Schizotypy, childhood trauma and brain morphometry

Subcortical neural mechanisms of childhood trauma impacts on personality traits

This study aims to explore the relationships between childhood trauma (CT), personality traits, and subcortical structures. 171 healthy individuals completed the Childhood Trauma Questionnaire (CTQ), the Neuroticism-Extraversion-Openness Five-Factor Inventory (NEO-FFI), and underwent 3D T1-weighted MRI scans. Linear regression analyses indicated the complex relationship between CT, personality traits, and subcortical gray matter volume (GMV). Mediation analyses revealed that the right hippocampal GMV partially mediated the effects of CT on neuroticism. These findings suggest that CT affects the development of the Big Five personality traits, and alterations in subcortical structures are closely related to this process. Altered GMV in the right hippocampus may be a key neural mechanism for CT-induced neuroticism.

Childhood trauma moderates schizotypy-related brain morphology: analyses of 1182 healthy individuals from the ENIGMA schizotypy working group

BACKGROUND

Schizotypy represents an index of psychosis-proneness in the general population, often associated with childhood trauma exposure. Both schizotypy and childhood trauma are linked to structural brain alterations, and it is possible that trauma exposure moderates the extent of brain morphological differences associated with schizotypy.

METHODS

We addressed this question using data from a total of 1182 healthy adults (age range: 18-65 years old, 647 females/535 males), pooled from nine sites worldwide, contributing to the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Schizotypy working group. All participants completed both the Schizotypal Personality Questionnaire Brief version (SPQ-B), and the Childhood Trauma Questionnaire (CTQ), and underwent a 3D T1-weighted brain MRI scan from which regional indices of subcortical gray matter volume and cortical thickness were determined.

RESULTS

A series of multiple linear regressions revealed that differences in cortical thickness in four regions-of-interest were significantly associated with interactions between schizotypy and trauma; subsequent moderation analyses indicated that increasing levels of schizotypy were associated with thicker left caudal anterior cingulate gyrus, right middle temporal gyrus and insula, and thinner left caudal middle frontal gyrus, in people exposed to higher (but not low or average) levels of childhood trauma. This was found in the context of morphological changes directly associated with increasing levels of schizotypy or increasing levels of childhood trauma exposure.

CONCLUSIONS

These results suggest that alterations in brain regions critical for higher cognitive and integrative processes that are associated with schizotypy may be enhanced in individuals exposed to high levels of trauma.

Interaction between childhood trauma experience and TPH2 rs7305115 gene polymorphism in brain gray matter volume

BACKGROUND

Childhood trauma is one of the most extensively studied and well-supported environmental risk factors for the development of mental health problems. The human tryptophan hydroxylase 2 (TPH2) gene is one of the most promising candidate genes in numerous psychiatric disorders. However, it is now widely acknowledged that neither genetic variation nor environmental exposure alone can fully explain all the phenotypic variance observed in psychiatric disorders. Therefore, it is necessary to consider the interaction between the two factors in psychiatric research.

METHODS

We enrolled a sizable nonclinical cohort of 786 young, healthy adults who underwent structural MRI scans and completed genotyping, the Childhood Trauma Questionnaire (CTQ) and behavioural scores. We identified the interaction between childhood trauma and the TPH2 rs7305115 gene polymorphism in the gray matter volume (GMV) of specific brain subregions and the behaviour in our sample using a multiple linear regression framework. We utilized mediation effect analysis to identify environment /gene-brain-behaviour relationships.

RESULTS

We found that childhood trauma and TPH2 rs7305115 interacted in both behaviour and the GMV of brain subregions. Our findings indicated that the GMV of the right posterior parietal thalamus served as a significant mediator supporting relationship between childhood trauma (measured by CTQ score) and anxiety scores in our study population, and the process was partly modulated by the TPH2 rs7305115 gene polymorphism. Moreover, we found only a main effect of childhood trauma in the GMV of the right parahippocampal gyrus area, supporting the relationship between childhood trauma and anxiety scores as a significant mediator.

CONCLUSIONS

Our findings suggest that early-life trauma may have a specific and long-term structural effect on brain GMV, potentially leading to altered cognitive and emotional processes involving the parahippocampal gyrus and thalamus that may also be modulated by the TPH2 gene polymorphism. This finding highlights the importance of considering genetic factors when examining the impact of early-life experiences on brain structure and function. Gene‒environment studies can be regarded as a powerful objective supplement for targeted therapy, early diagnosis and treatment evaluation in the future.

The neural, stress hormone and inflammatory correlates of childhood deprivation and threat in psychosis: A systematic review

Childhood adversity increases the risk of developing psychosis, but the biological mechanisms involved are unknown. Disaggregating early adverse experiences into core dimensions of deprivation and threat may help to elucidate these mechanisms. We therefore systematically searched the literature investigating associations between deprivation and threat, and neural, immune and stress hormone systems in individuals on the psychosis spectrum. Our search yielded 74 articles, from which we extracted and synthesized relevant findings. While study designs were heterogeneous and findings inconsistent, some trends emerged. In psychosis, deprivation tended to correlate with lower global cortical volume, and some evidence supported threat-related variation in prefrontal cortex morphology. Greater threat exposure was also associated with higher C-reactive protein, and higher and lower cortisol measures. When examined, associations in controls were less evident. Overall, findings indicate that deprivation and threat may associate with partially distinct biological mechanisms in the psychosis spectrum, and that associations may be stronger than in controls. Dimensional approaches may help disentangle the biological correlates of childhood adversity in psychosis, but more studies are needed.

Sex Differences in the Neurobiology of Stress

This review highlights the existing knowledge and data that explain the physiologic impacts of stress, especially pertaining to neurobiology, and how these impacts differ by sex. Furthermore, this review explains the benefits of interventions aimed at preventing or mitigating the adverse effects of stress, because of both the significant toll of stress on the body and the disproportionate impact of these changes experienced by women.

Relationships between childhood trauma and dimensional schizotypy: A network analysis and replication

OBJECTIVES

Childhood trauma (CT) has been found to increase the risk of developing schizophrenia and other psychiatric disorders. Little is known regarding the complex interplay between CT, subclinical psychotic, and affective symptoms in the general population. This cross-sectional study adopted network analysis to examine such a complex relationship. We hypothesized that CT would show strong connections with schizotypy dimensions, and the high schizotypy subgroup would show a network with higher global strength compared with the low schizotypy subgroup.

METHODS

A total of 1813 college students completed a set of self-report questionnaires measuring CT, schizotypal features, bipolar traits, and depressive symptoms. The subscales of these questionnaires were used as nodes, and the partial correlations between nodes were used as edges to construct a network. Network Comparison Tests were used to investigate the differences between participants with high schizotypy and low schizotypy. An independent sample (n = 427) was used to examine the replicability of the results.

RESULTS

Findings from the main dataset showed that CT was closely connected with schizotypy and motivation, after controlling for the inter-relationships between all nodes in the network. Relative to the low schizotypy subgroup, the network of the high schizotypy subgroup showed higher global strength. The two subgroups did not differ in network structure. Network analysis using the replication dataset showed comparable global strength and network structure.

CONCLUSIONS

Our findings support specific links between CT and schizotypy dimensions in healthy youth populations, and such links appear to become stronger in those with high schizotypy.

The effect of schizotypy on spatial learning in an environment with a distinctive shape

In two experiments, participants completed the Oxford-Liverpool Inventory of Feelings and Experiences measuring schizotypal traits across four dimensions (unusual experiences, cognitive disorganization, introvertive anhedonia, and impulsive non-conformity). They then took part in a virtual navigation task where they were required to learn about the position of a hidden goal with reference to geometric cues of a rectangular arena or rely on colored wall panels to find the hidden goal in a square-shaped arena. Unusual experience and cognitive disorganization were significant predictors of the use of geometric cues, but no significant predictors were found for the use of wall panels. Implications to hippocampal function and the clinical domain are considered.

The effects of developmental trauma on theory of mind and its relationship to psychotic experiences: A behavioural study

BACKGROUND

Developmental psychological trauma induces vulnerability to psychosis. However, the mechanisms underlying this association are poorly understood. Impairments in Theory of Mind (ToM) have been observed in adult survivors of developmental trauma and individuals with psychosis. ToM is therefore a candidate mechanism underlying the association between developmental trauma and psychosis.

METHODS

We used a computerised version of the Director task - where a participant is instructed by a confederate to move an object around a 4 × 4 grid, whilst taking account of whether these objects are visible to a confederate who instructs the participant - to investigate impairments in ToM in 209 participants (age: M = 37.8, SD=13.6; 56% female). Participants were divided into a) developmental trauma-positive (DT+) and control groups (DT-) based on their history of developmental trauma and b) then further into subclinical (S) and healthy groups (H) as based on psychotic experiences indexed by the CAPE-P15. After exclusion, the numbers in each group were: DT+H (47), DT+S (84), DT-H (54), DT-S (12). (Total: 197).

RESULTS

Developmental trauma exposure was associated with psychotic experiences (OR: 7.89, p < .001), which remained significant after controlling for demographic and clinical confounds (adjusted R² = 0.452, R² change = 0.0184, p = .009). Participants with developmental trauma (F_{1, 194}) = 5.46, p = .020, ηp² = 0.027) and participants more prone to psychotic experiences (F_{1, 194}) = 4.71, p = .031, ηp² = 0.024) demonstrated significantly lower accuracy on the Director task relative to their respective control, after controlling for the effects of age.

CONCLUSIONS

ToM deficits are associated with self-reported developmental trauma and psychotic experiences. Further work is needed to explore these relationships further and whether they represent generalised or specific effect effects on developmental trauma and psychopathological domains.