Investigating two mobile just-in-time adaptive interventions to foster psychological resilience: research protocol of the DynaM-INT study.

BACKGROUND: Stress-related disorders such as anxiety and depression are highly prevalent and cause a tremendous burden for affected individuals and society. In order to improve prevention strategies, knowledge regarding resilience mechanisms and ways to boost them is highly needed. In the Dynamic Modelling of Resilience - interventional multicenter study (DynaM-INT), we will conduct a large-scale feasibility and preliminary efficacy test for two mobile- and wearable-based just-in-time adaptive interventions (JITAIs), designed to target putative resilience mechanisms. Deep participant phenotyping at baseline serves to identify individual predictors for intervention success in terms of target engagement and stress resilience. METHODS: DynaM-INT aims to recruit N = 250 healthy but vulnerable young adults in the transition phase between adolescence and adulthood (18-27 years) across five research sites (Berlin, Mainz, Nijmegen, Tel Aviv, and Warsaw). Participants are included if they report at least three negative burdensome past life events and show increased levels of internalizing symptoms while not being affected by any major mental disorder. Participants are characterized in a multimodal baseline phase, which includes neuropsychological tests, neuroimaging, bio-samples, sociodemographic and psychological questionnaires, a video-recorded interview, as well as ecological momentary assessments (EMA) and ecological physiological assessments (EPA). Subsequently, participants are randomly assigned to one of two ecological momentary interventions (EMIs), targeting either positive cognitive reappraisal or reward sensitivity. During the following intervention phase, participants' stress responses are tracked using EMA and EPA, and JITAIs are triggered if an individually calibrated stress threshold is crossed. In a three-month-long follow-up phase, parts of the baseline characterization phase are repeated. Throughout the entire study, stressor exposure and mental health are regularly monitored to calculate stressor reactivity as a proxy for outcome resilience. The online monitoring questionnaires and the repetition of the baseline questionnaires also serve to assess target engagement. DISCUSSION: The DynaM-INT study intends to advance the field of resilience research by feasibility-testing two new mechanistically targeted JITAIs that aim at increasing individual stress resilience and identifying predictors for successful intervention response. Determining these predictors is an important step toward future randomized controlled trials to establish the efficacy of these interventions.

The STRESS-NL database: A resource for human acute stress studies across the Netherlands.

Stress initiates a cascade of (neuro)biological, physiological, and behavioral changes, allowing us to respond to a challenging environment. The human response to acute stress can be studied in detail in controlled settings, usually in a laboratory environment. To this end, many studies employ acute stress paradigms to probe stress-related outcomes in healthy and patient populations. Though valuable, these studies in themselves often have relatively limited sample sizes. We established a data-sharing and collaborative interdisciplinary initiative, the STRESS-NL database, which combines (neuro)biological, physiological, and behavioral data across many acute stress studies in order to accelerate our understanding of the human acute stress response in health and disease (www.stressdatabase.eu). Researchers in the stress field from 12 Dutch research groups of 6 Dutch universities created a database to achieve an accurate inventory of (neuro)biological, physiological, and behavioral data from laboratory-based human studies that used acute stress tests. Currently, the STRESS-NL database consists of information on 5529 individual participants (2281 females and 3348 males, age range 6-99 years, mean age 27.7 ±â€¯16 years) stemming from 57 experiments described in 42 independent studies. Studies often did not use the same stress paradigm; outcomes were different and measured at different time points. All studies currently included in the database assessed cortisol levels before, during and after experimental stress, but cortisol measurement will not be a strict requirement for future study inclusion. Here, we report on the creation of the STRESS-NL database and infrastructure to illustrate the potential of accumulating and combining existing data to allow meta-analytical, proof-of-principle analyses. The STRESS-NL database creates a framework that enables human stress research to take new avenues in explorative and hypothesis-driven data analyses with high statistical power. Future steps could be to incorporate new studies beyond the borders of the Netherlands; or build similar databases for experimental stress studies in rodents. In our view, there are major scientific benefits in initiating and maintaining such international efforts.

Increased responses of the reward circuitry to positive task feedback following acute stress in healthy controls but not in siblings of schizophrenia patients.

Acute stress is known to affect the way we process rewards. For example, during, or directly after stress, activity within key brain areas of the reward circuitry is reduced when a reward is presented. Generally, the effects of stress on the brain are time-dependent, changing neural and cognitive processing in the aftermath of stress to aid recovery. Such a dynamic response to stress is important for resilience on the longer term. However, relatively little is known about reward processing during the recovery phase of stress and whether this is changed in individuals at increased risk for stress-related psychopathology. Healthy male individuals (N = 40) and unaffected siblings of schizophrenia patients (N = 40) were randomized to either an acute stress task (Trier Social Stress Test) or a no-stress task. Neural responses during reward anticipation and reward feedback (monetary gain or no gain) were examined 50 min later using an fMRI monetary incentive delay task. The ventral striatum and orbitofrontal cortex (OFC) were used as predefined hypothesis-driven regions of interest. Neural responses following stress differed between controls and siblings during reward feedback (group × stress interaction OFC p = 0.003, ventral striatum p = 0.031), showing increased ventral striatum and OFC responses following stress in healthy controls only. Exploratory analyses revealed that this effect was most pronounced during hit trials (compared to when a reward was omitted), and independent of monetary value. Stress did not affect subsequent reward processing in siblings of schizophrenia patients. We found no significant differences between controls and siblings in ventral striatum and OFC responses during reward anticipation following stress. This study shows that ventral striatum and OFC responses to positive task feedback are increased in the aftermath of stress in healthy male controls, regardless of monetary value. This indicates a dynamic shift from previously reported reduced responses in the striatum and OFC to reward feedback directly after stress to increased responses to both reward and non-reward feedback during the recovery phase of stress. These increased neural responses following stress were absent in siblings of schizophrenia patients. Together, these findings indicate that stress recovery is affected in this at-risk group, particularly in responses to positive feedback following stress.

At-risk individuals display altered brain activity following stress.

Stress is a major risk factor for almost all psychiatric disorders, however, the underlying neurobiological mechanisms remain largely elusive. In healthy individuals, a successful stress response involves an adequate neuronal adaptation to a changing environment. This adaptive response may be dysfunctional in vulnerable individuals, potentially contributing to the development of psychopathology. In the current study, we investigated brain responses to emotional stimuli following stress in healthy controls and at-risk individuals. An fMRI study was conducted in healthy male controls (N = 39) and unaffected healthy male siblings of schizophrenia patients (N = 39) who are at increased risk for the development of a broad range of psychiatric disorders. Brain responses to pictures from the International Affective Picture System (IAPS) were measured 33 min after exposure to stress induced by the validated trier social stress test (TSST) or a control condition. Stress-induced levels of cortisol, alpha-amylase, and subjective stress were comparable in both groups. Yet, stress differentially affected brain responses of schizophrenia siblings versus controls. Specifically, control subjects, but not schizophrenia siblings, showed reduced brain activity in key nodes of the default mode network (PCC/precuneus and mPFC) and salience network (anterior insula) as well as the STG, MTG, MCC, vlPFC, precentral gyrus, and cerebellar vermis in response to all pictures following stress. These results indicate that even in the absence of a psychiatric disorder, at-risk individuals display abnormal functional activation following stress, which in turn may increase their vulnerability and risk for adverse outcomes.

How the brain connects in response to acute stress: A review at the human brain systems level.

The brain's response to stress is a matter of extensive neurocognitive research in an attempt to unravel the mechanistic underpinnings of neural adaptation. In line with the broadly defined concept of acute stress, a wide variety of induction procedures are used to mimic stress experimentally. We set out to review commonalities and diversities of the stress-related functional activity and connectivity changes of functional brain networks in healthy adults across procedures. The acute stress response is consistently associated with both increased activity and connectivity in the salience network (SN) and surprisingly also with increased activity in the default mode network (DMN), while most studies show no changes in the central executive network. These results confirm earlier findings of an essential, coordinating role of the SN in the acute stress response and indicate a dynamic role of the DMN whose function is less clear. Moreover, paradigm specific brain responses have to be taken into account when investigating the role and the within and between network connectivity of these three networks.

Gonadal hormone regulation of the emotion circuitry in humans.

Gonadal hormones are known to influence the regulation of emotional responses and affective states. Whereas fluctuations in progesterone and estradiol are associated with increased vulnerability for mood disorders, testosterone is mainly associated with social dominance, aggressive, and antisocial behavior. Here, we review recent functional neuroimaging studies that have started to elucidate how these hormones modulate the neural circuitry that is important for emotion regulation, which includes the amygdala and the medial prefrontal (mPFC) and orbitofrontal cortex (OFC). The amygdala is thought to generate emotional responses, and the prefrontal brain regions to regulate those responses. Overall, studies that have investigated women during different phases of the menstrual cycle suggest that progesterone and estradiol may have opposing actions on the amygdala and prefrontal cortex. In addition, the influence of exogenous progesterone appears to be dose-dependent. Endogenous testosterone concentrations are generally positively correlated to amygdala and OFC responses, and exogenous testosterone increases amygdala reactivity. Whereas the administration of progesterone increases amygdala reactivity and its connectivity with the mPFC, testosterone administration increases amygdala reactivity but decreases its connectivity with the OFC. We propose that this opposing influence on amygdala-prefrontal coupling may contribute to the divergent effects of progesterone and testosterone on emotion regulation and behavioral inhibition, respectively, which may promote the differential vulnerability to various psychiatric disorders between women and men. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.