The role of environmental sensitivity in the mental health of Syrian refugee children: a multi-level analysis

Individuals with high environmental sensitivity have nervous systems that are disproportionately receptive to both the protective and imperilling aspects of the environment, suggesting their mental health is strongly context-dependent. However, there have been few consolidated attempts to examine putative markers of sensitivity, across different levels of analysis, within a single cohort of individuals with high-priority mental health needs. Here, we examine psychological (self-report), physiological (hair hormones) and genetic (polygenic scores) markers of sensitivity in a large cohort of 1591 Syrian refugee children across two waves of data. Child-caregiver dyads were recruited from informal tented settlements in Lebanon, and completed a battery of psychological instruments at baseline and follow-up (12 months apart). Univariate and multivariate Bayesian linear mixed models were used to examine a) the interrelationships between markers of sensitivity and b) the ability of sensitivity markers to predict anxiety, depression, post-traumatic stress disorder, and externalising behaviour. Self-reported sensitivity (using the Highly Sensitive Child Scale) significantly predicted a higher burden of all forms of mental illness across both waves, however, there were no significant cross-lagged pathways. Physiological and genetic markers were not stably predictive of self-reported sensitivity, and failed to similarly predict mental health outcomes. The measurement of environmental sensitivity may have significant implications for identifying and treating mental illness, especially amongst vulnerable populations, but clinical utility is currently limited to self-report assessment.

Hair hormone data from Syrian refugee children: Perspectives from a two-year longitudinal study

For numerous issues of convenience and acceptability, hair hormone data have been increasingly incorporated in the field of war trauma and forced displacement, allowing retrospective examination of several biological metrics thought to covary with refugees' mental health. As a relatively new research method, however, there remain several complexities and uncertainties surrounding the use of hair hormones, from initial hair sampling to final statistical analysis, many of which are underappreciated in the extant literature, and restrict the potential utility of hair hormones. To promote awareness, we provide a narrative overview of our experiences collecting and analyzing hair hormone data in a large cohort of Syrian refugee children (n = 1594), across two sampling waves spaced 12 months apart. We highlight both the challenges faced, and the promising results obtained thus far, and draw comparisons to other prominent studies in this field. Recommendations are provided to future researchers, with emphasis on longitudinal study designs, thorough collection and reporting of hair-related variables, and careful adherence to current laboratory guidelines and practices.

Risk and resilience in Syrian refugee children: A multisystem analysis

Refugee children are often exposed to substantial trauma, placing them at increased risk for mental illness. However, this risk can be mitigated by a capacity for resilience, conferred from multiple ecological systems (e.g., family, community), including at an individual biological level. We examined the ability of hair cortisol concentrations and polygenic scores for mental health to predict risk and resilience in a sample of Syrian refugee children (n = 1359). Children were categorized as either at-risk or resilient depending on clinical thresholds for posttraumatic stress disorder, depression, and externalizing behavior problems. Logistic regression was used to examine main and interacting effects while controlling for covariates. Elevated hair cortisol concentrations were significantly associated with reduced resilience (odds ratio (OR)=0.58, 95%CI [0.40, 0.83]) while controlling for levels of war exposure. Polygenic scores for depression, self-harm, and neuroticism were not found to have any significant main effects. However, a significant interaction emerged between hair cortisol and polygenic scores for depression (OR=0.04, 95%CI [0.003 0.47]), suggesting that children predisposed to depression were more at risk for mental health problems when hair cortisol concentrations were high. Our results suggest that biomarkers (separately and in combination) might support early identification of refugee children at risk for mental health problems.

Effects of war exposure on pubertal development in refugee children

Increasing research shows pubertal development accelerates following threats while it decelerates following deprivation. Yet, these environmental stressors are unlikely to occur in isolation. We investigated how war exposure and energetic stress impact pubertal development using data from the longitudinal Biological Pathways of Risk and Resilience in Syrian Refugee Children study. Our sample included 1,600 male and female Syrian refugee children and their caregivers who lived in temporary settlements in Lebanon. We hypothesized that (a) energetic stress suppresses pubertal development; (b) war exposure accelerates pubertal timing in boys and increases risk of menarche in girls, but only when energetic stress is low; and (c) when energetic stress is elevated, effects of war exposure on pubertal development will be attenuated. Among boys, we did not find support for Hypothesis 1, but Hypotheses 2 and 3 were supported. Exposure to morbidity/mortality threats accelerated pubertal timing; this effect was attenuated under conditions of elevated energetic stress. Among girls, we found support for Hypothesis 1, but not for Hypotheses 2 and 3. Elevated energetic stress decreased the risk of menarche in girls. Neither war exposure, nor any interactions with energetic stress, predicted risk of menarche. Sensitivity analyses revealed a significant interaction between bombing exposure and the amount of time since leaving Syria. Bombing decreased the risk of menarche, but only for girls who had left Syria four or more years prior to data collection. We discuss implications for translational efforts advocating for puberty screening in medical and mental health settings to identify trauma-exposed youth. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

War exposure, post-traumatic stress symptoms and hair cortisol concentrations in Syrian refugee children

Altered secretion of cortisol, the primary effector of the hypothalamus-pituitary-adrenal axis, has been proposed as a means by which traumatic experiences compromise later mental health. However, despite the popularity of cortisol as a potential biomarker for stress and adversity, findings are inconsistent, and little is known about the impact of war-related trauma on stress physiology of children and adolescents. Here we aimed to evaluate the relationships between war exposure, current living conditions, hair cortisol concentrations (HCC) and post-traumatic stress disorder (PTSD) symptoms in a large cohort of Syrian refugee children and adolescents (6-18 years) and their caregiver. This longitudinal observational study assessed Syrian refugee children and adolescents in two waves, 1 year apart, within informal tented settlements in Lebanon. The relationships between war exposure, time since leaving Syria, PTSD symptoms and HCC were investigated using linear mixed-model regression utilising both waves of data collected (Y1: N = 1574, Y2: N = 923). Hair cortisol concentration was positively, but weakly associated with the number of war-related events experienced. This was limited to those who were at least 12 years old at the time of war exposure. Conversely, HCC decreased with time since leaving Syria. HCC was also associated with PTSD symptoms but not with the quality of their current living conditions. This study revealed that changes to hypothalamic-pituitary-adrenal axis activity may accompany both earlier war exposure and current PTSD symptoms in children and adolescents. Additionally, early adolescence may be a particularly sensitive time in terms of trauma-related changes to the hypothalamic-pituitary-adrenal axis.

Cohort profile: biological pathways of risk and resilience in Syrian refugee children (BIOPATH)

The BIOPATH cohort was established to explore the interplay of psychosocial and biological factors in the development of resilience and mental health problems in Syrian refugee children. Based in Lebanon, a middle-income country significantly impacted by the refugee crisis, it is the first such cohort of refugees in the Middle East. Families were recruited from informal tented settlements in the Beqaa region using purposive cluster sampling. At baseline (October 2017-January 2018), N = 3188 individuals participated [n = 1594 child-caregiver dyads; child gender, 52.6% female; mean (SD) age = 11.44 (2.44) years, range = 6-19]. Re-participation rate at 1-year follow-up was 62.8%. Individual interviews were conducted with children and primary caregivers and biological samples collected from children. Measures include: (1) children's well-being and mental health problems (using tools validated against clinical interviews in a subsample of the cohort); (2) psychosocial risk and protective factors at the level of the individual (e.g. coping strategies), family (e.g. parent-child relationship), community (e.g. collective efficacy), and wider context (e.g. services); (3) saliva samples for genetic and epigenetic (methylation) analyses; (4) hair samples to measure cortisol, dehydroepiandrosterone (DHEA) and testosterone. This cohort profile provides details about sampling and recruitment, data collection and measures, demographic data, attrition and potential bias, key findings on resilience and mental health problems in children and strengths and limitations of the cohort. Researchers interested in accessing data should contact Professor Michael Pluess at Queen Mary University of London, UK (e-mail: m.pluess@qmul.ac.uk).

The Role of Lipid Biomarkers in Major Depression

In the UK, the lifetime-documented prevalence of major depressive disorder (MDD) is currently 10%. Despite its increasing prevalence and devastating impact on quality of life, the pathophysiological mechanisms underpinning MDD remain to be fully elucidated. Current theories of neurobiological components remain incomplete and protein-centric, rendering pharmacological treatment options suboptimal. In this review, we highlight the pivotal role of lipids in intra- and inter-neuronal functioning, emphasising the potential use of lipids as biomarkers for MDD. The latter has significant implications for improving our understanding of MDD at the cellular and circuit level. There is particular focus on cholesterol (high and low density lipoprotein), omega-3, and omega-6 polyunsaturated fatty acids due to established evidence in the literature of a link between atherosclerotic disease and major depression. We argue that there is significant potential scope for the use of such peripheral biomarkers in the diagnosis, stratification and treatment of MDD.

Abstract PR11: Medulloblastoma-associated mutations in the DEAD box RNA helicase DDX3X impair protein translation

Whole genome sequencing technologies recently identified novel recurrent mutations in childhood medulloblastomas (MB), including missense mutations in the DEAD box RNA helicase DDX3X. In the present study, we used complementary genomic approaches to illuminate normal DDX3X function and the impact of cancer-associated mutations. We used CLIPseq to identify the RNA targets of endogenous DDX3X. This analysis revealed that DDX3X primarily binds mature mRNAs and, further, that the distribution of DDX3X binding sites in targets spans the full length of these mRNAs, with enrichment in the coding regions, suggesting a role for DDX3X in translation elongation. Consistent with this observation, we detected a fraction of wild type DDX3X in polysomes by sedimentation experiments. In contrast, MB-associated DDX3X mutants appear to associate poorly with polysomes, but induce spontaneous stress granule (SG) formation in cells, suggesting a role of mutant DDX3X in triggering translation silencing. In fact, the RNA binding capabilities of DDX3X are still preserved in the context of cancer-associated mutations further supporting a role of mutant DDX3X in repressing translation of specific RNAs by retaining them within SGs. Interestingly, gene ontology analyses find mRNAs encoding translation factors themselves to be highly enriched among DDX3X RNA targets, suggesting that perturbations of DDX3X functions could have far-reaching impact on cellular translation. Indeed, knocking down DDX3X with siRNA or overexpressing a mutant led to a significant impairment in global translation as measured by S35-methionine metabolic labeling. Furthermore, assessment of whole-genome protein translation by ribosomal profiling analyses in cells overexpressing cancer-associated mutant DDX3X confirmed a decreased translation rate of direct DDX3X mRNA targets in particular, but also numerous other mRNAs. Finally, we have generated an allelic series of transgenic fruit flies expressing wild type or mutant versions of human DDX3X or its Drosophila ortholog Belle, and have captured mutation-dependent phenotypes when these transgenes are expressed in specific tissues. Together, our data show that DDX3X regulates the translation of a key subset of mRNAs and thereby indirectly influences cellular translation globally, and that this function is perturbed by cancer-associated mutations.

This abstract is also presented as poster C48.

Citation Format: Yasmine A. Valentin-Vega, Matthew Parker, Michael Rusch, Demelza Smeeth, Nam Chul Kim, Jinghui Zhang, Richard J. Gilbertson, Joseph P. Taylor. Medulloblastoma-associated mutations in the DEAD box RNA helicase DDX3X impair protein translation. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr PR11.