The Insidious Influence of Stress: An Integrated Model of Stress, Executive Control, and Psychopathology

Targeting Cognitive Resilience through Prebiotics: A Focused Perspective

This perspective article is a product of the work of an expert group within the Prebiotic Task Force convened by the International Life Sciences Institute Europe, a non-profit organization that brings together experts from academia, industry, and public service to catalyze nutrition science for public benefit. An expert group was conceived in October 2023 to discuss the evidence base on the use of prebiotics to promote cognitive functioning, with a focus on highlighting knowledge gaps and proposing a list of recommendations to guide this specific area of research forward. To address this, we evaluated existing systematic reviews and meta-analyses of human intervention studies that examine the effects of prebiotics on cognitive functioning. These are predominantly conducted in healthy participants under basal conditions and have, to date, revealed limited effects. In this perspective, we propose that prebiotics should be investigated as agents to promote cognitive resilience by testing their effects on cognitive performance under certain cognition-taxing factors that individuals encounter across their lifespan. These include stress, poor sleep outcomes, sedentary behavior, and unhealthy dietary patterns, all of which have been shown to be associated with altered microbiome and impact global cognition or specific cognitive domains. In addition, we recommend identifying vulnerable populations that are either subclinical or that struggle chronically or periodically with 1 or more cognition-taxing factors, to better uncover the boundary conditions for prebiotic effectiveness. By broadening the scope of research to include diverse populations and challenging conditions in daily life or experimental settings, we can expand our understanding of the role of prebiotics not only in cognitive health or impairment, but also as potential preventative agents that may promote cognitive resilience during aging and in response to various lifestyle-related challenges.

Contexts of urgency may go beyond emotion

Introduction

Urgency has been defined as the tendency towards rash speech and behavior in the context of emotion. Measures of Urgency have been found to have robust predictive power for psychopathologies and problematic behaviors. In the current study, we question whether emotions are unique drivers of urgency, or if emotions are potent exemplars of contexts that lead to rash speech and behavior. The Emotion Specific model and the Broader Contexts model correspond with these two conceptualizations of urgency, and they frame our pre-registered hypotheses.

Methods

Participants from two well-powered samples (n = 600,n = 588) completed 9 modified items from the Urgency and Positive Urgency scales to assess rash responses in each of four contexts - "Upset," "Excited," "Tired," and "Hungry" - and a fifth "In General" set. After data cleaning, we used principal components analysis to construct a unidimensional, 4-item set that was applied to capture impulsive behavior across the five contexts.

Results

We found that this research tool, called the Contexts of Impulsive Behaviors (CIBS), replicated in the second dataset, and it had adequate internal reliability in both samples. Although the Emotion Specific model was supported by the fact that the Upset context had a greater mean and greater variance than the Tired and Hungry contexts, most results supported the Broader Contexts model. That is, CIBS contexts were highly intercorrelated, and bivariate correlations with psychopathology were not significantly different across contexts. In partial correlations, effects of the Upset and Excited contexts were partially or fully statistically mediated by the Tired and Hungry contexts.

Discussion

These findings suggest that emotions are potent contexts for impulsive behaviors. At the same time, those with high urgency are vulnerable to impulsivity in other contexts, such as fatigue and hunger, that challenge the regulatory functions of the prefrontal cortex. Limitations, future directions, and clinical implications are discussed.

Stress from early life to adulthood: Is there a protective role of cognitive control?

Early life events can have long-lasting effects that may impact the quality of life into adulthood. The link between childhood adversities and adult mental and physical health is well documented, however, the underlying mechanisms remain poorly understood. Executive functions are assumed to be a key factor in successfully dealing with cognitive-emotional challenges thereby contributing to stress resilience and mental health across the lifespan. Here, we examined whether cognitive control moderates the link between early life adversity and depression. Data was available from a sample of 424 participants aged 20-70 years (Clinicaltrials.gov: NCT05155397). They performed in the Stroop task and behavior as well as frontal theta power were recorded. Negative childhood experiences were assessed with the Childhood Trauma Questionnaire (CTQ), chronic stress was measured with the Trier Inventory for Chronic Stress (TICS) and depression symptoms with Beck's Depression Inventory (BDI). The CTQ predicted symptoms of chronic stress and depression. Regression models pointed to the TICS as a crucial mediator in the relationship between CTQ and BDI. However, parameters of cognitive control demonstrated a rather weak effect as moderators. These results indicate that chronic stress is an important mediator linking childhood trauma to depression but suggest only a limited role for cognitive control.

No effects of acute stress on monetary delay discounting: A systematic literature review and meta-analysis

Many everyday decisions, including those concerning our health, finances and the environment, involve choosing between a smaller but imminent reward (e.g., €20 now) and a later but larger reward (e.g., €40 in a month). The extent to which an individual prefers smaller imminent rewards over larger delayed rewards can be measured using delay discounting tasks. Acute stress induces a cascade of biological and psychological responses with potential consequences for how individuals think about the future, process rewards, and make decisions, all of which can impact delay discounting. Several studies have shown that individuals focus more on imminent rewards under stress. These findings have been used to explain why individuals make detrimental choices under acute stress. Yet, the evidence linking acute stress to delay discounting is equivocal. To address this uncertainty, we conducted a meta-analysis of 11 studies (14 effects) to systematically quantify the effects of acute stress on monetary delay discounting. Overall, we find no effect of acute stress on delay discounting, compared to control conditions (SMD = -0.18, 95% CI [-0.57, 0.20], p = 0.32). We also find that neither the gender/sex of the participants, the type of stressor (e.g., physical vs. psychosocial) nor whether monetary decisions were hypothetical or incentivized (i.e. monetary decisions were actually paid out) moderated the impact of acute stress on monetary delay discounting. We argue that establishing the effects of acute stress on the separate processes involved in delay discounting, such as reward valuation and prospection, will help to resolve the inconsistencies in the field.

Acute stress influences the emotional foundations of executive control: Distinct effects on control-related affective and cognitive processes

Acute stress is known to influence performance on various task outcomes indicative of executive functioning (i.e., the top-down, goal-directed control of cognition and behavior). The most common interpretation of these effects is that stress influences control processes themselves. Another possibility, though, is that stress does not impair control per se, but instead alters the affective dynamics underlying the recruitment of control (e.g., reducing the extent to which making an error is aversive), resulting in less recruitment of control and thus poor performance. To date, however, no work has examined whether stress effects on executive function outcomes are driven by affective dynamics related to the recruitment of control. In the current study, we found that acute stress influenced-and cortisol responses related to-both executive control-related performance outcomes (e.g., post-error slowing) and control-related affective dynamics (e.g., negative affect following recruitment of control) in a modified Stroop task, but that these effects appeared to be independent of each other: The effects of stress on, and associations of cortisol with, control-related cognitive outcomes were not statistically mediated by task- or control-related affective dynamics. These results thus suggest that although stress influences affective dynamics underlying executive function, the effects of stress on executive function outcomes appear to be at least partially dependent on nonaffective processes, such as control processes themselves.

Early executive control buffers risk for adolescent psychopathology during the COVID-19 pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had a global impact on youth mental health, and there is a critical need for research examining individual factors that contribute to increased psychopathology during the pandemic. The current study explored whether executive control (EC) abilities in early childhood interact with COVID-related stress to attenuate risk for adolescent psychopathology during the first 6 months of the pandemic.

METHODS

Participants were 337 youth (49% female) living in a small midwestern city in the United States. Participants completed EC tasks when they were approximately 4.5 years old as part of a longitudinal study investigating cognitive development. At annual laboratory visits during adolescence and before the pandemic, participants (Mage  = 14.57) reported on mental health symptoms. In July and August of 2020, participants (Mage  = 16.57) reported on COVID-related stress and depression, anxiety, and trauma symptoms.

RESULTS

COVID-related stress was associated with increased internalizing problems after controlling for prepandemic symptom levels. Further, the impact of COVID-related stress on adolescent internalizing problems was moderated by preschool EC, with higher levels of EC buffering the effects of COVID-related stress on adolescent internalizing problems.

CONCLUSIONS

Findings highlight the importance of promoting EC early in development, as well as screening for EC deficits and implementing targeted intervention strategies across the lifespan to help reduce the impact of stress on adolescent internalizing problems.