Sex differences in stress-related psychiatric disorders: neurobiological perspectives

Sex shapes phenotype-linked metabolic signatures of stress exposure in the mouse hypothalamus and pituitary

In chronic stress-induced anxiodepression, sex differences in the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis are well-documented, yet the underlying molecular mechanisms remain largely unexplored. This study investigated sex-specific metabolic signatures associated with stress exposure in the hypothalamus and pituitary, given the potential significance of brain metabolism in sex-related mechanisms underlying anxiodepression. Utilizing a chronic restraint stress (CRS) model, we conducted a comparative analysis of the metabolic profiles in female and male mice to identify distinct phenotypic expressions related to sex differences. Our findings revealed that metabolite alterations in the pituitary were more pronounced than those in the hypothalamus, indicating significant sex-based variations. These differences facilitated phenotypic differentiation and underscored the relevance of sex-specific metabolic changes and their functional associations to behavioral phenotypes. Moreover, diverging and converging pathways were identified to elucidate the molecular and physiological bases of stress susceptibility in both sexes. Key metabolic and immune-related pathways in the hypothalamus and pituitary, such as histidine, tryptophan, lipid, glycerophospholipid, amino acid, and carbohydrate metabolism, showed specific associations with sex and phenotype. Additionally, correlation analysis uncovered several differential metabolites that were significantly linked to mouse behaviors, with marked sex differences. Collectively, our results demonstrate a pronounced sexual dimorphism at the metabolic level in the hypothalamus and pituitary in response to chronic stress. This study provides a valuable molecular resource for further exploration of the interplay between sex and behavioral phenotypes within the dysregulation of the HPA axis that contributes to stress susceptibility and immune response, emphasizing the critical role of sex-specific metabolic mechanisms in anxiodepressive disorder.

Pathways to Resistance: Theorizing Trauma and Women's Use of Force in Intimate Relationships

Using a feminist pathways general strain perspective, we explore the victim-offender continuum for women who perpetrated intimate partner violence/abuse (IPV/A). We use data from 86 women court-mandated to "female offender" domestic violence treatment programs, located in an American East Coast state, who were surveyed about their adverse childhood experiences and mental health/well-being as adults. Findings from bivariate linear regressions indicate childhood trauma negatively affects adult mental health/well-being, exacerbated for Black Indigenous People of Color women, suggesting a victim rather than an offender categorization for women using force against their abusive partner. Results imply the need to consider women's traumatic histories and IPV/A victimization, given an incident-driven system that criminalizes victimization over the life course.

Repeated footshock stress enhances cocaine self-administration in male and female rats: Role of the cannabinoid receptor 1

Stress is a significant contributor to the development and progression of substance use disorders (SUDs) and is problematic as it is unavoidable in daily life. Therefore, it is important to understand the neurobiological mechanisms that underlie the influence of stress on drug use. We have previously developed a model of rat self-administration that employs an electric footshock stressor at the time of cocaine self-administration, resulting in an enhancement of cocaine self-administration. This stress enhancement of cocaine intake involves neurobiological mediators of stress and reward such as cannabinoid signaling. However, all of this work has been conducted in male rats. Here we test the hypothesis that repeated daily stress enhances cocaine self-administration in male and female rats. We further hypothesize that cannabinoid receptor 1 (CB1R) signaling is recruited by repeated stress to influence cocaine self-administration in both male and female rats. Male and female Sprague-Dawley rats self-administered cocaine (0.5 mg/kg/inf, i.v.) during a modified short-access paradigm wherein the 2 hr access was separated into four 30 min self-administration blocks separated by four 5 min drug free periods. Footshock stress significantly increased cocaine self-administration similarly in both male and female rats. Females displayed greater stress-enhanced time-out, non-reinforced responding, and stress-specific "front-loading" behavior. In males, systemic administration of a CB1R inverse agonist/antagonist Rimonabant only attenuated cocaine intake in rats with a history of combined repeated stress and cocaine self-administration. However, in females, Rimonabant attenuated cocaine self-administration in the no stress control group but only at the highest dose of Rimonabant (3 mg/kg, i.p.) suggesting that females show a greater sensitivity to CB1R antagonism. However, female rats with a history of stress showed even greater sensitivity to CB1R antagonism as both doses of Rimonabant (1, 3 mg/kg) attenuated cocaine self-administration in stress-enhanced rats, similar to males. Altogether these data demonstrate that stress can produce significant changes in cocaine self-administration and suggests that repeated stress at the time of cocaine self-administration recruits CB1Rs to regulate cocaine-taking behavior across sexes.

Cumulative effect of stress on decisional exploration-to-exploitation switch assessed through a gambling task in female mice

Survival and well-being hinge on an organism's ability to evaluate options, weighing costs and benefits to make adaptive decisions. It has long been shown that stress influences cognition and reward-related behaviour, the nature of which depends on the stressor's type and duration as well as gene x environment interactions. However, how stress influence decision-making in females has not been completely elucidated. Here, we have developed a new mouse gambling task (mGT) adapted to assess decision-making under uncertainty and risk. Adult female C57BL/6JRj mice administered with corticosterone (CORT) for 5 or 8 weeks reached similar final performance in the mGT as vehicle-treated controls. All groups tended to learn to maximize gain as the task progressed. Our results revealed that individual choice kinetics is impacted by chronic exposure to CORT, showing an accentuated sensitivity to penalties in female mice. These results confirm the suitability of our new mGT to assess decision-making under uncertainty and risk and are in line with previous reports of the effect of chronic CORT treatment on decision-making in male mice. Thereby this study provides new insights into the influence of sex and stress on decision-making.

The age of onset and duration of childhood abuse: An extension of the childhood trauma screener

BACKGROUND

Childhood abuse is a significant risk factor for worse adult mental and physical health. Although reported as important moderators, only a few studies have analyzed the effects of the age of onset and duration of abuse, particularly including potential sex differences.

OBJECTIVE

To investigate the impact of timing and severity of childhood abuse on adult mental and physical health issues, with an emphasis on sex differences.

PARTICIPANTS AND SETTINGS

Data from 2412 participants (52 % women, 28-89 years) of the general population.

METHODS

The Childhood Trauma Screener (CTS) was extended to assess the severity additionally to the age of onset and cumulative exposure across predefined age intervals of physical, emotional, and sexual childhood abuse. Associations with adult health behavior, mental health issues, and inflammatory markers were investigated using regression analyses, complemented by sex interactions.

RESULTS

An earlier onset of emotional abuse was associated with lower resilience (b = -0.51, p = 0.034), whereas greater cumulative exposure to emotional abuse was associated with an earlier onset of depression (b = -4.53, p = 0.041) and more severe depressive symptoms (b = 0.94, p = 0.049). Effect directions differed between men and women for associations between the age of onset of emotional abuse and C-reactive protein levels (b = -0.03, p = 0.042) as well as the cumulative exposure of emotional abuse and fibrinogen levels (b = 0.04, p = 0.007).

CONCLUSIONS

The findings underscore the significance of both severity and timing on adult health outcomes, with notable sex differences. These results support the need for targeted prevention programs that consider multiple maltreatment aspects, along with tailored interventions based on sex-specific vulnerabilities.

Longitudinal relation between negative life events and non-suicidal self-injury among Chinese college students: a moderated mediation model

BACKGROUND

Non-suicidal self-injury (NSSI) poses a significant public health concern, characterized by its high prevalence, recurrence, and association with suicide. While prior research has identified a connection between negative life events (NLEs) and NSSI, only a few studies have longitudinally explored this relation and its underlying mechanisms.

OBJECTIVE

Our study investigated the longitudinal association between NLEs and NSSI among Chinese college students. We also examined the mediating role of rumination and emotional regulation difficulties, as well as the moderating role of sex.

METHODS

We recruited 4892 students from six colleges in northern China. We assessed NLEs, NSSI, rumination, and emotional regulation difficulties at baseline (T1) and after a 1-year follow-up (T2).

RESULT

The longitudinal moderated mediation model revealed that early NLEs exerted significant direct predictive effects on later NSSI and indirect predictive effects on NSSI through the independent mediation of rumination and emotional regulation difficulties, as well as a chain mediating effect through them. The first stage (predicting the effect of NLEs on NSSI) and second stage (predicting the effect of NLEs on rumination) were moderated by sex.

CONCLUSION

Our findings underscore the importance of considering recent stressors in assessing risks and implementing interventions for college students involved in NSSI. Mental health professionals should prioritize helping students develop emotional regulation skills and reduce rumination while being mindful of sex differences.

The functional role of locus coeruleus microglia in the female stress response

Neuropsychiatric disorders that result from stress exposure are highly associated with central inflammation. Our previous work established that females selectively exhibit heightened proinflammatory cytokine production within the noradrenergic locus coeruleus (LC) along with a hypervigilant behavioral phenotype in response to witnessing social stress. Notably, ablation of microglia using pharmacological techniques prevents this behavioral response. These studies were designed to further investigate the impact of stress-induced neuroimmune signaling on the long-term behavioral and neuronal consequences of social stress exposure in females using chemogenetics. We first characterized the use of an AAV-CD68-Gi-DREADD virus targeted to microglia within the LC and confirmed viral transduction, selectivity, and efficacy. Clozapine-n-oxide (CNO) was used for the suppression of microglial reactivity during acute and chronic exposure to vicarious/witness social defeat in female rats. Chemogenetic-mediated inhibition of microglial reactivity during stress blunted the neuroimmune response to stress and prevented both acute and long-term hypervigilant behavioral responses. Further, a history of microglial suppression during stress prevented the heightened LC activity typically observed in response to stress cues. These studies are among the first to use a chemogenetic approach to inhibit central microglia in vivo and establish LC microglia as a key driver of the behavioral and neuronal responses to social stress in females.

Stress and gender differences in brain development

This chapter investigates the ways in which male and female brains are differently affected by stress during early development, which in turn affects how susceptible each group is to stress-related illnesses. When examining the structure and function of the brain, gender differences and stress must be taken into account. Male and female brain development differs in response to the prenatal testis's secretion of androgen. It appears that when it comes to responding to stress, encoding memories, feeling emotions, solving specific issues, and making decisions, men and women use distinct areas of the brain. Findings revealed that stress led to specific changes in brain structure and function, with gender-specific differences observed. The prefrontal cortex, the hippocampus, and the amygdala are among the brain regions connected to the stress response. The stress response has been linked to the presentation of numerous mental and psychosomatic conditions. The way men and women respond to stress varies on a biological and psychological level. To gain more insight into the gender differences seen throughout brain development, these disparities must also be investigated. This chapter implies that gender-specific vulnerabilities should be addressed and healthy brain development should be promoted by stress-related interventions.

Traumatic stress-enhanced ethanol drinking: Sex, but not stress responsivity, alters sensitivity to the effects of a CRF-R1 antagonist and a GPR39 agonist in mice

BACKGROUND

Predator stress (PS) is used to model trauma leading to post-traumatic stress disorder, and it increases ethanol drinking in a proportion of male and female rodents. The goals of the present studies were to identify male and female mice with prior binge drinking experience that exhibited sensitivity and resilience to PS-enhanced drinking and then to test two target molecules (corticotropin releasing factor receptor 1 [CRF-R1] antagonist NBI-27914 [NBI] and G-protein coupled receptor 39 [GPR39] agonist TC-G 1008 [TC-G]) for their ability to selectively reduce PS-enhanced drinking.

METHODS

Adult male and female C57BL/6J mice received seven binge ethanol sessions, a period of abstinence, and acclimation to lickometer chambers to examine the effects of NBI or TC-G on stress-associated drinking. Following establishment of stable baseline (BL) drinking and four intermittent PS exposures, mice were classified into "Sensitive" and "Resilient" subgroups, based on the change in ethanol drinking from BL after PS2-4. Then, mice received injections of vehicle or drug (NBI or TC-G) in a within-subjects design. Control studies examined the effects of NBI or TC-G on binge drinking, locomotor activity, and saccharin intake.

RESULTS

NBI and TC-G significantly suppressed binge drinking in male and female mice in the control studies. However, sensitivity to the ability of the compounds to decrease PS-enhanced drinking did not differ between animals in the "PS-sensitive" versus "PS-resilient" subgroups, and female mice were insensitive to TC-G in the traumatic stress drinking model. Specifically, NBI doses of 5 and 10 mg/kg (males) and 12.5 mg/kg (females) significantly decreased PS-associated drinking in both subgroups. TC-G (7.5 mg/kg) significantly decreased PS-associated drinking in both subgroups of male mice but not in female mice.

CONCLUSIONS

The present findings suggest that stress sensitivity and subsequent enhanced ethanol drinking in the "Sensitive" subgroup may not increase sensitivity to CRF-R1 antagonism or GPR39 agonism.

Brain region and sex-dependent heterogeneity of PUFA/oxylipin profile, microglia morphology and their relationship

Lipid dyshomeostasis and neuroinflammation are key hallmarks of neuropsychiatric and neurodegenerative disorders, including major depressive disorder and Alzheimer's disease. In particular, polyunsaturated fatty acids (PUFAs) and their derivatives called oxylipins gained specific interest in this context, especially considering their capacity to orchestrate neuroinflammatory responses via direct modulation of microglia. The hippocampus and hypothalamus are crucial brain regions for regulating mood and cognition that are implicated in a variety of neuropsychiatric and neurodegenerative disorders and there is ample evidence for the sex-bias in risks for the development as well as sex-bias in the presentation of such psychiatric diseases, including the neuroinflammatory response. To better understand the local PUFA/oxylipin profiles and microglia responses in disease, we here assessed their brain region and sex-dependent profiles in homeostatic brains. In 2-month-old male and female mice, we measured non-esterified (free) PUFA/oxylipin profiles using liquid chromatography-tandem mass spectrometry and characterized microglia morphology via immunohistochemistry. The hypothalamus and hippocampus exhibit a different free PUFA/oxylipin profile, independent of sex. The hippocampus was characterized by a higher density of complex Iba1+ microglial cells than the hypothalamus, without sex effects. Hypothalamic microglial morphology correlated more strongly with free PUFA- and oxylipin species than hippocampal microglia, correlating with species from both the N-3 and N-6 PUFA metabolization pathways, while hippocampal microglial parameters correlated only with N-6 pathway-related species. Our findings provide a basis for future studies to investigate the relationship between PUFAs, their derivatives and neuroinflammation in the context of diseases.

The effect of Psilocybe cubensis alkaloids on depressive-like behavior in mice exposed to maternal separation with respect to hippocampal gene expression and DNA methylation of Slc6a4 and Nr3c1

Maternal separation as an early life stress can lead to long-lasting deleterious effects on cognitive and behavioral functions, and the mood state. On the other hand, Psilocybe cubensis (as one of the most well-known magic mushrooms) may be beneficial in the improvement or the treatment of neuropsychiatric disorders. In the present study, we aimed to investigate the effect of P. cubensis extract (PCE) on depressive-like and anxiety-like behaviors, and locomotor activity in mice exposed to early maternal separation. Also, we assessed the expression and methylation level of Slc6a4 and Nr3c1 in the hippocampus. Maternal separation was done in postnatal days (PNDs) 2-18. PCE was intraperitoneally injected at the dose of 20 mg/kg at PND 60, and our tests were done at days 1, 3, and 10, of administration. The results showed that maternal separation significantly induced depressive-like behavior in the forced swim test and anxiety-like behavior in the open field test (OFT). Also, maternal separation decreased locomotor activity in the OFT. In addition, maternal separation decreased the expression and increased the methylation level of both Slc6a4 and Nr3c1 in the hippocampus. However, PCE significantly reversed all these effects. In conclusion, it seems that P. cubensis affects serotonergic signaling via altering Slc6a4 expression and methylation level in the hippocampus of mice. The effect of P. cubensis on Nr3c1 expression and methylation level may also lead to alter the function of the hypothalamus-pituitary-adrenal axis and the stress response in mice exposed to maternal separation.

Divergent changes in social stress-induced motivation in male and female mice

Exposure to stressors has been shown to dysregulate motivated behaviors in a bidirectional manner over time. The relationship between stress and motivation is relevant to psychological disorders, including depression, binge eating, and substance use disorder; however, this relationship is not well characterized, especially in females, despite their increased risk of these disorders. Social defeat stress is a common model to study stress-induced motivation changes, however, historically this model excluded females due to lack of female-to-female aggression and unreliable male-to-female aggression. Additionally, changes in motivation are often assessed well after stress exposure ends, potentially missing or occluding changes to motivation during stress. Recently, the chronic non-discriminatory social defeat stress (CNSDS) model has demonstrated social defeat of male and female C57BL/6J mice by simultaneously exposing both mice to an aggressive male CD-1 mouse. Here we use this model to directly compare changes in the motivated behavior of male and female mice during and following chronic stress. We hypothesized that motivated behavioral responses would be dysregulated during stress and that the effects would worsen as the stress exposure continued. To monitor motivated behavior, mice had access to a Feeding Experimental Device.3 (FED3), a home cage device for operant responding. Operant responding was monitored prior to, during, and after stress by measuring nose pokes for sucrose pellets on a modified progressive ratio schedule of reinforcement. Our results demonstrated divergent behavioral outcomes between males and female mice in response to stress; where male mice increased motivated behavior during stress only, whereas female mice exhibited a decrease in motivation during and after stress. This study highlights the need to investigate the effects of stress-induced motivation over time, as well as the increased need to understand differences in the stress response in females.

Impact of sex and complex PTSD comorbidity on pharmacological treatment response in bipolar disorder patients

BACKGROUND

The prevalence of bipolar disorder (BD) is similar in men and women. However, factors such as sex and comorbid psychiatric conditions can influence its clinical presentation and treatment outcomes, including complex PTSD (cPTSD), a newly categorized trauma-related condition. Little is known about how sex and cPTSD comorbidity affect the response to mood stabilizers, a cornerstone treatment for BD. This observational, cross-sectional study examines the impact of sex and cPTSD comorbidity on clinical and behavioral BD features as well as their interplay in influencing pharmacological treatment response.

METHODS

A cohort of BD patients (females = 177, males = 166, age range: 19-76; BD-I = 253, BD-II = 90) was recruited over three years. Clinical assessments were conducted, and patients were administered the International Trauma Questionnaire to evaluate cPTSD comorbidity and the Alda Scale to assess response to mood stabilizers.

RESULTS

Our results show distinct clinical profiles based on sex and cPTSD. Female BD patients exhibit more hypomanic episodes, antidepressant-induced mania, and longer periods of untreated illness than males. Comorbid cPTSD was diagnosed in 154 patients (44.8 %), among which 69 were females. Patients with cPTSD display more severe BD symptoms, including earlier onset, more frequent episodes, and a higher prevalence of psychosis and suicidality. Importantly, comorbid cPTSD was associated with poorer mood stabilizer response, particularly in males, who otherwise responded better to treatment than females.

CONCLUSIONS

These findings underscore the importance of addressing trauma symptoms in BD treatment and highlight the need for individualized approaches considering both sex and comorbid trauma, as standard mood stabilizers may be insufficient for certain subgroups.

An Integrated Platform Combining Immersive Virtual Reality and Physiological Sensors for Systematic and Individualized Assessment of Stress Response (bWell): Design and Implementation Study

BACKGROUND

Stress is a pervasive issue in modern society, manifesting in various forms such as emotional, physical, and work-related stress, each with distinct impacts on individuals and society. Traditional stress studies often rely on psychological, performance, or social tests; however, recently, immersive virtual reality (VR), which provides a sense of presence and natural interaction, offers the opportunity to simulate real-world tasks and stressors in controlled environments. Despite its potential, the use of VR to investigate the multifaceted manifestations of stress has not been thoroughly explored.

OBJECTIVE

This study aimed to explore the feasibility of using a VR-based platform, bWell, to elicit multifaceted stress responses and measure the resulting behavioral and physiological changes. Specifically, we aimed to design various VR stress exercises based on neurocardiac models to systematically test cardiac functioning within specific contexts of self-regulation (executive functioning, physical efforts, and emotional regulation).

METHODS

The development process adhered to guidelines for VR clinical trials and complex health interventions, encompassing 3 phases: preparation, development, and verification. The preparation phase involved a comprehensive literature review to establish links between stress, the heart, and the brain, leading to the formulation of a conceptual model based on the Neurovisceral Integration Model (NVIM) and Vagal Tank Theory (VTT). The development phase involved designing VR exercises targeting specific stressors and integrating physiological sensors such as photoplethysmography (PPG) and electromyography (EMG) to capture heart rate variability (HRV) and facial expressions. The verification phase, conducted with a small number of trials, aimed to design a study and implement a workflow for testing the feasibility, acceptability, and tolerability of the VR exercises. In addition, the potential for capturing physiological measures along with subjective ratings of stress for specific dimensions was assessed.

RESULTS

Verification trials demonstrated that the VR exercises were well tolerated, with negligible cybersickness and high user engagement. The different VR exercises successfully elicited the intended stress demands, along with the physiological responses.

CONCLUSIONS

The study presents a novel VR-based experimental setup that allows a systematic and individualized assessment of stress responses, paving the way for future research to identify features that confer stress resilience and help individuals manage stress effectively. While our conceptual model highlights the role of HRV in providing valuable insights into stress responses, future research will involve multivariate and machine learning analyses to predict individual stress responses based on comprehensive sensor data, including EMG and the VR-based behavioral data, ultimately guiding personalized stress management interventions.

Why are adolescent girls more prone to stress-induced depression? Testing moderation, mediation, and reciprocal causality in a three-wave longitudinal study

The prevalence of depression in females after puberty is twice as high as in their male peers. Considering numerous studies that associate the onset of depression with stress, we tested three hypotheses to elucidate the role of biological sex in stress-induced depression on a sample of 1618 secondary school students from Zagreb, Croatia (Males, N = 671, Mage at baseline = 16.4 years, SD = 0.60; Females, N = 947, Mage at baseline = 16.3 years, SD = 0.65), in a three-wave longitudinal study. The study tested the hypotheses regarding: (a) sex-related differences in reciprocal causation of stress and depression, (b) the moderating role of biological sex in the effect of stress on depression, and (c) the mediating role of stress on the pathway from biological sex to depression. The data were analyzed using a random intercept cross-lagged panel model (RI-CLPM) and standard moderation and mediation analyses. Females consistently reported higher levels of stress (Cohen's d ranged from 0.76 to 0.83) and depression (0.59 to 0.69) compared with their male peers. The hypothesis that biological sex moderates the effect of stress on depression was not supported, as the interaction between sex and subjective stress was mostly nonsignificant or small in magnitude, with standardized regression coefficients not exceeding .126. The hypothesis of sex-differentiated reciprocal causation of stress and depression was also not supported since cross-lagged relations were found to be mostly nonsignificant, indicating that the association between stress and depression rests largely on stable dispositions. The data supported the hypothesis of stress mediating the effect of biological sex on depression, with indirect effects ranging from 0.23 to 0.25 (95% CI 0.19 to 0.30). The findings suggest that the increased vulnerability of adolescent girls may lie in stable dispositions possibly responsible for higher sensitivity and less effective coping with stressful situations that lead to depression.

Early life stress paired with adolescent alcohol consumption reduces two-bottle choice alcohol consumption in mice

BACKGROUND

In humans, early life stress (ELS) is associated with an increased risk for developing both alcohol use disorder (AUD) and posttraumatic stress disorder (PTSD). We previously used an infant footshock model in rats that produces stress-enhanced fear learning (SEFL) and increases aversion-resistant alcohol drinking to explore this shared predisposition. The goal of the current study was to test the viability of this procedure as a model of comorbid PTSD and AUD in male and female C57BL/6J mice.

METHODS

Acute ELS was induced using 15 footshocks on postnatal day (PND) 17. In adulthood, alcohol drinking behavior was tested in one of three two-bottle choice drinking paradigms. In continuous access, mice were given 24 h access to 5% and 10% ethanol and water for five consecutive drinking sessions each. In limited access drinking in the dark, mice were given 2 h of access to 15% ethanol and water across 15 sessions 3 h into the dark cycle. In intermittent access, mice were presented with 20% ethanol and water Monday, Wednesday, and Friday, for four consecutive weeks. In a fifth week of intermittent access drinking, increasing concentrations of quinine (10, 100, and 200 mg/L) were added to the ethanol to test aversion-resistant drinking. Intermittent access drinking was tested with and without a period of adolescent drinking (PND 35).

RESULTS

Infant footshock did not alter drinking in the continuous or limited access tasks. In the intermittent access task, adult consumption and preference were lower in shocked mice when adolescent drinking was included. Aversion resistance was greater in females following infant footshock and adolescent drinking.

CONCLUSIONS

Our results demonstrate that ELS, in the form of infant footshock on PND 17, must be followed by a period of adolescent drinking to affect adult alcohol consumption in mice.

Influence of strain on expression and habituation of autonomic and cardiovascular responses to restraint stress in rats

This study aimed to evaluate the influence of rat strain in expression of autonomic and cardiovascular changes during acute exposure to restraint stress, as well as in habituation of these physiological responses upon repeated exposure to restraint. For this, blood pressure, heart rate (HR) and sympathetically-mediated cutaneous vasoconstriction were assessed in Wistar (control strain), Long-Evans, Holtzman and spontaneously hypertensive (SHR) rats during acute or 10th 60-min session of restraint stress. We observed that HR returned faster to baseline values during recovery of the acute session of restraint in Long-Evans and SHR rats in relation to Wistar, thus indicating shorter tachycardia in these strains. Long-Evans also presented enhanced sympathetically-mediated cutaneous vasoconstriction to acute restraint stress. Habituation of the tachycardiac response evidenced as a faster HR return to baseline values during recovery of the 10th restraint session in relation to acute stress was similarly identified in both Wistar and Holtzman rats. However, cardiovascular changes were similarly evoked during acute and 10th restraint stress session in SHR and Long-Evans rats. Taken together, these findings indicate that both cardiovascular responses during acute stress and habituation of these physiological adjustments upon repeated exposure to the same stressor are strain-dependent. Differences were mainly observed in Long-Evans and SHR strains, whereas Holtzman rats seem to present similar autonomic and cardiovascular changes in relation to Wistar rats.

Caregiver mental, behavioral, and social health during the COVID-19 pandemic in South Africa: results from the Asenze cohort study

PURPOSE

The COVID-19 pandemic and subsequent lockdowns had significant impacts on the well-being of populations globally, however, most COVID-19 mental health research has been done in high-income countries. This study evaluates the impact of COVID-19 and lockdowns on the mental well-being of sequential groups of caregivers of adolescents in South Africa. We hypothesized that caregivers experienced worse mental, emotional and social health outcomes during the pandemic, compared to before its onset.

METHODS

Longitudinal data from Wave 3 of the Asenze Cohort, conducted between 2019 and 2021, was used to estimate multivariable regressions to assess the association between pandemic lockdowns and caregiver social support networks, mental and physical health related quality of life, parenting stress, hazardous alcohol use, psychiatric disorder, and intimate partner violence.

RESULTS

Results show that after the onset of the pandemic, caregivers experienced diminished social support networks, worse physical health related quality of life, and improvement in mental health related quality of life compared to before the pandemic. We observed no association between pandemic lockdowns with parenting stress, hazardous alcohol use, the presence of any psychiatric disorder, or experience of intimate partner violence.

CONCLUSION

This study shows the impact of COVID-19 and mandated lockdowns on caregiver social support, mental and physical health related quality of life among caregivers of adolescents in South Africa. Given the results, more research is needed to discern modifiable risk factors that can be intervened on to improve social support and physical health related quality of life, and to preserve mental health related quality of life.

Unlocking NAC's potential ATF4 and m6A dynamics in rescuing cognitive impairments in PTSD

In this study, we investigated the therapeutic potential of N-acetylcysteine (NAC) in a mouse model of post-traumatic stress disorder (PTSD) induced by a single prolonged stress (SPS) protocol. Our findings demonstrate that NAC treatment significantly improved cognitive function and mitigated hippocampal neuronal apoptosis in PTSD model mice. These positive effects were accompanied by a reduction in m6A methylation levels and activating transcription factor 4 (ATF4) expression. Silencing ATF4 further attenuated hippocampal neuronal apoptosis and cognitive dysfunction, while ATF4 overexpression partially reversed the beneficial effects of NAC. It suggests that NAC's efficacy in PTSD may be mediated by its regulation of ATF4 expression and m6A methylation levels. Overall, our study provides valuable insights into the potential mechanism of action for NAC in PTSD treatment, offering promising avenues for future therapeutic strategies.

Unraveling the Complex Interplay Between Neuroinflammation and Depression: A Comprehensive Review

The relationship between neuroinflammation and depression is a complex area of research that has garnered significant attention in recent years. Neuroinflammation, characterized by the activation of glial cells and the release of pro-inflammatory cytokines, has been implicated in the pathophysiology of depression. The relationship between neuroinflammation and depression is bidirectional; not only can inflammation contribute to the onset of depressive symptoms, but depression itself can also exacerbate inflammatory responses, creating a vicious cycle that complicates treatment and recovery. The present comprehensive review aimed to explore the current findings on the interplay between neuroinflammation and depression, as well as the mechanisms, risk factors, and therapeutic implications. The mechanisms by which neuroinflammation induces depressive-like behaviors are diverse. Neuroinflammation can increase pro-inflammatory cytokines, activate the hypothalamus-pituitary-adrenal (HPA) axis, and impair serotonin synthesis, all of which contribute to depressive symptoms. Furthermore, the activation of microglia has been linked to the release of inflammatory mediators that can disrupt neuronal function and contribute to mood disorders. Stress-induced neuroinflammatory responses can lead to the release of pro-inflammatory cytokines that not only affect brain function but also influence behavior and mood. Understanding these mechanisms is crucial for developing targeted therapies that can mitigate the effects of neuroinflammation on mood disorders.

Pituitary adenylate cyclase-activating polypeptide plays a role in neuropsychiatric and substance use disorders: sex-specific perspective

The neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) plays a pivotal role in regulating stress, fear, and anxiety responses. Genetic and molecular studies investigating PACAP demonstrate sex-dimorphic characteristics, with females exhibiting increased reactivity of PACAP signaling in neuropsychiatric disorders. Studies expand the role of PACAP to substance use disorders (SUD) by demonstrating modulation of PACAP can lead to neurobiological changes induced by nicotine, ethanol, stimulants and opioids. Given that females with SUD exhibit distinct drug use, relapse, and withdrawal sensitivity relative to males, we hypothesize that the PACAP system contributes to these sex-specific differences. Therefore, we review the role of PACAP in SUD by characterizing the role of PACAP at the molecular, brain regional, and behavioral levels relevant to the addiction cycle. We present literature linking PACAP to neuropsychiatric disorders, which demonstrate the intricate role of PACAP within neuronal signaling and pathways modulating addiction. We hypothesize that females are more particularly susceptible to PACAP-related changes during the intoxication and withdrawal phases of the addiction cycle. Altogether understanding the sex-specific differences in the PACAP system offers a foundation for future studies aimed at developing tailored interventions for addressing SUD.

Effects of sex and estrous cycle on action-outcome contingencies

Goal-directed and habitual-like behaviors are both necessary to efficiently and effectively navigate the environment. A dysregulation between these behaviors can lead to an overreliance on habitual-like behaviors and may contribute to symptoms experienced in some neuropsychiatric disorders such as substance use disorder. One behavioral task used to evaluate goal-directed and habitual-like behavior is an action-outcome task, contingency degradation, where an action (i.e., lever press) is degraded by decoupling the receipt of a reward from the action. However, little is known about how male and female rats and females across the estrous cycle respond during contingency degradation training and extinction testing. Here, we investigated how the variable of sex and estrous cycle influences contingency degradation training and extinction testing and the correlation between baseline anxiety-like behaviors and performance on contingency degradation extinction testing in adult male and female Long-Evans rats. We found that both males and females learned the contingency degradation task. However, during extinction testing, males respond more to the contingent lever than the non-contingent lever while females do not differ in their responses on the non-contingent and contingent levers. Lower baseline anxiety-like behavior predicted better performance on the contingency degradation test in males, but not females. Next, when we examined performance during extinction testing in females based on their estrous cycle stage on test day, we found that females in the proestrus and estrus stages of the estrous cycle do not differ in their responses on the non-contingent and contingent levers, while females in the metestrus and diestrus stages of the estrous cycle respond more on the contingent lever than the non-contingent lever on the extinction test day, similar to male rats. Our findings indicate that the estrous cycle influences how female rats respond during contingency degradation extinction testing that is dependent on their estrous cycle stage.

Hunger Games: A Modern Battle Between Stress and Appetite

Stress, an evolutionarily adaptive mechanism, has become a pervasive challenge in modern life, significantly impacting feeding-relevant circuits that play a role in the development and pathogenesis of eating disorders (EDs). Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, disrupts specific neural circuits, and dysregulates key brain regions, including the hypothalamus, hippocampus, and lateral septum. These particular structures are interconnected and key in integrating stress and feeding signals, modulating hunger, satiety, cognition, and emotional coping behaviors. Here we discuss the interplay between genetic predispositions and environmental factors that may exacerbate ED vulnerability. We also highlight the most commonly used animal models to study the mechanisms driving EDs and recent rodent studies that emphasize the discovery of novel cellular and molecular mechanisms integrating stress and feeding signals within the hippocampus-lateral septum-hypothalamus axis. In this review, we discuss the role of gut microbiome, an emerging area of research in the field of EDs and unanswered questions that persist and hinder the scientific progress, such as why some individuals remain resilient to stress while others become at high risk for the development of EDs. We finally discuss the need for future research delineating the impact of specific stressors on neural circuits, clarifying the relevance and functionality of hippocampal-septal-hypothalamic connectivity, and investigating the role of key neuropeptides such as CRH, oxytocin, and GLP-1 in human ED pathogenesis. Emerging tools like single-cell sequencing and advanced human imaging could uncover cellular and circuit-level changes in brain areas relevant for feeding in ED patients. Ultimately, by integrating basic and clinical research, science offers promising avenues for developing personalized, mechanism-based treatments targeting maladaptive eating behavior for patients suffering from EDs.

Sphingosine-1-phosphate receptor 3 activation promotes sociability and regulates transcripts important for anxiolytic-like behavior

We previously demonstrated that sphingosine-1-phosphate receptor 3 (S1PR3) in the medial prefrontal cortex (mPFC) prevents reductions in sociability normally caused by stress. S1PR3 is a ubiquitously expressed G-protein coupled receptor that regulates immune system function, although its regulation of other biological processes is not well understood. Pharmacological activators of S1PR3 might provide important insights for understanding the neural substrates underlying sociability. Here we show that in mice, systemic injections of an S1PR3-specific agonist, CYM5541, promotes sociability in males and females whereas an S1PR3-specific antagonist, CAY10444, increases amygdala activation and increases social avoidance, particularly in females. S1PR3 expression is increased in the mPFC and dentate gyrus of females compared to males. RNA sequencing in the mPFC reveals that S1PR3 activation alters the expression of transcripts related to immune function, neurotransmission, transmembrane ion transport, and intracellular signaling. This work provides evidence that S1PR3 agonists, which have classically been used as immune modulators, might also be used to promote social behavior and, potentially, relieve symptoms of social anxiety. S1PR3 might be an important hub gene for mitigating maladaptive effects of stress as it reduces inflammatory processes, increases transcripts linked to anxiolytic neurotransmission, and promotes social behavior.

Stay social, stay young: a bioanthropological outlook on the processes linking sociality and ageing

In modern human societies, social interactions and pro-social behaviours are associated with better individual and collective health, reduced mortality, and increased longevity. Conversely, social isolation is a predictor of shorter lifespan. The biological processes through which sociality affects the ageing process, as well as healthspan and lifespan, are still poorly understood. Unveiling the physiological, neurological, genomic, epigenomic, and evolutionary mechanisms underlying the association between sociality and longevity may open new perspectives to understand how lifespan is determined in a broader socio/evolutionary outlook. Here we summarize evidence showing how social dynamics can shape the evolution of life history traits through physiological and genetic processes directly or indirectly related to ageing and lifespan. We start by reviewing theories of ageing that incorporate social interactions into their model. Then, we address the link between sociality and lifespan from two separate points of view: (i) considering evidences from comparative evolutionary biology and bioanthropology that demonstrates how sociality contributes to natural variation in lifespan over the course of human evolution and among different human groups in both pre-industrial and post-industrial society, and (ii) discussing the main physiological, neurological, genetic, and epigenetic molecular processes at the interface between sociality and ageing. We highlight that the exposure to chronic social stressors deregulates neurophysiological and immunological pathways and promotes accelerated ageing and thereby reducing lifespan. In conclusion, we describe how sociality and social dynamics are intimately embedded in human biology, influencing healthy ageing and lifespan, and we highlight the need to foster interdisciplinary approaches including social sciences, biological anthropology, human ecology, physiology, and genetics.

Sex Differences in Endocannabinoid and Inflammatory Markers Associated with Posttraumatic Stress Disorder

Background

Posttraumatic stress disorder (PTSD) is one of the most sex-polarized psychiatric disorders, with women exhibiting twice the prevalence of men. The biological mechanisms underlying this sex disparity are not fully understood. Growing evidence suggests that alterations of the stress-buffering endocannabinoid (eCB) system and heightened inflammation are central to PTSD pathophysiology and may contribute to sex-biases in PTSD risk and severity. Here, we examined sex-differences in levels of circulating eCBs and peripheral pro-inflammatory markers in a cohort of men and women with PTSD and non-psychiatric controls.

Methods

88 individuals with PTSD and 85 sex- and age- matched controls (HC) were retrospectively selected from the Mass General Brigham Biobank. Serum was assayed to measure circulating eCBs [anandamide (AEA), 2-arachidonyl glycerol (2-AG), oleoylethanolamide (OEA), and arachidonic acid (AA] and inflammatory markers [interleukin-1β (IL-1β), IL-6, IL-8, IL-18, tumor necrosis factor-alpha (TNFα), and C-reactive Protein (CRP)]. Linear regression was used to predict differential abundance of each analyte by disease state (PTSD/HC) within the male and female subgroups. Two-sided t-tests with Benjamini-Hochberg correction were used to examine differences across subgroups. Analyses were repeated in those with comorbid major depressive disorder.

Results

Male PTSD patients showed a significant decrease in AEA, AA and OEA levels compared to male controls (p's < .001) and to female subgroups (PTSD and HCs) (p< .001). In contrast, among females, PTSD patients showed elevated levels of IL-6 (p<.05) and IL-8 (p<.05). Both male and female PTSD patients exhibited an increase in TNFα concentrations (p<.05), compared to HCs. Similar results were obtained in the subgroup of individuals with comorbid MDD and after controlling for the FAAH 385A genotype.

Conclusions

Our findings show for the first time that decrease in eCB levels is absent in women with PTSD, who in turn exhibit a broader increase in inflammatory markers, thus suggesting that biological perturbations underlying PTSD may vary by sex.

Prenatal Constant Light Exposure Induces Behavioral Deficits in Male and Female Rat Offspring: Effects of Prenatal Melatonin Treatment

Prenatal constant light exposure (CLE) impaired the anxiety response and circadian rhythms of testicular enzymes in adult male rat offspring, while melatonin corrected these deficiencies. However, the mechanism by which CLE induces these long-term behavioral consequences and the impact of melatonin system have not been examined. The aim of the present study was to investigate the effects of prenatal CLE and melatonin treatment on anxiety- and depression-like behaviors, and the melatonin system in male and female adult rat offspring. Six groups of male and female rat offspring (P60) exposed to either light/dark (LD) or CL regimes, and treated with vehicle or melatonin (10 mg/kg, s.c.) were evaluated for anxiety by open field (OF), elevated plus maze (EPM), and light/dark (LD) tests, and depressive-like response by splash test and sucrose preference test. Plasma adrenocorticotropic hormone (ACTH), corticosterone (CORT) and melatonin expression, and hippocampal MT1A and MT1b receptor expression were assessed by ELISA. Prenatal CLE induced behavioral deficits and elevated plasma CORT levels, while melatonin levels, their circadian rhythmicity, and hippocampal MT receptor expression were not altered in male and female offspring in the CLE regime. However, prenatal melatonin treatment corrected behavioral deficits in a sex-specific manner by up-regulating hippocampal MT receptors, even without altering systemic melatonin levels or normalizing CORT in either sex. The results of this study suggest critical insights into how prenatal environmental factors and therapeutic interventions shape physiological and behavioral outcomes.

Female Brain and Endocrinological Research-Veteran (FemBER-Vet) study: A study protocol for identifying endocrinological, lifestyle and psychosocial determinants of brain health outcomes in female veterans for future intervention success

BACKGROUND

Recent studies have demonstrated a greater risk of dementia in female veterans compared to civilians; with the highest prevalence noted for former service women with a diagnosis of psychiatric (trauma, alcoholism, depression), and/or a physical health condition (brain injury, insomnia, diabetes). Such findings highlight the need for increased and early screening of medical and psychiatric conditions, and indeed dementia, in the female veteran population. Further, they call for a better understanding of the underlying biopsychosocial mechanisms that might confer heightened risk for female veterans, to tailor preventative and interventional strategies that support brain health across the lifespan.

METHODS

The Female Brain and Endocrinological Research-Veteran (FemBER-Vet) Study will create a highly-phenotyped readiness cohort of ex-service persons as well as non-veterans to assess the impacts of, and risks associated with, military service on brain health, using state-of-the-art non-invasive cognitive, physiological and biomarker capture techniques. FEMBER-Vet will include 90 participants across three study groups (30 female veterans, 30 male veterans, 30 female civilians) to delineate the precise biological, socio-demographic, health, lifestyle, military-related, and life-course determinants of brain health outcomes (psychosocial, cognitive, neurophysiological, and other biomarkers).

DISCUSSION

This work addresses the poorly understood biopsychosocial outcomes that female veterans experience compared to their male counterparts and the general female population. Ultimately, it will provide evidence to support the development of tailored interventions for an emerging health priority that currently lacks sufficient evidence for screening and therapeutic intervention.

How trait mindfulness protects late adolescents from stress-induced sleep problems: the unique role of mindfulness facets and gender differences

BACKGROUND

Understanding sleep problems in late adolescents caused by daily stress is essential due to their increased vulnerability to stress-related sleep issues. While previous research has demonstrated the potential protective effect of trait mindfulness, facets of mindfulness were found to have unique functions against the negative impact of stress, and the unique impact of each facet of mindfulness on the sleep problems caused by the negative impact of stress remains unclear. Thus, this longitudinal study aimed to assess the impact of stressful life events on sleep problems a year later among late adolescents and to explore the moderating effects of the five trait mindfulness facets. Gender differences have been observed in mindfulness's protective effects, yet how gender influences each mindfulness facet remains unclear. This study also examines how gender moderates the effects of individual mindfulness facets.

METHODS

The study tracked 1,926 Chinese vocational high school students (Mage = 18.49) over a year, assessing them for their sleep problems, perceived impact of stressful life events, and mindfulness facets through self-reported questionnaires. Multivariate analysis was used to investigate the moderating effects of each mindfulness facet on the relationship between stressful life events and sleep problems one year later. Then, gender differences were examined through multi-group comparison.

RESULTS

A higher impact from stressful life events predicted more sleep problems a year later. Notably, among all five facets of mindfulness, only Observing significantly buffered the negative impact of stressful life events on sleep problems, in females but not in males, thus gender moderated the impact of Observing.

CONCLUSIONS

This study suggested that Observing uniquely protected young females from the negative impact of stressful life events on their sleep problems a year later. Since the measurement tool for the Observing facet only had 1 question tested on observing inner feelings, and other questions are all about observing bodily sensations and outer environments, this study implies that insomnia therapies focus on enhancing the ability to anchor attention in the present moment, especially towards bodily sensations and the outer environment, may be particularly effective in buffering the long-term impact of daily stressors on sleep for young females.

TRIAL REGISTRATION

Not applicable.

Sex matters: Differences in prodromes, clinical and neuropsychological features in individuals with a first episode mania or psychosis

OBJECTIVE

This study was aimed at identifying sex differences in patients presenting a first episode mania (FEM) or psychosis (FEP) to help shaping early treatment strategies focused on sex differences.

METHODS

Patients with a FEM or FEP underwent a clinical, neuropsychological (neurocognitive functions and emotional intelligence) and functional assessment. Performance on those variables was compared between groups through general linear model, with sex and group (FEM vs FEP) as main effects and group by sex interactions.

RESULTS

The total sample included 113 patients: FEM = 72 (45.83 % females) and FEP = 41 (46.34 % females). There were significant main effects for group (not for sex) for most of the clinical features (depressive, negative and positive symptoms) and psychosocial functioning (χ2 = 8.815, p = 0.003). As for neuropsychological performance, there were significant main effects for sex and group. Females performed better than males in verbal memory (χ2 = 9.038, p = 0.003) and obtained a higher emotional intelligence quotient (χ2 = 13.20, p < 0.001). On the contrary, males obtained better results in working memory (χ2 = 7.627, p = 0.006). FEP patients significantly underperformed FEM patients in most cognitive domains. There were significant group by sex interactions for few neuropsychological variables, namely processing speed (χ2 = 4.559, p = 0.033) and verbal fluency (χ2 = 8.913, p = 0.003).

LIMITATIONS

Differences between sexes were evaluated, but the influence of gender was not considered. Retrospective evaluation of prodromes and substance use. No healthy control group comparator.

CONCLUSION

The main finding is the presence of significant sex effect and group by sex interaction on specific neurocognitive cognition and emotional intelligence measures. Tailored sex-based early treatment strategies might be implemented.

Exploring the impact of biological sex on intrinsic connectivity networks in PTSD: A data-driven approach

INTRODUCTION

Sex as a biological variable (SABV) may help to account for the differential development and expression of post-traumatic stress disorder (PTSD) symptoms among trauma-exposed males and females. Here, we investigate the impact of SABV on PTSD-related neural alterations in resting-state functional connectivity (rsFC) within three core intrinsic connectivity networks (ICNs): the salience network (SN), central executive network (CEN), and default mode network (DMN).

METHODS

Using an independent component analysis (ICA), we compared rsFC of the SN, CEN, and DMN between males and females, with and without PTSD (n = 47 females with PTSD, n = 34 males with PTSD, n = 36 healthy control females, n = 20 healthy control males) via full factorial ANCOVAs. Additionally, linear regression analyses were conducted with clinical variables (i.e., PTSD and depression symptoms, childhood trauma scores) in order to determine intrinsic network connectivity characteristics specific to SABV. Furthermore, we utilized machine learning classification models to predict the biological sex and PTSD diagnosis of individual participants based on intrinsic network activity patterns.

RESULTS

Our findings revealed differential network connectivity patterns based on SABV and PTSD diagnosis. Males with PTSD exhibited increased intra-SN (i.e., SN-anterior insula) rsFC and increased DMN-right superior parietal lobule/precuneus/superior occipital gyrus rsFC as compared to females with PTSD. There were also differential network connectivity patterns for comparisons between the PTSD and healthy control groups for males and females, separately. We did not observe significant correlations between clinical measures of interest and brain region clusters which displayed significant between group differences as a function of biological sex, thus further reinforcing that SABV analyses are likely not confounded by these variables. Furthermore, machine learning classification models accurately predicted biological sex and PTSD diagnosis among novel/unseen participants based on ICN activation patterns.

CONCLUSION

This study reveals groundbreaking insights surrounding the impact of SABV on PTSD-related ICN alterations using data-driven methods. Our discoveries contribute to further defining neurobiological markers of PTSD among females and males and may offer guidance for differential sex-related treatment needs.

A potential candidate for prevention of PTSD: Prazosin prevents learned helplessness behavior in adult male rats

Post-Traumatic Stress Disorder (PTSD) is a debilitating psychiatric disorder that arises following exposure to an extreme stress. PTSD is characterized by five primary trauma-related symptom clusters, including symptoms of negative mood and hyperresponsivity to the traumatic event. Regrettably, the current therapy options are not highly effective. Therefore, prevention of PTSD is crucial and potentially applicable. Prazosin is an anti-adrenergic medication that is used to reduce nightmares in patient with PTSD, and can also mitigate the noradrenergic dysfunction caused by trauma. Here we show that administration of prazosin prior to the trauma prevented learned helplessness behavior in adult male rats. We show that the animals that were exposed to three days of inescapable foot shocks preceded by prazosin injections have fewer prazosin-treated animals showing learned helplessness compared to saline-treated animals. Nevertheless, there was no significant difference in anxiety-related behavior as measured in the elevated plus maze. Furthermore, the results of in vivo electrophysiological recordings of the ventral tegmental area shows that the prazosin group has a trend of increased number of active dopaminergic cells per track; this is significant when limited to central region of the ventral tegmental area. Our results demonstrate that prazosin has a potential for prevention of PTSD.

Changes in hippocampal volume, 5-HT4 receptor binding, and verbal memory over the course of antidepressant treatment in major depressive disorder

Serotonin reuptake inhibitors have been reported to increase hippocampal volume and improve memory function in patients with Major depressive disorder (MDD). The postsynaptic 5-HT4 receptor (5-HT4R) is involved in hippocampal development, familial risk for depression and depressive pathology. In an open-label trial with 91 patients (72% female, mean 27.2 years) with MDD, we investigated the relation between changes in hippocampal volume, 5-HT4R, and verbal memory during 12 weeks treatment with 10-20 mg escitalopram. Depression severity, verbal memory, MRI-determined hippocampus volume and PET-determined 5-HT4R were measured pretreatment. Forty-three patients were rescanned at week 8. HAMD17 was reassessed at week 8 and together with verbal memory at week 12. We used mixed-effects models and linear regressions. We estimated a 27 mm3 (p = 0.086) reduction in mean hippocampus volume over the course of eight weeks. In patients clinically responding to treatment, we estimated a 45 mm3 reduction (p = 0.019), 8 mm3 increase in non-responders (p = 0.78), and a 52 mm3 group difference (p = 0.12). Hippocampal 5-HT4 receptor binding before treatment and at week eight was negatively associated with hippocampal volume in females, regardless of treatment response (p-values≤0.006). However, no clear evidence for an association in males or sex interaction could be established (p-values≥0.16). Although the hippocampus volume did not increase with treatment, we found a decrease in clinically responsive patients. Our findings suggest an association between 5-HT4R signalling and changes in hippocampal volume in females with MDD during antidepressant treatment, highlighting the need for further investigation into the role of serotonergic mechanisms in hippocampal plasticity.

Current Status and Future Directions of Artificial Intelligence in Post-Traumatic Stress Disorder: A Literature Measurement Analysis

This study aims to explore the current state of research and the applicability of artificial intelligence (AI) at various stages of post-traumatic stress disorder (PTSD), including prevention, diagnosis, treatment, patient self-management, and drug development. We conducted a bibliometric analysis using software tools such as Bibliometrix (version 4.1), VOSviewer (version 1.6.19), and CiteSpace (version 6.3.R1) on the relevant literature from the Web of Science Core Collection (WoSCC). The analysis reveals a significant increase in publications since 2017. Kerry J. Ressler has emerged as the most influential author in the field to date. The United States leads in the number of publications, producing seven times more papers than Canada, the second-ranked country, and demonstrating substantial influence. Harvard University and the Veterans Health Administration are also key institutions in this field. The Journal of Affective Disorders has the highest number of publications and impact in this area. In recent years, keywords related to functional connectivity, risk factors, and algorithm development have gained prominence. The field holds immense research potential, with AI poised to revolutionize PTSD management through early symptom detection, personalized treatment plans, and continuous patient monitoring. However, there are numerous challenges, and fully realizing AI's potential will require overcoming hurdles in algorithm design, data integration, and societal ethics. To promote more extensive and in-depth future research, it is crucial to prioritize the development of standardized protocols for AI implementation, foster interdisciplinary collaboration-especially between AI and neuroscience-and address public concerns about AI's role in healthcare to enhance its acceptance and effectiveness.

Sex-specific fear acquisition following early life stress is linked to amygdala and hippocampal purine and glutamate metabolism

Early life stress (ELS) can negatively impact health, increasing the risk of stress-related disorders, such as post-traumatic stress disorder (PTSD). Importantly, PTSD disproportionately affects women, emphasizing the critical need to explore how sex differences influence the genetic and metabolic neurobiological pathways underlying trauma-related behaviors. This study uses the limited bedding and nesting (LBN) paradigm to model ELS and investigate its sex-specific effects on fear memory formation. Employing innovative unsupervised behavioral classification, the current study reveals distinct behavioral patterns associated with fear acquisition and retrieval in male and female mice following ELS. Females exposed to LBN display heightened active fear responses, contrasting with males. Furthermore, the study examined the crucial link between behavioral regulation and cellular metabolism in key brain regions involved in fear and stress processing. Sex-specific and stress-dependent alterations were observed in purine, pyrimidine, and glutamate metabolism within the basolateral amygdala, the dorsal hippocampus, and the ventral hippocampus. These findings provide crucial insights into the complex interplay between metabolic pathways, the neurobiological underpinnings of fear memory, and stress responses. Importantly, they emphasize the significance of considering sex-specific metabolic alterations when investigating stress-related disorders, opening potential avenues for the development of targeted interventions.

Impacts of social isolation stress in safety learning and the structure of defensive behavior during a spatial-based learning task involving thermal threat

Safety learning during threat and adversity is critical for behavioral adaptation, resiliency, and survival. Using a novel mouse paradigm involving thermal threat, we recently demonstrated that safety learning is highly susceptible to social isolation stress. Yet, our previous study primarily considered male mice and did not thoroughly scrutinize the relative impacts of stress on potentially distinct defensive mechanisms implemented by males and females during the thermal safety task. The present study assessed these issues while considering a variety of defensive behaviors related to safety-seeking, escape, coping, protection, ambivalence, and risk-taking. After a two-week social isolation stress period, mice were required to explore a box arena that had thermal threat and safety zones (5 vs. 30°C, respectively). Since visuospatial cues clearly differentiated the threat and safety zones, the majority of the no-stress controls (69-75%) in both sexes exhibited optimal memory formation for the safety zone. In contrast, the majority of the stress-exposed mice in both sexes (69-75%) exhibited robust impairment in memory formation for the safety zone. Furthermore, while the control groups exhibited many robust correlations among various defensive behaviors, the stress-exposed mice in both sexes exhibited disorganized behaviors. Thus, stress severely impaired the proper establishment of safety memory and the structure of defensive behavior, effects that primarily occurred in a sex-independent manner.

Nociceptors are functionally male or female: from mouse to monkey to man

The prevalence of many pain conditions often differs between sexes. In addition to such quantitative distinctions, sexual dimorphism may also be qualitative reflecting differences in mechanisms that promote pain in men and women. A major factor that influences the likelihood of pain perception is the threshold for activation of nociceptors. Peripheral nociceptor sensitization has been demonstrated to be clinically relevant in many pain conditions. Whether peripheral nociceptor sensitization can occur in a sexually dimorphic fashion, however, has not been extensively studied. To address this fundamental knowledge gap, we used patch clamp electrophysiology to evaluate the excitability of dorsal root ganglion neurons from male or female rodents, non-human primates, and humans following exposure to putative sensitizing agents. Previous studies from our laboratory, and others, have shown that prolactin promotes female-selective pain responses in rodents. Consistent with these observations, dorsal root ganglion neurons from female, but not male, mice were selectively sensitized by exposure to prolactin. The sensitizing action of prolactin was also confirmed in dorsal root ganglion neurons from a female macaque monkey. Critically, neurons recovered from female, but not male, human donors were also selectively sensitized by prolactin. In the course of studies of sleep and pain, we unexpectedly observed that an orexin antagonist could normalize pain responses in male animals. We found that orexin B produced sensitization of male, but not female, mouse, macaque, and human dorsal root ganglion neurons. Consistent with functional responses, increased prolactin receptor and orexin receptor 2 expression was observed in female and male mouse dorsal root ganglia, respectively. Immunohistochemical interrogation of cultured human sensory neurons and whole dorsal root ganglia also suggested increased prolactin receptor expression in females and orexin receptor 2 expression in males. These data reveal a functional double dissociation of nociceptor sensitization by sex, which is conserved across species and is likely directly relevant to human pain conditions. To our knowledge, this is the first demonstration of functional sexual dimorphism in human sensory neurons. Patient sex is currently not a common consideration for the choice of pain therapy. Precision medicine, based on patient sex could improve therapeutic outcomes by selectively targeting mechanisms promoting pain in women or men. Additional implications of these findings are that the design of clinical trials for pain therapies should consider the proportions of male or female patients enrolled. Lastly, re-examination of selected past failed clinical trials with subgroup analysis by sex may be warranted.

Role of the locus coeruleus-noradrenergic system in stress-related psychopathology and resilience: Clinical and pre-clinical evidences

Stressful events, from daily stressors to traumatic experiences, are common and occur at any age. Despite the high prevalence of trauma, not everyone develops stress-related disorders like major depressive disorder (MDD) and post-traumatic stress disorder (PTSD), a variation attributed to resilience, the ability to adapt and avoid negative consequences of significant stress. This review examines the locus coeruleus-norepinephrine (LC-NE) system, a critical component in the brain's stress response. It discusses the LC-NE system's anatomical and functional complexity and its role in individual variability in stress responses. How different etiological factors and stress modalities affect the LC-NE system, influencing both adaptive stress responses and psychopathologies, are discussed and supported by evidence from human and animal studies. It also explores molecular and cellular adaptations in the LC that contribute to resilience, including roles of neuropeptide, inflammatory cytokines, and genetic modulation, and addresses developmental and sex differences in stress vulnerability. The need for a multifaceted approach to understand stress-induced psychopathologies is emphasized and pave the way for more personalized interventions for stress-related disorders.

Applying the Research Domain Criteria to Rodent Studies of Sex Differences in Chronic Stress Susceptibility

Women have a 2-fold increased rate of stress-associated psychiatric disorders such as depression and anxiety, but the mechanisms that underlie this increased susceptibility remain incompletely understood. Historically, female subjects were excluded from preclinical studies and clinical trials. Additionally, chronic stress paradigms used to study psychiatric pathology in animal models were developed for use in males. However, recent changes in National Institutes of Health policy encourage inclusion of female subjects, and considerable work has been performed in recent years to understand biological sex differences that may underlie differences in susceptibility to chronic stress-associated psychiatric conditions. Here, we review the utility as well as current challenges of using the framework of the National Institute of Mental Health's Research Domain Criteria as a transdiagnostic approach to study sex differences in rodent models of chronic stress including recent progress in the study of sex differences in the neurobehavioral domains of negative valence, positive valence, cognition, social processes, and arousal.

Sex differences in fear expression and persistence in an animal model of Post-Traumatic Stress Disorder

Post-Traumatic Stress Disorder (PTSD) is a complex psychiatric condition arising from traumatic experiences, marked by abnormal fear memories. Despite women are twice as likely as men to develop PTSD, the biological mechanisms underlying this disparity remain inadequately explored, particularly in preclinical studies involving female subjects. Previous research shows that female rats exhibit active fear responses, while males display passive behaviors. Additionally, sex differences in ultrasonic vocalizations (USVs) during fear conditioning have been observed, indicating varying emotional responses. Here, we validated a traumatic stress model consisting of footshock exposure paired with social isolation - originally developed in male rats - on females for the first time, focusing on sex differences in fear memory expression, retention and extinction. Our findings reveal that only during trauma exposure, males predominantly exhibited passive responses, whereas females demonstrated more active responses, despite both sexes emitting similar numbers of alarm USVs. Females also showed lower levels of freezing and USV emissions throughout extinction sessions and displayed a higher extinction rate compared to males. Notably, only males displayed a conditioned fear response when triggered by a single mild stressor. These findings highlight sex differences in trauma responses and fear memory processes. The study emphasizes the importance of incorporating 22-kHz USV evaluations along with other behavioral metrics for a comprehensive understanding of fear memory. This research contributes to the existing literature on traumatic stress models as well as underscores the necessity of including female subjects in preclinical studies to better inform treatment and prevention strategies tailored to both sexes.

Sex Differences in the Neuroendocrine Stress Response: A View from a CRH-Reporting Mouse Line

Corticotropin-releasing hormone (CRH) neurons within the paraventricular hypothalamic nucleus (PVH) play a crucial role in initiating the neuroendocrine response to stress and are also pivotal in coordination of autonomic, metabolic, and behavioral stress reactions. Although the role of parvocellular CRHPVH neurons in activation of the hypothalamic-pituitary-adrenal (HPA) axis is well established, the distribution and function of CRH-expressing neurons across the whole central nervous system are less understood. Stress responses activate complex neural networks, which differ depending on the type of stressor and on the sex of the individual. Because of the technical difficulties of localizing CRH neurons throughout the rodent brain, several CRH reporter mouse lines have recently been developed. In this study, we used Crh-IRES-Cre;Ai9 reporter mice to examine whether CRH neurons are recruited in a stressor- or sex-specific manner, both within and outside the hypothalamus. In contrast to the clear sexual dimorphism of CRH-mRNA-expressing neurons, quantification of CRH-reporting, tdTomato-positive neurons in different stress-related brain areas revealed only subtle differences between male and female subjects. These results strongly imply that sex differences in CRH mRNA expression occur later in development under the influence of sex steroids and reflects the limitations of using genetic reporter constructs to reveal the current physiological/transcriptional status of a specific neuron population. Next, we compared the recruitment of stress-related, tdTomato-expressing (putative CRH) neurons in male and female Crh-IRES-Cre;Ai9 reporter mice that had been exposed to predator odor. In male mice, fox odor triggered more c-Fos in the CRH neurons of the paraventricular hypothalamic nucleus, central amygdala, and anterolateral bed nucleus of the stria terminalis compared to females. These results indicate that male mice are more sensitive to predator exposure due to a combination of hormonal, environmental, and behavioral factors.

Sex specific gut-microbiota signatures of resilient and comorbid gut-brain phenotypes induced by early life stress

Background

Alterations in gut-brain axis communication pathways and the gut microbiota ecosystem caused by early life stress have been extensively described as critical players in the pathophysiology of stress-induced disorders. However, the extent to which stress-induced gut microbiota alterations manifest in early life and contribute to the sex-specific susceptibility to distinct gut-brain phenotypes in adulthood has yet to be defined.

Methods

Male and female Sprague-Dawley rat offspring underwent maternal separation (3h/day from postnatal day 2-12). Faecal samples were collected before weaning for gut microbiota 16S rRNA sequencing and metabolomic analysis. Visceral pain sensitivity and negative valence behaviours were assessed in adulthood using colorectal distension and the forced swim test respectively. Behavioural data were processed in a two-step cluster analysis to identify groupings within the dataset. Multi-omics analysis was carried out to investigate if the microbial signatures following early life stress were already defined according to the membership of the adult behavioural phenotypes.

Results

Maternal separation resulted in increased visceral hypersensitivity while showing a trend for a sex-dependent increase in negative valence behaviour in adulthood. The cluster analysis revealed four clusters within the dataset representing distinct pathophysiological domains reminiscent of the behavioural consequences of early-life stress: 1. resilient, 2. pain, 3. immobile and 4. comorbid. The early life gut microbiota of each of these clusters show distinct alterations in terms of diversity, genus level differential abundance, and functional modules. Multi-omic integrations points towards a role for different metabolic pathways underlying each cluster-specific phenotype.

Conclusion

Our study is the first to identify distinct phenotypes defined by susceptibility or resilience to gut-brain dysfunction induced by early life stress. The gut microbiota in early life shows sex-dependent alterations in each cluster that precede specific behavioural phenotypes in adulthood. Future research is warranted to determine the causal relationship between early-life stress-induced changes in the gut microbiota and to understand the trajectory leading to the manifestation of different behavioural phenotypes in adulthood.

The longitudinal patterns of depression subtypes and stressors in depression severity in the Canadian longitudinal study on aging (CLSA)

AIM

The current study aims to characterize the longitudinal patterns of depression subtypes and investigate the associations among the stability of depression subtypes, COVID-19-related stressors, and depression severity.

METHODS

The study utilized data from the Canadian Longitudinal Study on Aging, which is a national, long-term study of Canadian adults aged 45 and older (n = 12,957). Latent profile analysis was used to identify latent depression subtypes. Latent transition analysis was then applied to assess the stability of these subtypes over time. Hierarchical multivariate linear regression was used to explore the relationships among these identified depression subtypes, COVID-19-related stressors, and depression severity among males and females, respectively.

RESULTS

Distinct depression subtypes were identified. Except for atypical depression, other depression subtypes showed greater stability over time. We also found that melancholic depression (B = 9.432) and typical depression (B = 6.677) were strongly associated with depression severity during the pandemic. Health-related stressors (B = 0.840), conflict (B = 3.639), difficulties accessing resources (B = 0.927), separation from family (B = 0.840), and caregiving experience (B = 0.764), were significantly associated with increased depression severity. Sex-specific analyses also revealed differences in the associations between stressors and depression severity between males and females.

CONCLUSIONS

This study contributes valuable insights into the latent clustering of depression subtypes and their stability. Stressors were associated with increased depression severity, with distinct associations observed among males and females. These findings have implications for targeted early interventions and integrated clinical management strategies by providing the evidence base for tailored mental health care during and after the pandemic.

Stress-enhanced ethanol drinking does not increase sensitivity to the effects of a CRF-R1 antagonist on ethanol intake in male and female mice

Research confirms that stress is associated with alcohol drinking and relapse in males and females and that there are sex differences in the alcohol-related adaptations of stress pathways. The predator stress (PS) model of traumatic stress produces an increase in alcohol drinking or self-administration in a subpopulation of rodents, so it is utilized as an animal model of comorbid alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD). Previous work determined that sensitivity to PS-enhanced drinking produced sex differences in proteins related to stress-regulating systems in the medial prefrontal cortex and hippocampus. The present studies examined whether male and female C57BL/6J mice differ in sensitivity to the ability of the corticotropin releasing factor receptor 1 antagonist CP-376395 to decrease PS-enhanced drinking. In control studies, CP-376395 doses of 5, 10, and 20 mg/kg dose-dependently decreased 4-h ethanol drinking. Next, CP-376395 doses of 5 and 10 mg/kg were tested for effects on ethanol drinking in mice with differential sensitivity to PS-enhanced drinking. Subgroups of "Sensitive" and "Resilient" male and female mice were identified based on changes in ethanol intake in an unrestricted-access ethanol-drinking procedure following four exposures to PS (dirty rat bedding). During the first 2 h post-injection of CP-376395, both doses significantly decreased ethanol licks versus vehicle in the females, with no significant interaction between subgroups, whereas the 10 mg/kg dose significantly decreased ethanol licks versus vehicle in the "Resilient" males. Thus, sensitivity to the suppressive effect of CP-376395 on stress-induced ethanol intake was greater in females versus males, whereas sensitivity and resilience to PS-enhanced drinking produced differential sensitivity to the ability of CP-376395 to decrease ethanol drinking only in male mice. Our results argue against greater efficacy of CRF-R1's ability to decrease ethanol intake in subjects with traumatic stress-enhanced ethanol drinking.

Decoding the transcriptomic signatures of psychological trauma in human cortex and amygdala

Psychological trauma has profound effects on brain function and precipitates psychiatric disorders in vulnerable individuals, however, the molecular mechanisms linking trauma with psychiatric risk remain incompletely understood. Using RNA-seq data postmortem brain tissue of a cohort of 304 donors (N=136 with trauma exposure), we investigated transcriptional signatures of trauma exposures in two cortical regions (dorsolateral prefrontal cortex, and dorsal anterior cingulate cortex) and two amygdala regions (medial amygdala and basolateral amygdala) associated with stress processing and regulation. We focused on dissecting heterogeneity of traumatic experiences in these transcriptional signatures by investigating exposure to several trauma types (childhood, adulthood, complex, single acute, combat, and interpersonal traumas) and interactions with sex. Overall, amygdala regions were more vulnerable to childhood traumas, whereas cortical regions were more vulnerable to adulthood trauma (regardless of childhood experience). Using cell-type-specific expression imputation, we identified a strong transcriptional response of medial amygdala excitatory neurons to childhood trauma, which coincided with dysregulation observed in a human induced pluripotent stem cell (hiPSC)-derived glutamatergic neurons exposed to hydrocortisone. We resolved multiscale coexpression networks for each brain region and identified modules enriched in trauma signatures and whose connectivity was altered with trauma. Trauma-associated coexpression modules provide insight into coordinated functional dysregulation with different traumas and point to potential gene targets for further dissection. Together, these data provide a characterization of the long-lasting human encoding of traumatic experiences in corticolimbic regions of human brain.

Sex differences in prelimbic cortex calcium dynamics during stress and fear learning

In recent years, research has progressively increased the importance of considering sex differences in stress and fear memory studies. Many studies have traditionally focused on male subjects, potentially overlooking critical differences with females. Emerging evidence suggests that males and females can exhibit distinct behavioral and neurophysiological responses to stress and fear conditioning. These differences may be attributable to variations in hormone levels, brain structure, and neural circuitry, particularly in regions such as the prefrontal cortex (PFC). In the present study, we explored sex differences in prelimbic cortex (PL) calcium activity in animals submitted to immobilization stress (IMO), fear conditioning (FC), and fear extinction (FE). While no significant sex differences were found in behavioral responses, we did observe differences in several PL calcium activity parameters. To determine whether these results were related to behaviors beyond stress and fear memory, we conducted correlation studies between the movement of the animals and PL activity during IMO and freezing behavior during FC and FE. Our findings revealed a clear correlation between PL calcium activity with movement during stress exposure and freezing behavior, with no sex differences observed in these correlations. These results suggest a significant role for the PL in movement and locomotion, in addition to its involvement in fear-related processes. The inclusion of both female and male subjects is crucial for studies like this to fully understand the role of the PFC and other brain areas in stress and fear responses. Recognizing sex differences enhances our comprehension of brain function and can lead to more personalized and effective approaches in the study and treatment of stress and fear-related conditions.

Diversity of ancestral brainstem noradrenergic neurons across species and multiple biological factors

The brainstem region, locus coeruleus (LC), has been remarkably conserved across vertebrates. Evolution has woven the LC into wide-ranging neural circuits that influence functions as broad as autonomic systems, the stress response, nociception, sleep, and high-level cognition among others. Given this conservation, there is a strong possibility that LC activity is inherently similar across species, and furthermore that age, sex, and brain state influence LC activity similarly across species. The degree to which LC activity is homogenous across these factors, however, has never been assessed due to the small sample size of individual studies. Here, we pool data from 20 laboratories (1,855 neurons) and show diversity across both intrinsic and extrinsic factors such as species, age, sex and brain state. We use a negative binomial regression model to compare activity from male monkeys, and rats and mice of both sexes that were recorded across brain states from brain slices ex vivo or under different anesthetics or during wakefulness in vivo. LC activity differed due to complex interactions of species, sex, and brain state. The LC became more active during aging, independent of sex. Finally, in contrast to the foundational principle that all species express two distinct LC firing modes ("tonic" or "phasic"), we discovered great diversity within spontaneous LC firing patterns. Different factors were associated with higher incidence of some firing modes. We conclude that the activity of the evolutionarily-ancient LC is not conserved. Inherent differences due to age and species-sex-brain state interactions have implications for understanding the role of LC in species-specific naturalistic behavior, as well as in psychiatric disorders, cardiovascular disease, immunology, and metabolic disorders.

Gender differences in preferences for mental health apps in the general population - a choice-based conjoint analysis from Germany

BACKGROUND

Men and women differ in the mental health issues they typically face. This study aims to describe gender differences in preferences for mental health treatment options and specifically tries to identify participants who prefer AI-based therapy over traditional face-to-face therapy.

METHOD

A nationally representative sample of 2,108 participants (53% female) aged 18 to 74 years completed a choice-based conjoint analysis (CBCA). Within the CBCA, participants evaluated twenty choice sets, each describing three treatment variants in terms of provider, content, costs, and waiting time.

RESULTS

Costs (relative importance [RI] = 55%) emerged as the most critical factor when choosing between treatment options, followed by provider (RI = 31%), content (RI = 10%), and waiting time (RI = 4%). Small yet statistically significant differences were observed between women and men. Women placed greater importance on the provider, while men placed greater importance on cost and waiting time. Age and previous experience with psychotherapy and with mental health apps were systematically related to individual preferences but did not alter gender effects. Only a minority (approximately 8%) of participants preferred AI-based treatment to traditional therapy.

CONCLUSIONS

Overall, affordable mental health treatments performed by human therapists are consistently favored by both men and women. AI-driven mental health apps should align with user preferences to address psychologist shortages. However, it is uncertain whether they alone can meet the rising demand, highlighting the need for alternative solutions.

Emotional eating and mental health of nurses working in Lebanese hospitals during the double crisis

The 2019 coronavirus (COVID-19) pandemic and strict quarantine increased the likelihood of mental symptoms and abnormal eating behaviours. This study aimed to assess the magnitude of emotional eating (EE) among nurses working in Lebanese hospitals and its association with mental health. A cross-sectional study was conducted among nurses aged between 18 and 50 years working in Lebanese hospitals during the COVID-19 outbreak and the economic crisis. A total of 303 nurses consented to participate. The mean EE score was 28.56 (±8.11). The results of this study revealed that 53.8% of the nurses reported depression, 58.1% suffered from anxiety and 95.1% experienced either moderate or severe stress. The study concluded that females (β = 8.112, P = 0.004), non-smokers (β = -4.732, P = 0.01) and depressed nurses (β = 0.596, P = 0.046) had a higher tendency towards EE. Additionally, it was found that EE was associated with weight gain (β = 6.048, P = 0.03) and increased consumption of fried foods (β = 5.223, P = 0.001). Females experienced more stress (β = 2.244, P = 0.003) and anxiety (β = 1.526, P = 0.021) than their male counterparts. With regard to mental health, depression was associated with weight gain (β = 2.402, P = 0.003) and with lower consumption of healthy foods such as nuts (β = -1.706, P = 0.009) and dishes prepared with sofrito sauce (β = -1.378, P = 0.012). These results can help the health authorities to design preparedness plans to ensure proper mental and physical well-being of nurses during any unforeseen emergencies.

Sex-dependent astrocyte reactivity: Unveiling chronic stress-induced morphological changes across multiple brain regions

Chronic stress is a major precursor to various neuropsychiatric disorders and is linked with increased inflammation in the brain. However, the bidirectional association between inflammation and chronic stress has yet to be fully understood. Astrocytes are one of the key inflammatory regulators in the brain, and the morphological change in reactive astrocytes serves as an important indicator of inflammation. In this study, we evaluated the sex-specific astrocyte response to chronic stress or systemic inflammation in key brain regions associated with mood disorders. We conducted the unpredictable chronic mild stress (UCMS) paradigm to model chronic stress, or lipopolysaccharide (LPS) injection to model systemic inflammation. To evaluate stress-induced morphological changes in astrocyte complexity, we measured GFAP fluorescent intensity for astrocyte expression, branch bifurcation by quantifying branch points and terminal points, branch arborization by conducting Sholl analysis, and calculated the ramification index. Our analysis indicated that chronic stress-induced morphological changes in astrocytes in all brain regions investigated. The effects of chronic stress were region and sex specific. Notably, females had greater stress or inflammation-induced astrocyte activation in the hypothalamus (HYPO), CA1, CA3, and amygdala (AMY) than males. These findings indicate that chronic stress induces astrocyte activation that may drive sex and region-specific effects in females, potentially contributing to sex-dependent mechanisms of disease.