Caregiving and 5-HTTLPR Genotype Predict Adolescent Physiological Stress Reactivity: Confirmatory Tests of Gene × Environment Interactions

Additive serotonergic genetic sensitivity and cortisol reactivity to lab-based social evaluative stress: Influence of severity across two samples

Prior work demonstrates that an additive serotonergic multilocus genetic profile score (MGPS) predicts amplified risk for depression following significant life stress, and that it interacts with elevations in the cortisol awakening response to predict depression. The serotonin system and HPA-axis have bidirectional influence, but whether this MGPS predicts acute cortisol reactivity, which might then serve as a mechanism for depression, is unknown. Our prior work suggests that depression risk factors predict blunted cortisol reactivity to explicit negative evaluative lab-based stress. Thus, we hypothesized that a 4-variant serotonergic MGPS (three SNPs from the original 5-variant version plus 5HTTLPR) would predict blunted cortisol reactivity to explicit negative evaluative stress versus a control. In Sample 1, growth curve modeling showed that the MGPS predicted heightened cortisol reactivity (p = 0.0001) in an explicitly negative evaluative Trier Social Stress Test variant (TSST) versus a control condition among non-depressed emerging adults (N = 152; 57% female). In Sample 2, 125 males completed the Socially Evaluative Cold Pressor Test (SECPT), an ambiguously negative evaluative manipulation; findings displayed a similar pattern but did not reach statistical significance (ps.075-.091). A participant-level meta-analysis of the two samples demonstrated a significant effect of negative evaluation severity, such that the MGPS effect size on reactivity increased linearly from control to SECPT to an explicitly negative evaluative TSST. Findings indicate that this MGPS contributes to sensitivity to social threat and that cortisol dysregulation in the context of social stress may be one mechanism by which this MGPS contributes to depression.

Multiomic biological approaches to the study of child abuse and neglect

Childhood maltreatment, occurring in up to 20-30% of the population, remains far too common, and incorporates a range of active and passive factors, from abuse, to neglect, to the impacts of broader structural and systemic adversity. Despite the effects of childhood maltreatment and adversity on a wide range of adult physical and psychological negative outcomes, not all individuals respond similarly. Understanding the differential biological mechanisms contributing to risk vs. resilience in the face of developmental adversity is critical to improving preventions, treatments, and policy recommendations. This review begins by providing an overview of childhood abuse, neglect, maltreatment, threat, and toxic stress, and the effects of these forms of adversity on the developing body, brain, and behavior. It then examines examples from the current literature of genomic, epigenomic, transcriptomic, and proteomic discoveries and biomarkers that may help to understand risk and resilience in the aftermath of trauma, predictors of traumatic exposure risk, and potential targets for intervention and prevention. While the majority of genetic, epigenetic, and gene expression analyses to date have focused on targeted genes and hypotheses, large-scale consortia are now well-positioned to better understand interactions of environment and biology with much more statistical power. Ongoing and future work aimed at understanding the biology of childhood adversity and its effects will help to provide targets for intervention and prevention, as well as identify paths for how science, health care, and policy can combine efforts to protect and promote the psychological and physiological wellbeing of future generations.

Vagal Tone as a Putative Mechanism for Pragmatic Competence: An Investigation of Carriers of the FMR1 Premutation

Pragmatic language skills exist across a continuum in typical and clinical populations, and are impaired in many neurodevelopmental disorders, most notably autism. The mechanisms underlying pragmatic impairment are poorly understood, although theory suggests dampened vagal tone plays a role. This study investigated the FMR1 premutation as a genetic model that may lend insight into the relationship between vagal function and pragmatic ability. Participants included 38 women with the FMR1 premutation and 23 controls. Vagal tone accounted for significant variance in pragmatics across both groups and statistically mediated the effect of FMR1 premutation status on pragmatic ability. Results support vagal tone as a biophysiological correlate of pragmatic ability, which informs potential mechanistic underpinnings and could have implications for targeted treatment.

A Conceptual Model and Clinical Framework for Integrating Mindfulness into Family Therapy with Adolescents

Individual and group-based psychotherapeutic interventions increasingly incorporate mindfulness-based principles and practices. These practices include a versatile set of skills such as labeling and attending to present-moment experiences, acting with awareness, and avoiding automatic reactivity. A primary motivation for integrating mindfulness into these therapies is compelling evidence that it enhances emotion regulation. Research also demonstrates that family relationships have a profound influence on emotion regulation capacities, which are central to family functioning and prosocial behavior more broadly. Despite this evidence, no framework exists to describe how mindfulness might integrate into family therapy. This paper describes the benefits of mindfulness-based interventions, highlighting how and why informal mindfulness practices might enhance emotion regulation when integrated with family therapy. We provide a clinical framework for integrating mindfulness into family therapy, particularly as it applies to families with adolescents. A brief case example details sample methods showing how incorporating mindfulness practices into family therapy may enhance treatment outcomes. A range of assessment modalities from biological to behavioral demonstrates the breadth with which the benefits of a family-based mindfulness intervention might be evaluated.

Gene × Environment contributions to autonomic stress reactivity in youth

Dysregulated physiological stress reactivity has been suggested to impact the development of children and adolescents with important health consequences throughout the life span. Both environmental adversity and genetic predispositions can lead to physiological imbalances in stress systems, which in turn lead to developmental differences. We investigated genetic and environmental contributions to autonomic nervous system reactivity to a psychosocial stressor. Furthermore, we tested whether these effects were consistent with the differential susceptibility framework. Composite measures of adverse life events combined with socioeconomic status were constructed. Effects of these adversity scores in interaction with a polygenic score summarizing six genetic variants, which were hypothesized to work as susceptibility factors, were tested on autonomic nervous system measures as indexed by heart rate and heart rate variability. Results showed that carriers of more genetic variants and exposed to high adversity manifested enhanced heart rate variability reactivity to a psychosocial stressor compared to carriers of fewer genetic variants. Conversely, the stress procedure elicited a more moderate response in these individuals compared to carriers of fewer variants when adversity was low.

Statistical tests of differential susceptibility: Performance, limitations, and improvements

Statistical tests of differential susceptibility have become standard in the empirical literature, and are routinely used to adjudicate between alternative developmental hypotheses. However, their performance and limitations have never been systematically investigated. In this paper I employ Monte Carlo simulations to explore the functioning of three commonly used tests proposed by Roisman et al. (2012). Simulations showed that critical tests of differential susceptibility require considerably larger samples than standard power calculations would suggest. The results also showed that existing criteria for differential susceptibility based on the proportion of interaction index (i.e., values between .40 and .60) are especially likely to produce false negatives and highly sensitive to assumptions about interaction symmetry. As an initial response to these problems, I propose a revised test based on a broader window of proportion of interaction index values (between .20 and .80). Additional simulations showed that the revised test outperforms existing tests of differential susceptibility, considerably improving detection with little effect on the rate of false positives. I conclude by noting the limitations of a purely statistical approach to differential susceptibility, and discussing the implications of the present results for the interpretation of published findings and the design of future studies in this area.

Infant Medical Trauma in the Neonatal Intensive Care Unit (IMTN): A Proposed Concept for Science and Practice

BACKGROUND

Trauma is an innately subjective experience ensuing from a deeply distressing event. Research has demonstrated that while the environment of the neonatal intensive care unit (NICU) is capable of providing extraordinary lifesaving measures following birth, the experience may be disruptive to several key aspects of early development, placing infants at risk for adverse behavioral, cognitive, and emotional outcomes.

PURPOSE

This article provides rationale for the concept of Infant Medical Trauma in the NICU (IMTN) as a means of describing this unique stress experience. A triad of cumulative early life NICU experiences (stress, parental separation, and pain) is proposed to influence an infant's swinging neurodevelopmental pendulum amid the potential outcomes of risk and resilience.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Creating language that describes the infant experience brings meaning and calls caregivers and parents to action to consider strategies that may improve long-term health. Actively seeking opportunities to decrease the allostatic load of at-risk infants may support an infant's pendulum to swing toward a path of resilience, thereby moderating his or her early life adverse experience.