Psychological trauma and the genetic overlap between posttraumatic stress disorder and major depressive disorder

Dissociative Amnesia: Remembrances Under Cover

The existence or questionability of "repressed memories" can be discussed as being a matter of definition. It seems, however, far-fetched to consider all "lost" memories as caused by encoding problems, brain damage, forgetfulness, failure to disclose events, and so on. We argue that dissociative amnesia (DA) (or "psychogenic amnesia," or "functional amnesia," or, as we favor to call it, "mnestic block syndrome") is caused by psychic alterations, but ultimately they can be traced to changes in the physiology of the brain, as we are of the opinion that all memory processes-positive or negative-alter brain functions, sometimes more permanently, sometimes transiently. We have proven this idea using functional imaging techniques, in particular fluoro-deoxy-d-glucose positron emission tomography. Having investigated dozens of patients with severe and long-lasting DA conditions, we believe it to be disrespectful to many (but not to all) of the affected patients to question their disease condition, which can be proven to be not caused by feigning, malingering, or direct brain damage.

Epistasis in neurotransmitter receptors linked to posttraumatic stress disorder and major depressive disorder comorbidity in traumatized Chinese

Background

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) comorbidity occurs through exposure to trauma with genetic susceptibility. Neuropeptide-Y (NPY) and dopamine are neurotransmitters associated with anxiety and stress-related psychiatry through receptors. We attempted to explore the genetic association between two neurotransmitter receptor systems and the PTSD-MDD comorbidity.

Methods

Four groups were identified using latent profile analysis (LPA) to examine the patterns of PTSD and MDD comorbidity among survivors exposed to earthquake-related trauma: low symptoms, predominantly depression, predominantly PTSD, and PTSD-MDD comorbidity. NPY2R (rs4425326), NPY5R (rs11724320), DRD2 (rs1079597), and DRD3 (rs6280) were genotyped from 1,140 Chinese participants exposed to earthquake-related trauma. Main, gene-environment interaction (G × E), and gene-gene interaction (G × G) effects for low symptoms, predominantly depression, and predominantly PTSD were tested using a multinomial logistic model with PTSD-MDD comorbidity as a reference.

Results

The results demonstrated that compared to PTSD-MDD comorbidity, epistasis (G × G) NPY2R-DRD2 (rs4425326 × rs1079597) affects low symptoms (β = -0.66, OR = 0.52 [95% CI: 0.32-0.84], p = 0.008, pperm = 0.008) and predominantly PTSD (β = -0.56, OR = 0.57 [95% CI: 0.34-0.97], p = 0.037, pperm = 0.039), while NPY2R-DRD3 (rs4425326 × rs6280) impacts low symptoms (β = 0.82, OR = 2.27 [95% CI: 1.26-4.10], p = 0.006, pperm = 0.005) and predominantly depression (β = 1.08, R = 2.95 [95% CI: 1.55-5.62], p = 0.001, pperm = 0.001). The two G × G effects are independent.

Conclusion

NPY and dopamine receptor genes are related to the genetic etiology of PTSD-MDD comorbidity, whose specific mechanisms can be studied at multiple levels.

Dimensional and transdiagnostic phenotypes in psychiatric genome-wide association studies

Genome-wide association studies (GWAS) provide biological insights into disease onset and progression and have potential to produce clinically useful biomarkers. A growing body of GWAS focuses on quantitative and transdiagnostic phenotypic targets, such as symptom severity or biological markers, to enhance gene discovery and the translational utility of genetic findings. The current review discusses such phenotypic approaches in GWAS across major psychiatric disorders. We identify themes and recommendations that emerge from the literature to date, including issues of sample size, reliability, convergent validity, sources of phenotypic information, phenotypes based on biological and behavioral markers such as neuroimaging and chronotype, and longitudinal phenotypes. We also discuss insights from multi-trait methods such as genomic structural equation modelling. These provide insight into how hierarchical 'splitting' and 'lumping' approaches can be applied to both diagnostic and dimensional phenotypes to model clinical heterogeneity and comorbidity. Overall, dimensional and transdiagnostic phenotypes have enhanced gene discovery in many psychiatric conditions and promises to yield fruitful GWAS targets in the years to come.

Genetic examination of the Mood Disorder Questionnaire and its relationship with bipolar disorder

The Mood Disorder Questionnaire (MDQ) is a common screening tool for bipolar disorder that assesses manic symptoms. Its utility for genetic studies of mania or bipolar traits has not been fully examined. We psychometrically compared the MDQ to self-reported bipolar disorder in participants from the United Kingdom National Institute of Health and Care Research Mental Health BioResource. We conducted genome-wide association studies of manic symptom quantitative traits and symptom subgroups, derived from the MDQ items (N = 11,568-19,859). We calculated genetic correlations with bipolar disorder and other psychiatric and behavioral traits. The MDQ screener showed low positive predictive value (0.29) for self-reported bipolar disorder. Neither concurrent nor lifetime manic symptoms were genetically correlated with bipolar disorder. Lifetime manic symptoms had a highest genetic correlation (rg  = 1.0) with posttraumatic stress disorder although this was not confirmed by within-cohort phenotypic correlations (rp  = 0.41). Other significant genetic correlations included attention deficit hyperactivity disorder (rg  = 0.69), insomnia (rg  = 0.55), and major depressive disorder (rg  = 0.42). Our study adds to existing literature questioning the MDQ's validity and suggests it may capture symptoms of general distress or psychopathology, rather than hypomania/mania specifically, in at-risk populations.

Trauma Matters: Integrating Genetic and Environmental Components of PTSD

Trauma is ubiquitous, but only a subset of those who experience trauma will develop posttraumatic stress disorder (PTSD). In this review, it is argued that to determine who is at risk of developing PTSD, it is critical to examine the genetic etiology of the disorder and individual trauma profiles of those who are susceptible. First, the state of current PTSD genetic research is described, with a particular focus on studies that present evidence for trauma type specificity, or for differential genetic etiology according to gender or race. Next, approaches that leverage non-traditional phenotyping approaches are reviewed to identify PTSD-associated variants and biology, and the relative advantages and limitations inherent in these studies are reflected on. Finally, it is discussed how trauma might influence the heritability of PTSD, through type, risk factors, genetics, and associations with PTSD symptomology.

Impact of traumatic life events and polygenic risk scores for major depression and posttraumatic stress disorder on Iraq/Afghanistan Veterans

Traumatic experiences and genetic heritability are among the most widely acknowledged risk factors leading to the development of psychopathology; including posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). The purpose of this study was to investigate if polygenic risk scores (PRS) among Veterans interacted with traumatic stress to predict PTSD and MDD. 1,389 Iraq-Afghanistan military service Veterans from the Mental Illness Research Education and Clinical Center dataset were analyzed. Genome-wide association study (GWAS) statistics were utilized to generate PRS for PTSD (PRS_PTSD) and PRS for MDD (PRS_MDD) in order to analyze PRS-by-environment (PRSxE) with trauma exposure to predict PTSD and MDD diagnoses. Trauma exposure and PRS_PTSD, were independently associated with a current PTSD diagnosis (p < 0.001 and p < 0.001, respectively). The interaction between trauma exposure and PRS_MDD to predict a current diagnosis of PTSD trended towards significance (p = 0.053). Stratifying by trauma thresholds, among those within the lowest trauma load, the association of PRS_MDD with PTSD was found to be nominally significant (p = 0.03). For a MDD diagnosis, there was a significant association with trauma exposure (p < 0.001); and the association with PRS_MDD was found to be nominally significant (p = 0.03). No significant PRSxE effects were found with MDD. Our findings corroborate previous research highlighting trauma exposure, and genetic heritability, as risk factors for the development of PTSD and MDD in a Veteran population. Additionally, findings suggest that genetic vulnerability may be less important as trauma exposure increases, with high levels of trauma likely to result in PTSD and MDD, regardless of genetic vulnerability.

Cross-Species Convergence of Brain Transcriptomic and Epigenomic Findings in Posttraumatic Stress Disorder: A Systematic Review

Introduction

Posttraumatic stress disorder (PTSD) is a complex multifactorial disorder influenced by the interaction of genetic and environmental factors. Analyses of epigenomic and transcriptomic modifications may help to dissect the biological factors underlying the gene-environment interplay in PTSD. To date, most human PTSD epigenetics studies have used peripheral tissue, and these findings have complex and poorly understood relationships to brain alterations. Studies examining brain tissue may help characterize the brain-specific transcriptomic and epigenomic profiles of PTSD. In this review, we compiled and integrated brain-specific molecular findings of PTSD from humans and animals.

Methods

A systematic literature search according to the PRISMA criteria was performed to identify transcriptomic and epigenomic studies of PTSD, focusing on brain tissue from human postmortem samples or animal-stress paradigms.

Results

Gene- and pathway-level convergence analyses revealed PTSD-dysregulated genes and biological pathways across brain regions and species. A total of 243 genes converged across species, with 17 of them significantly enriched for PTSD. Chemical synaptic transmission and signaling by G-protein-coupled receptors were consistently enriched across omics and species.

Discussion

Our findings point out dysregulated genes highly replicated across PTSD studies in humans and animal models and suggest a potential role for the corticotropin-releasing hormone/orexin pathway in PTSD's pathophysiology. Further, we highlight current knowledge gaps and limitations and recommend future directions to address them.

Central and Peripheral Immune Dysregulation in Posttraumatic Stress Disorder: Convergent Multi-Omics Evidence

Posttraumatic stress disorder (PTSD) is a chronic and multifactorial disorder with a prevalence ranging between 6–10% in the general population and ~35% in individuals with high lifetime trauma exposure. Growing evidence indicates that the immune system may contribute to the etiology of PTSD, suggesting the inflammatory dysregulation as a hallmark feature of PTSD. However, the potential interplay between the central and peripheral immune system, as well as the biological mechanisms underlying this dysregulation remain poorly understood. The activation of the HPA axis after trauma exposure and the subsequent activation of the inflammatory system mediated by glucocorticoids is the most common mechanism that orchestrates an exacerbated immunological response in PTSD. Recent high-throughput analyses in peripheral and brain tissue from both humans with and animal models of PTSD have found that changes in gene regulation via epigenetic alterations may participate in the impaired inflammatory signaling in PTSD. The goal of this review is to assess the role of the inflammatory system in PTSD across tissue and species, with a particular focus on the genomics, transcriptomics, epigenomics, and proteomics domains. We conducted an integrative multi-omics approach identifying TNF (Tumor Necrosis Factor) signaling, interleukins, chemokines, Toll-like receptors and glucocorticoids among the common dysregulated pathways in both central and peripheral immune systems in PTSD and propose potential novel drug targets for PTSD treatment.

Comparison of Prevalence and Risk Factors of PTSS Between Chinese Patients With Depression and Non-depressed Controls During COVID-19 Outbreak

Background: COVID-19 pandemic is a traumatic event all over the world, and may lead to post-traumatic stress symptom (PTSS) in different population who are under the threat of novel corona virus. Therefore, the aim of our study was to compare the prevalence and risk factors of PTSS between Chinese patients with depression and non-depressed controls during the COVID-19 outbreak. Methods: 437 depressed patients and 2,940 non-depressed controls were enrolled in this cross-sectional study between February 14 and May 9, 2020.The Impact of Events Scale-Revised (IES-R), Zung Self-Rating Depression Scale (SDS), Zung Self-Rating Anxiety Scale (SAS) and Pittsburgh Sleep Quality Index (PSQI) were used to evaluate the psychological status of all the participants. Results: The prevalence of PTSS (IES-R ≥ 33) in depressed patients (45.08%) was higher than that in non-depressed controls (5.31%). Patients with depression were 16 times more likely to suffer from PTSS than those without depression. Correlation analyses showed that the IES-R total score was positively correlated with SDS, SAS, and PSQI scores in both depressed and non-depressed groups (Bonferroni corrected all p < 0.001). Multiple linear regression analysis showed that SAS score, and PSQI score were independently associated with IES-R total score in both depression and non-depression groups. In depressed patients, education level and duration of media exposure to COVID-19 were positively associated with PTSS, while in the non-depressed group, subjects who were married, in the 31-50 year group or with higher SDS score were more likely to develop PTSS. Conclusions: These results indicate that the prevalence rate of PTSS in patients with depression is very higher than that in subjects without depression. PTSS are associated with a number of socio-demographic and clinical variables.