Neighborhood Socioeconomic Disadvantage and the Neurobiology of Uncertainty in Traumatically Injured Adults

Population-level normative models reveal race- and socioeconomic-related variability in cortical thickness of threat neurocircuitry

The inequitable distribution of economic resources and exposure to adversity between racial groups contributes to mental health disparities within the United States. Consideration of the potential neurodevelopmental consequences, however, has been limited particularly for neurocircuitry known to regulate the emotional response to threat. Characterizing the consequences of inequity on threat neurocircuitry is critical for robust and generalizable neurobiological models of psychiatric illness. Here we use data from the Adolescent Brain and Cognitive Development Study 4.0 release to investigate the contributions of individual and neighborhood-level economic resources and exposure to discrimination. We investigate the potential appearance of race-related differences using both standard methods and through population-level normative modeling. We show that, in a sample of white and Black adolescents, racial inequities in socioeconomic factors largely contribute to the appearance of race-related differences in cortical thickness of threat neurocircuitry. The race-related differences are preserved through the use of population-level models and such models also preserve associations between cortical thickness and specific socioeconomic factors. The present findings highlight that such socioeconomic inequities largely underlie race-related differences in brain morphology. The present findings provide important new insight for the generation of generalizable neurobiological models of psychiatric illness.

Neighborhood Disadvantage and Neural Correlates of Threat and Reward Processing in Survivors of Recent Trauma

Importance

Differences in neighborhood socioeconomic characteristics are important considerations in understanding differences in risk vs resilience in mental health. Neighborhood disadvantage is associated with alterations in the function and structure of threat neurocircuitry.

Objective

To investigate associations of neighborhood disadvantage with white and gray matter and neural reactivity to positive and negative stimuli in the context of trauma exposure.

Design, Setting, and Participants

In this cross-sectional study, survivors of trauma who completed sociodemographic and posttraumatic symptom assessments and neuroimaging were recruited as part of the Advancing Understanding of Recovery After Trauma (AURORA) study between September 2017 and June 2021. Data analysis was performed from October 25, 2022, to February 15, 2023.

Exposure

Neighborhood disadvantage was measured with the Area Deprivation Index (ADI) for each participant home address.

Main Outcomes and Measures

Participants completed separate threat and reward tasks during functional magnetic resonance imaging. Diffusion-weighted and high-resolution structural images were also collected. Linear models assessed the association of ADI with reactivity, microstructure, and macrostructure of a priori regions of interest after adjusting for income, lifetime trauma, sex at birth, and age. A moderated-mediation model tested whether ADI was associated with neural activity via microstructural changes and if this was modulated by PTSD symptoms.

Results

A total of 280 participants (183 females [65.4%]; mean [SD] age, 35.39 [13.29] years) completed the threat task and 244 participants (156 females [63.9%]; mean [SD] age, 35.10 [13.26] years) completed the reward task. Higher ADI (per 1-unit increase) was associated with greater insula (t274 = 3.20; β = 0.20; corrected P = .008) and anterior cingulate cortex (ACC; t274 = 2.56; β = 0.16; corrected P = .04) threat-related activity after considering covariates, but ADI was not associated with reward reactivity. Greater disadvantage was also associated with altered microstructure of the cingulum bundle (t274 = 3.48; β = 0.21; corrected P = .001) and gray matter morphology of the ACC (cortical thickness: t273 = -2.29; β = -0.13; corrected P = .02; surface area: t273 = 2.53; β = 0.13; corrected P = .02). The moderated-mediation model revealed that ADI was associated with ACC threat reactivity via cingulum microstructural changes (index of moderated mediation = -0.02). However, this mediation was only present in individuals with greater PTSD symptom severity (at the mean: β = -0.17; standard error = 0.06, t= -2.28; P = .007; at 1 SD above the mean: β = -0.28; standard error = 0.08; t = -3.35; P < .001).

Conclusions and Relevance

In this study, neighborhood disadvantage was associated with neurobiology that supports threat processing, revealing associations of neighborhood disadvantage with neural susceptibility for PTSD and suggesting how altered structure-function associations may complicate symptoms. Future work should investigate specific components of neighborhood disadvantage that may be associated with these outcomes.

Biopsychosocial Model of Traumatic Stress Symptoms in Women Experiencing Homelessness: A Qualitative Descriptive Study

Trauma is nearly ubiquitous among women experiencing homelessness (WEH). WEH develop post-traumatic stress disorder (PTSD) at rates far exceeding the general population. The consequences of untreated PTSD can cascade, exacerbating existing physical, mental, and social health inequities, placing this population at risk for disproportionate biopsychosocial health adversity. Despite the outsized impact of PTSD, WEH are less likely to access or receive appropriate trauma-focused services. Understanding the unique and intersecting factors that contribute to the disproportionate PTSD toll on WEH may elucidate risk and protective factors, as well as possible intervention pathways to address the disparate trauma burden. This study employed a qualitative descriptive approach to develop understanding of the determinants of trauma risk, exposure, and outcomes among WEH. Semi-structured interviews were completed with 10 WEH, six shelter staff, four mental health professionals. Six deductively biopsychosocial model-derived themes were identified, alongside supporting categories. Themes/categories highlighted the role of biological, psychological, and socio-environmental determinants in shaping risk for and actualization of traumatic events and adverse outcomes. Trauma played an outsized role in shaping the health of WEH participants in this study, and the need for and interest in tailored trauma screening, treatment, psychoeducation options was highlighted. Recursive relationships between biopsychosocial determinants and trauma impact were identified. Participants emphasized population tailored trauma-focused interventions, specifically brief co-designed and community partner implemented interventions that address substance use behaviors, while leveraging the strengths of WEH. Addressing the marked trauma burden in WEH shows promise in promoting measurable biopsychosocial health improvements in this resilient yet overlooked population.

Development in uncertain contexts: An ecologically informed approach to understanding decision-making during adolescence

Adolescence is a period of development in which youth have new opportunities for decision-making, often in situations where they may have little information or experience to guide their choices. Thus, learning to make decisions under uncertainty is a key challenge during adolescence. To date, researchers have applied economics formalisms to understand the processes that support adolescents in making decisions under two distinct forms of uncertainty: economic risk and economic ambiguity. Economic risk is when the probabilities of outcomes are known. Economic ambiguity is when the probabilities of outcomes are unknown or unknowable. This research has led to foundational knowledge about the basic processes involved in adolescent decision-making, but many experimental paradigms that dissociate economic risk and ambiguity rely on monetary or point-based choices. Given that adolescence is a period of development characterized by a changing social environment, it remains unclear whether the processes that adolescents engage during decision-making on monetary or point-based experimental tasks generalize to their day-to-day experiences in the real world. In this brief piece, we explore how developmental research applying economics formalisms can be bolstered by research on youth's social environments to advance our understanding of decision-making in adolescence. First, we review developmental research by using economic uncertainty paradigms. Next, we highlight research on adolescents' social environments to provide examples of the day-to-day choices that adolescents face among their peers and in their broader communities. Finally, we propose directions for future research integrating these separate approaches to create a more nuanced, ecologically informed understanding of adolescent decision-making.

Radically reframing studies on neurobiology and socioeconomic circumstances: A call for social justice-oriented neuroscience

Socioeconomic circumstances are associated with symptoms and diagnostic status of nearly all mental health conditions. Given these robust relationships, neuroscientists have attempted to elucidate how socioeconomic-based adversity "gets under the skin." Historically, this work emphasized individual proxies of socioeconomic position (e.g., income, education), ignoring the effects of broader socioeconomic contexts (e.g., neighborhood socioeconomic disadvantage) which may uniquely contribute to chronic stress. This omission represented a disconnect between neuroscience and other allied fields that have recognized health is undeniably linked to interactions between systems of power and individual characteristics. More recently, neuroscience work has considered how sociopolitical context affects brain structure and function; however, the products of this exciting line of research have lacked critical sociological and historical perspectives. While empirical evidence on this topic is burgeoning, the cultural, ethical, societal, and legal implications of this work have been elusive. Although the mechanisms by which socioeconomic circumstances impact brain structure and function may be similar across people, not everyone is exposed to these factors at similar rates. Individuals from ethnoracially minoritized groups are disproportionally exposed to neighborhood disadvantage. Thus, socioeconomic inequities examined in neuroscience research are undergirding with other forms of oppression, namely structural racism. We utilize a holistic, interdisciplinary approach to interpret findings from neuroscience research and interweave relevant theories from the fields of public health, social sciences, and Black feminist thought. In this perspective piece, we discuss the complex relationship that continues to exist between academic institutions and underserved surrounding communities, acknowledging the areas in which neuroscience research has historically harmed and/or excluded structurally disadvantaged communities. We conclude by envisioning how this work can be used; not just to inform policymakers, but also to engage and partner with communities and shape the future direction of human neuroscience research.