The genetic background to PTSD

BDNF Val66Met genotype and adolescent glucocorticoid treatment induce sex-specific disruptions to fear extinction and amygdala GABAergic interneuron expression in mice

BACKGROUND

The BDNF Val66Met single nucleotide polymorphism has been implicated in stress sensitivity and Post-Traumatic Stress Disorder (PTSD) risk. We previously reported that chronic young-adult stress hormone treatment enhanced fear memory in adult BDNF^Val66Met mice with the Met/Met genotype. This study aimed to extend this work to fear extinction learning, spontaneous recovery of fear, and neurobiological correlates in the amygdala.

METHODS

Male and female Val/Val and Met/Met mice received corticosterone in their drinking water during late adolescence to model chronic stress. Following a 2-week recovery period, the mice underwent fear conditioning and extinction training. Immunofluorescent labelling was used to assess density of three interneuron subtypes; somatostatin, parvalbumin and calretinin, within distinct amygdala nuclei.

RESULTS

No significant effects of genotype, treatment or sex were found for fear learning. However, adolescent CORT treatment selectively abolished fear extinction of female Met/Met mice. No effect of genotype, sex, or treatment was observed for spontaneous recovery of fear. Significant main effects of genotype and CORT emerged for somatostatin and calretinin cell density, again in females only, further supporting sex-specific effects of the Met/Met genotype and chronic CORT exposure.

CONCLUSION

BDNF Val66Met genotype interacts with chronic adolescent stress hormone exposure to abolish fear extinction in female Met/Met mice in adulthood. This effect was associated with female-specific interneuron dysfunction induced by either genotype or stress hormone exposure, depending on the interneuron subtype. These data provide biological insight into the role of BDNF in sex differences in sensitivity to stress and vulnerability to stress-related disorders in adulthood.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Towards a Holistic Understanding of Musician's Focal Dystonia: Educational Factors and Mistake Rumination Contribute to the Risk of Developing the Disorder

Musicians' Focal Dystonia (MFD) is a task-specific neurological movement disorder, affecting 1-2% of highly skilled musicians. The condition can impair motor function by creating involuntary movements, predominantly in the upper extremities or the embouchure. The pathophysiology of the disorder is not fully understood, and complete recovery is extremely rare. While most of the literature views the condition through a neurological lens, a handful of recent studies point out certain psychological traits and the presence of adverse playing-related experiences and preceding trauma as possible contributors to the onset. The nature and the frequency of these factors, however, are under-researched. The present quasi-experimental study aimed to compare musicians with and without MFD in terms of the frequency of various adverse psychosocial and psychological factors to explore their contribution to the onset of the condition. Professional musicians with MFD (n = 107) and without MFD (n = 68) were recruited from online platforms, musicians' unions, and organisations to fill out a survey. The survey was based on two previously conducted interview studies and included the Student-Instructor Relationship Scale (SIRS), the Mistake Rumination Scale (MRS), the Trauma History Screen, and self-constructed questions about the received music education, early success, and personal experiences. To identify potential risk factors, independent samples t-tests were conducted and found that there are significant differences in musicians with and without MFD in terms of mistake rumination, early success, and the received music education. A logistic regression showed that six factors contributed to the construct to various extents; we observed a significant model [χ2 (80) = 22.681, p < 0.001], which predicted 71.2% of the cases correctly. This exploratory study shows that psychological and psychosocial factors might play a role in the development of MFD. Understanding these in more detail could inform preventative strategies and complement the current therapeutic approaches to support this vulnerable population better.

Disentangling sex differences in the shared genetic architecture of posttraumatic stress disorder, traumatic experiences, and social support with body size and composition

There is a well-known association of traumatic experiences and posttraumatic stress disorder (PTSD) with body size and composition, including consistent differences between sexes. However, the biology underlying these associations is unclear. To understand the genetic underpinnings of this complex relationship, we investigated genome-wide datasets informative of African and European ancestries from the Psychiatric Genomic Consortium, the UK Biobank, the GIANT Consortium, and the Million Veteran Program. We used genome-wide association statistics to estimate sex-specific genetic correlations (r g ) of traumatic experiences, social support, and PTSD with multiple anthropometric traits. After multiple testing corrections (false discovery rate, FDR q < 0.05), we observed 58 significant r g relationships in females (e.g., childhood physical abuse and body mass index, BMI r g  = 0.245, p = 3.88 × 10-10) and 21 significant r g relationships in males (e.g., been involved in combat or exposed to warzone and leg fat percentage; r g  = 0.405, p = 4.42 × 10-10). We performed causal inference analyses of these genetic overlaps using Mendelian randomization and latent causal variable approaches. Multiple female-specific putative causal relationships were observed linking body composition/size with PTSD (e.g., leg fat percentage→PTSD; beta = 0.319, p = 3.13 × 10-9), traumatic experiences (e.g., childhood physical abuse→waist circumference; beta = 0.055, p = 5.07 × 10-4), and childhood neglect (e.g., "someone to take you to doctor when needed as a child"→BMI; beta = -0.594, p = 1.09 × 10-5). In males, we observed putative causal effects linking anthropometric-trait genetic liabilities to traumatic experiences (e.g., BMI→childhood physical abuse; beta = 0.028, p = 8.19 × 10-3). Some of these findings were replicated in individuals of African descent although the limited sample size available did not permit us to conduct a sex-stratified analysis in this ancestry group. In conclusion, our findings provide insights regarding sex-specific causal networks linking anthropometric traits to PTSD, traumatic experiences, and social support.

Oxytocin receptor variant rs53576 genotype is associated with dysphoric arousal symptoms of DSM-5 posttraumatic stress disorder in Chinese earthquake survivors

PURPOSE

Evidence suggests that the oxytocin receptor (OXTR) gene may be involved in the psychopathology of posttraumatic stress disorder (PTSD). This study aimed to investigate the effects of OXTR rs53576 genotype on PTSD symptoms introduced in the Diagnostic and Statistical Manual, Fifth Edition (DSM-5).

METHODS

This study was a cross-sectional study conducted among 1140 adults who had personally experienced the Wenchuan earthquake. PTSD symptoms were measured with the PTSD checklist for DSM-5. A custom-by-design 2 × 48-Plex SNPscan^TM Kit were used to determine the OXTR rs53576. Multiple regression models were used to analyze the independent and interactive effects of OXTR rs53576 genotype and earthquake exposure on the severity of total PTSD symptoms and different dimensions of PTSD symptoms.

RESULTS

The results revealed that the rs53576 genotype could significantly predict PTSD symptoms (β = 0.055, p = 0.045). Further analysis showed that the rs53576 genotype was only significantly associated with dysphoric arousal symptoms of PTSD (β = 0.080, p = 0.005). The rs53576 genotype × earthquake exposure interaction had no significant effect on different symptom clusters (p > 0.05).

CONCLUSION

This study showed that the rs53576 genotype was only associated with the dysphoric arousal symptoms but not with other symptom clusters of PTSD. These findings support the role of the OXTR on the psychopathology of PTSD and help us to understand the genetic basis of PTSD.

A Pilot Study Investigating the Role of Gender in the Intergenerational Relationships between Gene Expression, Chronic Pain, and Adverse Childhood Experiences in a Clinical Sample of Youth with Chronic Pain

Chronic pain is a highly prevalent and costly issue that often emerges during childhood or adolescence and persists into adulthood. Adverse childhood experiences (ACEs) increase risk for several adverse health conditions, including chronic pain. Recent evidence suggests that parental trauma (ACEs, post-traumatic stress disorder (PTSD) symptoms) confers risk of poor health outcomes in their children. Intergenerational relationships between parental trauma and child chronic pain may be mediated by epigenetic mechanisms. A clinical sample of youth with chronic pain and their parents completed psychometrically sound questionnaires assessing ACEs, PTSD symptoms, and chronic pain, and provided a saliva sample. These were used to investigate the intergenerational relationships between four epigenetic biomarkers (COMT, DRD2, GR, and SERT), trauma, and chronic pain. The results indicated that the significant biomarkers were dependent upon the gender of the child, wherein parental ACEs significantly correlated with changes in DRD2 expression in female children and altered COMT expression in the parents of male children. Additionally, the nature of the ACE (maltreatment vs. household dysfunction) was associated with the specific epigenetic changes. There may be different pathways through which parental ACEs confer risk for poor outcomes for males and females, highlighting the importance of child gender in future investigations.

Dopamine transporter (DAT1) gene in combat veterans with PTSD: A case-control study

The dopamine transporter (DAT1) gene has been postulated to be involved in PTSD; however, existing studies have shown inconsistencies when examining genotypic and allelic associations. The primary objective of this study was to examine whether DAT1-40bp-VNTR (DAT1) 9R polymorphism might increase the risk of PTSD development in combat veterans, utilizing a case-control gene association study with both control and PTSD cases having previous exposure to combat traumas. Participants with PTSD (N = 365) and combat-exposed controls without PTSD (N = 298) were included in analysis. After controlling for race, sex and age, when dichotomized, absence of DAT1 10R/10R genotypes was associated with PTSD diagnosis compared to no PTSD diagnosis; these results were not statistically significant when trichotomized 10R/10R, 10R/X, 9R/9R. Similarly, odds ratio for absence of 10R/10R genotype showed a statistically significant increase in the risk of developing PTSD. DAT1 genotype was also associated with statistically significant mean total CAPS scores, both when dichotomized and trichotomized. In conclusion, our results indicate that the absence of 10R/10R is associated with an increased risk of PTSD and higher CAPS total scores.

Ventral Tegmental Area Dysfunction and Disruption of Dopaminergic Homeostasis: Implications for Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition characterized by intrusive recollections of the traumatic event, avoidance behaviors, hyper-arousal to event-related cues, cognitive disruption, and mood dysregulation. Accumulating preclinical and clinical evidence implicates dysfunction of the ventral tegmental area (VTA) dopaminergic system in PTSD pathogenesis. This article reviews recent advances in our knowledge of the relationship between dopaminergic dyshomeostasis and PTSD, including the contributions of specific dopaminergic gene variants to disease susceptibility, alterations in VTA dopamine neuron activity, dysregulation of dopaminergic transmission, and potential pharmacological and psychological interventions for PTSD targeting the dopaminergic system. An in-depth understanding of PTSD etiology is crucial for the development of innovative risk assessment, diagnostic, and treatment strategies following traumatic events.

Interaction between catechol-O-methyltransferase polymorphism and childhood trauma in suicidal ideation of patients with post-traumatic stress disorder

INTRODUCTION

Suicidal behavior of post-traumatic stress disorder (PTSD) patients is influenced by genetic and environmental factors. The catechol-O-methyltransferase (COMT) gene has been known to be associated with suicidal ideation. The present study aimed to explore the relationship of COMT polymorphism, childhood trauma, and suicidal ideation in patients with PTSD.

METHODS

Fifty patients with PTSD and 62 healthy controls (HCs) were recruited, and COMT variants rs4680 and rs4633 were genotyped through peripheral blood. Psychological assessments such as the childhood trauma questionnaire (CTQ), the scale for suicidal ideation, the clinician-administered PTSD scale for DSM-5, and a PTSD checklist were administered. A regression analysis, the Johnson-Neyman technique, and a two-way analysis of covariance were conducted.

RESULTS

Interaction of COMT polymorphism (rs4680, rs4633) and childhood emotional abuse (subscale of CTQ) predicted suicidal ideation in patients with PTSD. Patients with the rs4680 Val/Val genotype, compared to Met carriers genotype, showed higher suicidal ideation when childhood emotional abuse was high. Patients with the rs4633 CC genotype, compared to T carriers genotype, showed higher suicidal ideation when childhood emotional abuse was high.

CONCLUSION

Our results suggest that vulnerability to suicide could be increased in the Val/Val genotype of COMT rs4680 and the CC genotype of rs4633 in patients with PTSD. Moreover, PTSD group with high childhood emotional abuse demonstrated a significantly higher suicidal ideation than did those with low childhood emotional abuse.

Rats Lacking Dopamine Transporter Display Increased Vulnerability and Aberrant Autonomic Response to Acute Stress

The activity of the hypothalamus–pituitary–adrenal (HPA) axis is pivotal in homeostasis and presides the adaptative response to stress. Dopamine Transporter (DAT) plays a key role in the regulation of the HPA axis. We used young adult female DAT Knockout (KO) rats to assess the effects of DAT ablation (partial, heterozygous DAT+/-, or total, homozygous DAT-/-) on vulnerability to stress. DAT-/- rats show profound dysregulation of pituitary homeostasis, in the presence of elevated peripheral corticosterone, before and after acute restraint stress. During stress, DAT-/- rats show abnormal autonomic response at either respiratory and cardiovascular level, and delayed body temperature increase. DAT+/- rats display minor changes of hypophyseal homeostatic mechanisms. These rats display a similar pituitary activation to that of the control animals, albeit in the presence of higher release of peripheral corticosterone than DAT-/- after stress, and reduced temperature during stress. Our data indicate that DAT regulates the HPA axis at both the central and peripheral level, including autonomic function during stress. In particular, the partial deletion of DAT results in increased vulnerability to stress in female rats, which display central and peripheral alterations that are reminiscent of PTSD, and they might provide new insights in the pathophysiology of this disorder.

The potential role of the HCN1 ion channel and BDNF-mTOR signaling pathways and synaptic transmission in the alleviation of PTSD

The function of the hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) and the expression of brain-derived neurotrophic factor (BDNF) may be involved in the pathogenesis of post-traumatic stress disorder (PTSD). This study aims to explore the role of the HCN1 channel, BDNF, and mTOR in the actions of PTSD and to examine whether synaptic transmission or plasticity is involved in the regulation of this disease. In the present study, rats were exposed to the single prolonged stress and electric foot shock (SPS&S) procedure, which can induce PTSD-like behaviors in rats. ZD7288 was administered by intracerebroventricular (i.c.v.) injection to one experimental group to inhibit the function of the HCN1 ion channel while 8-Br-cAMP was administered to another group to activate the function of the HCN1 ion channel. A series of behavioral tests and biochemical assessments of certain proteins (HCN1, BDNF, and pmTOR) and synaptic ultrastructure in the prefrontal cortex (PFC) and hippocampus (Hip) were then conducted. The SPS&S procedure induced apparent PTSD-like symptoms in rats. The administration of ZD7288 reduced the immobility time and escape latency time in the forced swim test (FST) and water maze test (WMT) with a decreased level of HCN1, upregulated BDNF-mTOR signaling pathways in the PFC and Hip, and synaptic ultrastructure changes in the PFC. In contrast, the administration of 8-Br-cAMP, which led to a higher level of HCN1 in PFC and Hip, resulted in a decreased number of entries to the open arms without significant change in total arm entries in the elevated plus maze test (EPMT) as well as a shorter center square distance and total distance in the open field test (OFT). Extended escape latency time was also observed in the WMT although there was no alteration of BDNF-mTOR signaling pathways and synaptic ultrastructure in the PFC and Hip. Overall, the inhibition of HCN1, which can alleviate PTSD-like behavior of rats by relieving depression and improving learning ability, may be related to the upregulated BDNF-mTOR signaling pathways and synaptic transmission.

A novel theory on the predictive value of variation in the β-endorphin system on the risk and severity of PTSD

Despite growing interest in genetic and psychosocial indicators of heightened susceptibility to posttraumatic stress disorder (PTSD), a predictive model, which explains why some individuals develop PTSD in response to life-threatening traumatic events, while others, when faced with the same or similar experiences, do not, has thus far remained out of reach. In this paper, we review the literature on gene-environment interactions in β-endorphin system functioning with regard to PTSD and suggest that variation, both genetic and with regard to environmental stimuli, in systems which, like the β-endorphin system, distort human perception of life-threatening traumatic experiences may account for some of the variance in resilience to the disorder. Given the role of β-endorphin in both social connections and physical exercise, this becomes especially relevant with regard to military selection, training, and leadership processes.

Predictors of Current DSM-5 PTSD Diagnosis and Symptom Severity Among Deployed Veterans: Significance of Predisposition, Stress Exposure, and Genetics

BACKGROUND

Previously we reported a genetic risk score significantly improved PTSD prediction among a trauma-exposed civilian population. In the current study, we sought to assess this prediction among a trauma-exposed military population.

METHODS

We examined current PTSD diagnosis and PTSD symptom severity among a random sample of 1042 community-based US military veterans. Main effects and interaction effects were assessed for PTSD genetic risk by trauma exposure using cross-product terms for PTSD x trauma exposures, including combat, lifetime trauma, and adverse childhood exposures. The PTSD risk variants studied were within genetic loci previously associated with PTSD, including CRHR1, CHRNA5, RORA, and FKBP5 genetic variants, which were used to calculate a total PTSD genetic risk score (range=0-8, mean=3.6, SD=1.4).

RESULTS

Based on DSM-5 PTSD criteria, 7.1% of veterans (95% CI=5.6-8.8) met criteria for current PTSD. The PTSD genetic risk count was significantly higher among PTSD cases vs non-cases (3.92 vs 3.55, p=0.027). Since the PTSD genetic risk score was not significant in the PTSD diagnosis model, we assessed this association using PTSD symptom severity. Because these symptom data were skewed (mean=9.54, SD=12.71, range=0-76), we used negative binomial regression to assess this outcome. This symptom model included a PTSD genetic risk score, demographic factors, trauma exposures, current insomnia, current depression, concussion history, and attention-deficit disorder, expressed as incident rate ratios (IRR), which is an estimate of one-unit increase in PTSD severity, given other variables are held constant. Variables in the final model included age and sex (both p<0.001), PTSD genetic risk (IRR=1.02, p=0.028), warzone tours (IRR=0.94, p=0.003), childhood abuse (IRR=1.50, p<0.0001), current depression (IRR=1.89, p<0.0001), current insomnia (IRR=2.58, p<0.0001), low social support (IRR=1.19, p<0.0001), attention-deficit disorder (IRR=1.51, p<0.0001), agreeable personality (IRR=0.77, p<0.0001), and concussion (IRR=1.38, p<0.0001). Significant interactions were detected for combat and lifetime trauma exposure by PTSD genetic risk (both p<0.0001), suggesting that the impact of trauma exposures on PTSD severity was lower when the PTSD genetic risk was higher.

CONCLUSION

Both warzone and non-warzone factors predicted current PTSD symptoms among veterans, including a PTSD genetic risk score. Interaction effects were detected for combat exposure and lifetime trauma by genetic risk score for PTSD symptoms, suggesting that PTSD symptom manifestation was more dependent on PTSD risk variants than the level of trauma or combat exposure. This suggests that controlling for other factors, the absence of genetic risk variants may confer PTSD resilience. Further research is planned.

An epistasis between dopaminergic and oxytocinergic systems confers risk of post-traumatic stress disorder in a traumatized Chinese cohort

Post-traumatic stress disorder (PTSD) is a psychiatric syndrome that occurs after trauma exposure. Neurotransmitters such as dopamine and oxytocin have been reported to be involved in neuropathology of PTSD. Previous studies indicated that the dopamine–oxytocin interaction may contribute to behavioral disorders. Thus, exploring the epistasis (gene–gene interaction) between oxytocinergic and dopaminergic systems might be useful to reveal the genetic basis of PTSD. In this study, we analyzed two functional single nucleotide polymorphisms (SNPs), rs2268498 for oxytocinergic gene OXTR and rs1801028 for dopaminergic gene DRD2 based on putative oxytocin receptor–dopamine receptor D2 (OTR–DR2) heterocomplex in a Chinese cohort exposed to the 2008 Wenchuan earthquake (156 PTSD cases and 978 controls). Statistical analyses did not find any single variant or gene–environment interaction (SNP × earthquake-related trauma exposure) associated with provisional PTSD diagnosis or symptoms. An OXTR–DRD2 interaction (rs2268498 × rs1801028) was identified to confer risk of provisional PTSD diagnosis (OR = 9.18, 95% CI = 3.07–27.46 and P = 7.37e-05) and further subset analysis indicated that rs2268498 genotypes controlled the association directions of rs1801028 and rs1801028 genotypes also controlled the association directions of rs2268498. Rs2268498 × rs1801028 is also associated with PTSD symptoms (P = 0.043). Our study uncovered a genetic and putative function-based contribution of dopaminergic–oxytocinergic system interaction to PTSD.

FKBP5 Genotype Linked to Combined PTSD-Depression Symptom in Chinese Earthquake Survivors

BACKGROUND

Post-traumatic stress disorder (PTSD) and depression are common mental disorders in individuals experiencing traumatic events. To date, few studies have studied the relationship between genetic basis and phenotypic heterogeneity of traumatized individuals. The present study examined the effects of four FKBP5 SNPs (rs1360780, rs3800373, rs9296158, and rs9470080) in four postdisaster groups (low symptom, predominantly depressive, predominantly PTSD, and combined PTSD-depression symptom groups) as identified by latent profile analysis.

METHODS

A total of 1,140 adults who experienced the 2008 Wenchuan earthquake participated in our study. Earthquake-related trauma, PTSD, and depressive symptoms were measured using standard psychometric instruments. The four FKBP5 SNPs were genotyped using a custom-by-design 2 × 48-Plex SNP scan™ Kit.

RESULTS

After adjusting for covariates, the main and gene-environment interaction effects of rs9470080 were all significant when the combined PTSD-depression group was compared with the low symptoms, predominantly depression and predominantly PTSD groups. rs9470080 TT genotype carriers had a higher risk of developing high co-occurring PTSD and depression symptoms than the C allele carriers. However, when trauma exposure was severe, the TT genotype carriers and C allele carriers did not differ in the risk of developing high co-occurring PTSD and depressive symptoms. The other three SNPs demonstrated no significant effects. Moreover, the rs3800373-rs9296158-rs1360780-rs9470080 haplotype A-G-C-T was found significantly associated with combined PTSD-depression symptoms.

CONCLUSION

Our findings support the genetic basis of phenotypic heterogeneity in people exposed to trauma. Furthermore, the results reveal the possibility that the variants of FKBP5 gene may be associated with depression-PTSD comorbidity.

The evolution of mental health outcomes across a combat deployment cycle: A longitudinal study of the Guam Army National Guard

In the United States, National Guard soldiers have been called upon at unprecedented rates since 2001 to supplement active duty military forces. Frequent military deployments generate many occupational and environmental stressors for these citizen-soldiers, from serving in a dangerous zone to being away from family and home for long periods of time. Whereas there is a substantial amount of research focused on deployment-related health outcomes in relation to active duty (i.e., full-time) military populations, reserve forces are less understood. This study focuses on a United States Army National Guard combat unit deployed to Afghanistan. This prospective longitudinal study was conducted over the course an operational deployment cycle (i.e., before, during, and after) to document the evolution of salient mental health outcomes (i.e., post-traumatic stress, depression, general anxiety, and aggression). The findings show that both combat (e.g., killing others) and non-combat (e.g., boredom) stressors negatively affect mental health outcomes, and the severity of these outcomes increases over the course of a deployment cycle. Of special note, the study reveals key gender differences in the evolution of post-traumatic stress (PTS), depression, and anxiety across a deployment cycle: females report increased PTS, depression, and anxiety 6 months post-deployment, whereas the levels reported by males stabilize at their mid-deployment levels. The findings offer insights for medical providers and policymakers in developing more targeted health promotion campaigns and interventions, especially at the post-deployment phase.

Own or dam's genotype? Classical colony breeding may bias spontaneous and stress-challenged activity in DAT-mutant rats

There is considerable interest in understanding what makes an individual vulnerable or resilient to the deleterious effects of stressful events. From candidate genes, dopamine (DA) and dopamine transporter (DAT) have been linked to anxiety, depression, and post-traumatic stress disorder. We investigated role of DAT using the new DAT heterozygous (DAT-HET) and homozygous mutant (DAT-KO) rat models of hyperdopaminergia. We studied the impact of two breeding conditions in spontaneous locomotor behavior of female rats. The classical colony, through mating DAT-HET males × DAT-HET females (breeding HET-HET), was used. A second WT colony was derived and maintained (breeding WT-WT). Additionally, a subgroup of rats was bred through mating DAT-KO males × WT females (atypical HET, breeding KO-WT). We studied the effects of genotype and its interaction with maternal care (depending by breeding condition). HET-HET breeding led to reduced activity in HET females compared to WT rats (from WT-WT breeding). However, HET females from KO-WT breeding did not differ so much from WT rats (WT-WT breeding). The maternal-care impact was then confirmed: HET mothers (breeding HET-HET) showed reduced liking/grooming of pups and increased digging away from nest, compared to WT mothers (breeding WT-WT). In their female offspring (HET, breeding HET-HET vs. WT, breeding WT-WT), isolation plus wet bedding induced higher and more persistent impact on activity of HET rats, even when the stressor was removed. Our results highlight the importance of epigenetic factors (e.g., maternal care) in responses to stress expressed by offspring at adulthood, quite independently of genotype. DAT hypofunction could determinate vulnerability to stressful agents via altered maternal care.

Influence of childhood trauma and brain-derived neurotrophic factor Val66Met polymorphism on posttraumatic stress symptoms and cortical thickness

Interaction between childhood trauma and genetic factors influences the pathophysiology of posttraumatic stress disorder (PTSD). This study examined the interaction effect of childhood trauma and brain-derived neurotrophic factor (BDNF) Val66Met polymorphism on PTSD symptoms and brain cortical thickness. A total of 216 participants (133 healthy volunteers and 83 PTSD patients) were recruited. T1-weighted structural magnetic resonance imaging, BDNF rs6265 genotyping through blood sampling, and clinical assessments including the childhood trauma questionnaire (CTQ) and posttraumatic stress disorder Checklist (PCL) were performed. A moderated regression analysis, two-way multivariate analysis of covariance, and correlation analysis were conducted. An interaction between the CTQ and the BDNF polymorphism significantly influenced PTSD symptom severity. In fact, people with rs6265 Val/Val genotype and higher CTQ scores showed higher PCL scores. Additionally, this interaction was significant on both left fusiform and transverse temporal gyri thickness. Furthermore, the thickness of both brain regions was significantly correlated with psychological symptoms including depression, anxiety, rumination, and cognitive emotion regulation methods; yet this was mainly observed in people with the Val/Val genotype. The interaction between childhood trauma and BDNF polymorphism significantly influences both PTSD symptoms and cortical thickness and the Val/Val genotype may increase the risk in Korean population.

Fear Processing, Psychophysiology, and PTSD

The processing and regulation of fear is one of the key components of posttraumatic stress disorder (PTSD). Fear can involve both acute and potential threats that can manifest in different behaviors and result from activity within different neural nodes and networks. Fear circuits have been studied extensively in animal models for several decades and in human neuroimaging research for almost 20 years. Therefore, the centrality of fear processing to PTSD lends the disorder to be more tractable to investigation at the level of brain and behavior, and provides several observable phenotypes that can be linked to PTSD symptoms. Moreover, psychophysiological metrics of fear conditioning offer tools that can be used to shift diagnostic paradigms in psychiatry toward neurobiology-consistent with a Research Domain Criteria approach to PTSD. In general, mammalian fear processing can be divided into fear learning (or acquisition), during which an association develops between previously neutral stimuli and aversive outcomes, and fear extinction, in which the latter associations are suppressed by a new form of learning. This review describes translational research in both fear acquisition and extinction, along with their relevance to PTSD and PTSD treatment, focusing specifically on the empirical value and potential clinical utility of psychophysiological methods.

The preliminary investigation of orexigenic hormone gene polymorphisms on posttraumatic stress disorder symptoms

Orexigenic hormones are a group of hormones that can up-regulate appetite. Current studies have shown that orexigenic hormones also play important roles in stress responses and may be implicated in regulation of fear memory. However, these conclusions lack evidence from human studies. In this study, we examined associations between orexigenic hormone genes and fear-related mental disorders by investigating main, G × E, and G × G effects of ghrelin and orexin gene single nucleotide polymorphisms (SNPs) on human posttraumatic stress disorder (PTSD) symptoms in 1134 Chinese earthquake survivors. SNPs Leu72Met of the GHRL gene (rs696217), Ile408Val of the HCRTR1 gene (rs2271933) and Val308Ile of the HCRTR2 gene (rs2653349) were genotyped. None of the SNPs showed significant main or G × E effects. However, a significant interaction effect between GHRL rs696217 and HCRTR1 rs2271933 was found to predict the PTSD Checklist (PCL-5) total score (P =  0.007). Further analysis revealed different interaction patterns in males and females. For females, the rs2271933 G allele was associated with an increased PCL-5 total score (B = 2.59, P =  0.024) when the rs696217 genotype TT/TG was present. For males, the rs696217 T allele is associated with an increased PCL-5 total score (B = 3.62, P =  0.040) when the rs2271933 genotype GG/GA was present. These current findings expand our knowledge of physiological function of the orexigenic hormone system, and suggest its involvement in development of fear-related mental disorders such as PTSD.

Ensemble machine learning prediction of posttraumatic stress disorder screening status after emergency room hospitalization

Posttraumatic stress disorder (PTSD) develops in a substantial minority of emergency room admits. Inexpensive and accurate person-level assessment of PTSD risk after trauma exposure is a critical precursor to large-scale deployment of early interventions that may reduce individual suffering and societal costs. Toward this aim, we applied ensemble machine learning to predict PTSD screening status three months after severe injury using cost-effective and minimally invasive data. Participants (N = 271) were recruited at a Level 1 Trauma Center where they provided variables routinely collected at the hospital, including pulse, injury severity, and demographics, as well as psychological variables, including self-reported current depression, psychiatric history, and social support. Participant zip codes were used to extract contextual variables including population total and density, average annual income, and health insurance coverage rates from publicly available U.S. Census data. Machine learning yielded good prediction of PTSD screening status 3 months post-hospitalization, AUC = 0.85 95% CI [0.83, 0.86], and significantly outperformed all benchmark comparison models in a cross-validation procedure designed to yield an unbiased estimate of performance. These results demonstrate that good prediction can be attained from variables that individually have relatively weak predictive value, pointing to the promise of ensemble machine learning approaches that do not rely on strong isolated risk factors.

Applying ketamine to alleviate the PTSD-like effects by regulating the HCN1-related BDNF

BACKGROUND

Post-traumatic stress disorder (PTSD) is commonly associated with concurrent anxiety and depression symptoms, and reduce the expression of the Brain-Derived Neurotrophic Factor (BDNF) which promotes the proliferation and survival of neurons. The hyperpolarization-activated cyclic nucleotide-gated channel 1(HCN1) could be inhibited by the ketamine, a drug to alleviate depression and anxiety, and regulated the BDNF expression, however, the effects of ketamine in alleviating PTSD symptoms by regulating the HCN1-related BDNF have been poorly perceived.

METHODS

In the present study, the effects of ketamine were examined on the PTSD-like effects in a rat model of PTSD induced by SPS&S procedure. After the SPS&S procedure and model testing, PTSD rats were subjected to behavioral testing and biochemical assessments, followed by single treatment with certain doses of ketamine (5, 10, 15 and 20 mg/kg IP).

RESULTS

The results showed that the SPS&S procedure induced severe PTSD-like behaviors, with lower levels of BDNF protein levels and higher level of the HCN1 protein in the prefrontal cortex (PFC). These were reversed by a single administration of ketamine. The ketamine with dose of 15 mg/kg significantly increased locomotor behavior in the open field test, aggrandized exploratory behavior in the elevated plus maze test, and decreased immobility time spent in the forced swim test. Meanwhile, ketamine with dose of 15 mg/kg could increase the BDNF protein level, while down-regulate the expression of the HCN1. Eventually, there was a negative correlation between the level of BDNF and HCN1 in the PFC.

CONCLUSION

Ketamine affects the HCN1-related BDNF signaling pathways to alleviate PTSD-like effects in rat.

A Review of the Historical, Criminological, and Theoretical Understandings of the Cambodian American Population: A Call for More Comprehensive Research

The collective view of Asian Americans as model minorities is evident with the extensive amount of statistical data showing support for the academic and socioeconomic success of Asian Americans in the United States. This perception, however, often presents an inaccurate portrayal of Asian Americans, in general, as it overlooks many of the difficulties and hardships experienced by Asian American ethnic groups such as Southeast Asians. Within this group, Cambodian Americans are at the highest risk for experiencing socioeconomic hardships, behavioral health problems, substance use disorders, and contact with the criminal justice system, with deportation also being a prevailing issue. Unfortunately, research in this area is scant and contemporary research on Cambodian Americans has several limitations. To begin to address this issue, the present article merges information from existing research on this population from a sociohistorical, criminological, and theoretical standpoint to call for more comprehensive research on Cambodian Americans.

The role of suboptimal mitochondrial function in vulnerability to post-traumatic stress disorder

Post-traumatic stress disorder remains the most significant psychiatric condition associated with exposure to a traumatic event, though rates of traumatic event exposure far outstrip incidence of PTSD. Mitochondrial dysfunction and suboptimal mitochondrial function have been increasingly implicated in several psychopathologies, and recent genetic studies have similarly suggested a pathogenic role of mitochondria in PTSD. Mitochondria play a central role in several physiologic processes underlying PTSD symptomatology, including abnormal fear learning, brain network activation, synaptic plasticity, steroidogenesis, and inflammation. Here we outline several potential mechanisms by which inherited (genetic) or acquired (environmental) mitochondrial dysfunction or suboptimal mitochondrial function, may contribute to PTSD symptomatology and increase susceptibility to PTSD. The proposed pathogenic role of mitochondria in the pathophysiology of PTSD has important implications for prevention and therapy, as antidepressants commonly prescribed for patients with PTSD have been shown to inhibit mitochondrial function, while alternative therapies shown to improve mitochondrial function may prove more efficacious.

Genetic variant in CACNA1C is associated with PTSD in traumatized police officers

Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder that may develop after a traumatic event. Here we aimed to identify epigenetic and genetic loci associated with PTSD. We included 73 traumatized police officers with extreme phenotypes regarding symptom severity despite similar trauma history: n = 34 had PTSD and n = 39 had minimal PTSD symptoms. Epigenetic and genetic profiles were based on the Illumina HumanMethylation450 BeadChip. We searched for differentially methylated probes (DMPs) and differentially methylated regions (DMRs). For genetic associations we analyzed the CpG-SNPs present on the array. We detected no genome-wide significant DMPs and we did not replicate previously reported DMPs associated with PTSD. However, GSE analysis of the top 100 DMPs showed enrichment of three genes involved in the dopaminergic neurogenesis pathway. Furthermore, we observed a suggestive association of one relatively large DMR between patients and controls, which was located at the PAX8 gene and previously associated with other psychiatric disorders. Finally, we validated five PTSD-associated CpG-SNPs identified with the array using sanger sequencing. We subsequently replicated the association of one common SNP (rs1990322) in the CACNA1C locus with PTSD in an independent cohort of traumatized children. The CACNA1C locus was previously associated with other psychiatric disorders, but not yet with PTSD. Thus, despite the small sample size, inclusion of extreme symptom severity phenotypes in a highly homogenous traumatized cohort enabled detection of epigenetic and genetic loci associated with PTSD. Moreover, here we showed that genetically confounded 450K probes are informative for genetic association analysis.

DBS in Treatment of Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition for which pharmacological therapy is not always solvable. Various treatments have been suggested and deep brain stimulation (DBS) is currently under investigation for patients affected by PTSD. We review the neurocircuitry and up-to-date clinical concepts which are behind the use of DBS in posttraumatic stress disorder (PTSD). The role of DBS in treatment-refractory PTSD patients has been investigated relying on both preclinical and clinical studies. DBS for PTSD is in its preliminary phases and likely to provide hope for patients with medical refractory PTSD following the results of randomized controlled studies.

A DRD2/ANNK1-COMT Interaction, Consisting of Functional Variants, Confers Risk of Post-traumatic Stress Disorder in Traumatized Chinese

Objective: Post-traumatic stress disorder (PTSD) is a trauma- and stress-related psychiatric syndrome that occurs after exposure to extraordinary stressors. The neurotransmitter dopamine (DA) plays important roles in neurobiological processes like reward and stress, and a link between PTSD and the dopaminergic system has been reported. Thus, the investigation of an association between PTSD and gene-gene interaction (epistasis) within dopaminergic genes could uncover the genetic basis of dopamine-related PTSD symptomatology and contribute to precision medicine. Methods: We genotyped seven single nucleotide polymorphisms (SNPs) of three dopaminergic genes DRD2/ANNK1 (rs1800497 and rs1801028), COMT (rs6269, rs4633, rs4818 and rs4680) and DBH (rs1611115), in a Chinese predominantly adult cohort that had been exposed to an earthquake (156 PTSD cases and 978 controls). Results: Statistical genetics analysis identified a DRD2/ANNK1-COMT interaction (rs1800497 × rs6269), which is associated with PTSD diagnosis (P_interaction = 0.0008055 and P_corrected = 0.0169155). Single-variant and haplotype-based subset analyses showed that rs1800497 modulates the association directions of both the rs6269 G allele and the rs6269-rs4633-rs4818-rs4680 haplotype G-C-G-G. The interaction (rs1800497 × rs6269) was replicated in a Chinese young female cohort (32 cases and 581 controls, P_interaction = 0.01329). Conclusions: Rs1800497 is related to the DA receptor D2 density and rs6269-rs4633-rs4818-rs4680 haplotypes affect the catechol O-methyltransferase level and enzyme activity. Thus, the interaction was inferred to be at protein-protein and DA activity level. The genotype combinations of the two SNPs indicate a potential origin of DA homeostasis abnormalities in PTSD development.

Trauma and Pain in Family-Orientated Societies

People from family-oriented societies in particular, in addition to having a post-traumatic stress disorder (PTSD) suffer from chronic pain and physical complaints. Such people have a different understanding of physical illness and pain and, compared to patients from western societies, have different ideas on healing, even when confronted with the therapist. Hitherto, these factors have not been sufficiently taken into account in modern, multi-module therapy approaches. Trauma can be perceived via pain and physical complaints, whereby the pain is not restricted to one part of the body but is seen as covering the body as a whole. Therefore, in the treatment and above all in the patient-therapist relationship, it is necessary to understand what importance is attached to the perceived pain in relation to the trauma. The afflicted body expresses the trauma in the shape of its further-reaching consequences such as the patient's social, collective, economic and cultural sensitivity. Therefore, for the effective treatment of trauma and chronic pain, it is necessary to use a multi-modal, interdisciplinary, and culture-sensitive approach when treating patients from traditional cultural backgrounds.

Meta-analysis of the interaction between serotonin transporter promoter variant, stress, and posttraumatic stress disorder

Exposure to stress predicts the occurrence of posttraumatic stress disorder (PTSD) in individuals harboring the serotonin transporter promoter variant 5-HTTLPR. We carried out a meta-analysis of studies investigating the interaction between 5-HTTLPR, stress, and PTSD to clarify the interrelatedness of these factors. We reviewed all relevant studies published in English before May 2016. The Lipták-Stouffer z-score method for meta-analysis was applied to combined data. The z score was separately calculated for the stressful life events, childhood adversity, bi- and triallelic loci, and cross-sectional and longitudinal studies subgroups. A total of 14 studies with 15,883 subjects met our inclusion criteria. We found strong evidence that the presence of 5-HTTLPR influenced the relationship between stress and PTSD (P = 0.00003), with the strongest effects observed in the cross-sectional and longitudinal groups (P = 0.01 and 2.0 × 10-6, respectively). Stressful life events and childhood adversity separately interacted with 5-HTTLPR in PTSD (P = 2.0 × 10-8 and 0.003, respectively). When the studies were stratified by locus classification, the evidence was stronger for the triallelic (P = 4.0 × 10-8) than for the biallelic (P = 0.054) locus subgroup. There was strong evidence that 5-HTTLPR influences the relationship between stress and PTSD.

Single-nucleotide polymorphisms in genes related to the hypothalamic-pituitary-adrenal axis as risk factors for posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a common psychiatric disorder. The etiology of PTSD is multifactorial, depending on many environmental and genetic risk factors, and the exposure to life or physical integrity-threatening events. Several studies have shown significant correlations of many neurobiological findings with PTSD. Hypothalamic-pituitary-adrenal (HPA) axis dysfunction is strongly correlated with this disorder. One hypothesis is that HPA axis dysfunction may precede the traumatic event, suggesting that genes expressed in the HPA axis may be involved in the development of PTSD. This article reviews molecular genetic studies related to PTSD collected through a literature search performed in PubMed, MEDLINE, ScienceDirect, and Scientific Electronic Library Online (SciELO). The results of these studies suggest that several polymorphisms in the HPA axis genes, including FKBP5, NR3C1, CRHR1, and CRHR2, may be risk factors for PTSD development or may be associated with the severity of PTSD symptoms.

Brain-Derived Neurotropic Factor Val66Met Polymorphism and Posttraumatic Stress Disorder among Survivors of the 1998 Dongting Lake Flood in China

OBJECTIVE

This study mainly aimed to explore the association between brain-derived neurotropic factor (BDNF) Val66Met polymorphism and posttraumatic stress disorder (PTSD) among flood survivors in China.

METHODS

Individuals who experienced the 1998 Dongting Lake flood in Southeast Huarong, China, were enrolled in this study. Qualified health personnel carried out face-to-face interviews with participants. PTSD was identified using PTSD Checklist-Civilian version (PCL-C). Blood samples were collected from the participants to extract DNA for genotyping.

RESULTS

A total of 175 participants were enrolled in this study. The prevalence of PTSD among flood survivors at 17-year follow-up was 16.0% (28/175). Individuals with PTSD were more likely to be female, experience at least three flood-related stressors, experience at least three postflood stressors, and carry the Met than those without PTSD. Compared with Val/Val homozygotes, Met carriers had higher scores of PCL-C (mean ± standard error: 23.60 ± 7.23 versus 27.19 ± 9.48, P < 0.05). Multivariable logistic regression analysis indicated that Met carriers (aOR = 4.76, 95% CI = 1.02-22.15, P < 0.05) were more likely to develop PTSD than Val/Val homozygotes.

CONCLUSIONS

Met carriers for BDNF rs6265 are at higher risk of developing PTSD and also exhibit more severe PTSD symptoms than Val/Val homozygotes among flood survivors in China.

Genetic approaches for the study of PTSD: Advances and challenges

Post-traumatic stress disorder (PTSD) is a highly debilitating stress and anxiety-related disorder that occurs in response to specific trauma or abuse. Genetic risk factors may account for up to 30-40% of the heritability of PTSD. Understanding the gene pathways that are associated with PTSD, and how those genes interact with the fear and stress circuitry to mediate risk and resilience for PTSD will enable the development of targeted therapies to prevent the occurrence of or decrease the severity of this complex multi-gene disorder. This review will summarize recent research on genetic approaches to understanding PTSD risk and resilience in human populations, including candidate genes and their epigenetic modifications, genome-wide association studies and neural imaging genetics approaches. Despite challenges faced within this field of study such as inconsistent results and replications, genetic approaches still offer exciting opportunities for the identification and development of novel therapeutic targets and therapies in the future.

Support for the association between RORA gene polymorphisms and the DSM-5 posttraumatic stress disorder symptoms in male earthquake survivors in China

BACKGROUND

This study examined the association between interaction of retinoid-related orphan receptor alpha (RORA) (rs8042149) genotype x trauma exposure and post-traumatic stress disorder (PTSD) symptoms.

METHODS

A total of 1196 Chinese adults who suffered from a deadly 2008 Wenchuan earthquake participated in this study. PTSD symptoms were measured with the PTSD Checklist for DSM-5 (PCL-5). A custom-by-design 2×48-Plex SNPscan™Kit were used to genotype the RORA rs8042149 SNP.

RESULTS

Our results showed that the interaction of rs8042149 genotype x trauma exposure was associated with total PTSD symptoms in males. Moreover, the rs8042149 genotype x trauma exposure interaction was only associated with severity of the negative affect, anhedonia and dysphoric arousal symptoms in males.

LIMITATIONS

A moderate sample exposed to a specific event was assessed with a self-reported PTSD measure.

CONCLUSIONS

This study provides preliminary evidence supporting the functional role of RORA in PTSD, and adds to the knowledge for understanding the genetic underpinnings of PTSD. Moreover, this study carries implications for understanding the comorbidity of PTSD and the sex-specific expression of PTSD's symptoms.

Family-Related Stress versus External Stressors: Differential Impacts on Alcohol and Illicit Drug Use in Young Men

Intense stress increases substance use (SU). However, little is known about the extent to which distinctive forms of stress should be weighted with regard to their effects on SU. This study aimed to determine whether family-related stress factors (FSF) influenced SU in a different way than external stress factors (ESF). Data was drawn from a Swiss cohort study on SU risk factors (C-SURF), involving 5,308 young adult men. Twelve month use of alcohol and of illicit substances was assessed. FSF and ESF for the time period preceding SU were measured. FSF and ESF were both significantly associated with SU. FSF had a greater impact on the use of most substances than did ESF. The FSF with the strongest association with SU was lack of parental monitoring. Regarding ESF, the cumulative number of stressful external events had a higher impact on SU than previous physical or sexual assault by a stranger. In contrast, physical or sexual assault by a family member was not found to be associated with subsequent SU. These findings have important implications for SU prevention programmes focusing on male teenagers, as it is difficult to screen and intervene in subtle forms of maltreatment in families.

Prediction of Possible Biomarkers and Novel Pathways Conferring Risk to Post-Traumatic Stress Disorder

Post-traumatic stress disorder is one of the common mental ailments that is triggered by exposure to traumatic events. Till date, the molecular factors conferring risk to the development of PTSD is not well understood. In this study, we have conducted a meta-analysis followed by hierarchical clustering and functional enrichment, to uncover the potential molecular networks and critical genes which play an important role in PTSD. Two datasets of expression profiles from Peripheral Blood Mononuclear Cells from 62 control samples and 63 PTSD samples were included in our study. In PTSD samples of GSE860 dataset, we identified 26 genes informative when compared with Post-deploy PTSD condition and 58 genes informative when compared with Pre-deploy and Post-deploy PTSD of GSE63878 dataset. We conducted the meta-analysis using Fisher, roP, Stouffer, AW, SR, PR and RP methods in MetaDE package. Results from the rOP method of MetaDE package showed that among these genes, the following showed significant changes including, OR2B6, SOX21, MOBP, IL15, PTPRK, PPBPP2 and SEC14L5. Gene ontology analysis revealed enrichment of these significant PTSD-related genes for cell proliferation, DNA damage and repair (p-value ≤ 0.05). Furthermore, interaction network analysis was performed on these 7 significant genes. This analysis revealed highly connected functional interaction networks with two candidate genes, IL15 and SEC14L5 highly enriched in networks. Overall, from these results, we concluded that these genes can be recommended as some of the potential targets for PTSD.

Posttraumatic Stress Disorder: Perspectives for the Use of Deep Brain Stimulation

OBJECTIVES

Deep Brain Stimulation (DBS) has been either approved or is currently under investigation for a number of psychiatric disorders.

MATERIALS AND METHODS

We review clinical and preclinical concepts as well as the neurocircuitry that may be of relevance for the implementation of DBS in posttraumatic stress disorder (PTSD).

RESULTS

PTSD is a chronic and debilitating illness associated with dysfunction in well-established neural circuits, including the amygdala and prefrontal cortex. Although most patients often improve with medications and/or psychotherapy, approximately 20-30% are considered to be refractory to conventional treatments. In other psychiatric disorders, DBS has been investigated in treatment-refractory patients. To date, preclinical work suggests that stimulation at high frequency delivered at particular timeframes to different targets, including the amygdala, ventral striatum, hippocampus, and prefrontal cortex may improve fear extinction and anxiety-like behavior in rodents. In the only clinical report published so far, a patient implanted with electrodes in the amygdala has shown striking improvements in PTSD symptoms.

CONCLUSIONS

Neuroimaging, preclinical, and preliminary clinical data suggest that the use of DBS for the treatment of PTSD may be practical but the field requires further investigation.

Neuronal networks in mental diseases and neuropathic pain: Beyond brain derived neurotrophic factor and collapsin response mediator proteins

The brain is a complex network system that has the capacity to support emotion, thought, action, learning and memory, and is characterized by constant activity, constant structural remodeling, and constant attempt to compensate for this remodeling. The basic insight that emerges from complex network organization is that substantively different networks can share common key organizational principles. Moreover, the interdependence of network organization and behavior has been successfully demonstrated for several specific tasks. From this viewpoint, increasing experimental/clinical observations suggest that mental disorders are neural network disorders. On one hand, single psychiatric disorders arise from multiple, multifactorial molecular and cellular structural/functional alterations spreading throughout local/global circuits leading to multifaceted and heterogeneous clinical symptoms. On the other hand, various mental diseases may share functional deficits across the same neural circuit as reflected in the overlap of symptoms throughout clinical diagnoses. An integrated framework including experimental measures and clinical observations will be necessary to formulate a coherent and comprehensive understanding of how neural connectivity mediates and constraints the phenotypic expression of psychiatric disorders.

The Association Between Genetic Variants in the Dopaminergic System and Posttraumatic Stress Disorder: A Meta-Analysis

Posttraumatic stress disorder (PTSD) is a complex mental disorder and can severely interfere with the normal life of the affected people. Previous studies have examined the association of PTSD with genetic variants in multiple dopaminergic genes with inconsistent results. To perform a systematic literature search and conduct meta-analysis to examine whether genetic variants in the dopaminergic system is associated with PTSD. Data Sources: PubMed, Cochrane Library, Embase, Google Scholar, and HuGE. Study eligibility criteria and participants: The studies included subjects who had been screened for the presence of PTSD; the studies provided data for genetic variants of genes involved in the dopaminergic system; the outcomes of interest included diagnosis status of PTSD; and the studies were case-control studies. Study appraisal and synthesis methods: Odds ratio was used as a measure of association. We used random-effects model in all the meta-analyses. Between-study heterogeneity was assessed using I², and publication bias was evaluated using Egger test. Findings from meta-analyses were confirmed using random-effects meta-analyses under the framework of generalized linear model (GLM). A total of 19 studies met the eligibility criteria and were included in our analyses. We found that rs1800497 in DRD2 was significantly associated with PTSD (OR = 1.96, 95% CI: 1.15-3.33; P = 0.014). The 3'-UTR variable number tandem repeat (VNTR) in SLC6A3 also showed significant association with PTSD (OR = 1.62, 95% CI: 1.12-2.35; P = 0.010), but there was no association of rs4680 in COMT with PTSD (P = 0.595). Sample size is limited for some studies; type and severity of traumatic events varied across studies; we could not control for potential confounding factors, such as age at traumatic events and gender; and we could not examine gene-environment interaction due to lack of data. We found that rs1800497 in DRD2 and the VNTR in SLC6A3 showed significant association with PTSD. Future studies controlling for confounding factors, with large sample sizes and more homogeneous traumatic exposure, are needed to validate the findings from this study.

Does BDNF Val66Met Polymorphism Confer Risk for Posttraumatic Stress Disorder?

BACKGROUND

Evidence has indicated that BDNF (brain-derived neurotrophic factor) Val66Met genetic variant could be linked to the development of posttraumatic stress disorder (PTSD). However, clinical observations studying the BDNF polymorphism and the risk of PTSD yielded contradictory results. In this meta-analysis we evaluated the association between BDNF Val66Met and PTSD risk.

METHOD

Systematic searches in online databases retrieved 6 relevant publications. Different inherited models were utilized to perform the pooled analysis. Subgroup analyses and sensitive analyses based on Hardy-Weinberg equilibrium (HWE) test results were also carried out.

RESULTS

Our study did not found a significant overall effect of BDNF Val66Met on the susceptibility to PTSD under various genetic models. In contrast, subgroup analyses suggested that the stress status of the control group, but not ethnicity, may influence the relationship of BDNF Val66Met with PTSD risk. After the exclusion of a study that was not in HWE, our conclusions remained unchanged during the influence analyses.

CONCLUSIONS

This meta-analysis suggested no genetic association of BDNF Val66Met with vulnerability to PTSD. Further research studies are warranted to clarify the impact of BDNF variants on the occurrence of PTSD.

Sleep and REM sleep disturbance in the pathophysiology of PTSD: the role of extinction memory

Post-traumatic stress disorder (PTSD) is accompanied by disturbed sleep and an impaired ability to learn and remember extinction of conditioned fear. Following a traumatic event, the full spectrum of PTSD symptoms typically requires several months to develop. During this time, sleep disturbances such as insomnia, nightmares, and fragmented rapid eye movement sleep predict later development of PTSD symptoms. Only a minority of individuals exposed to trauma go on to develop PTSD. We hypothesize that sleep disturbance resulting from an acute trauma, or predating the traumatic experience, may contribute to the etiology of PTSD. Because symptoms can worsen over time, we suggest that continued sleep disturbances can also maintain and exacerbate PTSD. Sleep disturbance may result in failure of extinction memory to persist and generalize, and we suggest that this constitutes one, non-exclusive mechanism by which poor sleep contributes to the development and perpetuation of PTSD. Also reviewed are neuroendocrine systems that show abnormalities in PTSD, and in which stress responses and sleep disturbance potentially produce synergistic effects that interfere with extinction learning and memory. Preliminary evidence that insomnia alone can disrupt sleep-dependent emotional processes including consolidation of extinction memory is also discussed. We suggest that optimizing sleep quality following trauma, and even strategically timing sleep to strengthen extinction memories therapeutically instantiated during exposure therapy, may allow sleep itself to be recruited in the treatment of PTSD and other trauma and stress-related disorders.

The Comorbidity of PTSD and MDD: Implications for Clinical Practice and Future Research

The high prevalence of post-traumatic stress disorder (PTSD) and major depressive disorder (MDD) comorbidity is well established, with comorbidity rates often between 30 and 50%. However, despite the high prevalence of this comorbidity, very few researchers have explored specific treatments for individuals who present with comorbid PTSD and MDD. Further, there has not been explicit examination of the mechanisms through which MDD influences trauma-focused therapy. As individuals with comorbid PTSD and MDD often present with a more chronic course of impairment and in some instances, a more delayed response to treatment, the need for such research is imperative. It will be proposed that there is merit in targeting depression within the treatment of comorbid PTSD and MDD. Accordingly, in this article we review explanations for the high PTSD and MDD comorbid relationship and highlight variables likely to explain such comorbidity. Theoretical accounts for how depression impedes optimal recovery from PTSD and the associated empirical findings are illustrated. We consequently argue that there is a need to develop and test treatments that target both PTSD and MDD symptoms. Directions for future research are highlighted.

Anxiolytic effects of ketamine in animal models of posttraumatic stress disorder

This study investigated the effectiveness of ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, in alleviating the enhanced anxiety and fear response in both a mouse model of PTSD induced by inescapable electric foot shocks and a rat model of PTSD induced by a time-dependent sensitization (TDS) procedure. First, we evaluated the effect of ketamine on behavioral deficits in a mouse model of PTSD that consisted of foot shocks followed by three situational reminders. Our results showed that the aversive procedure induced several behavioral deficiencies, such as increased freezing behavior and anxiety, as well as reduced time spent in an aversive-like context, which were reversed by repeated treatment with ketamine. The effect of ketamine on behavioral changes after exposure to TDS was also investigated, and the levels of brain-derived neurotrophic factor (BDNF) in the hippocampus were measured. The results revealed that after TDS, the rats showed a significant increase in contextual freezing and a decrease in the percentage of time spent in and numbers of entries into open arms in the elevated plus maze test. As a positive control drug, sertraline (Ser, 15 mg/kg, i.g.), a selective serotonin reuptake inhibitor (SSRI) ameliorated these behavioral deficits. These behavioral effects were mimicked by chronic ketamine treatment. Furthermore, ketamine normalized the decreased BDNF level in the hippocampus in post-TDS rats. Taken together, these results suggest that ketamine exerts a therapeutic effect on PTSD that might be at least partially mediated by an influence on BDNF signaling in the hippocampus.

Trauma Management Therapy for a Veteran With Co-Occurring Combat PTSD and Hallucinations

Despite the development of evidence-based treatment protocols for posttraumatic stress disorder (PTSD), many clinicians are hesitant to begin trauma-focused treatment for individuals presenting with co-occurring conditions, particularly disorders with psychotic features. The current clinical case describes the treatment of a male veteran with PTSD with hallucinogenic features and recurrent depression who was treated with Trauma Management Therapy, a comprehensive treatment program for combat-related PTSD incorporating virtual-reality assisted exposure therapy and group therapy. Following treatment, the veteran demonstrated clinically significant decreases in overall PTSD symptoms as well as combat-themed hallucinations. Treatment gains were maintained at the 3-month follow-up. This case illustrates how exposure therapy can safely and effectively be delivered to individuals with complex co-occurring conditions.

Baclofen add-on to citalopram in treatment of posttraumatic stress disorder

OBJECTIVE

Posttraumatic stress disorder (PTSD) is a chronic disabling illness, resulting from exposure to extreme traumatic event. Although different pharmacologic agents are suggested for treatment of PTSD, none have been completely effective in eliminating symptoms. The purpose of this study was to assess the use of baclofen as an add-on to citalopram in treatment of PTSD.

METHODS

In this double-blind clinical trial, 40 Iranian combat veterans with PTSD were randomly assigned to 2 groups. The first group received a combination treatment of 20 to 60 mg/d citalopram and 40 mg/d baclofen, and the second group received 20 to 60 mg/d citalopram plus placebo. Symptom severity was assessed by Clinician-Administered PTSD Scale at the beginning of the study and after 2, 4, 6, and 8 weeks. Global Assessment of Functioning and Hamilton Rating Scale for Anxiety and Depression were also used at the same periods. Data were analyzed with independent t test and paired t test using SPSS software version 13 (IBM, Armonk, NY).

RESULTS

Twenty-three male patients (baclofen group, 13 patients; placebo group, 10 patients) completed the study. Dropout from the treatment was not caused by adverse effects of the new medications in any of the subjects. Baclofen group showed significantly larger improvement in Clinician-Administered PTSD Scale total (P = 0.040), hyperarousal (P = 0.020), and avoidance (0.020) scores, Global Assessment of Functioning score (0.001), depression (P = 0.000), and anxiety (P = 0.000) after 8 weeks of treatment. No intergroup difference was found in improvement of reexperience symptoms (P = 0.740).

CONCLUSIONS

Baclofen showed to be an effective add-on to selective serotonin reuptake inhibitors in treatment of PTSD for better symptom recovery and functional improvement.

Affiliation buffers stress: cumulative genetic risk in oxytocin-vasopressin genes combines with early caregiving to predict PTSD in war-exposed young children

Research indicates that risk for post-traumatic stress disorder (PTSD) is shaped by the interaction between genetic vulnerability and early caregiving experiences; yet, caregiving has typically been assessed by adult retrospective accounts. Here, we employed a prospective longitudinal design with real-time observations of early caregiving combined with assessment of genetic liability along the axis of vasopressin-oxytocin (OT) gene pathways to test G × E contributions to PTSD. Participants were 232 young Israeli children (1.5-5 years) and their parents, including 148 living in zones of continuous war and 84 controls. A cumulative genetic risk factor was computed for each family member by summing five risk alleles across three genes (OXTR, CD38 and AVPR1a) previously associated with psychopathology, sociality and caregiving. Child PTSD was diagnosed and mother-child interactions were observed in multiple contexts. In middle childhood (7-8 years), child psychopathology was re-evaluated. War exposure increased propensity to develop Axis-I disorder by threefold: 60% of exposed children displayed a psychiatric disorder by middle childhood and 62% of those showed several comorbid disorders. On the other hand, maternal sensitive support reduced risk for psychopathology. G × E effect was found for child genetic risk: in the context of war exposure, greater genetic risk on the vasopressin-OT pathway increased propensity for psychopathology. Among exposed children, chronicity of PTSD from early to middle childhood was related to higher child, maternal and paternal genetic risk, low maternal support and greater initial avoidance symptoms. Child avoidance was predicted by low maternal support and reduced mother-child reciprocity. These findings underscore the saliency of both genetic and behavioral facets of the human affiliation system in shaping vulnerability to PTSD as well as providing an underlying mechanism of post-traumatic resilience.

Genetic approaches to understanding post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is increasingly recognized as both a disorder of enormous mental health and societal burden, but also as an anxiety disorder that may be particularly understandable from a scientific perspective. Specifically, PTSD can be conceptualized as a disorder of fear and stress dysregulation, and the neural circuitry underlying these pathways in both animals and humans are becoming increasingly well understood. Furthermore, PTSD is the only disorder in psychiatry in which the initiating factor, the trauma exposure, can be identified. Thus, the pathophysiology of the fear and stress response underlying PTSD can be examined and potentially interrupted. Twin studies have shown that the development of PTSD following a trauma is heritable, and that genetic risk factors may account for up to 30-40% of this heritability. A current goal is to understand the gene pathways that are associated with PTSD, and how those genes act on the fear/stress circuitry to mediate risk vs. resilience for PTSD. This review will examine gene pathways that have recently been analysed, primarily through candidate gene studies (including neuroimaging studies of candidate genes), in addition to genome-wide associations and the epigenetic regulation of PTSD. Future and on-going studies are utilizing larger and collaborative cohorts to identify novel gene candidates through genome-wide association and other powerful genomic approaches. Identification of PTSD biological pathways strengthens the hope of progress in the mechanistic understanding of a model psychiatric disorder and allows for the development of targeted treatments and interventions.

A review on the evidence of transgenerational transmission of posttraumatic stress disorder vulnerability

OBJECTIVE

To understand the risks of posttraumatic stress disorder (PTSD) development in the next generation of PTSD patients, we conducted a review on the biological, but not genetic, evidence of transgenerational transmission of PTSD vulnerability.

METHODS

Pertinent articles published from 1985 to September 2011 were searched using online academic search engines, including MEDLINE, EMBASE, ScienceDirect, OVID, PsycLIT, and SCOPUS, and a non-systematic review was conducted.

RESULTS

There is paradoxical evidence that hypothalamic-pituitary-adrenal axis changes in PTSD patients may also be evident in their offspring. This effect and biological vulnerability to PTSD may be transmitted across generations through maternal epigenetic programming during pregnancy. The samples of most studies, which were not large enough and represented the outcome of few research groups, consisted of a specific type of patients with a particular trauma.

CONCLUSIONS

There is still a need to conduct studies in other geographical areas with different genetic background and larger samples considering different types of trauma other than those specified in the current literature, so as to strengthen the evidence of transgenerational transmission of PTSD vulnerability.

The 5-HTTLPR polymorphism and posttraumatic stress disorder: a meta-analysis

Environmental and genetic factors contribute to the development of posttraumatic stress disorder (PTSD). Variation in the 5-HTTLPR polymorphism of the serotonin transporter gene has been hypothesized to affect risk for PTSD. With the aim of investigating this association, we conducted a meta-analysis to shed light on prior controversial results and increase statistical power to detect smaller effect sizes. PubMed and ISI databases were searched for studies published until December 2012. Twelve studies have been included, all based on trauma-exposed samples. Data were analyzed with Cochrane Collaboration Review Manager Software (Version 5). Quality and publication bias were assessed. Metaregressions were performed using Comprehensive Meta-Analysis software, Version 2. Taking into account all studies, no association was found between 5-HTTLPR and PTSD (p = .10), with evidence of between-study heterogeneity, which could be partly explained by gender differences. In sensitivity analyses, we found an association between SS genotype and PTSD in high trauma-exposed participants (p < .001). To be a carrier of the SS genotype seems to represent a risk factor for PTSD in high trauma exposure. Further studies focusing on Gene × Environment interactions are needed to better understand the role of this polymorphism in PTSD.

Persistent fear of aftershocks, impairment of working memory, and acute stress disorder predict post-traumatic stress disorder: 6-month follow-up of help seekers following the L'Aquila earthquake

The aim of our 6-month follow-up study was to assess predictors of post-traumatic stress disorder (PTSD) among individuals seeking treatment at the General Hospital Psychiatric Unit within the first month following the L'Aquila earthquake. Clinical, trauma-related and neurocognitive variables were considered. At the 6-month follow-up, 91 (74.5%) out of 122 subjects were re-assessed and administered the Impact of Events Scale-revised (IES-R) for the detection of PTSD according to DSM-IV criteria. Within 4 weeks following the earthquake, patients were assessed with a checklist of traumatic-event-related variables, along with the Stanford Acute Stress Disorder Questionnaire (SASDQ) for the detection of ASD, with a short battery on working (Wechler Memory Scale-R, Digit Forward and Backward) and verbal memory (subtest of Milan Overall Dementia Assessment, MODA). A statistically significant higher proportion of subjects affected by 'partial' ASD showed a PTSD diagnosis (80.6%, N = 29) compared to not diagnosed subjects (40%, N = 22) and a PTSD diagnosis was shown by all the 4 subjects (4.4%) affected by 'full' ASD at the entry in the study. At the 6-month follow-up 56% of the sample could be considered affected by PTSD on the IES-R scale. The results of the logistic regression analysis on our selected predictors indicated that the persistent fear of aftershocks seemed to increase by over 57 times the likelihood of positive estimate of PTSD, followed by impairment of working memory backward (OR 48.2), and having being diagnosed as ASD case in the first 4 week after the earthquake (OR 17.4). This study underlines the importance of identifying PTSD predictors, in order to planning early treatment interventions after natural disasters.