The impact of physical fitness on resilience to modern life stress and the mediating role of general self-efficacy

Substantial evidence shows that physical activity and fitness play a protective role in the development of stress related disorders. However, the beneficial effects of fitness for resilience to modern life stress are not fully understood. Potentially protective effects may be attributed to enhanced resilience via underlying psychosocial mechanisms such as self-efficacy expectations. This study investigated whether physical activity and fitness contribute to prospectively measured resilience and examined the mediating effect of general self-efficacy. 431 initially healthy adults participated in fitness assessments as part of a longitudinal-prospective study, designed to identify mechanisms of resilience. Self-efficacy and habitual activity were assessed in parallel to cardiorespiratory and muscular fitness, which were determined by a submaximal step-test, hand strength and standing long jump test. Resilience was indexed by stressor reactivity: mental health problems in relation to reported life events and daily hassles, monitored quarterly for nine months. Hierarchical linear regression models and bootstrapped mediation analyses were applied. We could show that muscular and self-perceived fitness were positively associated with stress resilience. Extending this finding, the muscular fitness-resilience relationship was partly mediated by self-efficacy expectations. In this context, self-efficacy expectations may act as one underlying psychological mechanism, with complementary benefits for the promotion of mental health. While physical activity and cardiorespiratory fitness did not predict resilience prospectively, we found muscular and self-perceived fitness to be significant prognostic parameters for stress resilience. Although there is still more need to identify specific fitness parameters in light of stress resilience, our study underscores the general relevance of fitness for stress-related disorders prevention.

Impact of COVID-19 lockdown on mental health in Germany: longitudinal observation of different mental health trajectories and protective factors

The COVID-19 pandemic and resulting measures can be regarded as a global stressor. Cross-sectional studies showed rather negative impacts on people's mental health, while longitudinal studies considering pre-lockdown data are still scarce. The present study investigated the impact of COVID-19 related lockdown measures in a longitudinal German sample, assessed since 2017. During lockdown, 523 participants completed additional weekly online questionnaires on e.g., mental health, COVID-19-related and general stressor exposure. Predictors for and distinct trajectories of mental health outcomes were determined, using multilevel models and latent growth mixture models, respectively. Positive pandemic appraisal, social support, and adaptive cognitive emotion regulation were positively, whereas perceived stress, daily hassles, and feeling lonely negatively related to mental health outcomes in the entire sample. Three subgroups ("recovered," 9.0%; "resilient," 82.6%; "delayed dysfunction," 8.4%) with different mental health responses to initial lockdown measures were identified. Subgroups differed in perceived stress and COVID-19-specific positive appraisal. Although most participants remained mentally healthy, as observed in the resilient group, we also observed inter-individual differences. Participants' psychological state deteriorated over time in the delayed dysfunction group, putting them at risk for mental disorder development. Consequently, health services should especially identify and allocate resources to vulnerable individuals.

Lithium prevents grey matter atrophy in patients with bipolar disorder: an international multicenter study

BACKGROUND

Lithium (Li) is the gold standard treatment for bipolar disorder (BD). However, its mechanisms of action remain unknown but include neurotrophic effects. We here investigated the influence of Li on cortical and local grey matter (GM) volumes in a large international sample of patients with BD and healthy controls (HC).

METHODS

We analyzed high-resolution T1-weighted structural magnetic resonance imaging scans of 271 patients with BD type I (120 undergoing Li) and 316 HC. Cortical and local GM volumes were compared using voxel-wise approaches with voxel-based morphometry and SIENAX using FSL. We used multiple linear regression models to test the influence of Li on cortical and local GM volumes, taking into account potential confounding factors such as a history of alcohol misuse.

RESULTS

Patients taking Li had greater cortical GM volume than patients without. Patients undergoing Li had greater regional GM volumes in the right middle frontal gyrus, the right anterior cingulate gyrus, and the left fusiform gyrus in comparison with patients not taking Li.

CONCLUSIONS

Our results in a large multicentric sample support the hypothesis that Li could exert neurotrophic and neuroprotective effects limiting pathological GM atrophy in key brain regions associated with BD.

Longitudinal determination of resilience in humans to identify mechanisms of resilience to modern-life stressors: the longitudinal resilience assessment (LORA) study

Resilience is the maintenance and/or quick recovery of mental health during and after periods of adversity. It is conceptualized to result from a dynamic process of successful adaptation to stressors. Up to now, a large number of resilience factors have been proposed, but the mechanisms underlying resilience are not yet understood. To shed light on the complex and time-varying processes of resilience that lead to a positive long-term outcome in the face of adversity, the Longitudinal Resilience Assessment (LORA) study has been established. In this study, 1191 healthy participants are followed up at 3- and 18-month intervals over a course of 4.5 years at two study centers in Germany. Baseline and 18-month visits entail multimodal phenotyping, including the assessment of mental health status, sociodemographic and lifestyle variables, resilience factors, life history, neuropsychological assessments (of proposed resilience mechanisms), and biomaterials (blood for genetic and epigenetic, stool for microbiome, and hair for cortisol analysis). At 3-monthly online assessments, subjects are monitored for subsequent exposure to stressors as well as mental health measures, which allows for a quantitative assessment of stressor-dependent changes in mental health as the main outcome. Descriptive analyses of mental health, number of stressors including major life events, daily hassles, perceived stress, and the ability to recover from stress are here presented for the baseline sample. The LORA study is unique in its design and will pave the way for a better understanding of resilience mechanisms in humans and for further development of interventions to successfully prevent stress-related disorder.

A Translational Paradigm to Study the Effects of Uncontrollable Stress in Humans

Theories on the aetiology of depression in humans are intimately linked to animal research on stressor controllability effects. However, explicit translations of established animal designs are lacking. In two consecutive studies, we developed a translational paradigm to study stressor controllability effects in humans. In the first study, we compared three groups of participants, one exposed to escapable stress, one yoked inescapable stress group, and a control group not exposed to stress. Although group differences indicated successful stress induction, the manipulation failed to differentiate groups according to controllability. In the second study, we employed an improved paradigm and contrasted only an escapable stress group to a yoked inescapable stress group. The final design successfully induced differential effects on self-reported perceived control, exhaustion, helplessness, and behavioural indices of adaptation to stress. The latter were examined in a new escape behaviour test which was modelled after the classic shuttle box animal paradigm. Contrary to the learned helplessness literature, exposure to uncontrollable stress led to more activity and exploration; however, these behaviours were ultimately not adaptive. We discuss the results and possible applications in light of the findings on learning and agency beliefs, inter-individual differences, and interventions aimed at improving resilience to stress-induced mental dysfunction.

Cerebellar parcellation in schizophrenia and bipolar disorder

OBJECTIVE

The cerebellum is involved in cognitive processing and emotion control. Cerebellar alterations could explain symptoms of schizophrenia spectrum disorder (SZ) and bipolar disorder (BD). In addition, literature suggests that lithium might influence cerebellar anatomy. Our aim was to study cerebellar anatomy in SZ and BD, and investigate the effect of lithium.

METHODS

Participants from 7 centers worldwide underwent a 3T MRI. We included 182 patients with SZ, 144 patients with BD, and 322 controls. We automatically segmented the cerebellum using the CERES pipeline. All outputs were visually inspected.

RESULTS

Patients with SZ showed a smaller global cerebellar gray matter volume compared to controls, with most of the changes located to the cognitive part of the cerebellum (Crus II and lobule VIIb). This decrease was present in the subgroup of patients with recent-onset SZ. We did not find any alterations in the cerebellum in patients with BD. However, patients medicated with lithium had a larger size of the anterior cerebellum, compared to patients not treated with lithium.

CONCLUSION

Our multicenter study supports a distinct pattern of cerebellar alterations in SZ and BD.

Prospective cohort study of early biosignatures of response to lithium in bipolar-I-disorders: overview of the H2020-funded R-LiNK initiative

Background

Lithium is recommended as a first line treatment for bipolar disorders. However, only 30% of patients show an optimal outcome and variability in lithium response and tolerability is poorly understood. It remains difficult for clinicians to reliably predict which patients will benefit without recourse to a lengthy treatment trial. Greater precision in the early identification of individuals who are likely to respond to lithium is a significant unmet clinical need.

Structure

The H2020-funded Response to Lithium Network (R-LiNK; http://www.r-link.eu.com/) will undertake a prospective cohort study of over 300 individuals with bipolar-I-disorder who have agreed to commence a trial of lithium treatment following a recommendation by their treating clinician. The study aims to examine the early prediction of lithium response, non-response and tolerability by combining systematic clinical syndrome subtyping with examination of multi-modal biomarkers (or biosignatures), including omics, neuroimaging, and actigraphy, etc. Individuals will be followed up for 24 months and an independent panel will assess and classify each participants’ response to lithium according to predefined criteria that consider evidence of relapse, recurrence, remission, changes in illness activity or treatment failure (e.g. stopping lithium; new prescriptions of other mood stabilizers) and exposure to lithium. Novel elements of this study include the recruitment of a large, multinational, clinically representative sample specifically for the purpose of studying candidate biomarkers and biosignatures; the application of lithium-7 magnetic resonance imaging to explore the distribution of lithium in the brain; development of a digital phenotype (using actigraphy and ecological momentary assessment) to monitor daily variability in symptoms; and economic modelling of the cost-effectiveness of introducing biomarker tests for the customisation of lithium treatment into clinical practice. Also, study participants with sub-optimal medication adherence will be offered brief interventions (which can be delivered via a clinician or smartphone app) to enhance treatment engagement and to minimize confounding of lithium non-response with non-adherence.

Conclusions

The paper outlines the rationale, design and methodology of the first study being undertaken by the newly established R-LiNK collaboration and describes how the project may help to refine the clinical response phenotype and could translate into the personalization of lithium treatment.

Electronic supplementary material

The online version of this article (10.1186/s40345-019-0156-x) contains supplementary material, which is available to authorized users.

Neurodevelopmental subtypes of bipolar disorder are related to cortical folding patterns: An international multicenter study

OBJECTIVES

Brain sulcation is an indirect marker of neurodevelopmental processes. Studies of the cortical sulcation in bipolar disorder have yielded mixed results, probably due to high variability in clinical phenotype. We investigated whole-brain cortical sulcation in a large sample of selected patients with high neurodevelopmental load.

METHODS

A total of 263 patients with bipolar disorder I and 320 controls were included in a multicentric magnetic resonance imaging (MRI) study. All subjects underwent high-resolution T1-weighted brain MRI. Images were processed with an automatized pipeline to extract the global sulcal index (g-SI) and the local sulcal indices (l-SIs) from 12 a priori determined brain regions covering the whole brain. We compared l-SI and g-SI between patients with and without early-onset bipolar disorder and between patients with and without a positive history of psychosis, adjusting for age, gender and handedness.

RESULTS

Patients with early-onset bipolar disorder had a higher l-SI in the right prefrontal dorsolateral region. Patients with psychotic bipolar disorder had a decreased l-SI in the left superior parietal cortex. No group differences in g-SI or l-SI were found between healthy subjects and the whole patient cohort. We could replicate the early-onset finding in an independent cohort.

CONCLUSIONS

Our work suggests that bipolar disorder is not associated with generalized abnormalities of sulcation, but rather with localized changes of cortical folding restricted to patients with a heavy neurodevelopmental loading. These findings support the hypothesis that bipolar disorder is heterogeneous but may be disentangled using MRI, and suggest the need for investigations into neurodevelopmental deviations in the disorder.

Brain activation during fear conditioning in humans depends on genetic variations related to functioning of the hypothalamic-pituitary-adrenal axis: first evidence from two independent subsamples

BACKGROUND

Enhanced acquisition and delayed extinction of fear conditioning are viewed as major determinants of anxiety disorders, which are often characterized by a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis.

METHOD

In this study we employed cued fear conditioning in two independent samples of healthy subjects (sample 1: n=60, sample 2: n=52). Two graphical shapes served as conditioned stimuli and painful electrical stimulation as the unconditioned stimulus. In addition, guided by findings from published animal studies on HPA axis-related genes in fear conditioning, we examined variants of the glucocorticoid receptor and corticotropin-releasing hormone receptor 1 genes.

RESULTS

Variation in these genes showed enhanced amygdala activation during the acquisition and reduced prefrontal activation during the extinction of fear as well as altered amygdala-prefrontal connectivity.

CONCLUSIONS

This is the first demonstration of the involvement of genes related to the HPA axis in human fear conditioning.

Neuroimaging biomarkers in bipolar disorder

There is an urgent need to identify objective biomarkers for the assessment of bipolar disorder, to improve diagnosis and prognostic evaluation. Neuroimaging is a particularly promising approach. We review here the structural and functional neuroimaging studies carried out on bipolar disorder. These studies have led to the development of neurobiological models of bipolar disorder assuming cortical-limbic dysregulation. Dorsal brain structures are thought to decrease in volume and activity in bipolar disorder, reducing inhibition of the ventral-limbic network and enhancing emotional responses. These models also assume abnormal prefrontal-subcortical limbic connectivity. This abnormal connectivity has been identified by both diffusion tensor imaging studies (anatomical connectivity) and functional MRI (functional connectivity). However, studies are currently limited by the heterogeneity of the patients included. Future research should include studies to validate biomarkers for the assessment of bipolar disorder and studies of large and well characterized samples of patients with bipolar disorder.

Neuroimaging biomarkers in bipolar disorder

There is an urgent need to identify objective biomarkers for the assessment of bipolar disorder, to improve diagnosis and prognostic evaluation. Neuroimaging is a particularly promising approach. We review here the structural and functional neuroimaging studies carried out on bipolar disorder. These studies have led to the development of neurobiological models of bipolar disorder assuming cortical-limbic dysregulation. Dorsal brain structures are thought to decrease in volume and activity in bipolar disorder, reducing inhibition of the ventral-limbic network and enhancing emotional responses. These models also assume abnormal prefrontal-subcortical limbic connectivity. This abnormal connectivity has been identified by both diffusion tensor imaging studies (anatomical connectivity) and functional MRI (functional connectivity). However, studies are currently limited by the heterogeneity of the patients included. Future research should include studies to validate biomarkers for the assessment of bipolar disorder and studies of large and well characterized samples of patients with bipolar disorder.

An agent harms a victim: a functional magnetic resonance imaging study on specific moral emotions

The statement: "An agent harms a victim," depicts a situation that triggers moral emotions. Depending on whether the agent and the victim are the self or someone else, it can lead to four different moral emotions: self-anger ("I harm myself"), guilt ("I harm someone"), other-anger ("someone harms me"), and compassion ("someone harms someone"). In order to investigate the neural correlates of these emotions, we examined brain activation patterns elicited by variations in the agent (self vs. other) and the victim (self vs. other) of a harmful action. Twenty-nine healthy participants underwent functional magnetic resonance imaging while imagining being in situations in which they or someone else harmed themselves or someone else. Results indicated that the three emotional conditions associated with the involvement of other, either as agent or victim (guilt, other-anger, and compassion conditions), all activated structures that have been previously associated with the Theory of Mind (ToM, the attribution of mental states to others), namely, the dorsal medial prefrontal cortex, the precuneus, and the bilateral temporo-parietal junction. Moreover, the two conditions in which both the self and other were concerned by the harmful action (guilt and other-anger conditions) recruited emotional structures (i.e., the bilateral amygdala, anterior cingulate, and basal ganglia). These results suggest that specific moral emotions induce different neural activity depending on the extent to which they involve the self and other.

Cross-cultural validation of the empathy quotient in a French-speaking sample

OBJECTIVE

The Empathy Quotient (EQ) is a self-report that was developed to measure the cognitive and affective aspects of empathy. We further evaluated its validity in 2 studies.

METHOD

The psychometric qualities of the French version of the EQ, and its correspondence with 2 other measures of empathy (Interpersonal Reactivity Index and the Empathy Scale of the Impulsiveness-Venturesomeness-Empathy Questionnaire), and with dimensions of the emotional state (depression and anxiety), were evaluated in a sample of 410 students (201 men and 209 women). Second, the clinical validity of the EQ was investigated in participants expected to have dysfunctional empathy. For this purpose, EQ scores of 16 people with autistic spectrum disorder (ASD) were collected.

RESULTS

The EQ showed satisfying internal, convergent, test-retest and discriminant validity. The confirmatory factorial analyses suggested a 3-factor structure offered a good fit to the data. The women's superiority in empathy was replicated. As expected, the ASD EQ scores were very low.

CONCLUSION

This study provides further evidence that the EQ is reliable in this population and should be recommended to estimate empathy problems, notably in individuals with troubled interpersonal interaction patterns.

Increased white matter connectivity in euthymic bipolar patients: diffusion tensor tractography between the subgenual cingulate and the amygdalo-hippocampal complex

Bipolar disorder has been associated with anatomical as well as functional abnormalities in a brain network that mediates normal and impaired emotion regulation. Previous brain imaging studies have highlighted the subgenual cingulate (SC) and the amygdalo-hippocampal (AH) complex as core regions of this network. Thus we investigated white matter (WM) fiber tracts between the SC and the AH region, the uncinate fasciculus, as well as between two control regions (pons and cerebellum), using diffusion tensor imaging tractography in 16 euthymic bipolar patients (BP) and 16 sex-, age- and handedness-matched controls. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the reconstructed fiber bundle and the number of virtual reconstructed fibers were compared between groups. The tractography results revealed a significantly increased number of reconstructed fibers between the left SC and left AH in BP as compared to healthy controls. FA and ADC of the reconstructed fiber tract did not differ significantly between the groups. Furthermore, no significant group differences were observed neither for reconstructed fiber tracts between the right SC and right AH nor between the control regions. The present results suggest an altered WM pathway between the left SC and AH region and thus extend previous findings of anatomical and functional modifications in these structures in BP.

Hippocampal volume in chronic posttraumatic stress disorder (PTSD): MRI study using two different evaluation methods

The hippocampus is discussed as one of the key regions in the pathogenesis of Posttraumatic Stress Disorder (PTSD). MRI results concerning the volume of the hippocampus are, however, inconsistent. This may be due to the heterogeneity of patients' traumata or postprocessing of the imaging data. To overcome these problems, the present study investigates volume changes in well-characterized chronic PTSD patients in comparison to controls using two different evaluation methods.

MATERIAL AND METHODS

15 patients with chronic PTSD, traumatized at the same air show plane crash in 1988 (Ramstein, Germany), and 15 matched healthy controls participated in this study. All patients suffered from significant impairment by the PTSD; none had a history of drug or alcohol abuse. Hippocampus volume changes were processed by a semi-automated standard procedure performed with BRAINS2 as well as the voxel based morphometry (VBM) using SPM2.

RESULTS

No differences in total brain grey or white matter were detected between patients and controls. No differences in total hippocampal volume or in right and left parts were seen, even when hippocampal volumes were corrected by total brain volume or correlated with clinical data. Finally, no significant differences were detected between patients and controls in hippocampal regions using VBM.

DISCUSSION

This is the first study examining long-term changes in hippocampal volumes in chronic PTSD patients compared to matched controls using two different evaluation methods. Neither conventional volumetry nor VBM could detect any differences in the volume and structure. This supports the hypothesis that previously described hippocampal volume reduction is not necessarily due to PTSD or at least that, after 15 years, volume changes have been restored or have not yet developed.

Stimulus-induced craving and startle potentiation in abstinent alcoholics and controls

Abstinent alcoholics often deny craving for alcohol but still show a high level of relapse. The eyeblink response to startling noise was used as an indicator of the emotional response to alcohol-related, positive, negative and neutral visual stimuli in abstinent alcoholics, social drinkers and rarely drinking controls. The cognitive evaluation of the stimuli was assessed by ratings of subjective craving, valence and arousal. The startle response of the alcoholics to alcohol-related stimuli was significantly inhibited despite an aversive overt stimulus-evaluation. These findings indicate that alcohol-related stimuli may have appetitive incentive salience for alcoholics in spite of verbal reports of craving and valence to the opposite.