The neurobiological reward system and binge eating: A critical systematic review of neuroimaging studies.

OBJECTIVE: Changes in reward processing are hypothesized to play a role in the onset and maintenance of binge eating (BE). However, despite an increasing number of studies investigating the neurobiological reward system in individuals who binge eat, no comprehensive systematic review exists on this topic. Therefore, this review has the following objectives: (1) identify structural and functional changes in the brain reward system, either during rest or while performing a task; and (2) formulate directions for future research. METHODS: A search was conducted of articles published until March 31, 2022. Neuroimaging studies were eligible if they wanted to study the reward system and included a group of individuals who binge eat together with a comparator group. Their results were summarized in a narrative synthesis. RESULTS: A total of 58 articles were included. At rest, individuals who binge eat displayed a lower striatal dopamine release, a change in the volume of the striatum, frontal cortex, and insula, as well as a lower frontostriatal connectivity. While performing a task, there was a higher activity of the brain reward system when anticipating or receiving food, more model-free reinforcement learning, and more habitual behavior. Most studies only included one patient group, used general reward-related measures, and did not evaluate the impact of comorbidities, illness duration, race, or sex. DISCUSSION: Confirming previous hypotheses, this review finds structural and functional changes in the neurobiological reward system in BE. Future studies should compare disorders, use measures that are specific to BE, and investigate the impact of confounding factors. PUBLIC SIGNIFICANCE STATEMENT: This systematic review finds that individuals who binge eat display structural and functional changes in the brain reward system. These changes could be related to a higher sensitivity to food, relying more on previous experiences when making decisions, and more habitual behavior. Future studies should use a task that is specific to binge eating, look across different patient groups, and investigate the impact of comorbidities, illness duration, race, and sex.

OBJETIVO: Se plantea la hipótesis de que los cambios en el procesamiento de la recompensa desempeñan un papel en el inicio y mantenimiento de los atracones (BE). Sin embargo, a pesar de un número creciente de estudios que investigan el sistema de recompensa neurobiológica en individuos que comen en atracones, no existe una revisión sistemática exhaustiva sobre este tema. Por lo tanto, esta revisión tiene los siguientes objetivos: (1) identificar cambios estructurales y funcionales en el sistema de recompensa cerebral, ya sea en reposo o mientras se realiza una tarea; (2) formular direcciones para futuras investigaciones. MÉTODOS: Se realizó una búsqueda de artículos publicados hasta el 31 de marzo de 2022. Los estudios de neuroimagen eran elegibles si querían estudiar el sistema de recompensa e incluían a un grupo de individuos que comían en atracón junto con un grupo de comparación. Sus resultados se resumieron en una síntesis narrativa. RESULTADOS: Se incluyeron un total de 58 artículos. En reposo, los individuos que comen en atracón mostraron una menor liberación de dopamina estriatal, un cambio en el volumen del cuerpo estriado, la corteza frontal y la ínsula, así como una menor conectividad frontostriatal. Al realizar una tarea, hubo una mayor actividad del sistema de recompensa cerebral al anticipar o recibir alimentos, más aprendizaje de refuerzo sin modelos y un comportamiento más habitual. La mayoría de los estudios sólo incluyeron un grupo de pacientes, utilizaron medidas generales relacionadas con la recompensa y no evaluaron el impacto de las comorbilidades, la duración de la enfermedad, la raza o el sexo. DISCUSIÓN: Confirmando hipótesis anteriores, esta revisión encuentra cambios estructurales y funcionales del sistema de recompensa neurobiológica en BE. Los estudios futuros deben comparar los trastornos, utilizar medidas que sean específicas para el comer en atracones e investigar el impacto de los factores de confusión.

Regulation of CD4+ and CD8+ T Cell Biology by Short-Chain Fatty Acids and Its Relevance for Autoimmune Pathology.

The gut microbiota encodes a broad range of enzymes capable of synthetizing various metabolites, some of which are still uncharacterized. One well-known class of microbiota-derived metabolites are the short-chain fatty acids (SCFAs) such as acetate, propionate, butyrate and valerate. SCFAs have long been considered a mere waste product of bacterial metabolism. Novel results have challenged this long-held dogma, revealing a central role for microbe-derived SCFAs in gut microbiota-host interaction. SCFAs are bacterial signaling molecules that act directly on host T lymphocytes by reprogramming their metabolic activity and epigenetic status. They have an essential biological role in promoting differentiation of (intestinal) regulatory T cells and in production of the anti-inflammatory cytokine interleukin-10 (IL-10). These small molecules can also reach the circulation and modulate immune cell function in remote tissues. In experimental models of autoimmune and inflammatory diseases, such as inflammatory bowel disease, multiple sclerosis or diabetes, a strong therapeutic potential of SCFAs through the modulation of effector T cell function was observed. In this review, we discuss current research activities toward understanding a relevance of microbial SCFA for treating autoimmune and inflammatory pathologies from in vitro to human studies.

The transition from restrictive anorexia nervosa to binging and purging: a systematic review and meta-analysis.

Numerous studies addressed the topic of behavioral and symptomatic changes in eating disorders. Rates of transition vary widely across studies, ranging from 0 to 70.8%, depending on the diagnoses taken into account and the study design. Evidence shows that the specific transition from restrictive-type anorexia nervosa (AN-R) to disorders involving binging and purging behaviors (BPB) is related to a worsening of the clinical picture and worse long-term outcomes. The aim of this systematic review and meta-analysis is to focus on this specific transition, review existing literature, and summarize related risk factors. Medline and PsycINFO databases were searched, including prospective and retrospective studies on individuals with AN-R. The primary outcome considered was the rate of onset of BPB. Twelve studies (N = 725 patients) were included in the qualitative and quantitative analysis. A total of 41.84% (95% CI 33.58-50.11) of patients with AN-R manifested BPB at some point during follow-up. Risk factors for the onset of BPB included potentially treatable and untreatable factors such as the family environment, unipolar depression and higher premorbid BMI. These findings highlight that patients with AN-R frequently transition to BPB over time, with a worsening of the clinical picture. Existing studies in this field are still insufficient and heterogeneous, and further research is needed. Mental health professionals should be aware of the frequent onset of BPB in AN-R and its risk factors and take this information into account in the treatment of AN-R. LEVEL OF EVIDENCE: Evidence obtained from a systematic review and meta-analysis, Level I.

Investigating the stress-related fluctuations of level of personality functioning: A critical review and agenda for future research.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the International Classification of Diseases (ICD-11) proposed a dimensional approach to the assessment of personality disorders (PDs). Both models dictate that the clinician first determines PD severity before assessing maladaptive traits, invoking the level of personality functioning (LPF) construct. We consider LPF a promising dimensional construct for translational research because of its clinical importance and conceptual overlap with the Research Domain Criteria (RDoC) Social Processes. We aim to identify biomarkers that co-vary with fluctuations in LPF in adulthood, ultimately to predict persistent decrease in LPF, associated with suicidality and morbidity. However, a theoretical framework to investigate stress-related oscillations in LPF is currently missing. In this article, we aim to fill this hiatus with a critical review about stress and LPF. First, we discuss acute stress and LPF. We briefly present the basics of the neurophysiological stress response and review the literature on momentary and daily fluctuations in LPF, both at a subjective and physiological level. Second, we review the effects of chronic stress on brain function and social behaviour and recapitulate the main findings from prospective cohort studies. This review underlies our suggestions for multimethod assessment of stress-related oscillations in LPF and our theoretical framework for future longitudinal studies, in particular studies using the experience sampling method (ESM).

Sociodemographic and clinical characteristics of eating disorder patients treated in the specialized residential settings in Belgium.

INTRODUCTION: Epidemiologic information on sociodemographic and clinical characteristics in eating disorders in Western European countries are scarce. PURPOSE: In this study, we report demographic and clinical characteristics of eating disorder (ED) patients undergoing treatment in five specialized ED centers in Flanders (Belgium). METHOD: Data from 642 ED patients were collected by means of a structured questionnaire. RESULTS: Data show that 93.8% of patients are female, with an average age of 22.6 years. The largest subgroup in our sample suffers from anorexia nervosa, namely 52.8%. Bulimia nervosa (BN), binge eating disorder (BED) and eating disorder not otherwise specified (EDNOS) account for 17.7%, 10.7% and 18.8% of the sample, respectively. Mean age of onset was 17 years. Mean duration of illness was 5.6 years, but 20.2% of patients had their illness for over 8 years. Anorexia nervosa patients of the restricting type (AN-R) have the shortest duration of illness. BED patients stood out because they were older on average, more often in a relationship and more often in ambulatory treatment. 70% of patients over 20 years old completed higher education, but one-third of this group was unemployed and/or disabled. Remarkably, ED patients grow more up in intact families compared to the general population. CONCLUSIONS: Epidemiology of ED patients in treatment in Flanders (Belgium) seems to resemble worldwide findings. The long duration of illness, the common evolution towards chronicity and the early work impairment underline the severe personal and societal impact of ED and call to the need for early detection and treatment of these patients. LEVEL OF EVIDENCE: Level V: cross-sectional descriptive study.

Depression and suicidality: A link to premature T helper cell aging and increased Th17 cells.

BACKGROUND: Previous research has demonstrated a strong link between immune system abnormalities and Major Depressive Disorder (MDD). High suicide risk is a major complication of MDD and has recently been linked to strong (neuro-)immune alterations, but little is known on the link between circulating immune cell composition and suicidal risk status. METHODS: Here, we assessed percentages of circulating peripheral blood mononuclear cells with focus on T helper cell subsets (memory T helper cells, Th1, Th2, Th17 and T regulatory cells) in a large and well-matched cohort of 153 patients diagnosed with MDD and 153 age and sex matched controls. We explored the association of these cell populations with suicide risk while accounting for age, sex, BMI, depression severity and childhood trauma. RESULTS: Patients with MDD had reduced percentages of NK cells, and higher percentages of B and T cells in line with current literature. Further exploration of T-cells revealed a robustly elevated number of memory T helper cells, regardless of age group. Patients at high risk for suicide had the highest memory T helper cells and additionally showed a robust increase of Th17 cells compared to other suicide risk groups. CONCLUSIONS: The higher abundance of memory T helper cells points towards premature aging of the immune system in MDD patients, even during young adulthood. Patients at high risk for suicide show the clearest immune abnormalities and may represent a clinically relevant subtype of depression.

Binge eating and purging in first-year college students: Prevalence, psychiatric comorbidity, and academic performance.

BACKGROUND: Binge eating and purging behaviors (BPB) are common among college students, but evidence is scant on prevalence and associations of BPB with mental health problems and objective academic performance. This study aims to investigate: (a) 12-month prevalence of BPB among college first-year students, (b) comorbidity patterns of BPB with various mental health problems, and (c) the association of BPB with objective academic functioning. METHODS: Using data from the Leuven College Surveys (Belgium), as part of the World Mental Health Surveys International College Student initiative, we cross-sectionally assessed 12-month BPB and mental health problems among college first-year students (n = 4,889; response rate = 73.2%) at the beginning of the academic year. Objective measures of academic functioning (final grades, expressed in academic year percentage "AYP" [0-100%] and academic failure) were obtained from administrative records at the end of the academic year. RESULTS: Twelve-month prevalence of BPB was 7.6% (7.3%binge eating and 1.0%purging), with higher rates among females than males. Bivariate models showed an association between BPB and numerous mental health problems (ORs = 3.4-18.4). Multivariate models showed associations with non-suicidal self-injury, post-traumatic stress, internalizing/externalizing problems and suicidal ideation. After controlling for sociodemographic characteristics and comorbid mental health problems, BPB were still associated with lower AYP (-4.1 to -11.2% range) and elevated odds of academic year failure (ORs = 1.4-4.2). CONCLUSIONS: BPB (especially binge eating) are relatively common and associated with mental health problems, comparatively low academic performance, and higher risk of academic failure among college first-year students. Further study is needed to examine the causal dynamics underlying these associations.

The effect of trauma and dissociation on the outcome of cognitive behavioural therapy for binge eating disorder: A 6-month prospective study.

BACKGROUND: Binge eating disorder (BED) is commonly associated with a history of trauma. Yet, there is little insight into the potential effect that trauma, dissociation, and depressive symptoms may have on the outcome of treatment interventions. METHODS: A total of 142 treatment-seeking patients admitted with a diagnosis of DSM-5 BED (88% female; mean age = 38.7; SD = 10.8) took part in a 6-month, protocolized, group cognitive behavioural therapy (CBT). Self-report questionnaires were administered to assess lifetime traumatic experiences, dissociation, and depression. Body mass index and the number of binges per week (BPW) were measured throughout treatment. The main outcomes were the percentage reduction in BPW and remission (i.e., less than one BPW; cf. DSM-5). RESULTS: Most BED patients (91.5%) reported a history of trauma, with two in three patients reporting three or more traumatic experiences. Whereas the number of traumatic experiences was not significantly associated with a reduction in BPW or remission, a higher traumatic impact score significantly decreased the likelihood of obtaining remission at the end of treatment (OR = 0.96; 95% CI [0.92, 0.99]). Higher levels of dissociative symptoms partially mediated this prospective association. CONCLUSIONS: The impact of traumatic experiences, as opposed to the number of traumatic experiences experienced, negatively predicts remission after 6 months of CBT. These findings highlight the importance of addressing trauma and dissociative features in the CBT treatment of BED.

Heart rate and high frequency heart rate variability during stress as biomarker for clinical depression. A systematic review.

The interaction of physical and mental vulnerability and environmental constraints is thought to foster the development of psychiatric disorders such as major depressive disorder (MDD). A central factor in the development of psychopathology is mental stress. Despite some evidence for parasympathetic withdrawal and sympathetic overactivity in MDD, the psychophysiological response to stress in depression is not clear-cut. Given the growing interest in heart rate and heart rate variability as indicators for remote monitoring of patients, it is important to understand how patients with MDD react to stress in a laboratory-controlled environment. We conducted a systematic review of studies using electrocardiography to derive heart rate and heart rate variability during stress in patients with clinical depression. We focused on well-validated stress tasks- the mental arithmetic stress task, the Trier social stress task and public speaking task- to minimize confounding effects due to the nature of the stressor. The majority of studies found hypo-reactivity during stress as a hallmark of depression as evidenced by lower fluctuation in heart rate and heart rate variability in the high-frequency band. We address the potential underlying biological mechanisms, the influence of covariates on these measures and briefly discuss the specificity and potential for remote monitoring by using these variables.

Characteristics and content of intrusive images in patients with eating disorders.

The aim of this study was to examine the characteristics and content of intrusive images in patients with different subtypes of eating disorders (EDs). Data were collected from 74 ED patients, 22 dieting, and 29 nondieting controls. Participants completed a set of self-report questionnaires. Intrusive images of ED patients were significantly more repetitive, detailed, vivid, and distressing than intrusive images of dieting and/or nondieting controls. Most of the intrusive images were the same for the ED subtypes; however, patients with anorexia nervosa were more likely to report an observer vantage perspective than patients with bulimia nervosa, who were more likely to report a field vantage perspective. As expected, intrusive images' content was related to body checking (weight and shape) or negative self (evaluated by themselves or others). Finally, there were significant associations between intrusive images' vividness and weight and shape concerns. These findings indicate that intrusive images may be a core element of EDs and targeting intrusive images in therapy may be helpful.

The relation between stress-induced dopamine release in the ventromedial prefrontal cortex, fronto-striatal functional connectivity, and negative urgency: A multimodal investigation using [18F]Fallypride PET, MRI and experience sampling.

Negative urgency (NU), or the tendency to act rashly when stress of negative affect is high, could be the result of an insufficient control of the ventromedial prefrontal cortex (vmPFC) over the striatum, through an impaired dopamine (DA) transmission. Therefore, we investigated in vivo human stress-induced DA release in the vmPFC, its relation with fronto-striatal functional connectivity (FC), and NU in daily life. In total, 12 female healthy participants performed a simultaneous [18 F]fallypride PET and fMRI scan during which stress was induced. Regions displaying stress-induced DA release were identified and used to investigate stress-induced changes in fronto-striatal FC. Additionally, participants enrolled in an experience sampling study, reporting on daily life stress and rash actions over a 12-month-long period. Mixed models explored whether stress-induced DA release and FC moderated NU in daily life. Stress led to a lower FC between the vmPFC and dorsal striatum, but a higher FC between the vmPFC and contralateral ventral striatum. Participants with a higher FC between the vmPFC and dorsal striatum displayed more NU in daily life. A higher stress-induced DA release in the vmPFC was related to a higher stress-induced change in FC between the vmPFC and striatum. Participants with a higher DA release in the vmPFC displayed more NU in daily life. In conclusion, stress could differentially impact fronto-striatal FC whereby the connectivity with the dorsal striatum is especially important for NU in daily life. This could be mediated by a higher, but not a lower, stress-induced DA release in the vmPFC.

Measuring extrastriatal dopamine release during a reward learning task.

OBJECTIVES: Reward learning is critical for survival. Animal research emphasizes the role of dopaminergic (DA) mesocorticolimbic pathways in reward learning, but few studies have evaluated extrastriatal DA functioning in humans. The purpose of this study was to examine presynaptic DA release in extrastriatal regions of the reward circuit by measuring displacement of the high affinity D(2) /D(3) radioligand [(18) F]Fallypride during a reward task. DESIGN: Ten healthy volunteers underwent a [(18) F]Fallypride positron emission tomography protocol while performing a reward task, allowing us to assess participants' ability to modulate behavior as a function of reward. DA receptor ligand displacement was correlated with task performance and self-reported anhedonia. OBSERVATIONS: Parametric t-maps revealed significant decrease in [(18) F]Fallypride binding in the medial orbitofrontal cortex (mOFC), ventromedial prefrontal cortex (vmPFC), and dorsal anterior cingulate cortex (dACC), indicating endogenous DA release in these regions. Increasing anhedonic symptoms correlated with DA release in the left vmPFC, left dACC, and right dACC emerged (all r's > 0.65, P's < 0.05). Similarly, reduced reward learning correlated with higher DA release in left vmPFC, right vmPFC, and left dACC (all r's < -0.64, P's < 0.05). Left dACC (r = 0.66, P = 0.04) and left vmPFC (r = 0.74, P = 0.01) DA release showed a significant positive correlation with impaired tendency to modulate behavior as a function of prior positive reinforcements. CONCLUSIONS: These findings support the hypothesis that DA release in mOFC, vmPFC, and dACC regions plays an important role in reinforcement learning in the human brain.

Neuronal activity and reward processing in relation to binge eating.

PURPOSE OF REVIEW: Studies increasingly show the importance of reward processing in binge eating and provide evidence of associated changes in the neurobiological reward system. This review gives an up-to-date overview of the neurobiological substrates of reward processing subconstructs in binge eating. Neural findings are linked to different behavioral theories and the clinical relevance is discussed. RECENT FINDINGS: Increased neural responses in the orbitofrontal cortex, anterior cingulate cortex as well as striatum during anticipation and receipt of food rewards are found in association to binge eating. Increased model-free learning is also found and associated with altered brain reward reactivity. Data in rest report reduced striatal dopamine release and lower frontostriatal connectivity. Mechanisms of onset of binge eating are less clear, but specific personality traits, related to frontostriatal dysconnectivity, probably increase the risk of binge eating onset. SUMMARY: Both structural and task-based imaging studies show differences in the neurobiological reward system in binge eating. These changes are linked to specific reward processing, such as altered reward responsiveness to food cues, reinforcement learning, and habitual behavior. Findings are lined with different behavioral theories of binge eating, and a staging model is described, from onset to full illness development. Understanding the specific underlying aberrant reward mechanism in binge eating, associated with different stages of the illness, enables caregivers to focus their treatment more precisely.

How negative affect does and does not lead to binge eating-The importance of craving and negative urgency in bulimia nervosa.

Studies suggest that negative affect (NA) can trigger binge eating (BE) in patients with bulimia nervosa (BN). Important factors in this relation between NA and BE could be craving (an intense desire for a BE episode) and negative urgency (the tendency to act rashly when NA is high). Therefore, this study wants to firstly explore the relations between NA, craving, rash action, and BE in daily life and secondly whether craving and rash action mediate the relationship between NA and BE. A sample of 70 female patients with BN and 76 female healthy controls (HC) took part in an experience sampling study where they reported on momentary NA, craving, rash action, and eating behaviors in daily life in a burst-measurement design over a period of 12 months. Assessments occurred eight times a day on Thursdays, Fridays, and Saturdays in seven bursts of 3 weeks, all separated by 5-week periods of no assessment. First, NA predicted subsequent rash action in the whole sample but this was more pronounced in patients with BN. Second, NA predicted subsequent craving in patients with BN, but not in HC. Third, rash action and craving predicted subsequent BE in patients with BN. Fourth, NA had competing effects on eating in patients with BN, predicting subsequent BE through rash action and craving, but also predicting subsequent not eating. These results suggest that NA can lead to BE in daily life through rash action and craving, but that NA can also lead to dietary restriction. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The role of short-chain fatty acids (SCFAs) in regulating stress responses, eating behavior, and nutritional state in anorexia nervosa: protocol for a randomized controlled trial.

OBJECTIVE: This protocol proposes investigating the effects of short-chain fatty acids (SCFAs)-namely acetate, propionate, and butyrate-as mediators of microbiota-gut-brain interactions on the acute stress response, eating behavior, and nutritional state in malnourished patients with anorexia nervosa (AN). SCFAs are produced by bacterial fermentation of dietary fiber in the gut and have recently been proposed as crucial mediators of the gut microbiota's effects on the host. Emerging evidence suggests that SCFAs impact human psychobiology through endocrine, neural, and immune pathways and may regulate stress responses and eating behavior. METHOD: We will conduct a randomized, triple-blind, placebo-controlled trial in 92 patients with AN. Patients will receive either a placebo or a mixture of SCFAs (acetate propionate, butyrate) using pH-dependent colon-delivery capsules for six weeks. This clinical trial is an add-on to the standard inpatient psychotherapeutic program focusing on nutritional rehabilitation. HYPOTHESES: We hypothesize that colonic SCFAs delivery will modulate neuroendocrine, cardiovascular, and subjective responses to an acute laboratory psychosocial stress task. As secondary outcome measures, we will assess alterations in restrictive eating behavior and nutritional status, as reflected by changes in body mass index. Additionally, we will explore changes in microbiota composition, gastrointestinal symptoms, eating disorder psychopathology, and related comorbidities. DISCUSSION: The findings of this study would enhance our understanding of how gut microbiota-affiliated metabolites, particularly SCFAs, impact the stress response and eating behavior of individuals with AN. It has the potential to provide essential insights into the complex interplay between the gut, stress system, and eating behavior and facilitate new therapeutic targets for stress-related psychiatric disorders. This protocol is prospectively registered with ClinicalTrials.gov, with trial registration number NCT06064201.

The influence of maternal cortisol and emotional state during pregnancy on fetal intrauterine growth.

BACKGROUND: This exploratory study investigates the influence of maternal cortisol and emotional state during pregnancy on fetal intrauterine growth (IUG). We expected higher basal cortisol levels, or more depressive and anxious complaints during pregnancy, to be associated with slower IUG and lower birth weight. METHODS: A total of 91 pregnant women were recruited from the antenatal clinic and were seen once each trimester. In addition to psychological assessments, a diurnal cortisol profile was derived from saliva samples. IUG was evaluated using ultrasound. RESULTS: In mid-pregnancy (trimester (T)2), basal cortisol levels significantly predicted the variance of weight (proportion of variance in growth variable explained (PVE) = 11.6%) and body mass index (BMI) at birth (PVE = 6.8%). In late pregnancy (T3) emotional state, particularly depressive symptoms (BMI at birth: PVE = 6.9%; ponderal index (PI) at birth: PVE = 8.2%; head circumference at T3: PVE = 10.3%; head circumference at birth PVE = 9.1%) and attachment (BMI at birth: PVE = 6.9%; PI at birth: PVE = 7.2%) had an influence on growth. Analysis of growth between T2 and T3 showed that attachment and cortisol in T3 had an influence on the variation in increase in estimated fetal weight (PVE = 12.5-8.6%). CONCLUSION: These data indicate basal cortisol levels were more important in T2 whereas emotional state was more important in T3.

Exhausted Heart Rate Responses to Repeated Psychological Stress in Women With Major Depressive Disorder.

Past research links depression and blunted cardiac vagal reactivity to chronic stress. Yet, to our knowledge no experiment investigates heart rate (variability) responses to a repeated laboratory stressor in patients with depression. Repeated exposure may provide valuable information on stress reactivity in depression. Fifty-nine women (30 inpatients diagnosed with depression and 29 matched controls) underwent two consecutive runs of a mental arithmetic stress paradigm consisting of one baseline and two exposures to control, stress, and recovery phases of 5 min each, in a case-control design. Subjective stress and electrocardiography were recorded. Variance of heart rate (HR) and root mean square of successive RR interval differences (RMSSD) were analyzed using linear mixed models. Overall, physiological parameters (HR and RMSSD) and subjective stress showed a strong group effect (all p < 0.001). In both groups, subjective stress and HR increased in response to stress, but the subjective stress levels of patients with depression did not return to baseline levels after the first stressor and for the remainder of the experiment (all p < 0.004 compared to baseline). Patients' HR reactivity responded oppositely: while HR recovered after the first stress exposure, no reactivity was observed in response to the second exposure. These findings may suggest that the often-reported blunted HR/HRV response to stressors results from exhaustion rather than an incapacity to react to stress. The altered HR reactivity could indicate allostatic (over-) load in depression.

The cumulative effect of chronic stress and depressive symptoms affects heart rate in a working population.

Background: Chronic stress and depressive symptoms have both been linked to increased heart rate (HR) and reduced HR variability. However, up to date, it is not clear whether chronic stress, the mechanisms intrinsic to depression or a combination of both cause these alterations. Subclinical cases may help to answer these questions. In a healthy working population, we aimed to investigate whether the effect of chronic stress on HR circadian rhythm depends on the presence of depressive symptoms and whether chronic stress and depressive symptoms have differential effects on HR reactivity to an acute stressor. Methods: 1,002 individuals of the SWEET study completed baseline questionnaires, including psychological information, and 5 days of electrocardiogram (ECG) measurements. Complete datasets were available for 516 individuals. In addition, a subset (n = 194) of these participants completed a stress task on a mobile device. Participants were grouped according to their scores for the Depression Anxiety Stress Scale (DASS) and Perceived Stress Scale (PSS). We explored the resulting groups for differences in HR circadian rhythm and stress reactivity using linear mixed effect models. Additionally, we explored the effect of stress and depressive symptoms on night-time HR variability [root mean square of successive differences (RMSSD)]. Results: High and extreme stress alone did not alter HR circadian rhythm, apart from a limited increase in basal HR. Yet, if depressive symptoms were present, extreme chronic stress levels did lead to a blunted circadian rhythm and a lower basal HR. Furthermore, blunted stress reactivity was associated with depressive symptoms, but not chronic stress. Night-time RMSSD data was not influenced by chronic stress, depressive symptoms or their interaction. Conclusion: The combination of stress and depressive symptoms, but not chronic stress by itself leads to a blunted HR circadian rhythm. Furthermore, blunted HR reactivity is associated with depressive symptoms and not chronic stress.

How COVID-19 lockdown measures could impact patients with bulimia nervosa: Exploratory results from an ongoing experience sampling method study.

OBJECTIVE: The impact of COVID-19 lockdown measures on patients with an eating disorder remains unclear, but preliminary results indicate that some patients could be more vulnerable to experience an increase in eating disorder pathology than others. To provide possible directions for future research, this report explored the impact of the Belgian COVID-19 lockdown measures on patients with bulimia nervosa (BN). METHODS: The data of 15 female patients with BN from an ongoing experience sampling method study were analyzed. Mixed effects models compared surroundings, social context, negative affect (NA), positive affect (PA) and binge eating before and after the implementation of the lockdown measures. RESULTS: After the implementation of the lockdown measures, significant changes in surroundings and social context were found as well as an increase in NA and decrease in PA. Patients who experienced a higher binge eating frequency during the lockdown also experienced a stronger change in NA and PA. CONCLUSIONS: Future research should also look at changes in surroundings, social context, affect and how these interact with factors such as personality traits and coping styles when investigating why some patients are more susceptible to the negative effects of lockdown measures than others.