Effectiveness of Ketamine for the Treatment of Post-Traumatic Stress Disorder - A Systematic Review and Meta-Analysis.

Objective: Post-traumatic stress disorder (PTSD) is an enduring condition characterized by a chronic course and impairments across several areas. Despite its significance, treatment options remain limited, and remission rates are often low. Ketamine has demonstrated antidepressant properties and appears to be a promising agent in the management of PTSD. Method: A systematic review was conducted in PubMed/MEDLINE, Cochrane Library, Clinicaltrials.gov, Lilacs, Scopus, and Embase, covering studies published between 2012 and December 2022 to assess the effectiveness of ketamine in the treatment of PTSD. Ten studies, consisting of five RCTs, two crossover trials, and three non-randomized trials, were included in the meta-analysis. Results: Ketamine demonstrated significant improvements in PCL-5 scores, both 24 hours after the initial infusion and at the endpoint of the treatment course, which varied between 1 to 4 weeks in each study. Notably, the significance of these differences was assessed using the Two Sample T-test with pooled variance and the Two Sample Welch's T-test, revealing a statistically significant effect for ketamine solely at the endpoint of the treatment course (standardized effect size= 0.25; test power 0.9916; 95% CI = 0.57 to 17.02, p=0.0363). It is important to note that high heterogeneity was observed across all analyses. Conclusions: Our findings suggest that ketamine holds promise as an effective treatment option for PTSD. However, further trials are imperative to establish robust data for this intervention.

Prospective Measurement of Skin Conductance Response during Trauma Interview Predicts Future PTSD Severity in Trauma Exposed Children.

Previous cross-sectional studies have shown that sympathetic nervous system (SNS) arousal is positively associated with posttraumatic stress disorder (PTSD) symptoms in children with trauma exposure. One of the ways that SNS activity is measured is through skin conductance response (SCR), which has been shown to predict future PTSD severity in adults. In this study, we explored the utility of a novel, low-cost mobile SCR device, eSense, to predict future PTSD symptom severity in trauma exposed children. We recruited children (N=43, age 9 years at initial visit) for a longitudinal study in which SCR was recorded at baseline visit, and PTSD symptoms were assessed two years later. Results indicated an interaction between SCR and trauma exposure, such that children with lower trauma exposure who demonstrated greater SCR reported higher PTSD severity two years later. This association remained significant even after controlling for baseline PTSD symptoms. Children with higher levels of trauma exposure did not show this association, potentially due to ceiling effects of PTSD symptoms. Together these findings suggest the utility of SCR as a biomarker for predicting trauma related disorders in children, and that it may be a valuable tool in clinical interventions targeting sympathetic arousal.

Gender differences in the associations of psychosocial trauma and acute medical stressors with immune system activation and dementia risk.

Objective: The purpose of this article is to provide a narrative review synthesizing the literature on differences between women and men in relationships among certain stressors associated with immune system activation and their relationship to cognitive dysfunction and dementia. Method: We review the cycle of stress leading to neuroinflammation via cortisol and neurochemical alterations, cell-mediated immune system activation, and pro-inflammatory cytokines, and how this is implicated in the development of dementia. We follow this by discussing sex differences in stress physiology and immune function. We then review the work on early life adversity (ELA) and adverse childhood experiences (ACEs), post-traumatic stress disorder, acute medical stressors, and their associations with cognitive dysfunction and dementia. Throughout, we emphasize women's presentations and issues unique to women (e.g. trauma disorder prevalence). Conclusions: There is a need for more mechanistic and longitudinal studies that consider trauma accumulation, both physical and emotional, as well as a greater focus on traumas more likely to occur in women (e.g. sexual abuse), and their relationship to early cognitive decline and dementia.

Mental health in genocide: Balancing between posttraumatic distress and growth among displaced Yazidi mothers.

Background. The Islamic State of Iraq and Syria (ISIS) committed genocide of the Yazidis in Sinjar 2014, resulting in dispersion and enslavement. Research shows severe mental health problems, such as posttraumatic stress disorder (PTSD) among survivors, but less is known about their resources and strengths, conceptualized as posttraumatic growth (PTG). Aims. are to examine the balance between symptoms and strengths among Yazidi women caring for their infants by identifying groups differing in PTSD and PTG, and analyze how demographic, obstetric, and infant-related factors associate with the groups. Method. Participants were 283 Yazidi mothers with their 1-18-month-old infants displaced in Kurdish Region of North Iraq. PTSD symptoms were measured by Harvard Trauma Questionnaire and PTG by the Posttraumatic Growth Inventory. Results. identified four groups: "Severe symptoms and low growth" (39%), "Low symptoms and moderate growth" (38%), "Moderate symptoms and very high growth" (13%), and "Moderate symptoms and low growth" (10%). Low education, economic difficulties and obstetric problems related to the "Severe symptoms and low growth" group, whereas newborn and infant health problems did not have an impact. Conclusion. Effective help for genocide survivors should both alleviate suffering and encourage resources through tools of recreating a sense of cultural security and pride.

Spirituality/Religion Among First Responders With and Without Posttraumatic Stress Disorder and Alcohol Misuse.

Objective: To examine the co-occurrence of alcohol misuse and posttraumatic stress disorder (PTSD) and potential sources of coping (e.g., spirituality/religion) and clinically relevant variables among first responders (e.g., firefighters, law enforcement corrections officers, paramedics). Method: We assessed rates of independent and co-occurring alcohol misuse and PTSD among a national online sample of 320 first responders as well as the prevalence and salience of S/R, guilt, shame, moral injury, aspects of S/R, and treatment interest. Results: In our sample, 46.88% (n = 150) met criteria for comorbid alcohol misuse and probable PTSD and individuals with these comorbid conditions reported significantly greater negative religious coping, moral injury, and shame than all other diagnostic groups (i.e., independent alcohol misuse, independent PTSD, and neither). Correlations also revealed significant relationships between alcohol misuse and PTSD symptomatology with positive and negative religious coping, moral injury, shame, guilt, interest in treatment, and interest in spiritually integrated treatment. Conclusions: Findings highlight the high rates of independent and co-occurring alcohol misuse and PTSD among first responders as well as the salience of S/R in this population.

Participants' experiences of a counsellor-supported PTSD Coach intervention in a resource-constrained setting.

We explored participants' experiences of a counsellor-supported PTSD Coach mobile application intervention (PTSD Coach-CS) in a randomised controlled trial. PTSD Coach-CS participants, who received the intervention and self-completed a custom-designed questionnaire at intervention completion were included (n = 25; female = 20; ages 19-59; isiXhosa = 22). This questionnaire comprised questions regarding the feasibility, acceptability and potential impact of the PTSD Coach-CS intervention, and general psychological support in our setting. Data were analysed using Braun and Clarke's thematic analysis. Three main themes emerged. (i) Participants' largely positive experiences of treatment procedures included the safe space created by the counsellor support in combination with the PTSD Coach application, allowing them to learn about and understand their lived experiences, and to accept their PTSD diagnoses. (ii) Positive perceptions of the PTSD Coach application, yet raising important concerns (e.g., lack of family involvement) for future consideration. (iii) Intervention-specific and systemic treatment barriers (e.g., stigma) providing important information to inform and increase the usefulness of the PTSD Coach-CS intervention. The findings suggest that the PTSD Coach-CS intervention may help address the need for access to suitable care for South African adults with PTSD. Some contextual barriers must be considered in further intervention implementation.

[Did entry into nursing home during the health crisis favor the emergence of traumatic symptoms in the elderly?: Entry into nursing home and Covid]. / L'entrée en Ehpad, durant la crise sanitaire, a-t-elle favorisé l'émergence de symptômes traumatiques chez le sujet âgé ?

Our aim is to explore the possible emergence of traumatic symptoms and the identity-related repercussions of the restrictions on elderly, who entered into nursing homes during the Covid-19 health crisis in France. Twenty-five subjects institutionalised before the health crisis and twenty-six subjects institutionalised during the periods of lockdown into nursing homes completed scales assessing anxiety-depressive symptomatology, traumatic symptoms and identity. Anxiety and depression symptoms were similar between the groups. The institutionalised group showed a significantly higher prevalence of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria D and E on the Post traumatic Stress Disorder Checklist version DSM-5 (PCL-5) during lockdown. Entry into an institution during the health crisis would have favored the emergence of traumatic symptoms in the participants. Consideration of the ethical issues raised by this study could make it possible to offer more individualised support to elderly during their transition to a new home.

Longitudinal change in symptoms of depression, anxiety and post-traumatic stress disorder during the COVID-19 pandemic among Mexican college students.

Longitudinal studies suggest the psychological difficulties precipitated by the COVID-19 pandemic have gradually declined, but our understanding of the factors that predict change in mental health is limited. We evaluated the mental health of Mexican college students during the early stage of the pandemic and 4 months later, as well as predictors of change in students' mental health. Participants were 648 students (71% women, Mage = 21.46) from a private University in Northern Mexico who completed online surveys from May 2020 to September 2020. Students' self-reported levels of mental health symptoms (depression, anxiety and post-traumatic stress disorder) significantly decreased from May to September. Poor physical health, more COVID-related worry and higher initial levels of peer social support predicted less change in psychological symptoms. On the other hand, more hours of sleep per night and a pre-existing mental health diagnosis predicted steeper decreases in symptoms. Findings suggest reductions in mental health difficulties that are consistent with theoretical frameworks of resilience among Mexican college students. In addition, results underscore the interplay between physical, psychological and social functioning, and the need for continued monitoring of mental health and intervention efforts that address physical health, sleep and pandemic-related worry in University settings.

When one tool is not enough: An integrative psychotherapeutic approach to treating complex PTSD.

Complex posttraumatic stress disorder (CPTSD) is a term representing the psychopathological implications of exposure to chronic, inter-personal trauma. These include the main symptoms of PTSD, as well as changes in identity, emotion regulation, and inter-personal relationships. Self-harm and dissociation (i.e., disintegration of mental processes) are also quite common in CPTSD. Considering this complex and often severe clinical picture, mental health professionals often find it difficult to effectively treat CPTSD. In this paper, we present an integrative approach to the treatment of CPTSD based on a combination of techniques from several psychotherapy approaches. The case described here illustrates the need for therapeutic flexibility and eclecticism when treating individuals exposed to chronic trauma. We show the advantages of flexible therapeutic attunement, which enables the therapist to respond to the changing need of the patient, as well as her fluid clinical picture and symptom manifestation. The case also illustrates how interventions taken from psychodynamic therapy, Dialectical behavior therapy, and Eye Movement Desensitization and Reprocessing may be applicable in various stages of treatment, alleviating the patient's distress in several psychological and physical domains.

Genetic influences on testosterone and PTSD.

Females are twice as likely to experience PTSD as compared to males. Although sex differences in prevalence are well-established, little is known about why such sex differences occur. Biological factors that vary with sex, including sex hormone production, may contribute to these differences. Considerable evidence links sex hormones, such as testosterone, to PTSD risk though less is known about the shared genetic underpinnings. The objective of the present study was to test for genetic relationships between testosterone and PTSD. To do so, we used summary statistics from large, publicly available genetic consortia to conduct linkage disequilibrium score regression to estimate the genetic correlations between PTSD and testosterone in males and females, and two-sample, bi-directional Mendelian randomization to examine potential causal relationships of testosterone on PTSD and the reverse. Heritability estimates of testosterone were significantly higher in males (0.17, SE = 0.02) than females (0.11, SE = 0.01; z = 2.46, p = 00.01). The correlation between testosterone and PTSD was negative in males (rg = -0.11, SE = 0.02, p = 6.7 x 10-6), but not significant in females (rg = 0.002, SE = 0.03, p = 0.95). MR analyses found no evidence of a causal effect of testosterone on PTSD or the reverse. Findings are consistent with phenotypic literature suggesting a relationship between testosterone and PTSD that may be sex-specific. This work provides early evidence of a relationship between testosterone and PTSD genotypically and suggests an avenue for future research that will enable a better understanding of disparities in PTSD.

Posttraumatic stress disorder and spousal relationships in natural disaster victims: a longitudinal study.

BACKGROUND: Posttraumatic stress disorder (PTSD) symptoms after natural disaster can have a detrimental effect on marital relationships, which may be through parenting-related factor. AIMS: The study aimed to examine the mechanism underlying the long-term effects of PTSD symptoms on marital satisfaction via coparenting, and its differences between men and women following the Super Typhoon Lekima. METHODS: Participants were 465 married victims with children. They reported their PTSD, coparenting, and marital satisfaction at three and fifteen months after the tropical cyclone. RESULTS: The results showed that for women, only higher negative cognitive and emotional alterations (NCEA) symptoms were associated with lower marital satisfaction through conflict coparenting. For men, higher intrusion, NCEA, and hyperarousal symptoms were associated with marital satisfaction through different coparenting. To be specific, for men, higher intrusion symptoms were associated with lower marital satisfaction via less reprimand coparenting; higher NCEA symptoms were associated with lower marital satisfaction via less integrity coparenting, and associated with higher marital satisfaction via less conflict coparenting; higher hyperarousal symptoms were associated with lower marital satisfaction via more conflict coparenting. CONCLUSIONS: These findings suggested that the long-term effect of PTSD symptoms on marital satisfaction via coparenting mainly showed for men.

Incidence of mental disorders in soldiers deployed to Afghanistan who have or have not experienced a life-threatening military incident-a quasi-experimental cohort study.

Introduction: There is very good international research on deployment-related mental disorders in military personnel. The incidence rates show a very wide range. A new strategy is therefore proposed in order to achieve better standardization and thus better comparability of the studies. In addition to a non-deployed comparison group, we propose to compare deployed soldiers with and without critical military incidents during the deployment. This additional distinction makes it possible to differentiate between the influencing variables of actual threat and general deployment stress. Methods: N = 358 male combat soldiers deployed to Afghanistan were included in the study. Clinical interviews were conducted several days before deployment and after deployment. Of them, n = 80 soldiers suffered a life-threatening military incident during deployment, whereas 278 soldiers did not. Odds ratios (OR) were calculated for the groups with and without critical military incidents and the new onset for PTSD, anxiety disorders and depressive disorders. Results: When comparing both groups, we found significantly higher 1-year incidence rates in the group with critical military incidents: 6.4% vs. 1.1% (OR 6.2) for post-traumatic stress disorder (PTSD); 7.0% vs. 1.1% (OR 6.5) for depression; and 15.9% vs. 2.8% (OR 6.6) for anxiety disorders. The 1-year incidence rate of mental multimorbidity (PTSD with anxiety or depression) was 4.8% vs. 0.4% (OR 12.0). Discussion: These results indicate that life-threatening military incidents during military deployment are important to mental health. As the different threat levels of the various missions are taken into account, additional predictors could be determined more precisely in further research.

Risk and protection factors of mental stress among medical staff in the third year of the COVID-19 pandemic.

Background: The COVID-19 pandemic placed an extraordinary burden on health care workers (HCW), who are reported to suffer from great mental stress. The current study investigates the mental health of HCW in the later phases of the pandemic. Methods: HCW completed the following questionnaires online (06/2021-02/2022, N=159): demographics (age, gender, profession, ward), Impact of Event Scale (IES-R, posttraumatic stress), State Trait Anxiety Inventory (STAI-S, state anxiety), stress-coping questionnaire (SVF-78), and bespoke corona-specific stress and protective-factor questions (5 items each). We used factor analysis to test scale properties and regression-type methods (t-tests, ANOVA, multiple regression) for hypothesis tests and effect-size estimation. Results/discussion: Mental stress in HCW is influenced by similar factors as described for earlier phases. However, differences to earlier phases were found in ward affiliation which is no longer a variable of concern for explaining differences in mental health of HCW. Further, even if nurses are the occupational group with the highest mental stress as in prior research, detailed analysis shows that medical specialists with close proximity to patients with a high-level of responsibility are the most burdened sub-group. Unlike nurses, they suffer from high levels of anxiety in addition to high levels of post-traumatic and COVID-specific stress. Analyses showed further that COVID-specific stress is the strongest predictor of mental stress, wherein COVID-specific stress factors remain the same as reported in literature on the early pandemic phases. HCW showed to use still more positive than negative coping strategies. Negative strategies increased as expected mental stress, whereas positive strategies alleviated only anxiety. Additionally, we found that doctors benefited from many protective factors while nurses had access to fewer protective factors like earlier waves. Conclusion: Data show that HCW still suffer from mental stress in the third year of the pandemic. HCW of all hospital wards may be affected by mental stress and need attention and protective measures. Medical specialists are the most burdened subgroup. Detailed analyses show that properties other than occupation, gender, or ward affiliation are more appropriate to evaluate mental stress of HCW. The findings have implications for developing specialized protection strategies for the post-pandemic phase and future pandemics.

Data of the multi-wave population-based prospective Victims in Modern Society (VICTIMS) study on potential traumatic events, social support, mental health, coping self-efficacy and services use.

We present the data of the first six annual surveys of the large prospective population-based Dutch VICTIMS-study that started in 2018. Each survey systematically examines exposure to potential traumatic events in the past 12 months, including time of event and amount of stress during the event. Furthermore, each survey assesses anxiety and depression symptomatology, lack of social support, physical, mental, work, partner/family, religious, legal, administrative and financial problems, and problem-related services use. Among the by potentially traumatic events (PTEs) affected respondents, current PTSD-symptomatology, social acknowledgement, events-related contacts with various professional, and coping self-efficacy related to the (most stressful) PTE in the past 12 months was examined. This multi-wave study is conducted using the Dutch Longitudinal Internet studies for the Social Sciences panel (LISS panel) that is based on a large traditional probability sample of the Dutch population (16+). People cannot register themselves as a panel member which minimizes the risks of selection bias. Panel members receive a financial compensation for each completed questionnaire, which has a positive effect on the response rate. Households that would otherwise be unable to participate are provided with a simple, remotely managed computer and internet connection. The set-up of the LISS panel in 2007 was funded by the Dutch Research Council and is managed by Centerdata, a non-profit institute housed at the campus of Tilburg University (The Netherlands). The number of invited (adult) panel members for the VICTIM-study varies between 6119 and 7096 across the years, and the response rate varies between 82.4 % and 87.9 %. The data of the VICTIMS-study can efficiently be linked with archived data of all other (past or future) studies conducted with the LISS panel, such as the annual Core studies on Health and Personality, and the 300+ Assembled studies conducted with the LISS panel. This offers unique opportunities for researchers to address numerous research questions related to potential traumatic and stressful life-events.

A genetic exploration of the relationship between Posttraumatic Stress Disorder and cardiovascular diseases.

Background and Aims: Experiencing a traumatic event may lead to Posttraumatic Stress Disorder (PTSD), including symptoms such as flashbacks and hyperarousal. Individuals suffering from PTSD are at increased risk of cardiovascular disease (CVD), but it is unclear why. This study assesses shared genetic liability and potential causal pathways between PTSD and CVD. Methods: We leveraged summary-level data of genome-wide association studies (PTSD: N= 1,222,882; atrial fibrillation (AF): N=482,409; coronary artery disease (CAD): N=1,165,690; hypertension: N=458,554; heart failure (HF): N=977,323). First, we estimated genetic correlations and utilized genomic structural equation modeling to identify a common genetic factor for PTSD and CVD. Next, we assessed biological, behavioural, and psychosocial factors as potential mediators. Finally, we employed multivariable Mendelian randomization to examine causal pathways between PTSD and CVD, incorporating the same potential mediators. Results: Significant genetic correlations were found between PTSD and CAD, HT, and HF (rg =0.21-0.32, p≤ 3.08 · 10-16), but not between PTSD and AF. Insomnia, smoking, alcohol dependence, waist-to-hip ratio, and inflammation (IL6, C-reactive protein) partly mediated these associations. Mendelian randomization indicated that PTSD causally increases CAD (IVW OR=1.53, 95% CIs=1.19-1.96, p=0.001), HF (OR=1.44, CIs=1.08-1.92, p=0.012), and to a lesser degree hypertension (OR=1.25, CIs=1.05-1.49, p=0.012). While insomnia, smoking, alcohol, and inflammation were important mediators, independent causal effects also remained. Conclusions: In addition to shared genetic liability between PTSD and CVD, we present strong evidence for causal effects of PTSD on CVD. Crucially, we implicate specific lifestyle and biological mediators (insomnia, substance use, inflammation) which has important implications for interventions to prevent CVD in PTSD patients.

Potentially morally injurious experiences and associated factors among Dutch UN peacekeepers: a latent class analysis.

Background: During peacekeeping missions, military personnel may be involved in or exposed to potentially morally injurious experiences (PMIEs), such as an inability to intervene due to a limited mandate. While exposure to such morally transgressive events has been shown to lead to moral injury in combat veterans, research on moral injury in peacekeepers is limited.Objective: We aimed to determine patterns of exposure to PMIEs and associated outcome- and exposure-related factors among Dutch peacekeepers stationed in the former Yugoslavia during the Srebrenica genocide.Method: Self-report data were collected among Dutchbat III veterans (N = 431). We used Latent Class Analysis to identify subgroups of PMIE exposure as assessed by the Moral Injury Scale-Military version. We investigated whether deployment location, posttraumatic stress disorder (PTSD), posttraumatic growth, resilience, and quality of life differentiated between latent classes.Results: The analysis identified a three-class solution: a high exposure class (n = 79), a moderate exposure class (n = 261), and a betrayal and powerlessness-only class (n = 135). More PMIE exposure was associated with deployment location and higher odds of having probable PTSD. PMIE exposure was not associated with posttraumatic growth. Resilience and quality of life were excluded from analyses due to high correlations with PTSD.Conclusions: Peacekeepers may experience varying levels of PMIE exposure, with more exposure being associated with worse outcomes 25 years later. Although no causal relationship may be assumed, the results emphasize the importance of better understanding PMIEs within peacekeeping.

Peacekeeping veterans reported different patterns of exposure to potentially morally injurious experiences: high exposure, moderate exposure, or experiences of betrayal and powerlessness only.Deployment location predicted the pattern of exposure.More exposure was associated with worse psychological outcomes 25 years later.

Prevalence and validity of ICD-11 posttraumatic stress disorder (PTSD) and complex PTSD: A population-based survey of Hong Kong adults.

The present study aimed to report the prevalence of ICD-11 posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) in the general adult Hong Kong population, and examine the validity of the Chinese International Trauma Questionnaire (ITQ). This descriptive cross-sectional population-based telephone survey included a representative sample of 1070 non-institutionalized permanent Hong Kong residents ages 18-64 years. Participants provided responses to the Chinese version of the ITQ, and measures of adverse childhood experiences (ACEs), depression, anxiety, and stress. Based on the diagnostic algorithm of the ITQ, 5.9% of the sample screened positive for either CPTSD or PTSD, with CPTSD (4.2%) being more common that PTSD (1.7%). Results of the confirmatory factor analysis indicated the first-order correlated 6-factor model to be the best fitting solution. Symptom cluster summed scores were all positively and significantly correlated with all criterion variables. This investigation established the prevalence rates of ICD-11 PTSD and CPTSD using a general adult population sample in Hong Kong. The Chinese ITQ demonstrated sound factorial validity and concurrent validity. Future research can further characterize ICD-11 PTSD and CPTSD in subgroups using the Chinese ITQ.

Downregulation of lncRNAs Gomafu, NONMMUT033604.2, and NONMMUT064397.2 in the hippocampus of mice with model of post-traumatic stress disorder.

Objectives. Molecular mechanisms of post-traumatic stress disorder (PTSD) development have been analyzed by evaluati-ng changes in the expression level of long non-coding RNA (lncRNA) as a potential biomarker of the disease and as one of the molecular aspects associated with the disease development.Methods. In our study, we used quantitative polymerase chain reaction (qPCR) to evaluate changes in the expression level of long non-coding RNA - Gomafu, NONMMUT033604.2, and NONMMUT064397.2 - in the hippocampus of mice that were subjected to an artificially induced middle single prolonged stress (mSPS) model of post-traumatic stress disorder.Results. We found a significant reduction in the expression levels of each of the three lncRNAs tested: Gomafu in 45,4 times, NONMMUT033604.2 in 53,4 times, and NONMMUT064397.2 in 5,2 times. The results of the present study provide evidence that mSPS model effectively induces PTSD-like behavior in mice leading to a significant decrease in the expression level of Gomafu, NONMMUT033604.2 and NONMMUT064397.2 lncRNA in mice hippocampus.Conclusions. This data provides evidence that the three studied lncRNAs could be potential biomarkers of PTSD development.

Effects of chronic social equality and inequality conditions on passive avoidance memory and PTSD-like behaviors in rats under chronic empathic stress.

INTRODUCTION: Social inequality conditions induce aversion and affect brain functions and mood. This study investigated the effects of chronic social equality and inequality (CSE and CSI, respectively) conditions on passive avoidance memory and post-traumatic stress disorder (PTSD)-like behaviors in rats under chronic empathic stress. METHODS: Rats were divided into different groups, including control, sham-observer, sham-demonstrator, observer, demonstrator, and co-demonstrator groups. Chronic stress (2 h/day) was administered to all stressed groups for 21 days. Fear learning, fear memory, memory consolidation, locomotor activity, and PTSD-like behaviors were evaluated using the passive avoidance test. Apart from the hippocampal weight, the correlations of memory and right hippocampal weight with serum corticosterone (CORT) levels were separately assessed for all experimental groups. RESULTS: Latency was significantly higher in the demonstrator and sham-demonstrator groups compared to the control group. It was decreased significantly in other groups compared to the control group. Latency was also decreased in the observer and co-demonstrator groups compared to the demonstrator group. Moreover, the right hippocampal weight was significantly decreased in the demonstrator and sham-demonstrator groups compared to the control group. Pearson's correlation of memory and hippocampal weight with serum CORT levels supported the present findings. CONCLUSION: Maladaptive fear responses occurred in demonstrators and sham-demonstrators. Also, extremely high levels of psychological stress, especially under CSI conditions (causing abnormal fear learning) led to heightened fear memory and PTSD-like behaviors. Right hippocampal atrophy confirmed the potential role of CSI conditions in promoting PTSD-like behaviors. Compared to inequality conditions, the abnormal fear memory was reduced under equality conditions.