and oxidative stress parameters in brain tissues. In addition, we also checked the histopathological features of the gastric mucosa wall.

Results

Administration of MOO ameliorated anxiety-like, depression-like and memory impairment phenotypes in the WIRS mouse model although the plasma cortisol concentrations were comparable among the groups. Of note, MOO both in two doses could suppress the AChE activity in hippocampus tissue and ameliorated the MDA level in prefrontal cortex tissue in mice exposed to WIRS. Although only WIRS+MOO2 group could increase the mRNA expression of BDNF, the histopathological gastric mucosa wall features were improved in all MOO groups.

Conclusion

Taken together, these finding suggested that MOO may have a neuroprotective effect in the mouse model of WIRS as evidenced by improving the abnormal behaviors through enhancing mRNA expression level of BDNF, inhibited AChE activity, and prevented the increase of MDA level in the brain.

Familial Linkage and Association of the NR3C1 Gene with Type 2 Diabetes and Depression Comorbidity

Impairment in the hypothalamic-pituitary-adrenal (HPA) axis and cortisol pathway may be major contributing factors to the common pathogenesis of major depressive disorders (MDD) and type 2 diabetes (T2D). A significant player in the neuroendocrine HPA axis and cortisol response is the glucocorticoid receptor (GR), which is encoded by the nuclear receptor subfamily 3 group C member (NR3C1) gene. Variants in the NR3C1 gene have been reported in patients with MDD and obesity and found to confer reduced risk for quantitative metabolic traits and T2D in Cushing syndrome; variants have not been reported in T2D and MDD-T2D comorbid patients. We studied 212 original Italian families with a rich family history for T2D and tested 24 single nucleotide polymorphisms (SNPs) in the NR3C1 gene for linkage to and linkage disequilibrium (LD) with T2D and MDD across different inheritance models. We identified a total of 6 novel SNPs significantly linked/in LD to/with T2D (rs6196, rs10482633, rs13186836, rs13184611, rs10482681 and rs258751) and 1 SNP (rs10482668) significantly linked to/in LD with both T2D and MDD. These findings expand understanding of the role that NR3C1 variants play in modulating the risk of T2D-MDD comorbidity. Replication and functional studies are needed to confirm these findings.

Cortisol Awakening Response and Stress in Female Nurses on Monthly Shift Rotations: A Longitudinal Study

The majority of shift nurses are female, there is still an expectation that they fulfil the traditional role of women in the family in Asia, often conflicting with shift work, increases stress, and affects cortisol secretion patterns. This study was to understand the changes in the cortisol awakening response (CAR) and work stress in nursing personnel working in different shifts. We recruited 41 female shift nurses. We administered the Taiwan Nurse Stress Checklist (NSC), and the nurses themselves collected saliva samples upon waking and 30 minutes after waking for three consecutive days at home. The saliva samples enabled us to analyze the increase in cortisol levels following waking (CARi) of nurses working different shifts (day, evening, and night). We then analyzed the data obtained using a hierarchical linear model (HLM). The results indicated that in terms of stress from the inability to complete personal tasks, the regression coefficients of night-shift nurses vs. day-shift nurses (B = 4.39, p < .001) and night-shift nurses vs. evening-shift nurses (B = 3.95, p < .001) were positive, which means that night-shift nurses were under significantly greater stress than day-shift and evening-shift nurses. With regard to CARi, the regression coefficients of night-shift nurses vs. day-shift nurses (B = −3.41, p < .001) and night-shift nurses vs. evening-shift nurses (B = −2.92, p < .01) were negative, which means that night-shift nurses have significantly lower CARi values than day-shift and evening-shift nurses. With regard to cortisol levels 30 minutes after waking, the regression coefficients of night-shift nurses vs. day-shift nurses (B = −3.88, p < .01) and night-shift nurses vs. evening-shift nurses (B = −3.31, p < .01) were negative, which means that night-shift nurses have significantly lower cortisol levels 30 minutes after waking than day-shift and evening-shift nurses. These results indicate that female night-shift nurses display the lowest CARi and cortisol levels 30 minutes after waking and are more negatively affected by being unable to complete personal tasks.

Hair cortisol as a risk marker for increased depressive symptoms among older adults during the COVID-19 pandemic

Determining pre-existing biological risk markers of incident depression and other mental health sequelae after exposure to a new stressor would help identify vulnerable individuals and mechanistic pathways. This study investigated primarily whether hair cortisol predicted elevated depressive symptoms in middle-aged and older adults during the COVID-19 pandemic, 6 years later. A secondary aim was to deduce whether any association differed by sex.

METHODS

We studied 1025 adults aged 50 and older (75% female) as part of The Irish Longitudinal Study on Ageing. Hair cortisol samples were collected at 2014 (Wave 3) and depressive symptoms were assessed using the 8-item Center for Epidemiological Studies Depression Scale in 2014 (Wave 3), 2016 (Wave 4), 2018 (Wave 5) and again in 2020 as part of TILDA's COVID-19 Study. Hierarchical mixed effects logistic regression models were applied to investigate the association between cortisol levels and clinically significant depressive symptoms before and during the COVID-19 pandemic.

RESULTS

In a full covariate adjusted model there was a significant interaction between cortisol and wave on depressive symptoms (χ2 = 8.5, p = .03). Cortisol was positively and significantly associated with elevated depressive symptoms during the COVID-19 Study (OR =1.3, 95% CI 1.11, 1.56, p = .003), and was associated with an increased likelihood of reporting clinically significant depressive symptoms during first year of the COVID-19 pandemic, when compared with before, OR = 1.4, 95% CI 1.05, 1.9, p = .015. There was no evidence of effect modification by sex.

CONCLUSIONS

Higher hair cortisol, assessed 6 years previously, predicted clinically significant depressive symptoms among middle-aged and older adults during (but not before) the pandemic. Findings suggest a biological phenotype which denotes increased susceptibility to the negative impact of environmental stress on psychological health.

Comorbidity of Novel CRHR2 Gene Variants in Type 2 Diabetes and Depression

The corticotropin-releasing hormone receptor 2 (CRHR2) gene encodes CRHR2, contributing to the hypothalamic–pituitary–adrenal stress response and to hyperglycemia and insulin resistance. CRHR2−/− mice are hypersensitive to stress, and the CRHR2 locus has been linked to type 2 diabetes and depression. While CRHR2 variants confer risk for mood disorders, MDD, and type 2 diabetes, they have not been investigated in familial T2D and MDD. In 212 Italian families with type 2 diabetes and depression, we tested 17 CRHR2 single nucleotide polymorphisms (SNPs), using two-point parametric-linkage and linkage-disequilibrium (i.e., association) analysis (models: dominant-complete-penetrance-D1, dominant-incomplete-penetrance-D2, recessive-complete-penetrance-R1, recessive-incomplete-penetrance-R2). We detected novel linkage/linkage-disequilibrium/association to/with depression (3 SNPs/D1, 2 SNPs/D2, 3 SNPs/R1, 3 SNPs/R2) and type 2 diabetes (3 SNPs/D1, 2 SNPs/D2, 2 SNPs/R1, 1 SNP/R2). All detected risk variants are novel. Two depression-risk variants within one linkage-disequilibrium block replicate each other. Two independent novel SNPs were comorbid while the most significant conferred either depression- or type 2 diabetes-risk. Although the families were primarily ascertained for type 2 diabetes, depression-risk variants showed higher significance than type 2 diabetes-risk variants, implying CRHR2 has a stronger role in depression-risk than type 2 diabetes-risk. In silico analysis predicted variants’ dysfunction. CRHR2 is for the first time linked to/in linkage-disequilibrium/association with depression-type 2 diabetes comorbidity and may underlie the shared genetic pathogenesis via pleiotropy.

Implication of Melanocortin Receptor Genes in the Familial Comorbidity of Type 2 Diabetes and Depression

The melanocortin receptors are G-protein-coupled receptors, which are essential components of the hypothalamic–pituitary–adrenal axis, and they mediate the actions of melanocortins (melanocyte-stimulating hormones: α-MSH, β-MSH, and γ-MSH) as well as the adrenocorticotropin hormone (ACTH) in skin pigmentation, adrenal steroidogenesis, and stress response. Three melanocortin receptor genes (MC1R, MC2R, and MC5R) contribute to the risk of major depressive disorder (MDD), and one melanocortin receptor gene (MC4R) contributes to the risk of type 2 diabetes (T2D). MDD increases T2D risk in drug-naïve patients; thus, MDD and T2D commonly coexist. The five melanocortin receptor genes might confer risk for both disorders. However, they have never been investigated jointly to evaluate their potential contributing roles in the MDD-T2D comorbidity, specifically within families. In 212 Italian families with T2D and MDD, we tested 11 single nucleotide polymorphisms (SNPs) in the MC1R gene, 9 SNPs in MC2R, 3 SNPs in MC3R, 4 SNPs in MC4R, and 2 SNPs in MC5R. The testing used 2-point parametric linkage and linkage disequilibrium (LD) (i.e., association) analysis with four models (dominant with complete penetrance (D1), dominant with incomplete penetrance (D2), recessive with complete penetrance (R1), and recessive with incomplete penetrance (R2)). We detected significant (p ≤ 0.05) linkage and/or LD (i.e., association) to/with MDD for one SNP in MC2R (rs111734014) and one SNP in MC5R (rs2236700), and to/with T2D for three SNPs in MC1R (rs1805007 and rs201192930, and rs2228479), one SNP in MC2R (rs104894660), two SNPs in MC3R (rs3746619 and rs3827103), and one SNP in MC4R genes (Chr18-60372302). The linkage/LD/association was significant across different linkage patterns and different modes of inheritance. All reported variants are novel in MDD and T2D. This is the first study to report risk variants in MC1R, MC2R, and MC3R genes in T2D. MC2R and MC5R genes are replicated in MDD, with one novel variant each. Within our dataset, only the MC2R gene appears to confer risk for both MDD and T2D, albeit with different risk variants. To further clarity the role of the melanocortin receptor genes in MDD-T2D, these findings should be sought among other ethnicities as well.

Characterization of antidepressant activity of Saraca asoca flower (Roxb.) Wilde in mice subjected to acute restraint stress

BACKGROUND

Long-term stress and chronic stress events play an important role in the etiology of depression. The study aimed to investigate the antidepressant-like effect of freshly prepared crude ethanolic extract of Saraca asoca flower (ESAF) in a mice model of acute restraint stress.

METHODOLOGY

Rhamnazin, Myricetin and Quercetin were analytically characterized through liquid chromatography-mass spectrometry and high-performance liquid chromatography from Saraca asoca flower in a 0.1% acetic acid fraction of ethanol. The antidepressant effect was tested by repeated administration of freshly prepared ESAF on mice subjected to repeated and different forms of stress induction for 2 hours every day in the morning and night for seven consecutive days. The antidepressant activity was measured by known behavioral animal models: forced swim test (FST) and tail suspension test (TST). At the end of the experiment, each group of mice was sacrificed by cervical dislocation, followed by an estimation of the biochemical data.

RESULTS

The oral administration of ESAF in doses of 50, 100, & 250 mg/kg for seven consecutive days gave a significant decrease in the time of immobility (P<0.05) and reversed the depression-like behavior induced by acute restraint methods and behavioral models. ESAF treated groups showed a significant increase in glutathione peroxidase (GSH-PX) activity in the hippocampus of the acutely restrained mice. In addition, ESAF 250 mg/kg reduced plasma corticosterone levels in mice subjected to different forms of acute restraint stress compared to other groups, comparable to the standard imipramine.

CONCLUSION

Our study showed the antidepressant activity of the ESAF. This effect may be attributed to the presence of antioxidant bioflavonoids namely, Rhamnazin, Myricetin and quercetin. Reduction in the plasma corticosterone levels along with an increase in the antioxidant enzymatic activity such as GSP-PX and SOD in the mice's hippocampus is the proposed molecular hypothesis for its neuroprotective mechanism.

The etiology of poststroke-depression: a hypothesis involving HPA axis

Approximately, one in three ischemic stroke survivors suffered from depression, namely, post-stroke depression (PSD). PSD affects functional rehabilitation and may lead to poor quality of life of patients. There are numerous explanations about the etiologies of PSD. Here, we speculated that PSD are likely to be the result of specific changes in brain pathology. We hypothesized that the stroke-induced hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis plays an important role in PSD. Stroke initiates a complex sequence of events in neuroendocrine system including HPA axis. The HPA axis is involved in the pathophysiology of depression, especially, the overactivity of the HPA axis occurs in major depressive disorder. This review summarizes the possible etiologies of PSD, focusing on the stroke-induced activation of HPA axis, mainly including the stress followed by severe brain damage and the proinflammatory cytokines release. The role of hyperactive of HPA axis in PSD was discussed in detail, which includes the role of high level corticotropin-releasing hormone in PSD, the effects of glucocorticoids on the alterations in specific brain structures, the expression of enzymes, excitotoxicity, the change in intestinal permeability, and the activation of microglia. The relationship between neuroendocrine regulation and inflammation was also described. Finally, the therapy of PSD by regulating HPA axis, neuroendocrine, and immunity was discussed briefly. Nevertheless, the change of HPA axis and the occurring of PSD maybe interact and promote on each other, and future investigations should explore this hypothesis in more depth.

The emotional impact of disrupted environmental contexts: Enrichment loss and coping profiles influence stress response recovery in Long-Evans rats

With increasing rates of anxiety and mood disorders across the world, there is an unprecedented need for preclinical animal models to generate translational results for humans experiencing disruptive emotional symptoms. Considering that life events resulting in a perception of loss are correlated with depressive symptoms, the enrichment-loss rodent model offers promise as a translational model for stress-initiated psychiatric disorders. Additionally, predisposed temperament characteristics such as coping styles have been found to influence an individual's stress response. Accordingly, male rats were profiled as either consistent or flexible copers and assigned to one of three environments: standard laboratory housing, enriched environment, or enriched environment exposure followed by downsizing to standard laboratory cages (i.e., enrichment-loss group). Throughout the study, several behaviors were assessed to determine stress, social, and reward-processing responses. To assess recovery of the stress response, fecal samples were collected following the swim stress in 3-h increments to determine the recovery trajectory of corticosterone (CORT) and dehydroepiandrosterone (DHEA) metabolite levels. Upon death, neural markers of neuroplasticity including doublecortin, glial fibrillary acidic factor, and brain-derived neurotrophic factor were assessed via immunohistochemistry. Results indicated the flexible coping animals in the continuous enriched group had higher DHEA/CORT ratios (consistent with adaptive responses in past research); furthermore, the enrichment-loss animals exhibited a blunted CORT response throughout the assessments and enriched flexible copers had faster CORT recovery rates than consistent copers. Standard housed animals exhibited less exploratory behavior in the open field task and continuous enriched, flexible rats consumed more food rewards than the other groups. No differences in neuroplasticity neural markers were observed. In sum, the results of the present study support past research indicating the disruptive consequences of enrichment-loss, providing evidence that the model represents a valuable approach for the investigation of neurobiological mechanisms contributing to interindividual variability in responses to changing experiential landscapes.

Depression and ischemic heart disease

Depression is common in patients with ischemic heart disease, and depressed patients are more likely to develop atherosclerosis and experience major cardiac events compared with the general population. The underlying pathophysiological mechanisms of these two diseases are highly interwoven and include an increased release of stress hormones, dysregulation of the autonomic nervous system, alterations of pathways related to primary and secondary hemostasis, endothelial dysfunction, and higher level of residual inflammation. Furthermore, depression negatively impacts compliance with medication regimens. As such, early recognition and treatment of depression provide the opportunity to improve outcomes of patients with ischemic heart disease. In the present review, we provide a summary of the evidence on the epidemiology, pathophysiology and management of depression in patients with ischemic heart disease.

Cortisol, Prolactin, and Breastmilk Volume; A Promising Pattern for Reducing Postpartum Depression

BACKGROUND: Research shows postnatal depression and shorter breastfeeding are consistently related, but their causal effect remains debatable. To reduce the impact of mental disorders in the perinatal period, lactation may give a significant neuroendocrine effect. AIM: This study aimed to examine hormonal patterns and estimated breastmilk volume of mothers with depression. MATERIALS AND METHODS: This study was conducted during the three-trimester to 6-week postnatal period. It involved 60 pregnant women from South Sulawesi, Indonesia. Analysis of variance with repeated measures was used to compare and review fluctuations and effect sizes of cortisol, prolactin, and breastmilk volume of mothers with depression symptoms. RESULTS: The mean cortisol levels rose in the 4th week and decreased in the 6th week in both groups. There was no substantial difference in the cortisol levels between these periods (p = 0.534; p = 0.553; and p = 0.660), but the prolactin levels continuously increased by 2 weeks and substantially progressed in the 4th and 6th weeks (p < 0.028, p < 0.009), respectively. There was no positive association between cortisol and prolactin levels (p = 0.384). The breastmilk volume was higher every week only in mothers without depression and it slightly decreased in other categories. This study emphasized the prolactin’s protective effect size on a stressful environment characterized by high cortisol; a significant rise in prolactin levels occurred in the 2nd and 4th weeks of postnatal, marking the higher lactation. CONCLUSIONS: Breastfeeding hormones may provide protection against postpartum depression in moms. It is critical to establish a history of prior trauma in nursing mothers in order to facilitate diagnosis and proper care.

Antidepressant-like Activity of Patchouli Oil var. Tapak Tuan (Pogostemon cablin Benth) via Elevated Dopamine Level: A Study Using Rat Model

Essential oils are gaining popularity for their use in treating depression, including that extracted from patchouli leaves and stems (Pogostemon cablin). Herein, we used patchouli oil (PO) containing a high amount of patchouli alcohol derived from P. cablin var. Tapak Tuan. The aim of this study was to investigate the antidepressant potential of PO, with a variety of patchouli alcohol concentrations obtained from a separation process using vacuum distillation with different temperature ranges. The initial patchouli oil (iPO) was traditionally distilled by a local farmer and further distilled using a rotary evaporator at temperature ranges of 115−160 °C (POF-1); 120−160 °C (POF-2), and 125−160 °C (POF-3), resulting in products with different patchouli alcohol concentrations. POF-3, with the highest patchouli alcohol content of 60.66% (based on gas chromatography-mass spectrometry), was used for cooling crystallization, resulting in 100% patchouli alcohol crystal (pPA). A tail suspension test (TST) was performed on a rat model to screen the antidepressant potential of iPO and its derivatives. The TST results revealed that POF-3 had the best antidepressant-like effect and was second only to the fluoxetine-based antidepressant, Kalxetin®, where both groups had significant reductions of immobility time post-treatment (p < 0.0001). Other than patchouli alcohol, POF-3 also contained ledol and trans-geraniol, which have been reported for their antidepressant-related activities. Brain dopamine levels increased significantly in the group treated with POF-3 (p < 0.05 as compared with the control group), suggesting its primary anti-depressant mechanism. These findings suggest the potential of vacuum-distilled patchouli oil in reducing depression via dopamine elevation.

Cell Model of Depression: Reduction of Cell Stress with Mirtazapine

Depression is a very prevalent and complex disease. This condition is associated with a high rate of relapse, making its treatment a challenge. Thus, an intensive investigation of this disease and its treatment is necessary. In this work, through cell viability assays (MTT and neutral red assays) and alkaline comet assays, we aimed to test the induction of stress in human SH-SY5Y cells through the application of hydrocortisone and hydrogen peroxide and to test the reversal or attenuation of this stress through the application of mirtazapine to the cells. Our results demonstrated that hydrogen peroxide, and not hydrocortisone, can induce cellular stress, as evidenced by DNA damage and a global cellular viability reduction, which were alleviated by the antidepressant mirtazapine. The establishment of a cellular model of depression through stress induction is important to study new possibilities of treatment of this disease using cell cultures.

Evaluating depression and anxiety throughout pregnancy and after birth: impact of the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic presents unique social, economic, and psychological challenges for individuals globally. Thus, women who are pregnant face unprecedented mental health challenges.

OBJECTIVE

We sought to determine the impact of the pandemic on perinatal depression and anxiety in a longitudinal pregnancy cohort. We hypothesized increased depression and anxiety scores in women during pregnancy and after birth in the pandemic at all time points.

STUDY DESIGN

Participants were enrolled in the Ontario Birth Study, a pregnancy cohort embedded in clinical care at Mount Sinai Hospital, Toronto, Canada. Perinatal depression and anxiety were assessed using the 2-Item Patient Health Questionnaire and 2-Item Generalized Anxiety Disorder Questionnaire in early pregnancy, whereas the Edinburgh Postnatal Depression Scale and 2-Item Generalized Anxiety Disorder Questionnaire were used in late pregnancy and after birth. Logistic regression models were created to examine the association of the pandemic with clinically elevated mental health scores in the prepandemic group vs pandemic group while adjusting for covariates.

RESULTS

A total of 1159 survey responses from 649 participants between March 1, 2019, and February 28, 2021, were used to conduct this study. Participants were assessed in early pregnancy (n=416), in late pregnancy (n=373), and after birth (n=370). Responses received on or before February 29, 2020, were considered the “prepandemic” responses, whereas responses after the aforementioned date were considered the “pandemic” responses. Mean rank scores of depression and anxiety were significantly higher in the pandemic group (P=.02 and P=.003, respectively) in the postpartum period. There was no significant association between pandemic time and antenatal scores. However, postnatally, mothers were 2.6 times more likely to score ≥13 on the Edinburgh Postnatal Depression Scale during the pandemic than before the pandemic (95% confidence interval, 1.2–5.7; P=.02). Adjustment for ethnicity and income strengthened this association as the odds ratio increased to 3.3 (95% confidence interval, 1.4–8.0; P=.007).

CONCLUSION

Pandemic-associated increases in depression and anxiety scores were confined to the postpartum period, highlighting a need for increased screening and interventions for perinatal mood and anxiety disorders postnatally as this pandemic continues.

Microglia and HPA axis in depression: An overview of participation and relationship

Objectives: This narrative review article provides an overview on the involvement of microglia and the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of depression, as well investigates the mutual relationship between these two entities: how microglial activation can contribute to the dysregulation of the HPA axis, and vice versa.Methods: Relevant studies and reviews already published in the Pubmed electronic database involving the themes microglia, HPA axis and depression were used to meet the objectives.Results: Exposition to stressful events is considered a common factor in the mechanisms proposed to explain the depressive disorder. Stress can activate microglial cells, important immune components of the central nervous system (CNS). Moreover, another system involved in the physiological response to stressors is the hypothalamic-pituitary-adrenal (HPA) axis, the main stress response system responsible for the production of the glucocorticoid hormone (GC). Also, mediators released after microglial activation can stimulate the HPA axis, inducing production of GC. Likewise, high levels of GCs are also capable of activating microglia, generating a vicious cycle.Conclusion: Immune and neuroendocrine systems seems to work in a coordinated manner and that their dysregulation may be involved in the pathophysiology of depression since neuroinflammation and hypercortisolism are often observed in this disorder.

Metabolomic characteristics of spontaneously hypertensive rats under chronic stress and the treatment effect of Danzhi Xiaoyao Powder, a traditional Chinese medicine formula

OBJECTIVE

Numerous studies have demonstrated the close relationship between chronic stress and blood pressure (BP). Hypertensive subjects exhibit exaggerated reactions to stress, especially higher BP. The mechanisms by which stress affects pre-existing hypertension still need to be explored. Danzhi Xiaoyao Powder (DP), a historical traditional Chinese medicine formula, is a promising treatment for BP control in hypertensive patients under stress. The present study investigated the metabolomic disruption caused by chronic stress and the treatment effect and mechanism of DP.

METHODS

Spontaneously hypertensive rats (SHRs) were subjected to chronic restraint stress (CRS) for 4 weeks. BP was measured via the tail-cuff method, and anxiety-like behavior was quantified using the elevated-plus-maze test. Meanwhile, DP was administered intragastrically, and its effects were observed. Global metabolomic analysis was performed using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, followed by multivariate statistical analysis to detect differential metabolites and pathways.

RESULTS

DP alleviated the CRS-induced increase in BP and anxiety-like behavior. Systematic metabolic differences were found among the three study groups. A total of 29 differential plasma metabolites were identified in both positive- and negative-ion modes. These metabolites were involved in triglyceride metabolism, amino acid (phenylalanine, tryptophan, and glycine) metabolism, and steroid hormone pathways.

CONCLUSION

These findings expose the metabolomic disturbances induced by chronic stress in SHRs and suggest an innovative treatment for this disorder.

Linking the Triad of Telomere Length, Inflammation, and Gut Dysbiosis in the Manifestation of Depression

Telomere length is an indispensable marker for cellular and biological aging, and it also represents an individual's physical and mental health status. Telomere shortening has been observed in chronic inflammatory conditions, which in turn accelerates aging and risk for psychiatric disorders, including depression. Considering the influence of inflammation and telomere shortening on the gut-brain axis, herein we describe a plausible interplay between telomere attrition, inflammation, and gut dysbiosis in the neurobiology of depression. Telomere shortening and hyperinflammation are well reported in depression. A negative impact of augmented inflammation has been noted on the intestinal permeability and microbial consortia and their byproducts in depressive patients. Moreover, gut dysbiosis provokes host-immune responses. As the gut microbiome is gaining importance in the manifestation and management of depression, herein we discuss whether telomere attrition is connected with the perturbation of commensal microflora. We also describe a pathological connection of cortisol with hyperinflammation, telomere shortening, and gut dysbiosis occurring in depression. This review summarizes how the triad of telomere attrition, inflammation, and gut dysbiosis is interconnected and modulates the risk for depression by regulating the systemic cortisol levels.

A momentary assessment study on emotional and biological stress in adult males and females with autism spectrum disorder

Prospective momentary psychological and biological measures of real-time daily life stress experiences have been examined in several psychiatric disorders, but not in adults with an autism spectrum disorder (ASD). The current electronic self-monitoring study examined associations between momentary daily life stressors and (i) negative affect (NA; emotional stress reactivity) and (ii) cortisol levels (biological stress reactivity) in males and females with ASD (N = 50) and without ASD (N = 51). The Experience Sampling Method, including saliva sampling, was used to measure three types of daily life stress (activity-related, event-related, and social stress), NA, and cortisol. Multilevel regression analyses demonstrated significant interactions between group and stress (i.e., activity-related and event-related stress) in the model of NA, indicating stronger emotional stress reactivity in the ASD than in the control group. In the model of cortisol, none of the group × stress interactions were significant. Male/female sex had no moderating effect on either emotional or biological stress reactivity. In conclusion, adults with ASD showed a stronger emotional stress (but not cortisol) reactivity in response to unpleasant daily life events and activities. The findings highlight the feasibility of electronic self-monitoring in individuals with ASD, which may contribute to the development of more personalized stress-management approaches.

Cortisol on Circadian Rhythm and Its Effect on Cardiovascular System

The synthesis and secretion of cortisol are controlled by the hypothalamic–pituitary–adrenal axis. Cortisol exhibits a proper 24-h circadian rhythm that affects the brain, the autonomic nervous system, the heart, and the vasculature that prepares the cardiovascular system for optimal function during these anticipated behavioral cycles. A literature search was conducted using databases such as Google Scholar, PubMed, and Scopus. Relevant search terms included “circadian rhythm and cardiovascular”, “cortisol”, “cortisol and acute coronary syndrome”, “cortisol and arrhythmias”, “cortisol and sudden cardiac death”, “cortisol and stroke”, and “cardioprotective agents”. A total of 120 articles were obtained on the basis of the above search. Lower levels of cortisol were seen at the beginning of sleep, while there was a rise towards the end of sleep, with the highest level reached at the moment the individual wakes up. In the present review, we discuss the role of 11β-hydroxysteroid dehydrogenase (11β-HSD1), which is a novel molecular target of interest for treating metabolic syndrome and type-2 diabetes mellitus. 11β-HSD1 is the major determinant of cortisol excess, and its inhibition alleviates metabolic abnormalities. The present review highlights the role of cortisol, which controls the circadian rhythm, and describes its effect on the cardiovascular system. The review provides a platform for future potential cardioprotective therapeutic agents.

Chronic unpredictable mild stress produces depressive-like behavior, hypercortisolemia, and metabolic dysfunction in adolescent cynomolgus monkeys

Adolescent depression is a common and serious mental disorder with unique characteristics that are distinct from adult depression. The adult non-human primate stress-induced model of depressive-like behavior is an excellent model for the study of mechanisms; however, an adolescent nonhuman primate model is still lacking. Ten male adolescent cynomolgus monkeys were divided into a chronic unpredictable mild stress (CUMS, n = 5) group and a control (CON, n = 5) group by age and weight-matched pairs. The CUMS group was exposed to multiple unpredictable mild stressors for five cycles over 55 days. At baseline, there were no differences between CUMS and CON groups. At endpoint, the CUMS group demonstrated significantly higher depressive-like behavior (huddle posture), and significantly lower locomotion compared with the CON group. Furthermore, depressive-like behavior increased from baseline to endpoint in the CUMS group, but not changed in the CON group. In the attempt for apple test, the CUMS group made significantly fewer attempts for the apple than the CON group. In the human intruder test, the CUMS group showed significantly higher anxiety-like behaviors in the stare phase than the CON group. Hair cortisol level was significantly higher in the CUMS group than the CON group at endpoint, and was also elevated from baseline to endpoint. Metabolic profiling of plasma at endpoint identified alterations in metabolite pathways which overlapped with those of adolescent depression patients. CUMS can induce depressive-like and anxiety-like behaviors, hypercortisolemia, and metabolic perturbations in adolescent cynomolgus monkeys. This is a promising model to study the mechanisms underlying adolescent depression.

Sleep Disturbances and Depression Are Co-morbid Conditions: Insights From Animal Models, Especially Non-human Primate Model

The incidence rates of depression are increasing year by year. As one of the main clinical manifestations of depression, sleep disorder is often the first complication. This complication may increase the severity of depression and lead to poor prognosis in patients. In the past decades, there have been many methods used to evaluate sleep disorders, such as polysomnography and electroencephalogram, actigraphy, and videography. A large number of rodents and non-human primate models have reproduced the symptoms of depression, which also show sleep disorders. The purpose of this review is to examine and discuss the relationship between sleep disorders and depression. To this end, we evaluated the prevalence, clinical features, phenotypic analysis, and pathophysiological brain mechanisms of depression-related sleep disturbances. We also emphasized the current situation, significance, and insights from animal models of depression, which would provide a better understanding for the pathophysiological mechanisms between sleep disturbance and depression.

The Combination of Serum BDNF, Cortisol and IFN-Gamma Can Assist the Diagnosis of Major Depressive Disorder

PURPOSE

Misdiagnosis and ineffective treatment are common in major depressive disorder (MDD) in current clinical practice, while the combination of various serum proteins may assist the correct diagnosis. The study aimed to explore whether the combination of serum inflammatory, stress, and neurotrophic factors could be helpful for the diagnosis of MDD and to investigate the predictors associated with early symptom improvements.

PATIENTS AND METHODS

Baseline serum levels of C-reactive protein (CRP), interleukin (IL)-6, IL-10, IL-1beta, tumor necrosis factor (TNF)-alpha, interferon (INF)-gamma, cortisol, and brain-derived neurotrophic factor (BDNF) were detected in 30 MDD patients and 30 age- and gender-matched healthy controls. 17-item Hamilton Depression Rating Scale (HAMD-17) and Hamilton Anxiety Rating Scale (HAMA) were applied to assess symptoms both at baseline and two weeks after antidepressant treatment. Stepwise multiple linear regression was employed to identify the early efficacy predictors, and a logistic regression model was built with the above serum proteins. The area under the receiver operating characteristic (AUC) curve was calculated to evaluate the model's diagnostic power.

RESULTS

Multiple linear regression revealed that baseline scores of retardation (β = -0.432, P = 0.012) and psychological anxiety (β = -0.423, P = 0.014) factors were negatively associated with the reduction rate of HAMD-17. A simple and efficient diagnostic model using serum BDNF, cortisol, and IFN-gamma levels was established by the forward stepwise logistic regression, and the model achieved an AUC of 0.884, with 86.7% sensitivity and 83.3% specificity.

CONCLUSION

The results showed that combining serum BDNF, cortisol and IFN-gamma could aid the diagnosis of MDD, while baseline retardation and psychological anxiety may predict the poor early symptom improvement.

Evaluation of Stress and Associated Biochemical Changes in Patients with Type 2 Diabetes Mellitus and Obesity

PURPOSE

Type 2 diabetes mellitus (T2DM), a metabolic disorder, remains associated with a physiological impairment affecting large populations worldwide. Onset of T2DM is multifactorial where obesity and abnormal basal metabolic rate are considered most critical. Of people diagnosed with T2DM, about 80% are also obese. It is also reported that obese individuals have an increased odds of developing depression, whereas T2DM is estimated to increase the incidence by two-fold. The preponderance of research data demonstrates that T2DM alters the serum level of cortisol and adiponectin which are known to be associated with neuronal physiology. The study explored, how a metabolic disorder like T2DM is linked with the altered plasma level of cortisol and adiponectin, the risk factors for stress and depression.

PATIENTS AND METHODS

A cross-sectional population study was conducted in T2DM patients using a bimodal approach. First approach used questionnaires, (1) Patient Health Questionnaire (PHQ-9) and (2) Stress Coping Inventory Questionnaire (SCQ) to assess signs and symptoms of depression and stress, respectively, in T2DM patients. In the second approach, robust biochemical analysis was conducted for serum adiponectin and cortisol levels.

RESULTS

An association of T2DM in stress and depression was evaluated in 158 subjects (105 T2DM obese patients and 53 healthy controls). A lower PHQ-9 score and adiponectin levels were seen in T2DM obese patients compared to healthy controls (p<0.05). Further, results also depicted a lower adiponectin levels in T2DM obese patients with depression compared to T2DM obese patients without depression (p<0.05). The study did not find a significant difference in cortisol serum levels among the T2DM and control groups. However, a higher level of serum cortisol was reported in T2DM obese patients with depression over those T2DM obese patients who lacked depression (p<0.05).

CONCLUSION

The findings suggest that T2DM obese patients might have a higher risk of developing stress and depression. Further, biochemical parameters, adiponectin and cortisol, might be the potential biomarkers for T2DM and may help in early diagnosis of these comorbid conditions.

Intracerebroventricular Administration of Interferon-Alpha Induced Depressive-Like Behaviors and Neurotransmitter Changes in Rhesus Monkeys

Interferon-alpha (IFN-α) is a cytokine widely used in the treatment of brain cancers and virus infections with side effects including causing depression. Monoamine neurotransmitter systems have been found playing important roles in peripheral IFN-α-induced depression, but how peripheral IFN-α accesses the central nervous system and contributes to the development of depression is poorly known. This study aimed to develop a non-human primate model using long-term intracerebroventricular (i.c.v.) administration of IFN-α (5 days/week for 6 weeks), to observe the induced depressive-like behaviors and to explore the contributions of monoamine neurotransmitter systems in the development of depression. In monkeys receiving i.c.v. IFN-α administration, anhedonia was observed as decreases of sucrose consumption, along with depressive-like symptoms including increased huddling behavior, decreases of spontaneous and reactive locomotion in home cage, as well as reduced exploration and increased motionless in the open field. Chronic central IFN-α infusion significantly increased the cerebrospinal fluid (CSF) concentrations of noradrenaline (NA), and 3,4-dihydroxyphenylacetic acid (DOPAC), but not 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA). These CSF monoamine metabolites showed associations with some specific depression-related behaviors. In conclusion, central IFN-α administration induced anhedonia and depression-related behaviors comparable to the results with peripheral administration, and the development of depression was associated with the dysfunction of monoamine neurotransmitters.

Effect of Bright Light Therapy on Depressive Symptoms in Middle-Aged and Older Patients Receiving Long-Term Hemodialysis

Depressive symptoms are common psychiatric comorbidities among individuals receiving long-term hemodialysis. The aim of this two-arm parallel design study is to assess the effects of bright light therapy (BLT) on depressive symptoms among middle-aged and older adults receiving long-term hemodialysis. Study participants are recruited using convenient sampling from four dialysis clinics in eastern Taiwan. The eligible participants are block-randomized to either the BLT group (n = 30), with 30 min sessions of BLT five times a week for six weeks at their own home, or to the routine care control group (n = 30). The Beck Depression Inventory-II (BDI-II) scores and the salivary cortisol levels are obtained from the participants at three time points: baseline (T₀), week 3 (T₁), and week 6 (T₂). The results, from the generalized estimating equations, indicate that the decline in the BDI-II scores over time is significant in the BLT group at T₁ (β = -7.57, p < 0.001) and at T₂ (β = -6.20, p = 0.002) compared to the control group. The decrease in salivary cortisol levels at each visit is also significant in the BLT group at T₁ (β = -7.37, p = 0.017) and at T₂ (β = -12.22, p = 0.005) compared to the control group. Our findings support the hypothesis that a six-week program of BLT is able to alleviate depressive symptoms in middle-aged and older patients who receive long-term hemodialysis.

Hippocampal and Amygdalar Volume Changes in Major Depressive Disorder: A Targeted Review and Focus on Stress

Medial temporal lobe structures have long been implicated in the pathogenesis of major depressive disorder. Although findings of smaller hippocampal and amygdalar volumes are common, inconsistencies remain in the literature. In this targeted review, we examine recent and significant neuroimaging papers examining the volumes of these structures in major depressive disorder. A targeted PubMed/Google Scholar search was undertaken focusing on volumetric neuroimaging studies of the hippocampus and amygdala in major depressive disorder. Where possible, mean volumes and accompanying standard deviations were extracted allowing computation of Cohen’s d_s effect sizes. Although not a meta-analysis, this allows a broad comparison of volume changes across studies. Thirty-nine studies in total were assessed. Hippocampal substructures and amygdale substructures were investigated in 11 and 2 studies, respectively. The hippocampus was more consistently smaller than the amygdala across studies, which is reflected in the larger cumulative difference in volume found with the Cohen’s d_s calculations. The left and right hippocampi were, respectively, 92% and 91.3% of the volume found in controls, and the left and right amygdalae were, respectively, 94.8% and 92.6% of the volume of controls across all included studies. The role of stress in temporal lobe structure volume reduction in major depressive disorder is discussed.

Intermingling of gut microbiota with brain: Exploring the role of probiotics in battle against depressive disorders

Depression is a debilitating psychiatric ailment which exerts disastrous effects on one's mental and physical health. Depression is accountable for augmentation of various life-threatening maladies such as neurodegenerative anomalies, cardiovascular diseases and diabetes. Depressive episodes are recurrent, pose a negative impact on life quality, decline life expectancy and enhance suicidal tendencies. Anti-depression chemotherapy displays marked adverse effects and frequent relapses. Thus, newer therapeutic interventions to prevent or combat depression are desperately required. Discovery of gut microbes as our mutualistic partner was made a long time ago and it is surprising that their functions still continue to expand and as of yet many are still to be uncovered. Experimental studies have revealed astonishing role of gut commensals in gut-brain signaling, immune homeostasis and hormonal regulation. Now, it is a well-established fact that gut microbes can alleviate stress or depression associated symptoms by modulating brain functions. Here in, we provide an overview of physiological alleyways involved in cross-talk between gut and brain, part played by probiotics in regulation of these pathways and use of probiotic bacteria as psychobiotics in various mental or depressive disorders.

Effects of Aerobic Exercise on Cortisol Stress Reactivity in Response to the Trier Social Stress Test in Inpatients with Major Depressive Disorders: A Randomized Controlled Trial

Physical activity is associated with a favourable (blunted) cortisol stress reactivity in healthy people. However, evidence from experimental study and with psychiatric patients is missing. This study examines whether exercise training impacts on cortisol stress reactivity in inpatients with major depressive disorder (MDD). These new insights are important because the stress reactivity of healthy people and patients with severe symptoms of depression might differ. Methods: The study was designed as a randomized controlled trial (trial registration number: NCT02679053). In total, 25 patients (13 women, 12 men, mean age: 38.1 12.0 years) completed a laboratory stressor task before and after a six-week intervention period. Nine samples of salivary free cortisol were taken before and after the Trier social stress test (TSST). Fourteen participants took part in six weeks of aerobic exercise training, while 11 patients were allocated to the control condition. While the primary outcome of the study was depressive symptom severity, the focus of this paper is on one of the secondary outcomes (cortisol reactivity during the TSST). The impact of aerobic exercise training was examined with a repeated-measures analysis of variance. We also examined the association between change in depression and cortisol response via correlational analysis. Cortisol reactivity did not change from baseline to post-intervention, either in the intervention or the control group. Participation in six weeks of aerobic exercise training was not associated with participants' cortisol reactivity. Moreover, depressive symptom change was not associated with change in cortisol response. Aerobic exercise training was not associated with patients' stress reactivity in this study. Because many patients initially showed a relatively flat/blunted cortisol response curve, efforts might be needed to find out which treatments are most efficient to promote a normalization of HPA axis reactivity.

Melatonergic agonist regulates circadian clock genes and peripheral inflammatory and neuroplasticity markers in patients with depression and anxiety

OBJECTIVE

Circadian dysfunction is a core manifestation and a risk factor for psychiatric disorders. Ramelteon (RMT), a melatonin receptor agonist, has been shown to induce sleep phase shifts and has been used to normalize sleep onset time. RMT has been used in sleep disorders, depression and anxiety. In this study, we aimed to investigate the effects of RMT in regulating gene expression profiles of the circadian clock and peripheral markers of inflammation and neuroplasticity.

METHODS

Sixteen patients with a diagnosis of primary insomnia comorbid with depression and anxiety and ten healthy controls were recruited in an 8-week open-label trial. The patients with primary insomnia received RMT 8 mg/day. The morning expression profiles of 15 core clock genes from peripheral blood mononuclear cells (PBMCs), urine and plasma levels of melatonin and its metabolite levels, and plasma inflammatory markers and neurotrophin levels were evaluated at baseline, 4th and 8th week of RMT treatment.

RESULTS

RMT treatment was associated with significant clinical improvement in depression scores at 8th week (Hamilton depression rating scale scores (Mean ± SEM) from 21.5 ± 2.44 to 14.31 ± 2.25, p ≤ 0.05). The overall poor sleep quality (Pittsburgh sleep quality index) of the patient group significantly improved (p ≤ 0.05) following RMT treatment. The mRNA level analysis showed a significant association between RMT treatment and alterations of the nine core circadian genes (CLOCK, PER1, PER2, CRY1, CRY2, NR1D1, NR1D2, DEC1 and TIMELESS) in the patient group when compared with the control group (p ≤ 0.05). Compared with the controls, the patient group had a decrease in neurotrophins (brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and beta-nerve growth factor; p ≤ 0.05) but an increase in pro-inflammatory cytokine levels (interleukin-6, interleukin-1b, tumour necrosis factor-alpha and interferon gamma; p ≤ 0.05); RMT treatment normalized the levels of neurotrophins and cytokine levels.

CONCLUSION

RMT treatment is able to restore phase-shifted melatonin markers, normalized the altered expression of the circadian genes, the levels of inflammatory cytokines and neurotrophins in patients with insomnia comorbid anxiety and depression.

Depression and Its Determinant Factors Among University of Gondar Medical and Health Science Students, Northwest Ethiopia: Institution-Based Cross-Sectional Study

BACKGROUND

Depression is a common mental disorder characterized by loss of interest or pleasure. Prevalence of depression is varied in different groups and countries. No adequate study has been undertaken in Ethiopia. This study aimed to determine the prevalence of depression and determinant factors among University of Gondar Medical and Health Sciences students, Northwest Ethiopia, 2019.

METHODS

An institution-based cross-sectional study was carried out using simple random sampling technique to select study participants and the study was conducted from June to July 2019. We used self-administered second edition of Beck's Depression Inventory (BDI-II) to collect data on depressive symptoms. The sample size was determined using a single population proportion formula. We entered the data using Epi Info 7 and then exported into Stata 14 for analysis. A binary logistic regression was used to identify determinant factors of depression. In the final model, a variable with a p<0.05 was considered as a significant factor for depression by an adjustment of odds ratio with 95% of uncertainty interval (UI).

RESULTS

Three hundred and eighty-three students completed the questionnaire with 97.7% response rate. The mean age of participants was 20.8 (±1.83, 18-34) years. The prevalence of depression was 34.73% (95% UI: 29.94-39.52%). The odds of having depression was higher among students who came from rural family (AOR=1.67, 95% UI: 1.02-2.72), who experienced tooth grinding (AOR=2.79, 95% UI: 1.36-5.74), who had night sleep disturbances (AOR=1.95, 95% UI: 1.17-3.25), who reported daytime sleepiness (AOR=1.93, 95% UI: 1.16-3.20), who had reported stress (AOR=4.20, 95% UI: 1.90-9.26), and those studying Health sciences (AOR=2.65, 95% UI: 1.34-5.26).

CONCLUSIONS

The prevalence of depression among university students was high which could lead to loss of personal control, disturbed learning capacity, and social interaction. Preventive strategies such as life skills training should be given for prevention and management of depression particularly targeting students coming from a rural family, those with stress, and having poor sleep quality.

Circulating Cortisol in a Cohort of Depressive Patients

It has long been suspected that the hypothalamic pituitary adrenal (HPA) axis plays a role in the pathophysiology of depression. Whether this association exists or not, and if it does, the degree of its significance, remain highly disputed. The issue is further complicated as no consensus currently exists on cortisol sampling timepoints or methods. Our study aimed to evaluate HPA functionality by evaluating plasma cortisol levels in a cohort of patients diagnosed with Major Depressive Disorder (MDD). We enrolled 96 subjects admitted for a major depressive episode and tested serum cortisol levels for 80 of them. We found that only 15 (12%) had values that were outside the normal reference range, with 14 of these being below the normal threshold. We also interviewed the patients and obtained self-reported information regarding previous depressive episodes, treatment administration, anxiety, suicidal ideas and suicidal gestures. Our study did not find a significant association between cortisol levels and the number of previous depressive episodes, the presence of feelings of anxiety, suicidal ideas or suicidal gestures. While our cohort did not find an association between cortisol levels and depression other authors have reported significantly different results and as such, more research is needed in order to establish or infirm this hypothesis.

Chronic mild stress leads to aberrant glucose energy metabolism in depressed Macaca fascicularis models

BACKGROUND

Major depressive disorder (MDD) is a pathophysiologically uncharacterized mental illness with complex etiology and clinical manifestations. Rodent depression-like models have been widely used to mimic the morbid state of depression. However, research on emotional disorders can also benefit from the use of models in non-human primates, which share a wide range of genetic and social similarities with humans.

METHODS

To investigate the pathophysiological mechanisms of depression, we established two models, naturally occurring depression cynomolgus (NOD) and social plus visual isolation-induced depression cynomolgus (SVC), imitating chronic mild or acute intense stress, respectively. We used i-TRAQ (isobaric tags for relative and absolute quantitation)-based quantitative proteomics and shotgun proteomics to identify differentially expressed proteins in cerebrospinal fluid (CSF) of the two monkey models and human MDD patients. We also used DAVID and ingenuity pathway analysis (IPA) for further bioinformatic investigation.

RESULTS

In behavioral tests, NOD monkeys achieved higher scores in depression-like and anxiety-like behavioral measures, and spent more time on ingesting, thermoregulatory, and locomotive actions than SVC monkeys. A total of 902 proteins were identified by i-TRAQ, and 40 differentially expressed proteins were identified in each of the NOD-CON1 and SVC-CON2 groups. Application of DAVID revealed dysregulation of energy metabolism in the NOD group, whereas lipid metabolism and inflammatory response pathways were significantly altered in the SVC group. Use of IPA and Cytoscape showed that the oxygen species metabolic process glycolysis I/gluconeogenesis I, accompanied by downregulation of tubulin beta 3 class III (TUBB3), RAC-alpha serine/threonine-protein kinase (AKT1), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was the most significantly affected pathway in the NOD group. Furthermore, 152 differentially expressed proteins in human MDD patients also revealed disruption of glucose energy metabolism. Significantly aberrant energy metabolism in various brain regions and the plasma and liver of chronic unpredictable mild stress rodent samples were also observed in a previous study.

CONCLUSIONS

Our results reveal for the first time the overall CSF protein profiles of two cynomolgus monkey models of depression. We propose that chronic mild stress may affect the disruption of glucose energy metabolism in NOD cynomolgus monkeys and rodents. These findings promote our understanding of the pathophysiology of MDD and may help to identify novel therapeutic targets.

Chronic Glucocorticoid Exposure Induces Depression-Like Phenotype in Rhesus Macaque (Macaca Mulatta)

It has long been observed in humans that the occurrence of depressive symptoms is often accompanied by the dysfunction of hypothalamic-pituitary-adrenal (HPA) axis. The rodent experiments also showed that chronic corticosterone exposure could induce depression-like phenotype. However, rodents are phylogenetically distant from humans. In contrast, non-human primates bear stronger similarities with humans, suggesting research on primates would provide an important complement. For the first time, we investigated the effects of chronic glucocorticoid exposure on rhesus macaques. Seven male macaques were selected and randomized to glucocorticoid or vehicle groups, which were subjected to either prednisolone acetate or saline injections, respectively. The depression-like behaviors were assessed weekly, and the body weights, HPA axis reactivity, sucrose solution consumption and monoaminergic neurotransmitters were further compared between these two groups. The glucocorticoid group was not found to display more depression-like behaviors than the vehicle group until 7 weeks after treatment. Chronic glucocorticoid exposure significantly decreased the levels of cortisol determined from blood (a biomarker for acute HPA axis reactivity) but increased the hair cortisol concentrations (a reliable indicator of chronic HPA axis reactivity) compared with controls. The glucocorticoid group was also found to consume less sucrose solution than controls, a good manifestation of anhedonia. This could be possibly explained by lower dopamine (DA) levels in cerebrospinal fluid induced by chronic glucocorticoid treatment. The results presented here indicate that chronic glucocorticoid exposure could disturb both the acute and chronic HPA axis reactivity, which eventually disturbed the neurotransmitter system and led monkeys to display depression-like phenotype.

Influence of Dietary Intake on Sleeping Patterns of Medical Students

Introduction

The aim of the study was to explore the association between the intake of specific food substances and the sleeping patterns of medical students.

Methods

A cross-sectional study was conducted with 440 medical students, aged 18-24 years, chosen through non-probability consecutive sampling from Karachi, Pakistan. The Pittsburgh sleep quality index (PSQI) was used to measure sleep quality and a self-made questionnaire that categorized foods according to their nutritional constitutions was used to measure the frequency of food consumption. Associations were evaluated using the chi-square test with the level of significance taken as p < 0.05 and strength of significance determined using Cramer’s V. logistic regression to predict good sleep quality.

Results

Significant associations were found with soybeans, whole grains, processed meats, leafy greens, dark chocolate, spices, dairy products, products high in fat and sugar, lima beans, and carbohydrates in relation to sleep quality, with soybeans exhibiting a particularly stronger relationship. The odds of good sleep quality were 2.5 times more likely with soybean intake, 3.26 times more likely with carbohydrates, and 6.57 times more likely with lima beans. Intake of papayas was associated with reduced sleep quality.

Conclusion

Intake of certain food substances has a significant association with sleep quality. Clinical trials focusing on the nutritional basis of these associations can lead to a new integrated focus on functional foods to combat poor sleep and sleep-related diseases.

Cortisol and Major Depressive Disorder-Translating Findings From Humans to Animal Models and Back

Major depressive disorder (MDD) is a global problem for which current pharmacotherapies are not completely effective. Hypothalamic-pituitary-adrenal (HPA) axis dysfunction has long been associated with MDD; however, the value of assessing cortisol as a biological benchmark of the pathophysiology or treatment of MDD is still debated. In this review, we critically evaluate the relationship between HPA axis dysfunction and cortisol level in relation to MDD subtype, stress, gender and treatment regime, as well as in rodent models. We find that an elevated cortisol response to stress is associated with acute and severe, but not mild or atypical, forms of MDD. Furthermore, the increased incidence of MDD in females is associated with greater cortisol response variability rather than higher baseline levels of cortisol. Despite almost all current MDD treatments influencing cortisol levels, we could find no convincing relationship between cortisol level and therapeutic response in either a clinical or preclinical setting. Thus, we argue that the absolute level of cortisol is unreliable for predicting the efficacy of antidepressant treatment. We propose that future preclinical models should reliably produce exaggerated HPA axis responses to acute or chronic stress a priori, which may, or may not, alter baseline cortisol levels, while also modelling the core symptoms of MDD that can be targeted for reversal. Combining genetic and environmental risk factors in such a model, together with the interrogation of the resultant molecular, cellular, and behavioral changes, promises a new mechanistic understanding of MDD and focused therapeutic strategies.