Cavum septum pellucidum in monozygotic twins discordant for combat exposure: relationship to posttraumatic stress disorder

Management of Pediatric Cavum Cysts: A Scoping Review and a Single Institution Case Series

INTRODUCTION

Pediatric cavum cysts are a rare yet complicated pathology to manage. The literature is scarce, primarily consisting of case series, and lacking a consensus regarding clear management. In this scoping review, we aimed to compile existing information in the literature regarding the management of pediatric cavum cysts across the last 10 years. We also present our management of 19 patients, the largest case series to date, highlighting knowledge gaps surrounding the management of this salient pathology.

METHODS

A literature search using PubMed and SCOPUS was conducted using the following search terms: (pediatric) AND (Cavum septum pellucidum) OR (cavum vergae) OR (cavum velum interpositum) AND (management). Eligibility criteria included peer-reviewed publication published in the last 10 years, pediatric population, cavum cyst, and English language. A retrospective search was conducted for all pediatric cavum cysts between 2013 and 2023 at our institution. Clinical and radiographic characteristics as well as intervention and outcome data were collected for both the scoping review and our cases.

RESULTS

330 total articles were populated using our search. 12 articles met our inclusion criteria. 41.7% (n = 5) of the articles were case series, 33.3% (n = 4) were case reports, 8.3% (n = 1) was a technical article, 8.3% (n = 1) was a systematic review, and 8.3% (n = 1) was a case questionnaire. Resolution of symptoms was noted in all articles of our scoping review, regardless of treatment modality. The average age in our case series was 9.84 years old and average age at diagnosis was 5.53 years old. 6 patients (31.6%) were female and 13 patients (68.4%) were male. 2 out of the 19 patients (10.5%) were surgically treated.

CONCLUSION

There is no clear consensus on the management of cavum cysts. A prospective, multicenter study is needed to create standardized pediatric cyst management guidelines. The current thought is that surgical intervention should be saved for those patients with obstructive hydrocephalus and signs of intracranial hypertension.

Gray matter differences in adults and children with posttraumatic stress disorder: A systematic review and meta-analysis of 113 studies and 11 meta-analyses

BACKGROUND

In this systematic review and meta-analysis, we aimed to provide a comprehensive overview of gray matter alterations of adult- and underage patients with posttraumatic stress disorder (PTSD) in comparison to healthy trauma-exposed (TC) and non-exposed (HC) individuals.

METHODS

We subdivided our groups into patients with PTSD after trauma exposure in adulthood (aa) or childhood (ac) as well as children with PTSD (cc). We identified 113 studies, including 6.800 participants in our review, which we divided into studies focusing on whole-brain and region-of-interest (ROI) analysis. We performed a coordinate-based meta-analysis on 14 studies in the group of aa-PTSD.

RESULTS

We and found lower gray matter volume in patients with PTSD (aa) in the medial frontal gyrus (PTSD<HC/TC) and Culmen/posterior cingulate cortex (PTSD<TC). Results from ROI-based studies mainly show alterations for patients with PTSD in the prefrontal cortex, hippocampus, anterior cingulate cortex, insula, corpus callosum, and amygdala.

LIMITATIONS

Due to a limited number of studies reporting whole-brain results, the meta-analyses could only be performed in one subgroup and within this subgroup for a limited number of studies.

CONCLUSIONS

Our results are in line with psychobiological models of PTSD that associate the identified regions with brain circuits involved in context processing, threat detection and emotion regulation.

Right parahippocampal volume deficit in an older population with posttraumatic stress disorder

BACKGROUND

Posttraumatic Stress Disorder (PTSD) is an increasingly prevalent condition among older adults and may escalate further as the general population including veterans from recent conflicts grow older. Despite growing evidence of higher medical comorbidity, cognitive impairment and dementia, and disability in older individuals with PTSD, there are very few studies examining brain cortical structure in this population. Hence, we examined cortical volumes in a cross-sectional study of veterans and civilians aged ≥50 years, of both sexes and exposed to trauma (interpersonal, combat, non-interpersonal).

METHODS

Cortical volumes were obtained from T1-weighted structural MRI and compared between individuals with PTSD and Trauma Exposed Healthy Controls (TEHC) adjusting for age, sex, estimated intracranial volume, depression severity, and time elapsed since trauma exposure.

RESULTS

The PTSD group (N = 55) had smaller right parahippocampal gyrus compared to TEHC (N = 36), corrected p(p_FWER) = 0.034, with an effect size of 0.75 (Cohen's d), with no significant group differences in other cortical areas.

CONCLUSIONS

These findings are different from the structural brain findings reported in studies in younger age groups (larger parahippocampal volume in PTSD patients), suggesting a possible significant change in brain structure as PTSD patients age. These results need replication in longitudinal studies across the age-span to test whether they are neuroanatomical markers representing disease vulnerability, trauma resilience or pathological neurodegeneration associated with cognitive impairment and dementia.

Neuroanatomical Risk Factors for Posttraumatic Stress Disorder in Recent Trauma Survivors

BACKGROUND

Low hippocampal volume could serve as an early risk factor for posttraumatic stress disorder (PTSD) in interaction with other brain anomalies of developmental origin. One such anomaly may well be the presence of a large cavum septum pellucidum (CSP), which has been loosely associated with PTSD. We performed a longitudinal prospective study of recent trauma survivors. We hypothesized that at 1 month after trauma exposure the relation between hippocampal volume and PTSD symptom severity will be moderated by CSP volume, and that this early interaction will account for persistent PTSD symptoms at subsequent time points.

METHODS

One hundred seventy-one adults (87 women, average age 34.22 years [range, 18-65 years of age]) who were admitted to a general hospital's emergency department after a traumatic event underwent clinical assessment and structural magnetic resonance imaging within 1 month after trauma. Follow-up clinical evaluations were conducted at 6 (n = 97) and 14 (n = 78) months after trauma. Hippocampal and CSP volumes were measured automatically by FreeSurfer software and verified manually by a neuroradiologist (D.N.).

RESULTS

At 1 month after trauma, CSP volume significantly moderated the relation between hippocampal volume and PTSD severity (p = .026), and this interaction further predicted symptom severity at 14 months posttrauma (p = .018). Specifically, individuals with a smaller hippocampus and larger CSP at 1 month posttrauma showed more severe symptoms at 1 and 14 months after trauma exposure.

CONCLUSIONS

Our study provides evidence for an early neuroanatomical risk factors for PTSD, which could also predict the progression of the disorder in the year after trauma exposure. Such a simple-to-acquire neuroanatomical signature for PTSD could guide early management as well as long-term monitoring.

The relationship between cavum septum pellucidum and psychopathic traits in female offenders

Cavum Septum Pellucidum (CSP) is a common anatomical variant of the septum pellucidum. CSP is considered a marker for abnormal limbic brain development, but its functional consequences are non-specific. In a recent report (Crooks et al., 2018), CSP size was significantly positively correlated with the affective/interpersonal traits of psychopathy in male offenders (N = 1742). Here we test the hypothesis that CSP is related to psychopathic traits in incarcerated females (N = 355). We examine continuous relationships as well as categorical assignments for CSP size corresponding to a number of prior reports. We also compare female offenders to healthy female controls (N = 385). Consistent with our reported findings in males, a positive association was observed between the interpersonal psychopathic traits and CSP size. In contrast to findings among males, an association between CSP and antisocial psychopathic traits was apparent in females. There was no significant difference in CSP size (in mm) or CSP presence/absence between incarcerated and non-incarcarated groups. However, categorical rates of medium and large CSP were more common in female inmates than in controls. This is the first systematic investigation of these variables in a female inmate sample. In combination with our prior study, these findings demonstrate that limbic abnormalities, as indexed by CSP, are related to psychopathic traits in both female and male inmates.

The relationship between cavum septum pellucidum and psychopathic traits in a large forensic sample

Cavum septum pellucidum (CSP) is a neuroanatomical variant of the septum pellucidum that is considered a marker for disrupted brain development. Several small sample studies have reported CSP to be related to disruptive behavior, persistent antisocial traits, and even psychopathy. However, no large-scale samples have comprehensively examined the relationship between CSP, psychopathic traits, and antisocial behavior in forensic samples. Here we test hypotheses about the presence of CSP and its relationship to psychopathic traits in incarcerated males (N = 1432). We also examined the incidence of CSP in two non-incarcerated male control samples for comparison (N = 208 and 125). Ethnic and racial composition was varied with a mean age of 33.1, and an average IQ of 96.96. CSP was evaluated via structural magnetic resonance imaging. CSP was measured by length (number of 1.0 mm slices) in continuous analyses, and classified as absent (0) or present (1+ mm), as well as by size (absent (0), small (1-3), medium (4-5), or large (6+ mm)) for comparison with prior work. The Wechsler Adult Intelligence Scale (WAIS-III), Structured Clinical Interview (SCID-I/P), and Hare Psychopathy Checklist-Revised (PCL-R) were used to assess IQ, substance dependence, and psychopathy, respectively. CSP length was positively associated with PCL-R total, Factor 1 (interpersonal/affective) and Facets 1 (interpersonal) and 2 (affective). CSP was no more prevalent among inmates than among non-incarcerated controls, with similar distributions of size. These results support the hypotheses that abnormal septal/limbic development may contribute to dimensional affective/interpersonal traits of psychopathy, but CSP is not closely associated with antisocial behavior, per se.

Enlarged Cavum Septi Pellucidi and Vergae in the Fetus: A Cause for Concern

OBJECTIVES

To investigate fetal cases identified at our institution to determine whether an enlarged cavum septi pellucidi or cavum vergae is associated with other fetal abnormalities and whether its presence warrants more detailed investigation of the fetus.

METHODS

In a retrospective study, 15 high- and low-risk patients undergoing prenatal sonography who had an enlarged cavum septi pellucidi or cavum vergae identified were reviewed. Data were collected for the sonographic study indication, gestation age at diagnosis of a prominent cavum, and associated anomalies. Follow-up outcome data regarding further imaging, karyotype, diagnosis of brain anomaly, and associated congenital abnormalities were obtained.

RESULTS

Fifteen patients met the inclusion criteria. Nine patients were identified as having a prominent cavum septi pellucidi, and 6 were identified as having a prominent cavum vergae. The mean gestational age ± SD was 22.7 ± 5.9 weeks. Eleven patients made it to delivery. Of the 15 patients, 4 were thought to have trisomy 21, and 13 had congenital anomalies. Outcomes included 10 major adverse outcomes, 4 cases with normal development or minor abnormalities, and 1 lost to follow-up. An isolated dilated cavum on prenatal sonography was seen in 5 cases: 1 with lissencephaly on a neonatal examination, 3 premature deliveries (1 demise, 1 hospice, and 1 normal), and 1 unknown.

CONCLUSIONS

Our cohort had many associated clinical anomalies: 3 confirmed trisomy 21 and 1 probable trisomy 21, 2 genetic disorders, and 10 major adverse outcomes, 5 of which were grave. Although we studied a small cohort, we conclude that an enlarged cavum septi pellucidi or cavum vergae warrants consideration of genetic counseling, which may include noninvasive prenatal testing (cell-free DNA), amniocentesis with microarray testing, or both.

Incidental radiologic findings in the 22q11.2 deletion syndrome

BACKGROUND AND PURPOSE

The 22q11.2 deletion syndrome is a common genetic microdeletion syndrome that results in cognitive delays and an increased risk of several psychiatric disorders, particularly schizophrenia. The current study investigates the prevalence of incidental neuroradiologic findings within this population and their relationships with psychiatric conditions.

MATERIALS AND METHODS

Brain MR imaging from 58 individuals with 22q11.2 deletion syndrome was reviewed by board-certified radiologists by using standard clinical procedures. Intracranial incidental findings were classified into 8 categories and compared with a large typically developing cohort.

RESULTS

The rate of incidental findings was significantly higher (P < .0001) in 22q11.2 deletion syndrome compared with typically developing individuals, driven by a high prevalence of cavum septum pellucidum (19.0%) and white matter abnormalities (10.3%). Both of these findings were associated with psychosis in 22q11.2 deletion syndrome.

CONCLUSIONS

Cavum septum pellucidum and white matter hyperintensities are significantly more prevalent in patients with the 22q11.2 deletion syndrome and may represent biomarkers for psychosis.

Enlarged cavum septum pellucidum as a neurodevelopmental marker in adolescent-onset opiate dependence

Objective

Adolescent-onset exposure to highly addictive substances such as opiates may induce far-reaching deleterious effects on later mental and physical health. However, little is known about the neurodevelopmental basis for adolescent-onset opiate dependence. Here we examined whether having an abnormally large cavum septum pellucidum (CSP), a putative marker of limbic structural maldevelopment, is associated with opiate dependence particularly beginning in adolescence.

Method

The overall length of the CSP and the prevalence of abnormal enlargement of the CSP were assessed and compared in 65 opiate-dependent subjects (41 adolescent-onset opiate users and 24 adult-onset opiate users) and 67 healthy subjects.

Results

Opiate-dependent subjects showed a greater prevalence of abnormal CSP enlargement relative to healthy subjects (odds ratio [OR]=3.64, p=0.034). The overall CSP length of adolescent-onset opiate-dependent subjects was greater, as compared not only with healthy subjects (F_1,104=11.03, p=0.001) but also with those who began opiate use during adulthood (F_1,61=4.43, p=0.039).

Conclusions

The current findings provide the first evidence that abnormal CSP enlargement, which reflects limbic system dysgenesis of neurodevelopmental origin, may be linked to later development of opiate dependence. In addition, a greater CSP length, which indicates more severe limbic abnormalities, appears to confer higher risk for earlier onset of opiate use.

The neurobiology of psychopathic traits in youths

Conduct disorder is a childhood behaviour disorder that is characterized by persistent aggressive or antisocial behaviour that disrupts the child's environment and impairs his or her functioning. A proportion of children with conduct disorder have psychopathic traits. Psychopathic traits consist of a callous-unemotional component and an impulsive-antisocial component, which are associated with two core impairments. The first is a reduced empathic response to the distress of other individuals, which primarily reflects reduced amygdala responsiveness to distress cues; the second is deficits in decision making and in reinforcement learning, which reflects dysfunction in the ventromedial prefrontal cortex and striatum. Genetic and prenatal factors contribute to the abnormal development of these neural systems, and social-environmental variables that affect motivation influence the probability that antisocial behaviour will be subsequently displayed.

Neuroimaging resilience to stress: a review

There is a high degree of intra-individual variation in how individuals respond to stress. This becomes evident when exploring the development of posttraumatic symptoms or stress-related disorders after exposure to trauma. Whether or not an individual develops posttraumatic symptoms after experiencing a traumatic event is partly dependent on a person's resilience. Resilience can be broadly defined as the dynamic process encompassing positive adaptation within the context of significant adversity. Even though research into the neurobiological basis of resilience is still in its early stages, these insights can have important implications for the prevention and treatment of stress-related disorders. Neuroimaging studies contribute to our knowledge of intra-individual variability in resilience and the development of posttraumatic symptoms or other stress-related disorders. This review provides an overview of neuroimaging findings related to resilience. Structural, resting-state, and task-related neuroimaging results associated with resilience are discussed. There are a limited number of studies available and neuroimaging research of resilience is still in its infancy. The available studies point at brain circuitries involved in stress and emotion regulation, with more efficient processing and regulation associated with resilience.

The relationship between large cavum septum pellucidum and antisocial behavior, callous-unemotional traits and psychopathy in adolescents

BACKGROUND

The presence of a large cavum septum pellucidum (CSP) has been previously associated with antisocial behavior/psychopathic traits in an adult community sample.

AIMS

The current study investigated the relationship between a large CSP and symptom severity in disruptive behavior disorders (DBD; conduct disorder and oppositional defiant disorder).

METHOD

Structural MRI scans of youth with DBDs (N = 32) and healthy comparison youth (N = 27) were examined for the presence of a large CSP and if this was related to symptom severity.

RESULTS

Replicating previous results, a large CSP was associated with DBD diagnosis, proactive aggression, and level of psychopathic traits in youth. However, the presence of a large CSP was unrelated to aggression or psychopathic traits within the DBD sample.

CONCLUSIONS

Early brain mal-development may increase the risk of a DBD diagnosis, but does not mark a particularly severe form of DBD within patients receiving these diagnoses.

Prevalence of and factors associated with subclinical posttraumatic stress symptoms and PTSD in urban and rural areas of Montana: a cross-sectional study

PURPOSE

Posttraumatic stress disorder (PTSD) is an important clinical problem, but little is known about PTSD in rural, nonclinical populations. To better understand PTSD in rural areas, we examined the prevalence and risk and protective factors in urban, rural, and highly rural communities in Montana for both subclinical posttraumatic stress symptoms (PTSS) and PTSD.

METHODS

We compared the prevalence of PTSS and PTSD in urban, rural, and highly rural communities in bivariate and multivariable regression analyses using self-reported cross-sectional survey data from the Montana Health Matters study (N = 3,512), a state-representative household-based survey done in 2010-2011. We also explore potential risk and protective factors for PTSS and PTSD and whether risk and protective factors for each differ by rurality.

FINDINGS

There were no differences in the level of PTSS by rurality in bivariate or multivariate models, and the bivariate relationship between rurality and PTSD became nonsignificant in a multivariate model. Only locus of control was predictive for PTSS; however, gender, age, marital status, income, employment status, community fit, locus of control, and religiosity were associated with PTSD. Some risk and protective factors operate differently by rurality.

CONCLUSIONS

Although our findings are subject to weaknesses common to cross-sectional data and are based on questionnaire reports, it appears that there are different risk and protective factors for PTSS and PTSD, suggesting that PTSD may be qualitatively different from PTSS. Furthermore, differences in risk and protective factors across urban and rural communities suggest more attention is needed to understand PTSD in rural communities.

Cavum velum interpositum, cavum septum pellucidum, and cavum vergae: a review

INTRODUCTION

Anterior midline intracranial cysts may be found most often in three forms: cavum septum pellucidum, cavum vergae, and cavum velum interpositum. A single offering that reviews these entities is difficult to find in the extant literature. Therefore, the present review was performed.

MATERIALS AND METHODS

Various search engines and germane texts were reviewed for the terms cavum septum pellucidum, cavum vergae, and cavum velum interpositum.

RESULTS

We report the findings of our search of the literature regarding these midline cystic structures.

CONCLUSIONS

A better understanding of the associated anatomy, embryology, and pathology of these cysts will assist the clinician who treats such patients.

Twin studies of posttraumatic stress disorder: differentiating vulnerability factors from sequelae

Posttraumatic stress disorder (PTSD) is defined by one's response to an environmental event. However, genetic factors are important in determining people's response to that event, and even their likelihood of being exposed to particular traumatic events in the first place. Classical twin designs can decompose genetic and environmental sources of variance. Such studies are reviewed extensively elsewhere, and we cover them only briefly in this review. Instead, we focus primarily on the identical co-twin control design. This design makes it possible to resolve the "chicken-egg" dilemma inherent in standard case-control designs, namely, distinguishing risk from sequelae. Abnormalities that are present in both the twin with PTSD and the unaffected co-twin suggest pre-existing vulnerability indicators. These include smaller hippocampal volume, large cavum septum pellucidum, more neurological soft signs, lower general intellectual ability, and poorer performance in the specific cognitive abilities of executive function, attention, declarative memory, and processing of contextual cues. In contrast, abnormalities in a twin with PTSD that are not present in the identical co-twin suggest consequences of PTSD or trauma exposure. These include psychophysiological responding, higher resting anterior cingulate metabolism, event-related potential abnormalities associated with attentional processes, recall intrusions, and possibly some types of chronic pain. Most co-twin control studies of PTSD have been small and come from the same twin registry of middle-aged male veterans. Consequently, there is a great need for replication and extension of the findings, particularly in women and younger individuals. The creation of new twin registries would do much toward accomplishing this goal. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Neurodevelopmental marker for limbic maldevelopment in antisocial personality disorder and psychopathy

BACKGROUND

Antisocial personality disorder and psychopathy have been hypothesised to have a neurodevelopmental basis, but this proposition has not been formally tested.

AIMS

This study tests the hypothesis that individuals with cavum septum pellucidum (CSP), a marker of limbic neural maldevelopment, will show higher levels of psychopathy and antisocial personality.

METHOD

Cavum septum pellucidum was assessed using anatomical magnetic resonance imaging in a community sample. Those with CSP (n = 19) were compared with those lacking CSP (n = 68) on antisocial personality, psychopathy and criminal offending.

RESULTS

Those with CSP had significantly higher levels of antisocial personality, psychopathy, arrests and convictions compared with controls. The pervasiveness of this association was indicated by the fact that those lacking a diagnosis of antisocial personality disorder, but who were charged or convicted for an offence, had a more extensive CSP than non-antisocial controls. Results could not be attributed to prior trauma exposure, head injury, demographic factors or comorbid psychiatric conditions.

CONCLUSIONS

Our findings appear to be the first to provide evidence for a neurodevelopmental brain abnormality in those with antisocial personality disorder and psychopathy, and support the hypothesis that early maldevelopment of limbic and septal structures predisposes to the spectrum of antisocial behaviours.

Gray matter density in limbic and paralimbic cortices is associated with trauma load and EMDR outcome in PTSD patients

There is converging evidence of gray matter (GM) structural alterations in different limbic structures in Post-Traumatic Stress Disorder (PTSD) patients. The aim of this study was to evaluate GM density in PTSD in relation to trauma load, and to assess the GM differences between responders (R) and non-responders (NR) to EMDR therapy. Magnetic Resonance Imaging (MRI) scans of 21 subjects exposed to occupational trauma, who developed PTSD (S), and of 22 who did not (NS), were compared by means of an optimized Voxel-Based Morphometry (VBM) analysis as implemented in SPM. Within S, further comparisons were made between 10 R and 5 NR. A regression analysis between GM density and the Traumatic Antecedents Questionnaire (TAQ) was also performed on all 43 subjects. Results showed a significantly lower GM density in S as compared to NS in the left posterior cingulate and the left posterior parahippocampal gyrus. Moreover, NR showed a significantly lower GM density as compared to R in bilateral posterior cingulate, as well as anterior insula, anterior parahippocampal gyrus and amygdala in the right hemisphere. Regression analysis showed that GM density negatively correlated with trauma load in bilateral posterior cingulate, left anterior insula, and right anterior parahippocampal gyrus. In conclusion, a GM lower density in limbic and paralimbic cortices were found to be associated with PTSD diagnosis, trauma load, and EMDR treatment outcome, suggesting a view of PTSD characterized by memory and dissociative disturbances.

Magnetic resonance imaging volumes of the hippocampus in drug-naïve patients with post-traumatic stress disorder without comorbidity conditions

Most brain imaging studies have showed smaller hippocampal volume in adults with chronic PTSD; however, some other studies have not replicated this finding. Most of these investigations included subjects with other psychiatric comorbidities, such as major depression or alcohol abuse. The prevalence of psychiatric comorbidities in PTSD is generally high and this makes it difficult, if not impossible, to disentangle the contribution of other disorders to hippocampal volume. Therefore, the main goal of the current study is to compare hippocampal volumes of healthy subjects and drug-naïve patients with PTSD caused by different types of mixed civilian traumas (i.e. car accident, physical abuse, sudden death of a family member, assault or robbery, natural disaster and traumatic abortion) and without comorbidity conditions. Magnetic resonance imaging (MRI) was used to measure the hippocampi, total cerebrum, gray matter, white matter and cerebrospinal fluid volumes in 34 patients with single diagnosis of PTSD, and 34 case-matched non-PTSD comparison subjects. The patients with single diagnosis of PTSD had an 11.8% smaller left hippocampus (p<0.001) and an 8.7% smaller right hippocampus (p=0.003) than the healthy controls. The results were controlled for the total brain volume and for gray matter volumes. Subjects with PTSD also displayed lower overall gray matter volume (p=0.006). There were no significant correlations between hippocampal volumes and illness duration or severity of PTSD. The findings indicate the presence of smaller hippocampal volumes in drug-naïve patients with single diagnosis of PTSD, compared with healthy subjects.

Genetics of post-traumatic stress disorder: informing clinical conceptualizations and promoting future research

The purpose of this article is to provide an overview of genetic research involving post-traumatic stress disorder (PTSD). First, we summarize evidence for genetic influences on PTSD from family investigations. Second, we discuss the distinct contributions to our understanding of the genetics of PTSD permitted by twin studies. Finally, we summarize findings from molecular genetic studies, which have the potential to inform our understanding of underlying biological mechanisms for the development of PTSD.

Neuroimaging in posttraumatic stress disorder and other stress-related disorders

Traumatic stress has a broad range of effects on the brain. Brain areas implicated in the stress response include the amygdala, the hippocampus, and the prefrontal cortex. Studies in patients who have posttraumatic stress disorder (PTSD) and other psychiatric disorders related to stress have replicated findings in animal studies by finding alterations in these brain areas. Brain regions implicated in PTSD also play an important role in memory function, highlighting the important interplay between memory and the traumatic stress response. Abnormalities in these brain areas are hypothesized to underlie symptoms of PTSD and other stress-related psychiatric disorders.

Volumetric analysis of septal region in schizophrenia and affective disorder

MRI and post-mortem studies indicate an increased prevalence of cavum septi pellucidi (CSP) in schizophrenia and affective disorder. The aim of this study was to characterize the CSP and the septal tissue among patients with schizophrenia, patients with affective disorder, and control subjects. The volumes of CSP and septal tissue were measured in post-mortem brains in 42 patients with schizophrenia, 14 patients with affective disorder, and 17 normal control cases by planimetry of serial sections. Enlargements of CSP (>100 mm(3)) were found in eight of the 42 (19%) patients with schizophrenia. There were no significant differences in CSP volumes between patients with affective disorder and controls. Enlarged CSP in schizophrenia were not associated with reduced septal tissue volumes. By contrast, a significant positive correlation between volumes of CSP and septal tissue volumes in patients with schizophrenia (P = 0.03) and in control cases (P < 0.01) was found, but not in patients with affective disorder (P = 0.53). The finding of enlarged CSP in schizophrenia strongly supports the hypothesis of an early developmental abnormality in this key structure of the limbic system.

PTSD and stress sensitisation: a tale of brain and body Part 1: human studies

Post-traumatic stress disorder (PTSD) is a chronic, debilitating psychiatric disorder that can follow exposure to extreme stressful experiences. It is characterised by hyperarousal and increased startle responses, re-experiencing of the traumatic event, withdrawal or avoidance behaviour and emotional numbing. The focus of this review is on aspects that have received less attention. PTSD develops only in a substantial minority of people exposed to traumatic stress, and possible individual traits that increase vulnerability are discussed. An overview is given of the wide variety of physiological disturbances that accompany PTSD and may contribute to disability, including neuroendocrine, cardiovascular, gastrointestinal and immune function and pain sensitivity. Brain imaging and pharmacological studies have generated some insight into the circuitry that may be involved in the generation of PTSD symptoms. Major limitations of human studies so far are the issue of causality and our lack of understanding of the underlying molecular substrates in the brain, which are easier to address in relevant animal models and will be discussed in a companion paper.

Endocrine and inflammatory alterations in post-traumatic stress disorder

Post-traumatic stress disorder has frequently been found associated with alterations in endogenous stress hormone systems, for example the hypothalamus-pituitary-adrenal axis and sympatho-adrenal-medullary system. Hormonal alterations are observed at the central and peripheral level of the central nervous system, and in the periphery for inflammatory disinhibition. Both consequences bear significant hazards for the individual, the former by sustaining or exacerbating the psychiatric condition, the latter by its detrimental effects on somatic health. However, the role of hormonal modifications in the development and maintenance of post-traumatic stress disorder symptoms and in the accompanying cognitive and emotional impairments still remains quite unclear.

The genetic background to PTSD

Although extensive research has already been done on the genetic bases of psychiatric disorders, little is known about polygenetic influences in posttraumatic stress disorder (PTSD). This article reviews molecular genetic studies relating to PTSD that were found in a literature search in Medline, Embase and Web of Science. Association studies have investigated 8 major genotypes in connection with PTSD. They have tested hypotheses involving key candidate genes in the serotonin (5-HTT), dopamine (DRD2, DAT), glucocorticoid (GR), GABA (GABRB), apolipoprotein systems (APOE2), brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY). The studies have produced inconsistent results, many of which may be attributable to methodological shortcomings and insufficient statistical power. The complex aetiology of PTSD, for which experiencing a traumatic event forms a necessary condition, makes it difficult to identify specific genes that substantially contribute to the disorder. Gene-finding strategies are difficult to apply. Interactions between different genes and between them and the environment probably make certain people vulnerable to developing PTSD. Gene-environmental studies are needed that focus more narrowly on specific, distinct endophenotypes and on influences from environmental factors.

Clarifying the origin of biological abnormalities in PTSD through the study of identical twins discordant for combat exposure

A biological abnormality found to be associated with posttraumatic stress disorder (PTSD) may be, among other things, a pretrauma vulnerability factor, that is, it may have been present prior to the event's occurrence and increased the individual's likelihood of developing PTSD upon traumatic exposure. Alternately, it may be an acquired PTSD sign, that is, it may have developed after the traumatic exposure, along with the PTSD. We have studied pairs of Vietnam combat veterans and their noncombat-exposed, identical twins in an effort to resolve these competing origins. Combat veterans were diagnosed as current PTSD or non-PTSD (i.e., never had). Average heart rate responses (HRRs) to a series of sudden, loud-tone presentations were larger in Vietnam combat veteran twins with PTSD, but these larger responses were not shared by their noncombat-exposed cotwins, whose responses were similar to those of the non-PTSD combat veterans and their noncombat-exposed cotwins. These results suggest that larger HRRs to sudden, loud tones represent an acquired sign of PTSD. In contrast, increased neurological soft signs (NSSs), diminished hippocampal volume, and presence of abnormal cavum septum pellucidum (CSP) were found in Vietnam combat veteran twins with PTSD and their "high-risk," unexposed cotwins compared to Vietnam combat veteran twins without PTSD and their "low-risk," unexposed cotwins. These results support the conclusion that the latter abnormalities represent antecedent, familial vulnerability factors for developing chronic PTSD upon exposure to a traumatic event.

Cavum septi pellucidi and intrusive recollections in cancer survivors

A previous study reported abnormally large cavum septi pellucidi (CSP) in posttraumatic stress disorder (PTSD). We utilized magnetic resonance imaging to examine the frequency of large CSP, as defined by Nopoulos et al. (1997), in cancer survivors with and without intrusive recollections in a sample identical to that of our previous study. The frequency of large CSP did not differ between the two groups. The results suggest that alteration in midline structures during the course of neurodevelopment may lead to severe PTSD, while subthreshold PTSD, such as intrusive recollections, appear not to be associated with such alterations.

Parahippocampal activation evoked by masked traumatic images in posttraumatic stress disorder: a functional MRI study

Posttraumatic stress disorder (PTSD) has been widely studied, but its neural mechanism is still unclear. The purpose of this study is to identify dysfunctional areas in PTSD throughout the whole brain to help to elucidate the neural mechanisms of PTSD. Sixteen patients with PTSD and sixteen healthy controls participated in this study. Traumatic images under perceptual threshold including scenes of earthquakes, traffic accidents, ambulances, emergency rooms, and crimes were presented to the participants, and brain activation was measured using functional MRI. Functional brain images of both groups were evaluated with random effect analysis for the whole brain. In the control group, activation in the ventral frontoparietal areas correlated significantly with presentation of the masked traumatic stimuli. In the PTSD group, activation was not observed in these areas, but significant activation correlated with the masked traumatic stimuli in the parahippocampal region including the left parahippocampal gyrus and tail of the left hippocampus. These results suggest that in PTSD patients activation in the ventral frontoparietal network associated with visual attention processing is attenuated, while the left hippocampal area associated with episodic and autobiographical memory is abnormally easily activated. This pattern of activation corresponds well to the clinical characteristics of PTSD, in which even slight traumatic stimuli tend to induce intrusive recollection or flashbacks, despite a general decrease in attention and ability to concentrate.

Regulation of affect by the lateral septum: implications for neuropsychiatry

Substantial evidence indicates that the lateral septum (LS) plays a critical role in regulating processes related to mood and motivation. This review presents findings from the basic neuroscience literature and from some clinically oriented research, drawing from behavioral, neuroanatomical, electrophysiological, and molecular studies in support of such a role, and articulates models and hypotheses intended to advance our understanding of these functions. Neuroanatomically, the LS is connected with numerous regions known to regulate affect, such as the hippocampus, amygdala, and hypothalamus. Through its connections with the mesocorticolimbic dopamine system, the LS regulates motivation, both by stimulating the activity of midbrain dopamine neurons and regulating the consequences of this activity on the ventral striatum. Evidence that LS function could impact processes related to schizophrenia and other psychotic spectrum disorders, such as alterations in LS function following administration of antipsychotics and psychotomimetics in animals, will also be presented. The LS can also diminish or enable fear responding when its neural activity is stimulated or inhibited, respectively, perhaps through its projections to the hypothalamus. It also regulates behavioral manifestations of depression, with antidepressants stimulating the activity of LS neurons, and depression-like phenotypes corresponding to blunted activity of LS neurons; serotonin likely plays a key role in modulating these functions by influencing the responsiveness of the LS to hippocampal input. In conclusion, a better understanding of the LS may provide important and useful information in the pursuit of better treatments for a wide range of psychiatric conditions typified by disregulation of affective functions.