Self-administered mindfulness interventions reduce stress in a large, randomized controlled multi-site study.

Mindfulness witnessed a substantial popularity surge in the past decade, especially as digitally self-administered interventions became available at relatively low costs. Yet, it is uncertain whether they effectively help reduce stress. In a preregistered (OSF https://doi.org/10.17605/OSF.IO/UF4JZ ; retrospective registration at ClinicalTrials.gov NCT06308744 ) multi-site study (nsites = 37, nparticipants = 2,239, 70.4% women, Mage = 22.4, s.d.age = 10.1, all fluent English speakers), we experimentally tested whether four single, standalone mindfulness exercises effectively reduced stress, using Bayesian mixed-effects models. All exercises proved to be more efficacious than the active control. We observed a mean difference of 0.27 (d = -0.56; 95% confidence interval, -0.43 to -0.69) between the control condition (M = 1.95, s.d. = 0.50) and the condition with the largest stress reduction (body scan: M = 1.68, s.d. = 0.46). Our findings suggest that mindfulness may be beneficial for reducing self-reported short-term stress for English speakers from higher-income countries.

The effect of cognitive reappraisal and early-life maternal care on neuroendocrine stress responses.

Early-life adversity (ELA) is related to profound dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, reflected in both, blunted or exaggerated cortisol stress responses in adulthood. Emotion regulation strategies such as cognitive reappraisal might contribute to this inconsistent finding. Here, we investigate an interaction of early-life maternal care (MC), where low MC represents a form of ELA, and instructed emotion regulation on cortisol responses to acute stress. Ninety-three healthy young women were assigned to a low (n = 33) or high (n = 60) MC group, based on self-reported early-life MC. In the laboratory, participants received regulation instructions, asking to cognitively reappraise (reappraisal group, n = 45) or to focus on senses (control group, n = 48) during subsequent stress exposure, induced by the Trier Social Stress Test. Salivary cortisol and subjective stress levels were measured repeatedly throughout the experiment. Multilevel model analyses confirmed a MC by emotion regulation interaction effect on cortisol trajectories, while controlling for hormonal status. Individuals with low MC in the control compared with the reappraisal group showed increased cortisol responses; individuals with high MC did not differ. These results highlight the significance of emotion regulation for HPA axis stress regulation following ELA exposure. They provide methodological and health implications, indicating emotion regulation as a promising target of treatment interventions for individuals with a history of ELA.

Estimation of antibody levels after COVID-19 vaccinations: Preliminary evidence for immune interoception.

To date, 72 % of the world's population has received at least one COVID-19 vaccination. The number of antibodies produced by some individuals is exponentially higher than in others, for various mostly unknown reasons. This variation causes great diversity in the future susceptibility to infection by the original or variants of the SARS-CoV-2 virus. The following study investigated whether individuals were able to estimate the strength of their antibody response after their COVID-19 vaccinations. 166 recently vaccinated participants provided a blood sample for determination of antibody titers. Participants were asked to estimate how many antibodies they thought they had produced, and were further asked how protected they felt from COVID-19 due to vaccination. Both self-rated antibody levels, and feelings of protection against COVID-19 were significantly related to their actual IgG spike antibody titers, after controlling for age, days since vaccination, BMI and cross vaccination. These results suggest that individuals may have a form of "immune interoception" which relates to their response to their COVID-19 vaccination.

Increased empathic distress in adults is associated with higher levels of childhood maltreatment.

While many studies investigated basic facets of empathy, less is known about the association with early life adversity (ELA). To investigate a possible association of empathy with ELA, we assessed self-reported ELA, using the Childhood Trauma Questionnaire (CTQ), the Parental Bonding Instrument (PBI) for mother and father, and empathy, using the Interpersonal Reactivity Index (IRI), in a sample of N = 228 (83% female, agemean = 30.51 ± 9.88 years, agerange = 18-60). Further, we measured willingness to donate a certain percentage of study compensation to a charity as an index of prosocial behavior. In line with our hypotheses that stated a positive association of empathy with ELA, increased levels of emotional, physical, and sexual abuse, and emotional and physical neglect were positively correlated with personal distress in response to others' suffering. Likewise, higher parental overprotection and lower parental care were related to higher personal distress. Furthermore, while participants with higher levels of ELA tended to donate more money on a merely descriptive level, only higher levels of sexual abuse were significantly related to larger donations after correction for multiple statistical tests. Other facets of the IRI (empathic concern, perspective taking and fantasy) were not related to any other ELA measure. This suggests ELA only affects levels of personal distress.

Validation of an online version of the trier social stress test in adult men and women.

The Trier Social Stress Test (TSST) is a reliable and efficient protocol to induce acute psychosocial stress in the laboratory. If circumstances do not allow in-person assessments, an online version of the TSST could create more flexible research opportunities. To date, studies have confirmed subjective and autonomic stress responses to online TSST protocols. In this preregistered study (https://osf.io/u57aj), we focused on the effect of a TSST online for adults (TSST-OA) on cortisol and alpha amylase levels, and pleasure and arousal ratings. As cortisol stress reactivity is mediated by sex, we further compared men and women. We hypothesized significant increases in cortisol, alpha amylase and arousal, and a decrease in pleasure in response to the TSST-OA. Also, we expected stronger cortisol responses in males as compared with females, as in the laboratory TSST. N = 48 adults (56% female, meanage=23.02 years, SD=3.19) participated in the study. Saliva sampling devices were sent to participants' home before testing sessions, during which the experimenter, a mixed-sex panel, and the participant joined a video call. Participants underwent the TSST-OA and overall provided five saliva samples for cortisol and alpha amylase detection. Pleasure and arousal ratings and psychometric questionnaires were also completed online. As hypothesized, the TSST-OA significantly increased cortisol, alpha amylase, and arousal levels, while it decreased pleasure. Moreover, cortisol responses were significantly stronger in males as compared to females. 64% of subjects were classified as responders (cortisol rise>1.5nmol/l). The TSST-OA successfully induced psychophysiological stress in adults. Our protocol offers new possibilities to study stress outside of the laboratory.

Nature-Based Relaxation Videos and Their Effect on Heart Rate Variability.

Growing evidence suggests that natural environments - whether in outdoor or indoor settings - foster psychological health and physiological relaxation, indicated by increased wellbeing, reduced stress levels, and increased parasympathetic activity. Greater insight into differential psychological aspects modulating psychophysiological responses to nature-based relaxation videos could help understand modes of action and develop personalized relaxation interventions. We investigated heart rate variability (HRV) as an indicator of autonomic regulation, specifically parasympathetic activity, in response to a 10-min video intervention in two consecutive studies as well as heart rate (HR). We hypothesized that a nature-based relaxation video elicits HRV increase and HR decrease, with response magnitude being affected by aspects of early life adversity (conceptualized as low parental care and high overprotection/constraint) and trait mindfulness. In Study 1, N = 60 participants (52% female, age mean = 23.92 ± 3.13 years, age range = 18-34 years) watched a relaxation video intervention depicting different natural scenery. We analyzed changes in HR and respiratory sinus arrhythmia (RSA) as a standard HRV measure, both based on 3-min segments from the experimental session, in multiple growth curve models. We found a decrease in HR and increase of RSA during the video intervention. Higher paternal care and lower trait mindfulness observing skills (assessed via questionnaires) were associated with higher RSA values before but not during video exposure. In Study 2, N = 90 participants (50% female, age mean = 22.63 ± 4.57 years, age range = 18-49 years) were assigned to three video conditions: natural scenery from Study 1, meditation video, or short clip from "The Lord of the Rings." Again, HR decreased, and RSA increased during video segments, yet without expected group differences across different video types. We found higher parental care and lower parental overprotection to predict higher RSA at different times during the experiment. Interestingly, lower paternal overprotection predicted overall higher RSA. These results suggest a generic relaxation effect of video interventions on autonomic regulation that we discuss in light of different theories mapping restorative effects of natural environments. Further, psychological characteristics like aspects of early life adversity and trait mindfulness could contribute to individual differences in autonomic regulation. This study contributes to a better understanding of autonomic and psychological responses to relaxation videos.

[Psychometric Properties of a German Translation of the Parental Bonding Instrument]. / Psychometrische Kennwerte einer deutschen Übersetzung des Parental Bonding Instrument.

Parenting behavior affects a child's development as well as the etiology and treatment of mental disorders. The Parental Bonding Instrument (PBI; Parker, Tupling & Brown, 1979) is a well-known measurement tool to retrospectively assess parenting styles. Yet, no sufficiently validated German version exists to date. Therefore, we developed an updated translation of the German PBI version (PBI-dt) and analyzed its psychometric properties in an online survey based on a sample of n=791 German-speaking participants with a focus on item and reliability characteristics, construct and criterion validity as well as factorial structure of the PBI-dt.Our results indicated good item characteristics and reliability (α=0.86-0.95). Correlations between PBI and CTQ-SF (Childhood Trauma Questionnaire Short Form) scales were in line with the literature. Significant differences in the reported parenting style were found between people with and without mental illness as well as between normal-weight and overweight people. These results indicated the presence of good construct and criterion validity. Confirmatory factor analyses indicated an acceptable model fit for all fit indices in the original 2-factor model of Parker et al. (1979) as well as in the 3-factor model with the scales CareCareCareCareCareCare, Discouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedom and Denial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomy. A 3-factor structure provided additional information, e. g., a better differentiation between normal and overweight people. Hence, this German translation of the PBI has good psychometric properties and is a reliable measuring instrument.

Effects of psychological, sensory, and metabolic energy prime manipulation on the acute endocrine stress response in fasted women.

The stress response supports survival through energy mobilization. Paradoxically, a low blood glucose level dampens the endocrine stress response, and sugar consumption prior to stress restores it. Thus, energy availability may play a causal role in the endocrine stress response. Yet, it has never been tested whether sweet taste or expectations towards a drink content modulate the stress response. We investigated the potential role of sweetness, energy load and expectations towards energy load of a drink consumed prior to stress in restoring stress reactivity after fasting. N = 152 women (meanage=21.53, sdage=2.61) participated in the Trier Social Stress Test for groups in the morning after an overnight fast. Prior to stress induction, participants consumed a drink containing saccharose (sugar, n = 51), an equally sweet drink containing non-caloric sweetener (sweetener, n = 46), or water (n = 56). Additionally, participants in the sugar and sweetener group (n = 97) were informed whether or not their drink contained any calories (energy prime), which was deceptive in 50% of the cases. Eight salivary cortisol (-30, -20, -10, 0, +12, +25, +35, +45 min) and three blood glucose samples (-30, 0, +25 min) were assessed throughout the experiment. The effects of the experimental manipulations on cortisol trajectories were tested using multilevel mixed models. We found that compared with water, sugar and sweetener both significantly increased cortisol stress reactivity and with comparable intensity. However, our sensitivity analysis revealed a significant effect of sugar on cortisol trajectories compared to water and to sweetener. Drink-induced changes in blood glucose concentration were not associated with increases in cortisol. The energy prime did not affect the stress response. Overall, we could replicate the boosting effect of sugar consumption in a female sample after 8 h of fasting. The specific contribution of sweet taste and metabolic hormones to this boosting effect should be tested more rigorously in sex-balanced designs in the future.

Influence of stress on physiological synchrony in a stressful versus non-stressful group setting.

Physiological synchrony (PS) is defined as the co-occurrence and interdependence of physiological activity between interaction partners. Previous research has uncovered numerous influences on the extent of PS, such as relationship type or individual characteristics. Here, we investigate the influence of acute stress on PS. We do so in a setting in which PS was not promoted, but contact between group members was explicitly minimized. We reanalyzed cortisol, alpha-amylase, and subjective stress data from 138 participants (mean age = [Formula: see text], 47.1% female) who previously underwent the Trier Social Stress Test for groups (TSST-G) or a non-stressful control task together, collected as part of a larger project by Popovic et al. (Sci Rep 10: 7845, 2020). Using a stability and influence model, an established method to test for synchrony, we tested whether individuals' cortisol and alpha-amylase concentrations could be predicted by group members' levels. We found cortisol PS in participants who were in the same group, the extent of which was stronger in the non-stressful control condition. For alpha-amylase, participants were synchronized as well; furthermore, there was an interaction between previous stress levels and PS. This suggests that while synchrony of both stress markers can occur in group settings even with spurious interaction, stressor exposure might attenuate its extent. We argue that if PS occurs in a sample where interaction was minimal, the phenomenon might be more widespread than previously thought. Furthermore, stressor exposure might influence whether a situation allows for PS. We conclude that PS should be investigated within group settings with various degrees of social interaction to further expose mechanisms of and influence on PS.

The impact of maternal care and blood glucose availability on the cortisol stress response in fasted women.

Individuals with a history of low maternal care (MC) frequently present a blunted, yet sometimes also show an increased cortisol stress response. Fasted individuals with low blood glucose levels who are exposed to acute stress typically show an attenuated response pattern in this endocrine marker. Despite well-documented metabolic dysregulations after low MC, a possible interaction of both factors has not been investigated yet. Here, we examined the effects of MC and blood glucose concentration on various aspects of the stress response. Fasted women (N = 122, meanage = 22.12, sdage = 2.56) who experienced either very high, high, or low MC (based on the Parental Bonding Instrument) were randomly assigned to consume grape juice (condition sugar), or water (condition water) prior to being exposed to the Trier-Social-Stress-Test for groups. Salivary cortisol and alpha amylase, blood glucose, and mood ratings were assessed repeatedly. Using multilevel mixed models, we replicated the boosting effect of glucose on the cortisol stress response. While we found neither an effect of MC, nor an interaction between MC and blood glucose availability on the cortisol stress response, we observed an effect of MC on the amylase stress response. We discuss the results in the light of links between various stress/energy systems that possibly mediate health-related MC effects.

Perception of atrial fibrillation in dependence of neuroticism.

OBJECTIVE: Atrial fibrillation (AF) is associated with a varying symptom burden, which ranges from completely unawareness to disabling conditions. The present cross-sectional study tried to assess if neuroticism is associated with a greater degree of perception of AF related symptoms. METHODS: 162 patients who were considered for catheter ablation of AF were included. AF related symptom burden was quantified according to the European Heart Rhythm Association (EHRA) score. Personality traits were assessed using the Big Five personality traits (5BT). RESULTS: Female patients reported higher symptom burden. Higher EHRA scores were furthermore associated with treatment with antiarrhythmic agents, digitalis, direct oral anticoagulants (DOAC), and antidepressant treatment, as well as suffering from heart failure or chronic kidney disease. Neuroticism showed a positive correlation to AF related symptom burden with significantly higher neuroticism scores in patients with higher EHRA scores (Rho = 0.41; 95%CI 0.26 to 0.53; p < .001), while no association was demonstrated for the other four personality traits. Multiple linear regression analysis revealed neuroticism as strongest independent predictor for symptomatic AF, followed by treatment with antiarrhythmic agents and DOAC. CONCLUSIONS: Perception of AF related symptoms is a multifactorial process, which in our cohort was independently associated with neuroticism. Patients with higher symptom burden were also more likely to receive antiarrhythmic agents and DOAC, as well as antidepressants. TRIAL REGISTRATION: German registry for clinical studies (DRKS), DRKS00019007.

Standardized massage interventions as protocols for the induction of psychophysiological relaxation in the laboratory: a block randomized, controlled trial.

Health and disease are strongly linked to psychophysiological states. While stress research strongly benefits from standardized stressors, no established protocol focuses on the induction of psychophysiological relaxation. To maintain health, functioning regenerative systems are however likely as important as functioning stress systems. Thus, the identification of validated relaxation paradigms is needed. Here, we investigated whether standardized massages are capable of reliably inducing physiological and psychological states of relaxation. Relaxation was indicated by changes in high frequency heart rate variability (HF-HRV), a vagally-mediated heart rate variability component, and repeated ratings of subjective relaxation, and stress levels. Sixty healthy women were randomly assigned to a vagus nerve massage (n = 19), a soft shoulder massage (n = 22), or a resting control group (n = 19). During the intervention, HF-HRV and subjective relaxation increased, while subjective stress decreased significantly in all groups. Both massage interventions elicited significantly higher HF-HRV compared to the control group. Accordingly, both massage protocols increased psychophysiological relaxation, and may serve as useful tools in future research. However, future work will have to determine which of several protocols might be used as a gold standard to induce a psychophysiological state of relaxation in the laboratory.

The Opposite of Stress.

Cognition is affected by psychophysiological states. While the influence of stress on cognition has been investigated intensively, less studies have addressed how the opposite of stress, a state of relaxation, affects cognition. We investigated whether the extent of parasympathetic activation is positively related to divergent thinking. Sixty healthy female participants were randomly allocated to a standardized vagus nerve massage (n = 19), a standardized soft shoulder massage (n = 22), or a resting control group (n = 19). Subsequently, participants completed the Alternative Uses Test (AUT), a measure of divergent thinking. Respiratory sinus arrhythmia (RSA), a vagally mediated heart rate variability component, was monitored throughout the experiment. The area under the curve with respect to the increase was calculated for RSA trajectories as an indicator of vagal tone during the relaxing intervention. Regressions tested the effect of vagal tone on AUT outcomes. We found an association between vagal tone and subsequent AUT outcomes. Yet, this association was no longer significant when controlling for the effect of the creative potential of an individual, which was strongly related to AUT outcomes. Being exploratory, we found a positive association between creative potential and vagal tone. These results imply that creative potential might be related to the capacity to relax.

The duration of the cortisol awakening pulse exceeds sixty minutes in a meaningful pattern.

The cortisol awakening response (CAR) is a well-established biomarker for the integrity of the hypothalamic-pituitary-adrenal (HPA) axis in healthy as well as clinical samples. Cortisol rise during the first 60 min after awakening is often used as a proxy of HPA axis regulation in health and disease. Ultradian pulsatility of cortisol is known to superimpose its circadian rhythmicity with the CAR being the first rise after awakening. However, the exact length of the complete first pulse (rise and fall) after awakening, as well as the association between the CAR, the complete first pulse, and successive ultradian pulses, has not yet been studied systematically. Aim of this study was to investigate cortisol dynamics after awakening beyond the standard assessment duration of 60 min in order to assess the cortisol awakening pulse, in relation to ultradian rhythmicity of cortisol after awakening. In a sample of 51 healthy participants, salivary cortisol was collected for the first 270 min after awakening in intervals of 30 min, on two separate days. Different parameters describing individual cortisol pulses over time with respect to inter- and intraindividual variations such as duration, amplitude and area under the curve (AUC) were calculated. Special emphasis was put on the first rise and fall after awakening, called the cortisol awakening pulse (CAP). Mean duration of the CAP was 108 min with high interindividual differences. Duration of first and second pulse were associated with subject's sex and menstrual cycle status, with a longer first pulse and an attenuated second pulse in male and female subjects in the luteal phase, compared to female subjects in the follicular phase, or women taking oral contraceptives. These results point to the potential usefulness of a longer sampling period for assessing ultradian pulsatility of cortisol in the morning, especially the CAP. To assess the complete pulse rather than the rise alone, measurement of cortisol levels after awakening for 120 min is recommended.

Successful smoking cessation is associated with prefrontal cortical function during a Stroop task: A preliminary study.

Although many smokers try to quit, relatively few are successful in their attempts. Here we investigated whether the ability to quit smoking is related to behavioral and neural measures of cognitive control. A functional magnetic resonance imaging study with a counting Stroop task was used to measure cognitive control in ex-smokers (N=10) who had successfully quit smoking and smokers (N=10) who continuously failed to quit smoking. Behavioral results showed a significant Stroop effect in ex-smokers and smokers. Ex-smokers exhibited less Stroop interference, indicating superior cognitive control compared with smokers. Furthermore, when incongruent trials were contrasted with congruent trials, ex-smokers showed stronger BOLD activity than smokers in the right superior frontal gyrus and anterior cingulate cortex. Although the present study does not permit us to draw strong conclusions regarding causality, the results suggest that successful smoking cessation may be mediated by superior cognitive control.