Gender differences in depression: findings from the STAR*D study

Age of onset of major depressive episode and association with lifetime psychiatric disorders, health-related quality of life and impact of gender: A cross sectional and retrospective cohort study

OBJECTIVE

To assess the long-term impact of the age of onset (AOO) of the first major depressive episode (MDE) according to 3 age groups and considering gender.

METHODS

Data were extracted from NESARC III, a representative U.S.

SAMPLE

We included 8053 participants with an MDE history in a cross-sectional and retrospective cohort study. We defined 3 AOO groups: childhood-onset (< 13 yo), adolescence-onset (13-18 yo), and adult-onset (> 18 yo). We compared sociodemographic characteristics, lifetime psychiatric disorders per DSM-5 criteria, and health-related quality of life (HRQOL) in each group and performed gender-stratified analyses.

RESULTS

Prevalence of childhood-onset MDE was 10.03 %, adolescence-onset was 14.12 %, and adult-onset was 75.85 %. Suicide attempts (AOR = 3.61; 95 % CI 2.90-4.50), anxiety disorders (AOR = 1.92; 95 % CI 1.62-2.27), and personality disorders (AOR = 3.08; 95 % CI 2.56-3.71) were more frequent in the childhood-onset than in the adult-onset one. Adolescence-onset group showed similar results. Physical Disability scale (p < 0.001) and Mental Disability scale (p < 0.001) were significantly lower in the childhood-onset group. Results were more nuanced in the adolescence-onset group. Women in childhood-onset and adolescence-onset groups had poorer outcomes than the adult-onset group. Differences were less pronounced in men.

LIMITATIONS

Recall and classification biases inherent to survey design.

CONCLUSION

Individuals, particularly women, who experienced their first MDE during childhood or adolescence exhibit higher lifetime psychiatric disorder prevalence and poorer HRQOL than those with adult-onset MDE. These findings highlight the importance of preventive measures, early diagnosis, and treatment of youth depression.

Prefrontal cortex-nucleus reuniens-hippocampus network exhibits sex-differentiated responses to stress and antidepressant treatment in rats

RATIONALE

Depression is a serious psychiatric disease, which is diagnosed twice as frequently in women than men. We have recently shown that lesioning or inactivation of the nucleus reuniens (RE), which interconnects the prefrontal cortex (PFC) and hippocampus, promoted resilience to stress in males, exerts an antidepressant effect in the Forced Swim Test (FST) and prevents the development of behavioral and neurobiological alterations induced by the chronic mild stress model of depression.

OBJECTIVES

In this study, we expand our findings on the FST in female rats and we investigate whether RE lesion presents sex differences following treatment with two distinct antidepressants, a selective serotonin reuptake inhibitor, i.e. sertraline and a tricyclic antidepressant, i.e. clomipramine.

METHODS

Male and female rats received either a surgical lesion of the RE or sham operation, then treated with vehicle, sertraline (10mg/kg) or clomipramine (10mg/kg) and were subjected to the FST. Activation of key brain areas of interest (PFC, Hippocampus and RE) were measured by c-Fos immunoreactivity.

RESULTS

RE lesion induced an antidepressant-like phenotype in both female and male rats, confirming its crucial role in the stress response. Similarly to RE lesion, sertraline treatment resulted in increased swimming and decreased immobility duration, as well as enhanced head shake frequency, in both sexes. Notably, climbing behavior was increased only following clomipramine treatment. RE area was less active in females compared to male rats and in clomipramine-treated males compared to their corresponding vehicle-group. Activation of the PFC and the CA1 hippocampal area was reduced in clomipramine-treated females, in comparison to vehicle-treated female rats. This effect was not evident in males, which exhibited less activation in the PFC and the hippocampus than females.

CONCLUSION

Re lesion proves equally effective in female and male rats, but sex is highlighted as a pivotal factor in behavioral and treatment response in FST, as well as in related circuit connectivity and activation.

Gender differences in risk factors for suicide attempts among young, first-episode and drug-naive major depressive disorder patients with anxiety symptoms

Background

Suicide attempts and anxiety are common commodities in patients with major depressive disorder (MDD), and suicide attempts are often associated with anxiety symptoms. Studies have found gender differences in several aspects of MDD; however, gender differences in suicide attempts in young first-episode and drug-naive (FEDN) MDD patients with anxiety remain unknown. This study aimed to investigate potential gender differences in the prevalence of suicide attempts and associated risk factors among young FEDN MDD patients with anxiety in a Chinese Han population.

Methods

A cross-sectional study was conducted on 1289 young patients with FEDN MDD. Demographics, clinical characteristics, and biochemical parameters of patients were collected.

Results

Suicide attempters accounted for 23.80% and 26.12% of male and female FEDN MDD patients with anxiety, respectively, with no significant gender differences. Binary logistic regression analyses showed that anxiety, clinical global impression severity, and thyroid peroxidase antibody significantly predicted suicide attempts in both male and female FEDN MDD patients with anxiety, while body mass index significantly predicted suicide attempts only in males, and psychotic symptoms predicted suicide attempts only in females.

Conclusion

The present study represents the first large-scale investigation of gender differences in the prevalence of suicide attempts and related risk factors among young FEND MDD patients with anxiety in the Chinese Han population. The results indicate that risk factors associated with suicide attempts vary by gender among young FEND MDD patients with anxiety, although a comparable rate of suicide attempts was observed in both female and male patients.

Twenty-five years of research on resting-state fMRI of major depressive disorder: A bibliometric analysis of hotspots, nodes, bursts, and trends

Major depressive disorder (MDD) is a debilitating mental health condition that poses significant risks and burdens. Resting-state functional magnetic resonance imaging (fMRI) has emerged as a promising tool in investigating the neural mechanisms underlying MDD. However, a comprehensive bibliometric analysis of resting-state fMRI in MDD is currently lacking. Here, we aimed to thoroughly explore the trends and frontiers of resting-state fMRI in MDD research. The relevant publications were retrieved from the Web of Science database for the period between 1998 and 2022, and the CiteSpace software was employed to identify the influence of authors, institutions, countries/regions, and the latest research trends. A total of 1501 publications met the search criteria, revealing a gradual increase in the number of annual publications over the years. China contributed the largest publication output, accounting for the highest percentage among all countries. Particularly, the University of Electronic Science and Technology of China, Capital Medical University, and Harvard Medical School were identified as key institutions that have made substantial contributions to this growth. Neuroimage, Biological Psychiatry, Journal of Affective Disorders, and Proceedings of the National Academy of Sciences of the United States of America are among the influential journals in the field of resting-state fMRI research in MDD. Burst keywords analysis suggest the emerging research frontiers in this field are characterized by prominent keywords such as dynamic functional connectivity, cognitive control network, transcranial brain stimulation, and childhood trauma. Overall, our study provides a systematic overview into the historical development, current status, and future trends of resting-state fMRI in MDD, thus offering a useful guide for researchers to plan their future research.

Sex-Specific Mechanisms Underlie Long-Term Potentiation at Hippocampus→Medium Spiny Neuron Synapses in the Medial Shell of the Nucleus Accumbens

Sex differences have complicated our understanding of the neurobiological basis of many behaviors that are key for survival. As such, continued elucidation of the similarities and differences between sexes is necessary to gain insight into brain function and vulnerability. The connection between the hippocampus (Hipp) and nucleus accumbens (NAc) is a crucial site where modulation of neuronal activity mediates reward-related behavior. Our previous work demonstrated that long-term potentiation (LTP) of Hipp→NAc synapses is rewarding, and mice can establish learned associations between LTP of these synapses and the contextual environment in which LTP occurred. Here, we investigated sex differences in the mechanisms underlying Hipp→NAc LTP using whole-cell electrophysiology and pharmacology. We observed similarities in basal synaptic strength between males and females and found that LTP occurs postsynaptically with similar magnitudes in both sexes. However, key sex differences emerged as LTP in males required NMDA receptors (NMDAR), whereas LTP in females utilized an NMDAR-independent mechanism involving L-type voltage-gated Ca2+ channels (VGCCs) and estrogen receptor α (ERα). We also uncovered sex-similar features as LTP in both sexes depended on CaMKII activity and occurred independently of dopamine-1 receptor (D1R) activation. Our results have elucidated sex-specific molecular mechanisms for LTP in an integral pathway that mediates reward-related behaviors, emphasizing the importance of considering sex as a variable in mechanistic studies. Continued characterization of sex-specific mechanisms underlying plasticity will offer novel insight into the neurophysiological basis of behavior, with significant implications for understanding how diverse processes mediate behavior and contribute to vulnerability to developing psychiatric disorders.

Relationship between sex biases in gene expression and sex biases in autism and Alzheimer's disease

BACKGROUND

Sex differences in the brain may play an important role in sex-differential prevalence of neuropsychiatric conditions.

METHODS

In order to understand the transcriptional basis of sex differences, we analyzed multiple, large-scale, human postmortem brain RNA-Seq datasets using both within-region and pan-regional frameworks.

RESULTS

We find evidence of sex-biased transcription in many autosomal genes, some of which provide evidence for pathways and cell population differences between chromosomally male and female individuals. These analyses also highlight regional differences in the extent of sex-differential gene expression. We observe an increase in specific neuronal transcripts in male brains and an increase in immune and glial function-related transcripts in female brains. Integration with single-nucleus data suggests this corresponds to sex differences in cellular states rather than cell abundance. Integration with case-control gene expression studies suggests a female molecular predisposition towards Alzheimer's disease, a female-biased disease. Autism, a male-biased diagnosis, does not exhibit a male predisposition pattern in our analysis.

CONCLUSION

Overall, these analyses highlight mechanisms by which sex differences may interact with sex-biased conditions in the brain. Furthermore, we provide region-specific analyses of sex differences in brain gene expression to enable additional studies at the interface of gene expression and diagnostic differences.

Serotonin Signaling through Lipid Membranes

Serotonin (5-HT) is a vital modulatory neurotransmitter responsible for regulating most behaviors in the brain. An inefficient 5-HT synaptic function is often linked to various mental disorders. Primarily, membrane proteins controlling the expression and activity of 5-HT synthesis, storage, release, receptor activation, and inactivation are critical to 5-HT signaling in synaptic and extra-synaptic sites. Moreover, these signals represent information transmission across membranes. Although the lipid membrane environment is often viewed as fairly stable, emerging research suggests significant functional lipid-protein interactions with many synaptic 5-HT proteins. These protein-lipid interactions extend to almost all the primary lipid classes that form the plasma membrane. Collectively, these lipid classes and lipid-protein interactions affect 5-HT synaptic efficacy at the synapse. The highly dynamic lipid composition of synaptic membranes suggests that these lipids and their interactions with proteins may contribute to the plasticity of the 5-HT synapse. Therefore, this broader protein-lipid model of the 5-HT synapse necessitates a reconsideration of 5-HT's role in various associated mental disorders.

Sex difference in association between suicide attempts and lipid profile in first-episode and drug naive patients with major depressive disorder

BACKGROUND

The relationship between suicide attempts and lipid profiles in patients with major depressive disorder (MDD) remains uncertain. The purpose of this study was to investigate sex differences in the relationship between suicide attempts and plasma lipid profiles in a large sample of first-episode and drug naive (FEDN) MDD patients.

METHODS

We recruited 1718 FEDN MDD patients and gathered demographic, clinical, and blood lipid data. The Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale and the Positive and Negative Syndrome Scale were used to assess the symptoms of patients.

RESULTS

There was no significant difference in the prevalence of suicide attempts between male and female MDD patients. The suicide attempt group had higher levels of depression, anxiety, psychotic symptoms, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), but lower levels of high-density lipoprotein cholesterol (HDL-C) levels than the non-suicide attempt group. Binary logistic regression showed that TC levels were significantly correlated with suicidal attempts in both male and female patients. Correlation analysis revealed that the levels of TC, HDL-C and LDL-C were significantly associated with the number of suicide attempts in both male and female patients. Further multiple linear regression revealed that TC levels were significantly associated with the number of suicide attempts in male patients only.

CONCLUSIONS

Lipid biomarkers, particularly high TC levels, are associated with suicide attempts in both male and female MDD patients. However, there is gender difference in association between lipid biomarkers, especially TC levels, and the number of suicide attempts in MDD patients.

Gender Differences in the Prevalence and Clinical Correlates of Metabolic Syndrome in First-Episode and Drug-Naïve Patients With Major Depressive Disorder

OBJECTIVE

Major depressive disorder (MDD) is a severe psychiatric symptom worldwide, and the coexistence of MDD with metabolic syndrome (MetS) is common in clinical practice. However, gender differences in comorbid MetS in first-episode and drug-naïve (FEDN) MDD patients have not been reported. Here, we explored potential gender differences in the prevalence and clinical correlates of comorbid MetS in FEDN MDD patients.

METHODS

A cross-sectional study of 1718 FEDN MDD patients was conducted. Demographic and clinical data were collected. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale, and Positive and Negative Syndrome Scale positive subscale were used to evaluate depression, anxiety, and psychotic symptoms, respectively.

RESULTS

The prevalence of MetS was 1.645-fold higher in female MDD patients (38.50%) than in male patients (26.53%). Patients with MetS had higher HAMD score, Hamilton Anxiety Scale score, and Positive and Negative Syndrome Scale positive subscale score than patients without MetS (p values < .001). Furthermore, suicide attempts (male: odds ratio [OR] = 1.706, p = .034; female: OR = 1.639, p = .004) and HAMD score (male: OR = 1.251, p < .001; female: OR = 1.148, p < .001) were independently associated with MetS in male and female patients, whereas age of onset was independently associated with MetS only in female patients (OR = 1.744, p = .047).

CONCLUSIONS

Our findings suggest significant gender differences in the prevalence and clinical correlates of comorbid MetS in FEDN MDD patients. Clinical variables (suicide attempts and HAMD scores) may be independently associated with MetS in MDD patients.

Sex Differences in the Association Between Depression and Incident Cardiovascular Disease

Background

Depression is a known risk factor for cardiovascular disease (CVD), but the potential sex differences in this association remain unclear.

Objectives

The aim of this study was to investigate the association between depression and subsequent CVD events, and to explore potential sex differences.

Methods

The authors conducted a retrospective analysis using the JMDC Claims Database between 2005 and 2022. The study population included 4,125,720 individuals aged 18 to 75 years without a history of cardiovascular disease or renal failure and missing data at baseline. Participants were followed up for a mean of 1,288 days to assess the association between depression and subsequent CVD events, such as myocardial infarction, angina pectoris, stroke, heart failure, and atrial fibrillation.

Results

Our analysis revealed a significant association between depression and subsequent composite CVD events in both men and women, with a stronger association observed in women. The HR for the composite endpoint was 1.64 (95% CI: 1.59-1.70) in women and 1.39 (95% CI: 1.35-1.42) in men after multivariable adjustment (P for interaction <0.001). Furthermore, the individual components of the composite endpoint were also associated with depression in both men and women, each of which was also observed to be more strongly associated in women.

Conclusions

Our study provides evidence of a significant association between depression and subsequent CVD events in both men and women, with a more pronounced association observed in women. These findings highlight the importance of addressing depression and tailoring prevention and management strategies according to sex-specific factors.

Premotor projections from the locus coeruleus and periaqueductal grey are altered in two rat models with inborn differences in emotional behavior

Emotionally motivated behaviors rely on the coordinated activity of descending neural circuits involved in motor and autonomic functions. Using a pseudorabies (PRV) tract-tracing approach in typically behaving rats, our group previously identified descending premotor, presympathetic, and dual-labeled premotor-presympathetic populations throughout the central rostral-caudal axis. The premotor-presympathetic populations are thought to integrate somatomotor and sympathetic activity. To determine whether these circuits are dysregulated in subjects with altered emotional regulation, subsequent neuroanatomical analyses were performed in male subjects of two distinct genetic models relevant to clinical depression and anxiety: the Wistar Kyoto (WKY) rat and selectively bred Low Novelty Responder (bLR) rat. The present study explored alterations in premotor efferents from locus coeruleus (LC) and subdivisions of the periaqueductal grey (PAG), two areas involved in emotionally motivated behaviors. Compared to Sprague Dawley rats, WKY rats had significantly fewer premotor projections to hindlimb skeletal muscle from the LC and from the dorsomedial (DMPAG), lateral (LPAG), and ventrolateral (VLPAG) subdivisions of PAG. Relative to selectively bred High Novelty Responder (bHR) rats, bLR rats had significantly fewer premotor efferents from LC and dorsolateral PAG (DLPAG). Cumulatively, these results demonstrate that somatomotor circuitry in several brain areas involved in responses to stress and emotional stimuli are altered in rat models with depression-relevant phenotypes. These somatomotor circuit differences could be implicated in motor-related impairments in clinically depressed patients.

Changes in depression symptom profile with gender-affirming hormone use in transgender persons

BACKGROUND

Women show higher prevalence of depression and different symptomatology than men, possibly influenced by sex hormones. Many transgender persons, who face a high risk of depression, use Gender-Affirming Hormone Therapy (GAHT), but the impact of GAHT on depressive symptom profiles is unknown.

METHODS

This study examined depressive symptoms in transgender persons before GAHT and after 3- and 12 months of GAHT. We used the Inventory of Depressive Symptomatology-Self Report to assess depressive symptoms, exploratory factor analysis (EFA) to assess symptom clusters, and linear mixed models to assess changes in symptom clusters.

RESULTS

This study included 110 transmasculine (TM) and 89 transfeminine (TF) participants. EFA revealed four symptom clusters: mood, anxiety, lethargy, and somatic symptoms. Changes in total depressive symptoms significantly differed between TM and TF groups. After 3 months of GAHT, TM participants reported improvement in lethargy (-16 %; 95%CI: -29 %; -2 %), and after 12 months TF participants reported worsening in low mood (24 %; 95%CI: 3 %; 51 %), but absolute score changes were modest. Neither group showed changes in anxiety or somatic symptoms.

LIMITATIONS

This study had limited sample sizes at 12 months follow-up and did not include relevant biological or psychosocial covariates.

DISCUSSION

Changes in depressive symptoms after GAHT use differ in TM and TF persons: TM persons report slight improvements in lethargy, whereas TF persons report a slight increase in low mood. Starting GAHT represents a significant life event with profound social and physical effects, and further research should assess social and biological effects of GAHT on mood-related symptoms.

Novel rapid treatment options for adolescent depression

There is an urgent need for novel fast-acting antidepressants for adolescent treatment-resistant depression and/or suicidal risk, since the selective serotonin reuptake inhibitors that are clinically approved for that age (i.e., fluoxetine or escitalopram) take weeks to work. In this context, one of the main research lines of our group is to characterize at the preclinical level novel approaches for rapid-acting antidepressants for adolescence. The present review summarizes the potential use in adolescence of non-pharmacological options, such as neuromodulators (electroconvulsive therapy and other innovative types of brain stimulation), as well as pharmacological options, including consciousness-altering drugs (mainly ketamine but also classical psychedelics) and cannabinoids (i.e., cannabidiol), with promising fast-acting responses. Following a brief analytical explanation of adolescent depression, we present a general introduction for each therapeutical approach together with the clinical evidence supporting its potential beneficial use in adolescence (mainly extrapolated from prior successful examples for adults), to then report recent and/or ongoing preclinical studies that will aid in improving the inclusion of these therapies in the clinic, by considering potential sex-, age-, and dose-related differences, and/or other factors that might affect efficacy or long-term safety. Finally, we conclude the review by providing future avenues to maximize treatment response, including the need for more clinical studies and the importance of designing and/or testing novel treatment options that are safe and fast-acting for adolescent depression.

Gender differences in prevalence and clinical correlates of anxiety in first-episode and drug-naïve patients with major depressive disorder comorbid with metabolic syndrome

BACKGROUND

Although gender differences in major depressive disorder (MDD) have been widely reported, there has not been much focus on gender differences in comorbidity. In patients with MDD and comorbid metabolic syndrome (Mets), the goal of this study was to investigate potential gender differences in the prevalence and clinical correlates of concomitant anxiety.

METHODS

Seven hundred and ninety-four first-episode and drug-naïve patients (FEDN) patients with MDD and comorbid Mets were recruited. For each patient, sociodemographic data, thyroid function indicators, and Mets parameters were acquired. Each participant completed the 14-item Hamilton Assessment Scale for Anxiety (HAMA) and the 17-item Hamilton Assessment Scale for Depression (HAMD).

RESULTS

There were no gender differences in the prevalence of anxiety in patients with MDD and comorbid Mets. Female patients with MDD had a shorter duration of illness. Correlation analysis showed that HAMD score, TSH, TgAb, and TPOAb were associated with anxiety prevalence in female patients, whereas anxiety onset in male patients was only associated with TSH, TgAb, and TPOAb levels. In addition, multiple logistic regression analysis showed that TSH and TgAb predicted anxiety in male patients, whereas HAMD score and age of onset significantly predicted anxiety in female patients.

LIMITATIONS

Cross-sectional design and no control for anxiety-related factors.

CONCLUSIONS

Our study showed no gender differences in the prevalence of anxiety in patients with MDD and comorbid Mets. HAMD score was associated with anxiety in female patients, whereas TSH, TgAb, and TPOAb were associated with anxiety in male patients.

Major depressive disorder: hypothesis, mechanism, prevention and treatment

Worldwide, the incidence of major depressive disorder (MDD) is increasing annually, resulting in greater economic and social burdens. Moreover, the pathological mechanisms of MDD and the mechanisms underlying the effects of pharmacological treatments for MDD are complex and unclear, and additional diagnostic and therapeutic strategies for MDD still are needed. The currently widely accepted theories of MDD pathogenesis include the neurotransmitter and receptor hypothesis, hypothalamic-pituitary-adrenal (HPA) axis hypothesis, cytokine hypothesis, neuroplasticity hypothesis and systemic influence hypothesis, but these hypothesis cannot completely explain the pathological mechanism of MDD. Even it is still hard to adopt only one hypothesis to completely reveal the pathogenesis of MDD, thus in recent years, great progress has been made in elucidating the roles of multiple organ interactions in the pathogenesis MDD and identifying novel therapeutic approaches and multitarget modulatory strategies, further revealing the disease features of MDD. Furthermore, some newly discovered potential pharmacological targets and newly studied antidepressants have attracted widespread attention, some reagents have even been approved for clinical treatment and some novel therapeutic methods such as phototherapy and acupuncture have been discovered to have effective improvement for the depressive symptoms. In this work, we comprehensively summarize the latest research on the pathogenesis and diagnosis of MDD, preventive approaches and therapeutic medicines, as well as the related clinical trials.

Sex-specific mechanisms underlie long-term potentiation at hippocampus-nucleus accumbens synapses

Sex differences have complicated our understanding of the neurobiological basis of many behaviors that are key for survival. As such, continued elucidation of the similarities and differences between sexes is necessary in order to gain insight into brain function and vulnerability. The connection between the hippocampus (Hipp) and nucleus accumbens (NAc) is a crucial site where modulation of neuronal activity mediates reward-related behavior. Our previous work demonstrated that long-term potentiation (LTP) of Hipp-NAc synapses is rewarding, and that mice can make learned associations between LTP of these synapses and the contextual environment in which LTP occurred. Here, we investigate sex differences in the mechanisms underlying Hipp-NAc LTP using whole-cell electrophysiology and pharmacology. We found that males and females display similar magnitudes of Hipp-NAc LTP which occurs postsynaptically. However, LTP in females requires L-type voltage-gated Ca 2+ channels (VGCC) for postsynaptic Ca 2+ influx, while males rely on NMDA receptors (NMDAR). Additionally, females require estrogen receptor α (ERα) activity for LTP while males do not. These differential mechanisms converge as LTP in both sexes depends on CAMKII activity and occurs independently of dopamine-1 receptor (D1R) activation. Our results have elucidated sex-specific molecular mechanisms for LTP in an integral excitatory pathway that mediates reward-related behaviors, emphasizing the importance of considering sex as a variable in mechanistic studies. Continued characterization of sex-specific mechanisms underlying plasticity will offer novel insight into the neurophysiological basis of behavior, with significant implications for understanding how diverse processes mediate behavior and contribute to vulnerability to developing psychiatric disorders.

SIGNIFICANCE STATEMENT

Strengthening of Hipp-NAc synapses drives reward-related behaviors. Male and female mice have similar magnitudes of long-term potentiation (LTP) and both sexes have a predicted postsynaptic locus of plasticity. Despite these similarities, we illustrate here that sex-specific molecular mechanisms are used to elicit LTP. Given the bidirectional relationship between Hipp-NAc synaptic strength in mediating reward-related behaviors, the use of distinct molecular mechanisms may explain sex differences observed in stress susceptibility or response to rewarding stimuli. Discovery and characterization of convergent sex differences provides mechanistic insight into the sex-specific function of Hipp-NAc circuitry and has widespread implications for circuits mediating learning and reward-related behavior.

Sex differences in prevalence and clinical correlates of suicide attempts in first-episode and drug-naïve patients with anxious depression in a Chinese Han population: A large-scale cross-sectional study

BACKGROUNDS

Anxious depression (AD) has been extensively studied. However, fewer studies have examined sex differences in the prevalence of suicide attempts among AD patients. This study aimed to explore sex differences in suicide attempts and risk factors in patients with AD.

METHODS

1380 first episode drug-naïve patients with AD were recruited. Sociodemographic and clinical characteristics were measured using a self-administered demographic questionnaire. The Hamilton Depression Scale (HAMD), Hamilton Anxiety Inventory (HAMA), and positive subscale of the Positive and Negative Syndrome Scale (PANSS) were used to assess patients' clinical symptoms. We also measured the patient's blood glucose, lipids, and thyroid axis hormone levels.

RESULTS

There were no sex differences in the prevalence of suicide attempts in patients with FEDN anxious depression. In addition, binary logistic regression analysis showed that HAMA score, TSH levels, and TPOAb levels significantly predicted suicide attempts in both male and female patients with AD, while HAMD score significantly predicted suicide attempts in female patients with AD only.

CONCLUSIONS

The severity of anxiety and higher levels of TSH and TPOAb were associated with an increased risk for suicide attempts in both male and female patients with AD, whereas the severity of depression was only associated with suicide attempts in females.

The role of the Toll like receptor 4 signaling in sex-specific persistency of depression-like behavior in response to chronic stress

Chronic stress is a major risk factor for Major Depressive Disorder (MDD), and it has been shown to impact the immune system and cause microglia activation in the medial prefrontal cortex (mPFC) involved in the pathogenesis of depression. The aim of this study is to further investigate cellular and molecular mechanisms underlying persistent depression behavior in sex specific manner, which is observed clinically. Here, we report that both male and female mice exhibited depression-like behavior following exposure to chronic stress. However, only female mice showed persistent depression-like behavior, which was associated with microglia activation in mPFC, characterized by distinctive alterations in the phenotype of microglia. Given these findings, to further investigate the underlying molecular mechanisms associated with persistent depression-like behavior and microglia activation in female mice, we used translating-ribosome affinity purification (TRAP). We find that Toll like receptor 4 (TLR4) signaling is casually related to persistent depression-like behavior in female mice. This is supported by the evidence that the fact that genetic ablation of TLR4 expression in microglia significantly reduced the persistent depression-like behavior to baseline levels in female mice. This study tentatively supports the hypothesis that the TLR4 signaling in microglia may be responsible for the sex differences in persistent depression-like behavior in female.

Sex Differences in Stress Response: Classical Mechanisms and Beyond

Neuropsychiatric disorders, which are associated with stress hormone dysregulation, occur at different rates in men and women. Moreover, nowadays, preclinical and clinical evidence demonstrates that sex and gender can lead to differences in stress responses that predispose males and females to different expressions of similar pathologies. In this curated review, we focus on what is known about sex differences in classic mechanisms of stress response, such as glucocorticoid hormones and corticotrophin-releasing factor (CRF), which are components of the hypothalamicpituitary- adrenal (HPA) axis. Then, we present sex differences in neurotransmitter levels, such as serotonin, dopamine, glutamate and GABA, as well as indices of neurodegeneration, such as amyloid β and Tau. Gonadal hormone effects, such as estrogens and testosterone, are also discussed throughout the review. We also review in detail preclinical data investigating sex differences caused by recentlyrecognized regulators of stress and disease, such as the immune system, genetic and epigenetic mechanisms, as well neurosteroids. Finally, we discuss how understanding sex differences in stress responses, as well as in pharmacology, can be leveraged into novel, more efficacious therapeutics for all. Based on the supporting evidence, it is obvious that incorporating sex as a biological variable into preclinical research is imperative for the understanding and treatment of stress-related neuropsychiatric disorders, such as depression, anxiety and Alzheimer's disease.

Sex differences in erythrocyte fatty acid composition of first-diagnosed, drug-naïve patients with major depressive disorders

Background: Since depression, sex hormones, and fatty acid status are interrelated, it is important to understand their relationships. In this study, we aimed to investigate sex differences in erythrocyte membrane fatty acid composition among first-diagnosed, drug-naïve patients with major depressive disorders. Methods: The study included 139 individuals with first-diagnosed, drug-naïve depression (male/female = 48/91) and 55 healthy controls (male/female = 24/31). The levels of erythrocyte membrane fatty acids were analyzed to compare the difference between males and females in both patients with depression and healthy controls, as well as to study their correlation with depressive symptoms. Results: In first-diagnosed, drug-naïve patients with major depressive disorders, sex disparities were observed in the levels of erythrocyte saturated fatty acids (SFAs) and n-6 PUFAs (such as C18:0, C20:4n6 and C22:4n6), where higher levels evident in females compared to in males. We found a noteworthy correlation between fatty acid levels and depressive symptoms, in which there is a significant association between female patients and depression but a weaker association between male patients and depression. Conclusion: Our findings demonstrate higher levels of n-6 PUFAs and SFAs in female patients with depression. The relationship between fatty acid composition and depressive symptoms was more prominent in females than males. These findings highlight the significance of considering sex as a crucial and interconnected factor in future investigations and potential adjunctive treatment for mood disorders by targeting fatty acid metabolism.

Sex-specific immune-inflammatory markers and lipoprotein profile in patients with anhedonia with unipolar and bipolar depression

BACKGROUND

Anhedonia is a core symptom in patients with unipolar and bipolar depression. However, sex-specific markers reflecting biological heterogeneity are lacking. Emerging evidence suggests that sex differences in immune-inflammatory markers and lipoprotein profiles are associated with anhedonia.

METHODS

The demographic and clinical data, immune-inflammatory markers (CD3, CD4, and CD8), and lipoprotein profiles [TC, TG, LDL-C, HDL-C, lipoprotein(a) Lp (a)] of 227 patients with unipolar and bipolar depression were collected. The Hamilton Depression Rating Scale (HAMD) and Snaith-Hamilton Pleasure Scale (SHAPS) were used to assess depression and anhedonia symptoms. Data were analyzed using ANOVA, logistic regression, and receiver operating characteristic curves.

RESULTS

Male patients in the anhedonia group had higher levels of CD3, CD4, and CD8, and lower levels of Lp (a) than the non-anhedonia group, while no significant difference was identified in female patients with and without anhedonia. Logistic regression analysis showed that CD3, CD4, CD8, and Lp (a) levels were associated with anhedonia in male patients. Furthermore, the combination of CD3, CD4, CD8, and Lp (a) had the strongest predictive value for distinguishing anhedonia in male patients than individual parameters.

CONCLUSIONS

We identified sex-specific associations between immune-inflammatory markers, lipoprotein profiles, and anhedonia in patients with unipolar and bipolar depression. The combination of CD3, CD4, CD8, and Lp (a) might be a possible biomarker for identifying anhedonia in male patients with unipolar and bipolar depression.

Repeated reserpine treatment induces depressive-like behaviors accompanied with hippocampal impairment and synapse deficit in mice

Depression remains a significant public health concern, and current animal models of depression are limited in their ability to accurately mimic human depression. However, studying the new development of antidepressants requires the use of progressive animal models. In this study, the mice were exposed to a low dose of reserpine (0.5 mg/kg) once daily for 14 days, followed by a 14-day period to allow for the development of spontaneous depression. We have successfully established a repeated reserpine-induced depressive animal model, which was characterized by emotional symptoms (anhedonia), cognitive symptoms, and psychomotor agitation or retardation. Our study demonstrated that repeated treatment with low-dose reserpine increased immobility time in the TST and FST. It also decreased the sucrose consumption ratio and induced anxiety-like behaviors. These anxiety-like behaviors were evidenced by decreased time spent in the center zone, longer first latency to center zone, and fewer entries into the center zone in the open field test. These findings support the utility of the low-dose reserpine repeated injection animal model for studying the pathogenesis of depression and the development of novel antidepressant treatments. Additionally, this study provides valuable insights into the potential of low-dose reserpine as a tool for modeling chronic depression in animals. Furthermore, our findings suggest that prolonged low-dose reserpine treatment could result in chronic depression. These findings have significant implications for the use of reserpine as a therapeutic agent for various conditions and emphasize the importance of closely monitoring patients' mental health.

Gender differences in transdiagnostic domains and function of adults measured by DSM-5 assessment scales at the first clinical visit: a cohort study

BACKGROUND

Measurement-based care has been called for as best practice in psychiatric care and learning health systems and use of transdiagnostic measures was suggested as part of the DSM-5. Our objective is to examine gender differences in first visit socioeconomic, transdiagnostic, and functional characteristics of a dynamic, real-world measurement-based care cohort.

METHODS

Transdiagnostic, functional, and clinical measures were collected from 3,556 patients at first visit in an ambulatory psychiatric clinic. All patients were evaluated at the first visit by board-certified psychiatrists or licensed clinical psychologists. Demographic variables and clinical diagnoses were collected from the Electronic Medical Record. Self-report measures were collected that assessed transdiagnostic symptoms (DSM-5 Level 1 Cross-cutting Measure and Level 2 symptom scales), disability, alcohol use, attention deficit hyperactivity disorder (ADHD) symptoms, depression, anxiety, mania, suicidal thoughts and behaviors, and trauma exposure.

RESULTS

Men and women did not differ in age, BMI, household income, high school graduation rate, race, or ethnicity, but women were more likely to be formerly married and less likely to have commercial insurance. Compared to men, women reported significantly higher overall psychopathology on the transdiagnostic Level 1 Cross-cutting measure and had higher depression, anxiety, sleep, anger, ADHD combined presentation, and suicidality severity. Women also had higher disability scores than men. However, men reported higher alcohol, tobacco and substance use, and more risky behavior than women. Trauma exposure differed significantly by gender; men reported more exposure to accidents, war-related trauma, serious accidents, and major disasters and women reported more unwanted sexual contact.

CONCLUSIONS

This cross-sectional study of a transdiagnostic, ecologically-valid real-word measurement-based care cohort demonstrates gender differences in socioeconomic factors, trauma exposure, transdiagnostic symptoms, and functioning.

Diet and Depression during Peri- and Post-Menopause: A Scoping Review Protocol

The aim of the proposed scoping review is to describe and summarize studies assessing the associations between diet-related variables and depression in peri- and post-menopausal women. Studies examining the associations between diet-related variables and mental health indicators in women undergoing menopausal transition or in the post-menopausal period will be systematically retrieved via Medline, EMBASE, PsycINFO, Web of Science, and Scopus databases. All articles identified through the database searches will be imported into Covidence. Following the removal of duplicates, two authors will independently perform title and abstract screening, as well as full-text assessment against eligibility criteria. Data will be extracted using tables developed for observational and experimental studies. The methodological quality of randomized trials, cohort and cross-sectional studies, and case-control studies, will be assessed using the Cochrane risk-of-bias (RoB-2) tool, the NHLBI Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies, and the NHLBI Quality Assessment Tool for Case-Control studies, respectively. Data extraction tables will be used to produce two tables summarizing the main characteristics and findings of the studies included in the review. In the proposed review, we will systematically identify and summarize the currently available evidence on the association between diet-related variables and depression in peri- and post-menopausal women. To our knowledge, this is the first review focusing on this subgroup of the population. Protocol registration: osf.io/b89r6.

Gender differences in the association between body mass index and recent suicide attempts in Chinese patients with first-episode drug-naïve major depressive disorder

Controversial evidence exists on the relationship between body mass index (BMI) and suicide attempts (SA) in patients with major depressive disorder (MDD). This cross-sectional study aimed to explore the association between BMI and SA in first-episode drug-naïve (FEDN) MDD patients in China. The study was conducted from 2016 to 2018 in Taiyuan, China. Univariate and multivariate logistic regression analyzed the BMI-SA association, with subgroup analysis for gender. Threshold effects were examined using two-piecewise regression. In males, BMI was significantly associated with SA (OR = 0.84, 95% CI 0.74-0.94, P = 0.003) after full adjustment, but not in females (OR = 0.97, 95% CI 0.89-1.06, P = 0.541). The interaction with gender was significant (P for interaction < 0.05). Smoothing plots revealed an L-shaped BMI-SA relationship in both genders, with BMI inflection points at 27.3 kg/m2 in males and 21.4 kg/m2 in females. Below the inflection points, BMI is negatively associated with SA in males (OR = 0.75, 95% CI 0.66-0.86, P < 0.001) and females (OR = 0.48, 95% CI 0.32-0.72, P < 0.001). Above the inflection points, no association existed for both genders (all P > 0.05). Results showed an L-shaped nonlinear BMI-SA relationship in FEDN MDD patients but differing BMI inflection points between genders, thus contributing to effective prevention programs for suicide.

Sex Significantly Impacts the Function of Major Depression-Linked Variants In Vivo

BACKGROUND

Genome-wide association studies have discovered blocks of common variants-likely transcriptional-regulatory-associated with major depressive disorder (MDD), though the functional subset and their biological impacts remain unknown. Likewise, why depression occurs in females more frequently than males is unclear. We therefore tested the hypothesis that risk-associated functional variants interact with sex and produce greater impact in female brains.

METHODS

We developed techniques to directly measure regulatory variant activity and sex interactions using massively parallel reporter assays in the mouse brain in vivo, in a cell type-specific manner, and applied these approaches to measure activity of >1000 variants from >30 MDD loci.

RESULTS

We identified extensive sex-by-allele effects in mature hippocampal neurons, suggesting that sex-differentiated impacts of genetic risk may underlie sex bias in disease. Unbiased informatics approaches indicated that functional MDD variants recurrently disrupt a number of transcription factor binding motifs, including those of sex hormone receptors. We confirmed a role for the latter by performing massively parallel reporter assays in neonatal mice on the day of birth (during a sex-differentiating hormone surge) and hormonally quiescent juveniles.

CONCLUSIONS

Our study provides novel insights into the influence of age, biological sex, and cell type on regulatory variant function and provides a framework for in vivo parallel assays to functionally define interactions between organismal variables such as sex and regulatory variation. Moreover, we experimentally demonstrate that a portion of the sex differences seen in MDD occurrence may be a product of sex-differentiated effects at associated regulatory variants.

Rumination symptoms in treatment-resistant major depressive disorder, and outcomes of repetitive Transcranial Magnetic Stimulation (rTMS) treatment

Rumination is a maladaptive style of regulating thoughts and emotions. It is a common symptom of Major Depressive Disorder (MDD), and more severe rumination is associated with poorer medication and psychotherapy treatment outcomes, particularly among women. It is unclear to what extent rumination may influence the outcomes of, or be responsive to, repetitive Transcranial Magnetic Stimulation (rTMS) treatment of MDD. We retrospectively examined data collected during rTMS treatment of 155 patients (age 42.52 ± 14.22, 79 female) with moderately severe treatment-resistant MDD. The severity of rumination and depression was assessed before and during a course of 30 sessions of measurement-based rTMS treatment using the Ruminative Responses Scale (RSS) and the Patient Health Questionnaire (PHQ-9), respectively. Relationships among baseline levels of rumination, depression, and treatment outcome were assessed using a series of repeated measures linear mixed effects models. Both depression and rumination symptoms significantly improved after treatment, but improvement in depression was not a significant mediator of rumination improvement. Higher baseline rumination (but not depression severity) was associated with poorer depression outcomes independently of depression severity. Female gender was a significant predictor of worse outcomes for all RRS subscales. Both depressive and ruminative symptoms in MDD improved following rTMS treatment. These improvements were correlated, but improvement in rumination was not fully explained by reduction in depressive symptoms. These findings suggest that while improvement in rumination and depression severity during rTMS treatment are correlated, they are partly independent processes. Future studies should examine whether rumination symptoms should be specifically targeted with different rTMS treatment parameters.

Relationship between sex biases in gene expression and sex biases in autism and Alzheimer's disease

Sex differences in the brain may play an important role in sex-differential prevalence of neuropsychiatric conditions. In order to understand the transcriptional basis of sex differences, we analyzed multiple, large-scale, human postmortem brain RNA-seq datasets using both within-region and pan-regional frameworks. We find evidence of sex-biased transcription in many autosomal genes, some of which provide evidence for pathways and cell population differences between chromosomally male and female individuals. These analyses also highlight regional differences in the extent of sex-differential gene expression. We observe an increase in specific neuronal transcripts in male brains and an increase in immune and glial function-related transcripts in female brains. Integration with single-cell data suggests this corresponds to sex differences in cellular states rather than cell abundance. Integration with case-control gene expression studies suggests a female molecular predisposition towards Alzheimer's disease, a female-biased disease. Autism, a male-biased diagnosis, does not exhibit a male predisposition pattern in our analysis. Finally, we provide region specific analyses of sex differences in brain gene expression to enable additional studies at the interface of gene expression and diagnostic differences.

Gender differences in the association between anxiety symptoms and thyroid hormones in young patients with first-episode and drug naïve major depressive disorder

Objective

Gender differences are prevalent in major depressive disorder (MDD), but the gender differences in the relationship between comorbid anxiety and thyroid hormones in young first-episode and drug-naive (FEND) MDD patients are unknown.

Methods

A total of 1,289 young outpatients with FEDN MDD were recruited. Demographic and clinical data were collected for each patient. The patient's blood glucose, blood pressure, thyroid hormone, and thyroid antibody levels were measured. The Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) were used to assess patients' depression, anxiety, and positive symptoms, respectively.

Results

The prevalence of comorbid anxiety disorders was 80.4 and 79.4% in male and female MDD patients, respectively. Patients with anxiety had higher HAMD and PANSS scores, higher serum thyroid stimulating hormone (TSH), anti-thyroglobulin antibody (A-TG), and thyroid peroxidase antibody (A-TPO) levels, higher blood glucose and blood pressure levels, and more patients with psychotic symptoms and suicide attempts. Male patients were younger and had a younger age of onset. Logistic regression analysis showed that HAMD score and comorbid suicide attempts were significant predictors of anxiety symptoms in both males and females, whereas A-TG predicted anxiety symptoms in female patients only. Limitations: No causal relationship could be drawn due to the cross-sectional design.

Conclusion

This study showed gender differences in factors associated with anxiety symptoms in patients with MDD. Some factors were associated with anxiety symptoms in both male and female patients, while A-TG was only associated with anxiety symptoms in female patients.

Effects of the dopamine depleting agent tetrabenazine in tests evaluating different components of depressive-like behavior in mice: sex-dependent response to antidepressant drugs with SERT and DAT blocker profiles

BACKGROUND

Depression is a disorder twice as common in women than in men. There are sex differences in the symptomatology and treatment response to this disorder. Impairments in behavioral activation (i.e. anergia, fatigue) are often seen in people with depression and are highly resistant to treatment. The role of mesolimbic dopamine (DA) in regulating behavioral activation has been extensively studied in male rodents, but little is known in female rodents.

OBJECTIVE

The present studies assessed potential sex differences in rodent paradigms used to study different components of depressive-like behavior, and in the treatment response to antidepressants with different mechanisms of action.

METHODS

Male and female CD1 mice received Tetrabenazine (TBZ), a VMAT-2 blocker that depletes DA and induces depressive symptoms in humans. Mice were tested on the Forced Swim Test, (FST), the Dark-Light box (DL), the elevated plus maze (EPM), Social Interaction (SI) test, and sucrose preference and consumption using the two bottles test. In addition, bupropion (a DA reuptake inhibitor) or fluoxetine (a serotonin reuptake inhibitor) were used to reverse TBZ-induced anergia.

RESULTS

In the FST, bupropion reversed TBZ effects in both sexes but fluoxetine was only effective in female mice. DA depletion did not affect other aspects of depression such as anxiety, sociability or sucrose consumption, and there was no interaction with bupropion on these parameters. In TBZ treated-females SERT-blockers may be effective at reversing anergia in aversive contexts (FST), and potentiating avoidance of anxiogenic stimuli.

CONCLUSIONS

Pro-dopaminergic antidepressants seem more efficacious at improving anergia in both sexes than SERT-blockers.

A sex-specific genome-wide association study of depression phenotypes in UK Biobank

There are marked sex differences in the prevalence, phenotypic presentation and treatment response for major depression. While genome-wide association studies (GWAS) adjust for sex differences, to date, no studies seek to identify sex-specific markers and pathways. In this study, we performed a sex-stratified genome-wide association analysis for broad depression with the UK Biobank total participants (N = 274,141), including only non-related participants, as well as with males (N = 127,867) and females (N = 146,274) separately. Bioinformatics analyses were performed to characterize common and sex-specific markers and associated processes/pathways. We identified 11 loci passing genome-level significance (P < 5 × 10-8) in females and one in males. In both males and females, genetic correlations were significant between the broad depression GWA and other psychopathologies; however, correlations with educational attainment and metabolic features including body fat, waist circumference, waist-to-hip ratio and triglycerides were significant only in females. Gene-based analysis showed 147 genes significantly associated with broad depression in the total sample, 64 in the females and 53 in the males. Gene-based analysis revealed "Regulation of Gene Expression" as a common biological process, but suggested sex-specific molecular mechanisms. Finally, sex-specific polygenic risk scores (PRSs) for broad depression outperformed total and the opposite sex PRSs in the prediction of broad major depressive disorder. These findings provide evidence for sex-dependent genetic pathways for clinical depression as well as for health conditions comorbid with depression.

Comprehensive Geriatric Care in Older Hospitalized Patients with Depressive Symptoms

BACKGROUND/OBJECTIVES

Depressive symptoms (DS) may interfere with comprehensive geriatric care (CGC), the specific multimodal treatment for older patients. In view of this, the aim of the current study was to investigate the extent to which DS occur in older hospitalized patients scheduled for CGC and to analyze the associated factors. Furthermore, we aimed to investigate whether DS are relevant with respect to outcomes after CGC.

METHODS

For this retrospective study, all patients fulfilling the inclusion criteria were selected by reviewing case files. The main inclusion criterion was the completion of CGC within the defined period (May 2018 and May 2019) in the geriatrics department of the Diakonie Hospital Jung-Stilling Siegen (Germany). The Geriatric Depression Scale was used to asses DS in older adults scheduled for CGC (0-5, no evidence of DS; 6-15 points, DS). Scores for functional assessments (Timed Up and Go test (TuG), Barthel Index, and Tinetti Gait and Balance test) were compared prior to versus after CGC. Factors associated with the presence of DS were studied.

RESULTS

Out of the 1263 patients available for inclusion in this study, 1092 were selected for the analysis (median age: 83.1 years (IQR 79.1-87.7 years); 64.1% were female). DS (GDS > 5) were found in 302 patients (27.7%). The proportion of female patients was higher in the subgroup of patients with DS (85.5% versus 76.3%, p = 0.024). Lower rates of patients diagnosed with chronic pulmonary obstructive disease were detected in the subgroup of patients without DS (8.0% versus 14.9%, p = 0.001). Higher rates of dizziness were observed in patients with DS than in those without (9.9% versus 6.2%, p = 0.037). After CGC, TuG scores improved from a median of 4 to 3 (p < 0.001) and Barthel Index scores improved from a median of 45 to 55 (p < 0.001) after CGC in both patients with and without DS. In patients with DS, the Tinetti score improved from a median of 10 (IQR: 4.75-14.25) prior to CGC to 14 (IQR 8-19) after CGC (p < 0.001). In patients without DS, the Tinetti score improved from a median of 12 (IQR: 6-7) prior to CGC to 15 (IQR 2-20) after CGC (p < 0.001).

CONCLUSIONS

DS were detected in 27.7% of the patients selected for CGC. Although patients with DS had a poorer baseline status, we detected no difference in the degree of improvement in both groups, indicating that the performance of CGC is unaffected by the presence of DS prior to the procedure.

Sex differences in depression: An immunological perspective

Depression is a heterogenous disorder with symptoms that present differently across individuals. In a subset of people depression is associated with alterations of the immune system that may contribute to disorder onset and symptomology. Women are twice as likely to develop depression and on average have a more sensitive adaptive and innate immune system when compared to men. Sex differences in pattern recognition receptors (PRRs), release of damage-associated molecular patterns (DAMPs), cell populations, and circulating cytokines play a critical role in inflammation onset. Sex differences in innate and adaptive immunity change the response of and repair to damage caused by dangerous pathogens or molecules in the body. This article reviews the evidence for sex specific immune responses that contribute to the sex differences in symptoms of depression that may account for the higher rate of depression in women.

The Effects of Acute and Repeated Administration of Ketamine on Memory, Behavior, and Plasma Corticosterone Levels in Female Mice

Ketamine is an anesthetic drug that has recently been approved for the treatment of treatment-resistant depression. Females are diagnosed with Major Depressive Disorder at higher rates than males, yet most of the pre-clinical research on ketamine has been conducted in male subjects. Additionally, the literature on the acute and long-term behavioral and cognitive effects of ketamine shows conflicting results. It is important to examine the acute and long-term cognitive and behavioral effects of ketamine exposure at lower sub-anesthetic doses, as the recreational use of the drug at higher doses is associated with cognitive and memory impairments. The current study examined the effects of acute and repeated ketamine exposure on anxiety-like behavior, novel object recognition memory, depression-like behavior, and plasma corticosterone levels in 20 adult female C57BL/6J mice. Mice were exposed acutely or repeatedly for 10 consecutive days to saline or 15 mg/kg ketamine and behavior was measured in the open field test, novel object recognition test, and the Porsolt forced swim test. Plasma corticosterone levels were measured following behavioral testing. Acute ketamine exposure decreased locomotor activity and increased anxiety-like behavior in the open field test compared to controls, while repeated ketamine exposure impaired memory in the novel object recognition test. There were no effects of acute or repeated ketamine exposure on depression-like behavior in the Porsolt forced swim test or on plasma corticosterone levels. These findings suggest that a subanesthetic dose of ketamine alters behavior and cognition in female mice and the effects are dependent on the duration of exposure.

The effect of chronic stress on behaviors, inflammation and lymphocyte subtypes in male and female rats

Excessively released proinflammatory mediators from activated macrophages and lymphocytes may contribute to the etiology of depression. However, the relationship between lymphocytes and depression is not fully understood. Although women have higher depression risk than men, sex/gender differences in psychoneuroimmunological mechanisms are still unclear. To explore these two questions, chronic unpredictable mild stress (CUMS) was used to evaluate the changes in behaviors, inflammation and lymphocyte subtypes in adult male and female Wistar rats. Results show that CUMS increased anhedonia and anxiety-like behaviors, along with increased serum corticosterone, hippocampal pro-inflammatory factors, CD11b, IFN-γ, IL-6 and IL-17, but decreased CD4, CD25, CD4/CD8 ratio, GFAP, 5-hydroxytryptamine (5-HT) and NE concentrations, regardless of sex. There was no positive correlation between sucrose preference and blood CD4/CD8 ratio, but a positive correlation between sucrose preference and spleen CD25, sucrose preference and neurotransmitters (NE and 5-HT), spleen CD25 and serum TGF-β1/IL-6 ratio were found, regardless of sex. Females presented higher basal locomotion, blood CD4, CD4/CD8 ratio, serum corticosteroid and IL-6 concentrations, but lower hippocampal norepinephrine (NE) than males. Although CUMS didn't induce significant sex differences, females presented more changes in CD4 and CD8 lymphocytes than male rats. CUMS caused abnormalities in corticosteroid, lymphocytes, cytokines and neurotransmitters, which might be the precursors for inducing depression-like behaviors in both sexes.

Constructing and validating an occupational job strain index based on five Norwegian nationwide surveys of living conditions on work environment

BACKGROUND

It has been claimed that Nordic register data are a "goldmine" for research. However, one limitation is the lack of information on working conditions. Job exposure matrices (JEMs) are one solution to this problem. Thus, the three aims of this study were (i) to investigate the reliability of an occupation-based psychosocial JEM, i.e., a Job Strain Index (job strain or JSI abbreviated), (ii) to examine the construct and criterion-related validity of this measure of job strain (iii) and assesses the concurrent and the predictive validity of an occupation-based Job Strain Index for use in analyses of Norwegian register data.

METHOD

The study utilized five waves of the nationwide Norway Survey of Living Conditions in the Work Environment with a total sample of 43,977 individuals and register data with a total sample of 1,589,535 individuals. Job strain was composed of items belonging to the two dimensions of Karasek's DC model, job demands and job control (1979). The reliability of the JSI and its dimensions and components were investigated by measuring the degree of agreement (Cohen's kappa), sensitivity, specificity, and internal consistency (Cronbach's alpha). Construct validity was assessed by confirmatory factor analysis, and criterion-related validity was measured by concurrent validity and predictive validity. The selected concurrent criteria were self-reported survey information on long-term sick absence, anxiety, depression, and sleeping difficulty. The predictive criteria were register information on receipt of disability benefits, mortality, and long-term sick leave.

RESULTS

Agreement between individual and occupation-based job strain and components was fair to poor. The sensitivity and specificity of occupation-based job strain and its components varied from acceptable to low. The consistency of the items comprising job demand and job control was clearly acceptable. Regarding concurrent validity, significant associations between (both individual and occupational) job strain, and long-term sick leave and sleeping difficulty were observed for both genders. Occupation-based job strain indicated an elevated risk for anxiety and depression among men, but not among women. As for predictive reliability, significant associations between occupation-based job strain and all three health outcomes were observed for both men and women.

CONCLUSION

Our occupation-based JSI serves as a reliable and valid indicator of psychosocial job exposure that can be used in analyses of Norwegian register data where individual information on such conditions is missing.

Sex Differences in Depression and Anxiety

Depression and anxiety disorders carry a tremendous worldwide burden and emerge as a significant cause of disability among western societies. Both disorders are known to disproportionally affect women, as they are twice more likely to be diagnosed and moreover, they are also prone to suffer from female-specific mood disorders. Importantly, the prevalence of these affective disorders has notably risen after the COVID pandemic, especially in women. In this chapter, we describe factors that are possibly contributing to the expression of such sex differences in depression and anxiety. For this, we overview the effect of transcriptomic and genetic factors, the immune system, neuroendocrine aspects, and cognition. Furthermore, we also provide evidence of sex differences in antidepressant response and their causes. Finally, we emphasize the importance to consider sex as a biological variable in preclinical and clinical research, which may facilitate the discovery and development of new and more efficacious antidepressant and anxiolytic pharmacotherapies for both women and men.

The Evolving Role of Animal Models in the Discovery and Development of Novel Treatments for Psychiatric Disorders

Historically, animal models have been routinely used in the characterization of novel chemical entities (NCEs) for various psychiatric disorders. Animal models have been essential in the in vivo validation of novel drug targets, establishment of lead compound pharmacokinetic to pharmacodynamic relationships, optimization of lead compounds through preclinical candidate selection, and development of translational measures of target occupancy and functional target engagement. Yet, with decades of multiple NCE failures in Phase II and III efficacy trials for different psychiatric disorders, the utility and value of animal models in the drug discovery process have come under intense scrutiny along with the widespread withdrawal of the pharmaceutical industry from psychiatric drug discovery. More recently, the development and utilization of animal models for the discovery of psychiatric NCEs has undergone a dynamic evolution with the application of the Research Domain Criteria (RDoC) framework for better design of preclinical to clinical translational studies combined with innovative genetic, neural circuitry-based, and automated testing technologies. In this chapter, the authors will discuss this evolving role of animal models for improving the different stages of the discovery and development in the identification of next generation treatments for psychiatric disorders.

Chronic Unpredictable Mild Stress Model of Depression: Possible Sources of Poor Reproducibility and Latent Variables

Major depressive disorder (MDD) is one of the most common mood disorders worldwide. A lack of understanding of the exact neurobiological mechanisms of depression complicates the search for new effective drugs. Animal models are an important tool in the search for new approaches to the treatment of this disorder. All animal models of depression have certain advantages and disadvantages. We often hear that the main drawback of the chronic unpredictable mild stress (CUMS) model of depression is its poor reproducibility, but rarely does anyone try to find the real causes and sources of such poor reproducibility. Analyzing the articles available in the PubMed database, we tried to identify the factors that may be the sources of the poor reproducibility of CUMS. Among such factors, there may be chronic sleep deprivation, painful stressors, social stress, the difference in sex and age of animals, different stress susceptibility of different animal strains, handling quality, habituation to stressful factors, various combinations of physical and psychological stressors in the CUMS protocol, the influence of olfactory and auditory stimuli on animals, as well as the possible influence of various other factors that are rarely taken into account by researchers. We assume that careful inspection of these factors will increase the reproducibility of the CUMS model between laboratories and allow to make the interpretation of the obtained results and their comparison between laboratories to be more adequate.

Sex differences in basal reelin levels in the paraventricular hypothalamus and in response to chronic stress induced by repeated corticosterone in rats

Repeated exposure to the stress hormone corticosterone results in depressive-like behaviours paralleled by the downregulation of hippocampal reelin expression. Reelin is expressed in key neural populations involved in the stress response, but whether its hypothalamic expression is sex-specific or involved in sex-specific vulnerability to stress is unknown. Female and male rats were treated with either daily vehicle or corticosterone injections (40 mg/kg) for 21 days. Thereafter, they were subjected to several behavioural tasks before being sacrificed to allow the analysis of reelin expression in hypothalamic nuclei. The basal density of reelin-positive cells in males was significantly higher in the paraventricular nucleus (19 %) and in the medial preoptic area (51 %) compared to females. Chronic corticosterone injections increased the immobility time in the forced swim test in males (107 %) and females (108 %) and decreased the exploration of the elevated plus maze in males (34 %). Corticosterone also caused a significant decrease in the density of reelin-positive cells in males, in both ventrodorsal (37 %) and ventrolateral (32 %) subdivisions of the paraventricular nucleus, while not affecting females. Moreover, in the paraventricular nucleus of males, 30 % of the basal reelin-positive cells co-expressed oxytocin while only 17.5 % did in females, showing a positive correlation between reelin and oxytocin levels. Chronic corticosterone did not significantly affect co-localization levels. For the first time, this study shows that there is a sexually dimorphic subpopulation of reelin-positive neurons in the paraventricular nucleus that can be differentially affected by chronic stress.

Association between serum 25 (OH) D levels and depression symptoms in adults with prediabetes

BACKGROUND AND AIM

Depression symptoms are a significant risk factor for prediabetes-related diabetes, and low vitamin D levels are connected with depression symptoms. The goal of this study is to examine the association between vitamin D and depression symptoms in prediabetic persons.

METHODS

This cross-sectional survey was conducted in Tianjin, China, among 4051 individuals. Symptoms of depression were assessed using the Self-Rating Depression Scale (SDS) (cut-off point SDS ≥45). Serum 25 (OH) D concentrations were determined using an enzyme immunoassay (OCTEIA 25-hydroxy Vitamin D, IDS Ltd, UK) and classified into three levels: 50 nmol/L, 50-75 nmol/L, and >75 nmol/L. The link between serum 25 (OH) D concentrations and depression symptoms in prediabetes was investigated using multiple logistic regression analysis. The models were adjusted for a variety of potential confounders.

RESULTS

The prevalence of symptoms of depression in prediabetic adults was 14.2% (12.5% males and 16.4% females). After adjusting for potentially confounding variables, the odds ratios - ORs for symptoms of depression in women across serum 25 (OH) D levels were 1.00 (reference), 1.03 (0.57, 1.39), and 0.28 (0.12, 0.57), respectively (p = 0.0015). However, no statistically significant connection was discovered in males.

CONCLUSION

In women with prediabetes, we showed a substantial negative connection between serum 25 (OH) D levels and depressed symptoms. Vitamin D supplementation may be an effective way to decrease the risk of depression symptoms in women with prediabetes.

Age- and sex-specific effects of maternal separation on the acoustic startle reflex in rats: early baseline enhancement in females and blunted response to ambiguous threat

Early life adversity (ELA) increases the incidence of later-life anxiety disorders. Dysregulated threat processing, including responsivity to ambiguous threats, is an indicator of anxiety disorders and can be influenced by childhood experiences. The acoustic startle response is a defensive reflex displayed by mammals when exposed to sudden intense stimuli reflecting individual variations in vigilance. These measures can be altered by previous experience and experimental modifications, including the introduction of unconditioned aversive stimuli. Rats emit ultrasonic vocalizations (USVs) in the 22 KHz range in negative contexts. As such, 22 KHz USVs are an ethologically relevant social cue of environmental threat shown to induce anxiety-like behavior in recipient rats. Because the timing of symptom manifestation after early life adversity can differ between sexes, the current study sought to identify the age- and sex-specific effects of daily maternal separation (MS) on responsivity to ambiguous threat in rats. In Experiment 1, rat pups underwent MS or control rearing from postnatal day (P) 2–20, then underwent behavioral testing beginning on P24, 34, or 54 to determine whether MS modified the baseline startle response or the modulation of startle by 22 KHz USVs. In Experiment 2, rats were tested in a light-enhanced startle paradigm at P54 after MS or control rearing to determine whether MS influenced light-enhanced startle. Results show an enhancement of the baseline startle magnitude by MS in females at P34. At P54, MS reduced the modulation of the startle response by 22 KHz USVs and prevented light-enhanced startle, indicating an MS-induced deficit in defensive responsivity when exposed to potential threat.

Cardiolipin Antibody: A Potential Biomarker for Depression

Background: Inflammation plays a pivotal role in the etiopathology of Major Depressive Disorder (MDD), at least in a subset of patients. It is crucial to first establish which specific inflammatory biomarkers are of clinical utility. Anti-cardiolipin antibody (aCL IgM) is an inflammatory marker that has the potential to be such a candidate but there are insufficient studies to confirm this potential. Objective: To investigate the baseline titer level and the longitudinal progression of plasma titers of aCL IgM in MDD subjects receiving antidepressant therapy in comparison to healthy control (HC) subjects; to determine if changes in aCL IgM plasma titers correlate to changes in depressive symptoms; and, to ascertain if baseline aCL IgM plasma titers could predict treatment response. Methods: Forty-eight medically healthy outpatients diagnosed with MDD were enrolled in one of two groups in two sequentially conducted clinical trials. In Group-E, patients received a 12-week regimen of escitalopram (n = 20). Those in Group-Q received a 12-week regimen of quetiapine (n = 28). The main outcome measure was plasma aCL IgM titers, the Hamilton Rating Scale for Depression (HAM-D17) and the Hamilton Rating Scale for Anxiety (HAM-A). There were 16 HC subjects. Results: When Group-Q and Group-E participants were grouped together (n = 48), MDD subjects had an elevated baseline aCL IgM (19.9 μg/mL) compared to HC subjects (8.32 μg/mL) (p = 0.006). aCL IgM correlated significantly with HAM-D17 scores at baseline in MDD subjects (p = 0.0185, r = 0.296). Examining the individual groups, Group-Q MDD patients had a significantly elevated baseline aCL IgM (p = 0.008) while Group-E's MDD patients did not. On the other hand, only Group-E MDD patients showed a significant correlation at baseline between aCL IgM and HAM-A score (p = 0.0392, r = 0.4327); they also showed a significant inverse correlation between week 12 HAMD-17 Item #10 (Anxiety, Psychic) and week 12 aCL IgM titer (p = 0.0268, r = -0.5516). Conclusions: MDD patients had significantly higher plasma titers of aCL IgM when compared to HC subjects. Moreover, at baseline, the higher the aCL IgM titer, the higher the depression severity, as measured by HAMD-17 score. However, this study did not demonstrate that aCL IgM titers changed significantly throughout a 12-week course of antidepressant treatment and revealed no correlation between changes in depressive symptoms and changes in aCL IgM titers. Baseline aCL IgM could not predict treatment response. We conclude that, despite lacking predictive ability as regards treatment response, plasma titers of aCL IgM have a diagnostic potential in MDD that necessitates further exploration.

Regional gene expression signatures are associated with sex-specific functional connectivity changes in depression

The neural substrates of depression may differ in men and women, but the underlying mechanisms are incompletely understood. Here, we show that depression is associated with sex-specific patterns of abnormal functional connectivity in the default mode network and in five regions of interest with sexually dimorphic transcriptional effects. Regional differences in gene expression in two independent datasets explained the neuroanatomical distribution of abnormal connectivity. These gene sets varied by sex and were strongly enriched for genes implicated in depression, synapse function, immune signaling, and neurodevelopment. In an independent sample, we confirmed the prediction that individual differences in default mode network connectivity are explained by inferred brain expression levels for six depression-related genes, including PCDH8, a brain-specific protocadherin integral membrane protein implicated in activity-related synaptic reorganization. Together, our results delineate both shared and sex-specific changes in the organization of depression-related functional networks, with implications for biomarker development and fMRI-guided therapeutic neuromodulation.

The Relationship Between Workplace Burnout and Male Depression Symptom Assessed by the Korean Version of the Gotland Male Depression Scale

Screening for depression in males is important because their symptoms differ from those of females, ranging from indications of aggression to attempts at suicide. Men and women differ in their responses to job stress. There are no tools that have been verified, developed, or translated for screening male depression in Korea. Our team translated the Gotland Male Depression Scale (GMDS) into Korean. The Korean version of GMDS (K-GMDS) and Maslach Burnout Inventory-General Survey (MBI-GS) were administered to 277 office workers in one public institution. Gender differences in each scale score were measured along with the correlation between the K-GMDS and the MBI-GS. There was no significant difference in the K-GMDS score between males and females, whereas females scored significantly higher on the MBI-GS (p < .001). The correlation between the K-GMDS total score and the MBI total score (male: r = .702, p < .001, female: r = .375, p < .001) and MBI subscale scores were higher in males than females. Gender moderated the relationship between total K-GMDS and total MBI scores (p < .001). The Korean version of the GMDS is suitable for screening male depression symptoms in the workplace. The results of the K-GMDS demonstrated a strong correlation between depressive symptoms and work-related burnout among men. This study can be used as a basis for studying male depression symptoms in Korea, which has not been studied extensively. This will prove beneficial for work environments.

Network structure of time-varying depressive symptoms through dynamic time warp analysis in late-life depression

OBJECTIVES

Late-life major depressive disorder (MDD) can be conceptualized as a complex dynamic system. However, it is not straightforward how to analyze the covarying depressive symptoms over time in case of sparse panel data. Dynamic time warping (DTW) analysis may yield symptom networks and dimensions both at the patient and group level.

METHODS

In the Netherlands Study of Depression in Older People (NESDO) depressive symptoms were assessed every 6 months using the 30-item Inventory of Depressive Symptomatology (IDS) with up to 13 assessments per participant. Our sample consisted of 182 persons, aged ≥ 60 years, with an IDS total score of 26 or higher at baseline. Symptom networks dimensions, and centrality metrics were analyzed using DTW and Distatis analyses.

RESULTS

The mean age was 69.8 years (SD 7.1), with 69.0% females, and a mean IDS score of 38.0 (SD = 8.7). DTW enabled visualization of an idiographic symptom network in a single NESDO participant. In the group-level nomothetic approach, four depressive symptom dimensions were identified: "core symptoms", "lethargy/somatic", "sleep", and "appetite/atypical". Items of the "internalizing symptoms" dimension had the highest centrality, whose symptom changes over time were most similar to those changes of other symptoms.

CONCLUSIONS

DTW revealed symptom networks and dimensions based on the within-person symptom changes in older MDD patients. Its centrality metrics signal the most influential symptoms, which may aid personalized care.

Opinions and options about COVID-19: Personality correlates and sex differences in two European countries

In the initial months of the COVID-19 pandemic in 2020, we collected data (N = 1,420) from Portugal and Spain in relation to personality (i.e., Dark Triad traits, Big Five traits, religiousness, and negative affect) and attitudes related to COVID-19 about its origins, opinions on how to deal with it, and fear of it. The most pervasive patterns we found were: (1) neurotic-type dispositions were associated with stronger opinions about the origins of the virus and leave people to have more fear of the virus but also more trust in tested establishments to provide help. (2): religious people were less trusting of science, thought prayer was answer, and attributed the existence of the virus to an act of God. We also found that sex differences and country differences in attitudes towards COVID-19 were mediate by sex/country differences in personality traits like emotional stability, religiousness, and negative affect. For instance, women reported more fear of COVID-19 than men did, and this was verified by women’s greater tendency to have negative affect and low emotional stability relative to men. Results point to the central role of neuroticism in accounting for variance in broad-spectrum attitudes towards COVID-19.

Revisiting the antidepressant-like effects of desipramine in male and female adult rats: sex disparities in neurochemical correlates

Background

The preclinical antidepressant-like characterization of desipramine relied almost exclusively in male rodents, with only a few contradictory reports done in females. Given that most experiments assessed a single dose and/or timepoint of analysis after-treatment, this study evaluated potential sex-differences in the length of the antidepressant-like response induced by different doses of desipramine as well as the molecular underpinnings driving the different responses by sex.

Methods

Male and female Sprague–Dawley rats were treated (i.p.) with 3 pulses of desipramine (5, 10 or 20 mg/kg) or vehicle (0.9% NaCl) within 24 h. The antidepressant-like effects were evaluated in the forced-swim test 1-h, 1- and 3-day post-treatment. The rate of cell proliferation and the regulation of key neuroplasticity markers (FADD, Cdk5, p35, p25) involved in antidepressant-like responses in the hippocampus were evaluated 1-h, 1-day and 5-day post-treatment.

Results

Desipramine induced similar antidepressant-like effects in male and female rats (effective doses of 10 and 20 mg/kg, with effects that lasted up to 1-day post-treatment), without altering the rate of cell proliferation. However, some sex-differences emerged when evaluating neuroplasticity markers in the hippocampus, while no changes were observed for female rats, desipramine regulated FADD, Cdk-5 and p25 in males in a way that suggested neuroprotective actions.

Conclusions

Our findings imply that while desipramine induced similar antidepressant-like responses for male and female rats, some differences emerged in the regulation of certain neuroplasticity markers, suggesting that distinctive molecular mechanisms might be participating in the therapeutic response of desipramine for both sexes.