Interoception in anxiety and depression

Altered functional connectivity of thalamic subregions in premenstrual syndrome

PURPOSE

This article aims to explore the relationship between the symptoms of PMS and changes of thalamic subregions.

METHODS AND MATERIALS

71 patients diagnosed with PMS and 81 healthy controls (HCs) were included in the study. Participant status was determined using the Daily Record of Severity of Problems (DRSP) scale. All participants underwent functional and structural scans, and peripheral venous blood samples were collected to assess the cytokine and hormone levels. Resting-state functional connectivity (rsFC) and grey matter volume (GMV) of thalamic subregions were calculated from the MRI data. Correlation analyses were then conducted to investigate the associations between these neuroimaging indicators and the clinical features of PMS.

RESULTS

The rsFC analysis revealed that PMS patients showed lower rsFC between the middle frontal gyrus (MFG) and the left thalamic medial posterior and ventral nuclei while higher rsFC between the insula and the left lateral posterior(LP) nuclei compared to HCs. Additionally, the findings demonstrated a correlation between the DRSP scores and rsFC, while the DRSP scores were positively correlated with (TNF-α) levels. Furthermore, the rsFC was found to be correlated with part of the inflammatory cytokines.

CONCLUSION

The findings suggest that the observed functional connectivity alterations of the thalamus subregions are associated with the score of DRSP. This relationship appears to be largely dependent on the inflammation affecting the thalamic neural circuit, particularly the thalamic-MFG-insula network.

The desegregation of neural networks during worry induction in late-life-an effective connectivity analysis

BACKGROUND

Severe worry is a core component of anxiety and depressive disorders and is independently associated with significant morbidity and mortality. However, the neural basis of worry is poorly understood. We investigated effective connectivity (EC) using functional magnetic resonance imaging (fMRI) of a naturalistic worry induction and reappraisal task in late-life.

METHODS

112 participants age >50 years with varying worry severity completed a personalized, in-scanner worry induction and reappraisal task. We calculated voxel-wise EC in neutral, worry, and reappraisal conditions with generalized psychophysiological interactions using seeds in the subgenual anterior cingulate cortex (ACC), dorsal ACC, and left and right amygdalae, and used paired t-tests to compare conditions. We assessed clusters for association with in-scanner worry severity using linear regression.

RESULTS

During the worry condition, EC increased between the subgenual ACC and the default mode network (DMN) and major hubs of the executive control and salience networks. Left amygdala EC to the posterior cingulate also increased during worry, and dorsal ACC connectivity to primary sensory and motor regions decreased. Reappraisal reduced subgenual and dorsal ACC EC observed during worry and the EC between the left amygdala and regions of the dorsal attention network. Broadly, left amygdala EC was robustly associated with in-scanner worry severity.

CONCLUSIONS

Worry induction robustly engaged the DMN and increased connectivity with other high-order associative networks, potentially subsuming cortical resources. Reappraisal reduced these connectivities and disengaged the amygdala from areas associated with top-down attention. These findings could inform targets for neuromodulatory treatment of severe worry in older adults.

Mindfulness-based stress reduction training supplemented with physiological signals from smartwatch improves mindfulness and reduces stress, but not anxiety and depression

INTRODUCTION

Mindfulness-Based Stress Reduction (MBSR) helps counteract the negative consequences of stress. An essential aspect of mind-body therapies is learning to be mindful of emotional reactions and bodily sensations, a process defined as interoceptive awareness. This awareness can also be enhanced by providing physiological feedback from a smartwatch. However, the impact of using smartwatch-generated physiological signals during mindfulness training has not been studied yet. The study aims at verifying, whether physiological signals from a smartwatch would support the MBSR.

METHODS

We conducted a mixed-design randomized controlled trial to investigate the effects of MBSR training, with and without monitoring physiological signals via a smartwatch, on mental functioning parameters, with measurements taken at baseline and after 8 weeks. Participants were classified into three groups (N = 72): the MBSR group, the MBSR + smartwatch group, and the control group. Between measurement sessions, two groups of participants were engaged in MBSR training, while the third group did not participate in any training.

RESULTS

Results showed a significant reduction in subjectively perceived stress levels, eating disorder symptoms, and intrusive ruminations in both groups participating in MBSR, compared to the control group. However, a notable difference emerged between the two MBSR groups: in the group with smartwatches, a significant increase in mindfulness was observed. In contrast, in the MBSR group without smartwatches, there was a significant decrease across multiple stress-related components, including: anxiety, cognitive impairment, addictions, sleep disorders symptoms, behaviors indicating lack of entertainment, and poor functioning.

CONCLUSIONS

The results suggest that supplementing MBSR with monitoring interoceptive signals by a smartwatch enhances mindfulness, and maintains the effect of stress and eating disorders symptoms reduction but does not decrease anxiety nor improve general mental functioning. This imposes the need for further research to investigate mechanisms involved when observing interoceptive signals by a smartwatch.

Heart rate increases during social isolation: matter of depressive mood and self-reported infection symptoms

While the mental health challenges posed by quarantine are well-documented, its physiological effects remain less understood. We examined cardiovascular trajectories over a 6-day quarantine following common cold infection, utilizing data from the Pittsburgh Cold Study 3 (n=213, 2007-2011). Specifically, we explored the relationship between depressive mood and heart rate (HR) patterns, hypothesizing that individuals prone to depressive mood might experience altered arousal during quarantine. We conducted similar analyses for blood pressure (BP) as well. Our findings revealed that, on average, HR increased during quarantine. Notably, individuals reporting higher depressive mood levels exhibited lower initial HR but experienced a sharper increase throughout the quarantine period. In contrast, no significant linear or quadratic changes were observed in systolic blood pressure (SBP). However, initial analyses did identify significant linear changes in diastolic blood pressure (DBP) and mean arterial pressure (MAP). These changes in DBP and MAP were not influenced by depressive mood and lost significance in sensitivity analyses that accounted for infection-related factors, health behaviors, and socio-demographic variables. Interestingly, HR trajectories remained significant in sensitivity analyses but lost significance when self-reported symptoms were included. Self-reported symptoms partially mediated the relationship between depressive mood and HR increases, suggesting that individuals with higher depressive tendencies also reported more infection-related symptoms, contributing to increased HR. These findings highlight how midterm social isolation can elevate HR, particularly in individuals prone to depressive mood. However, the absence of a control group limits broader interpretations, emphasizing the need for further research.

Interoception in Adolescence: Impacts on Mental Health and Adaptive Functioning

Interoception plays a critical role in emotion regulation and mental health during adolescence, a critical period marked by profound biological, cognitive, and emotional changes. Variability in interoceptive processing during adolescence is shaped by biological, hormonal, and psychosocial factors, with implications for both resilience and vulnerability to affective disorders such as anxiety, depression, disordered eating, and substance use. This chapter reviews the trajectory of interoceptive development in adolescence, emphasizing its role in shaping emotional and behavioral outcomes. Interventions aimed at improving interoceptive awareness, including mindfulness practices and body-awareness training, are also reviewed as promising strategies to support emotional resilience and mental well-being during this formative stage. Understanding the complexities of interoception in adolescence provides a foundation for advancing research and interventions that promote adaptive functioning and long-term mental health.

Under the surface: Low cardiac vagal tone and poor interoception in young adults with subclinical depressive symptoms

INTRODUCTION

Depressive symptoms are associated with alterations in central and autonomic nervous system activity, including misperception of bodily activity (e.g., low interoception), somatic symptoms and decreased vagally mediated heart rate variability (vmHRV). However, there is a lack of studies that examine both perception of bodily activity and autonomic function in depression. The present study investigated the association between interoception, vmHRV, and subclinical depressive symptoms.

METHOD

Eighty-eight students were enrolled and vmHRV was calculated from a 5-minute resting electrocardiogram. Interoceptive accuracy (heartbeat tracking task; heartbeat discrimination task), interoceptive sensibility (Body Perception Questionnaire), and depressive symptoms (Depression, Anxiety and Stress Scale - 21 Items) were assessed.

RESULTS

Interoceptive accuracy and sensibility positively correlated with vmHRV and negatively correlates with depressive symptoms. Cluster analysis performed on vmHRV, interoceptive accuracy, and sensibility provided two clusters: the first characterized by a pattern of low interoceptive accuracy, sensibility, and decreased resting vmHRV, the second characterized by an opposite pattern. Regression analyses showed that the first cluster was characterized by significantly higher depressive symptoms compared to the second (β = 1.97; pBonferroni = 0.04), even after controlling for sex, BMI, anxiety, and stress levels.

CONCLUSIONS

Subclinical depressive symptoms are associated with a consistent impairment in the perception and interpretation of bodily activity and altered regulatory function of the autonomic nervous system. The present results suggest that the alteration of brain-body communication could be involved in subclinical depressive symptoms. Early identification of such alterations could help with targeted preventive strategies.

A cross-sectional study on the relationship between interoceptive sensitivity and somatic symptoms in young bipolar disorder patients

BACKGROUND

Bipolar disorder (BD) with somatic symptoms is a prevalent and refractory clinical syndrome in young patients. Interoception is an important mechanism for coordinating internal physiological and mood states to maintain individual homeostasis, and its mediating physiological systems and brain network dynamics undergo significant development from adolescence to young adulthood. It remains unclear whether interoception is altered and how it relates to somatic and mood symptoms in youths with BD.

METHODS

This study recruited 71 youths (aged 14-25) with BD during maintenance status and 111 age-matched controls. Demographic characteristics, interoceptive sensitivity, somatic symptoms, and symptoms of depression and anxiety were assessed. Mann-Whitney U tests, Kruskal-Wallis H test, partial correlation analysis, and multiple linear regression were used to explore the alteration of interoception in BD patients and its association with somatic and mood symptoms.

RESULTS

BD patients showed lower interoception sensitivity and higher somatic and mood symptoms than controls (p < 0.001). Those with somatic symptoms had the highest depression and anxiety (p < 0.001) but the lowest scores in not-distracting, not-worrying, self-regulation, and trust (p < 0.05). Interoceptive indicators correlated with mood and somatic symptoms (p < 0.05). Not-distracting was the sole predictor of somatic and mood issues, maintaining significance after controlling for mood symptoms (p < 0.05), highlighting attentional focus as a key factor in BD youths.

CONCLUSION

BD youths exhibit deficits in interoception sensitivity, somatic symptoms, and mood issues. The not-distracting aspect of interoception significantly correlates with mood and somatic symptoms in youths with BD, providing insights and targeted strategies for managing psychosomatic symptoms in this demographic.

LIMITATIONS

This study has several limitations. First, the control group's inclusion and exclusion criteria lacking clinical validation. Second, assessment for mood and somatic symptoms relied on screening tools rather than validated questionnaires, and structured clinical evaluations for BD were not conducted. Third, medication effects were not considered. Fourth, some psychiatric conditions (e.g., borderline personality disorder, obsessive-compulsive disorder, etc.) comorbid were not considered. Finally, causal relationships cannot be inferred, highlighting the need for longitudinal studies.

Interoception and aging

Interoception refers to the body's perception and regulation of internal physiological states and involves complex neural mechanisms and sensory systems. The current definition of interoception falls short of capturing the breadth of related research; here, we propose an updated definition. Homeostasis, a foundational principle of integrated physiology, is the process by which organisms dynamically maintain optimal balance across all conditions through neural, endocrine, and behavioral functions. This review examines the role of interoception in body homeostasis. Aging is a complex process influenced by multiple factors and involving multiple levels, including physical, psychological, and cognitive. However, interoceptive and aging interoceptive interactions are lacking. A new perspective on interoception and aging holds significant implications for understanding how aging regulates interoception and how interoception affects the aging process. Finally, we summarize that arachidonic acid metabolites show promise as biomarkers of interoception-aging. The aim of this study is to comprehensively analyze interoceptive-aging interactions, understand the aging mechanism from a novel perspective, and provide a theoretical basis for exploring anti-aging strategies.

Breaking through the mind-body divide: patient priorities for interoception research

Background

Interoception-sensation, interpretation, and prediction of bodily signals-is reliably disrupted across a wide range of mental health conditions. A growing body of evidence suggests that interoception is a putative mechanism, or 'active ingredient', of effective psychological and pharmacological treatments. Anecdotally, patients with psychiatric disorders report differences in bodily experiences. However, formal priority setting by people with lived experience of mental health conditions has so far been overlooked in this rapidly expanding research area.

Methods

This article takes a mixed-methods approach to investigate experiences of bodily signals in individuals with mental health conditions and determine patients' research priorities. We recruited two UK samples in the context of an in-person workshop (N = 25) and online (N = 47), between April and July 2024. All contributors had a diagnosis of at least one mental health condition. Using a combination of written contributions and small group discussions, we explored the most relevant bodily sensations for patients' mental health, how bodily sensations were experienced by patients, and which research priorities were considered most important.

Findings

Patients' contributions emphasised the multimodal nature of interoception, in particular the importance of less frequently studied modalities such as the stomach and muscle tension, as well as the need to consider the causes and consequences of distressing bodily sensations. We summarise ten key research priorities for patients, spanning three themes: causes, management, and clinical/research approach to interoception in mental health. These priorities include investigating the impact of bodily signals on social contexts, techniques to manage distressing signals, and a shift of approach towards integrating mental and physical health in clinical/research settings.

Interpretation

Together, this broad scoping study establishes new, transdiagnostic, patient-led priorities for the developing field of interoception in psychiatry to ensure future research focusses on the areas of greatest impact for people with mental health conditions.

Funding

This work was supported by a Wellcome Mental Health award to C.L.N. and S.G. (226778/Z/22/Z), intramural funding from the UK Medical Research Council (MC/UU/00030/12), and a Wellcome Career Development Award to C.L.N. (226490/Z/22/Z). G.M. is funded by an ESRC DTP Studentship (RG84395). This research was also supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014).

The inside story: Interoceptive Pavlovian conditioning with the nicotine stimulus

Pavlovian conditioning plays a crucial role in promoting well-being and supporting healthy behaviors but also contributes to the development of diseases and psychopathologies. Much of the basic and applied research on these conditioning processes has focused on external or exteroceptive cues (tone, spider, context, and brewery) as the conditioned stimulus (CS) or occasion setter. Considerably less empirical effort has been devoted to studying Pavlovian conditioning involving internal or interoceptive stimuli, such as indigestion, low blood sugar, back pain, or drug intoxication function as the CS or occasion setter. In this targeted review, we focus on our research on the interoceptive stimulus effects of nicotine. We summarize methods employing discriminated goal-tracking that have been refined over the years to investigate how the function of the nicotine stimulus changes with excitatory or inhibitory conditioning protocols. That research provides substantive evidence indicating that what is known about Pavlovian conditioning with exteroceptive stimuli generally holds for the nicotine stimulus-extinction, CS salience, generalization, overshadowing, blocking, conditioned inhibition, devaluation, and overexpectation. Extension of the interoceptive conditioning methodology to include intravenous nicotine as a stimulus found that the nicotine stimulus acquires additional reinforcing value when previously paired with an appetitive outcome. In closing this review, we highlight notable gaps in the literature and discuss potential directions for research and conceptual development. Ultimately, we hope to encourage others to consider the intersection of interoception and Pavlovian conditioning in their area of scientific inquiry. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Nitric Oxide in the Hypnotizability-Related Interoception: A Scoping Review

Interoception - the sense of the body - includes the perception of visceral signals and its integration with many other information in the central nervous system. Hypnotizability levels are associated with interoceptive accuracy and sensitivity, likely due to different insula gray matter volume, and different availability of vascular nitric oxide during sensory and cognitive tasks in peripheral arteries and in the brain. This theoretical review deals with the relevance of possible hypnotizability-related nitric oxide availability at various levels of the central nervous system to interoception and, consequently, to physiological and pathological conditions, such as emotion, sleep disturbance, eating behavior, and cardiovascular illness. Moreover, the review suggests that hypnotic assessment could be a predictor of the efficacy of therapies based on improvement of interoception.

The relationship between sleep and interoception

The present study aimed to characterise the relationship between sleep and interoception in two independent studies. Theoretical grounds for such a relationship include a weak relationship between subjectively- and objectively-measured sleep, the covariance of sleep with pain, as well as the mass regulation of a number of visceral biological systems. In addition, such a relationship is often reflected in our language (i.e., 'feeling' tired). In both studies (Study 1: N = 118, 73% female, mean age 20.98 years; Study 2: N = 830, 49% female, mean age 38.04 years) sleep over the last month was self-reported. Confidence in interoceptive accuracy, which is the precision with which a person can monitor visceral signals, was measured using the Interoceptive Accuracy Scale, while interoceptive attention, which is the dispositional tendency to attend to bodily signals, was measured using the Body Perception Questionnaire. Study 1 revealed a relationship between long sleep latency and low confidence in interoceptive accuracy (β = -0.222, p = 0.021) and poor sleep quality and less interoceptive attention (β = -0.226, p = 0.016). Study 2 replicated these results as well as made clear a more general pattern whereby poor sleep-characterised by short duration, poor quality, less efficiency, long latency, and more frequent nighttime awakenings-related to an interoceptive phenotype of less confidence in interoceptive accuracy and more interoceptive attention (all β ≥ 0.047, p ≤ 0.17). In conclusion, results from these two independent studies provide robust cross-sectional evidence for associations between various dimensions of poor sleep and greater interoceptive attention, but less confidence in interoceptive accuracy.

Graded changes in local functional connectivity of the cerebral cortex in young people with depression

BACKGROUND

Major depressive disorder (MDD) is marked by significant changes to the local synchrony of spontaneous neural activity across various brain regions. However, many methods for assessing this local connectivity use fixed or arbitrary neighborhood sizes, resulting in a decreased capacity to capture smooth changes to the spatial gradient of local correlations. A newly developed method sensitive to classical anatomo-functional boundaries, Iso-Distant Average Correlation (IDAC), was therefore used to examine depression associated alterations to the local functional connectivity of the brain.

METHOD

One-hundred and forty-seven adolescents and young adults with MDD and 94 healthy controls underwent a resting-state functional magnetic resonance imaging (fMRI) scan. Whole-brain functional connectivity maps of intracortical neural activity within iso-distant local areas (5-10, 15-20, and 25-30 mm) were generated to characterize local fMRI signal similarities.

RESULTS

Across all spatial distances, MDD participants demonstrated greater local functional connectivity of the bilateral posterior hippocampus, retrosplenial cortex, dorsal insula, fusiform gyrus, and supplementary motor area. Local connectivity alterations in short and medium distances (5-10 and 15-20 mm) in the mid insula cortex were additionally associated with expressive suppression use, independent of depressive symptom severity.

CONCLUSIONS

Our study identified increased synchrony of the neural activity in several regions commonly implicated in the neurobiology of depression. These effects were relatively consistent across the three distances examined. Longitudinal investigation of this altered local connectivity will clarify whether these differences are also found in other age groups and if this relationship is modified by increased disease chronicity.

Preliminary Evidence That Shared Genetic Influences Underlie Comorbidity Between Self-Reported Eating and Internalizing Disorders and Gastrointestinal Disease in Adult Women and Men

INTRODUCTION

Accumulating research suggests both eating disorders (EDs) and internalizing disorders (e.g., anxiety, depression) are associated with gastrointestinal disease (e.g., irritable bowel syndrome, inflammatory bowel disease). However, the mechanisms underlying comorbidity with gastrointestinal disease-and whether they may differ for eating and internalizing disorders-remain poorly understood. Addressing these gaps is a critical first step to refining etiologic models of comorbidity and identifying potential targets for intervention.

METHOD

Participants included female and male twins ages 18-65 from the population-based MSU Twin Registry (N = 5883). Lifetime history of EDs, internalizing disorders, and gastrointestinal disease was assessed via questionnaire. We first examined whether EDs and internalizing disorders were independently associated with gastrointestinal disease phenotypically. We then used trivariate Cholesky decomposition twin models to investigate whether EDs and internalizing disorders were related to gastrointestinal disease through overlapping or distinct genetic/environmental pathways.

RESULTS

Eating (OR = 2.54, p = 0.009) and internalizing (OR = 2.14, p < 0.001) disorders were independently associated with gastrointestinal disease. Conclusions were unchanged after adjusting for important covariates (e.g., body mass index, age) and did not significantly differ across sex. Twin models suggested genetic influences shared by all three conditions explained their co-occurrence, with 31% of the variance in EDs and 12% of the variance in gastrointestinal disease attributable to genetic influences shared with internalizing disorders.

CONCLUSION

Shared genetic mechanisms may contribute to comorbidity between EDs, internalizing disorders, and gastrointestinal disease. Identifying overlapping molecular pathways could potentially lead to novel interventions that simultaneously address all three conditions.

Clinical neurocardiology: defining the value of neuroscience-based cardiovascular therapeutics - 2024 update

The intricate role of the autonomic nervous system (ANS) in regulating cardiac physiology has long been recognized. Aberrant function of the ANS is central to the pathophysiology of cardiovascular diseases. It stands to reason, therefore, that neuroscience-based cardiovascular therapeutics hold great promise in the treatment of cardiovascular diseases in humans. A decade after the inaugural edition, this White Paper reviews the current state of understanding of human cardiac neuroanatomy, neurophysiology and pathophysiology in specific disease conditions, autonomic testing, risk stratification, and neuromodulatory strategies to mitigate the progression of cardiovascular diseases.

No gender difference in cardiac interoceptive accuracy: Potential psychophysiological contributors in heartbeat counting task

Gender differences in interoceptive awareness-awareness of internal bodily signals such as heartbeat perception-have been suggested, with some findings indicating behaviourally reduced but subjectively enhanced awareness in women, though these findings are still contentious. This study aimed to comprehensively examine gender differences in three aspects of interoceptive awareness: behavioural accuracy, subjective confidence, and relationship between them (i.e., metacognition). We used a modified heartbeat counting task that prohibited estimation strategies and increased the number of trials up to 20. Using data from 74 healthy young adults (39 women and 35 men), we evaluated gender differences and practice effects for each measure via Bayesian linear mixed models, controlling for individual heart rate and trial duration on a trial-by-trial basis. Contrary to previous research, the results revealed no reduced interoceptive accuracy in women; instead, higher interoceptive accuracy score was associated with shorter trial durations and lower heart rates regardless of gender. Moreover, women exhibited underconfidence about their performance, and therefore lower metacognition scores, compared to men. Trial repetitions moderated women's lowered metacognition but did not affect accuracy or confidence. These findings highlight potential physiological and psychological confounding factors in the heartbeat counting task, such as heart rate and reporting style, and emphasise several cautions for studying gender differences in interoceptive awareness.

Computational Approaches for Uncovering Interoceptive Mechanisms in Psychiatric Disorders and Their Biological Basis

Interoception, the process of detecting, perceiving, and interpreting signals from within the body, is essential for physiological regulation and adaptive behavior. A growing body of research underscores important potential links between interoceptive dysfunction and psychiatric disorders. Parallel advancements in the field of computational psychiatry have led to the development of biologically plausible models of information processing in the brain. This review surveys the current state of traditional and computational research approaches to study interoceptive processes in psychiatry. We also provide a foundational description of predominant computational approaches and theoretical models of interoception. Finally, we discuss the potential molecular foundations of interoceptive computation and consider future directions for incorporating computational models to enhance clinical insights and inform personalized treatments. We conclude that combining interoception and computational modeling approaches holds considerable promise in moving the field forward, both in addressing unresolved mechanistic questions and identifying novel potential therapeutic targets.

The effects of the SARS-CoV-2 pandemic on self-reported interoception and mental health

BACKGROUND

Atypical interoception has been observed across multiple mental health conditions, including anxiety disorders and depression. Evidence suggests that not only pathological anxiety, but also heightened levels of state anxiety and stress are associated with interoceptive functioning. This study aimed to investigate the effects of the recent Coronavirus SARS-CoV-2 pandemic on self-reported interoception and mental health, and their relationship.

METHODS

Self-report measures of interoceptive attention and accuracy, anxiety, stress and depression taken during the pandemic (at three time points) were compared to the same measures taken from comparable samples prior to the pandemic. In the sample collected during the pandemic, the relationship between interoceptive and mental health measures and focus on COVID-19-related news and information, propensity to take objective measures of COVID-19 symptoms, and subjective beliefs concerning COVID-19 symptoms was assessed. Finally, a cross-lagged panel model (CLPM) was used to test directional relationships between self-reported interoceptive and mental health measures across three time points.

RESULTS

Higher self-reported anxiety was associated with a) increased self-reported attention to bodily signals, b) increased focus on COVID-19-related news and information, c) propensity to take objective measures of COVID-19 symptoms, and d) reduced self-reported interoceptive accuracy for bodily signals participants believed were associated with COVID-19. The CLPM revealed a mutual and comparable directional effect from T1 to T2 between interoceptive attention and measures of mental health.

CONCLUSIONS

Implications of these findings are discussed in the light of existing models and newly proposed accounts of the relationship between interoception and mental health.

Common threads: Altered interoceptive processes across affective and anxiety disorders

There is growing attention towards atypical brain-body interactions and interoceptive processes and their potential role in psychiatric conditions, including affective and anxiety disorders. This paper aims to synthesize recent developments in this field. We present emerging explanatory models and focus on brain-body coupling and modulations of the underlying neurocircuitry that support the concept of a continuum of affective disorders. Grounded in theoretical frameworks like peripheral theories of emotion and predictive processing, we propose that altered interoceptive processes might represent transdiagnostic mechanisms that confer common vulnerability traits across multiple disorders. A deeper understanding of the interplay between bodily states and neural processing is essential for a holistic conceptualization of mental disorders.

A novel analysis of interoceptive underpinnings of anxious psychopathology in COVID-19 survivors

INTRODUCTION

SARS-CoV-2 affects brain, body, and their interchange. We investigated interoceptive mechanisms in COVID-19 survivors focusing on their potential link with psychopathology and inflammatory biomarkers.

METHODS

We assessed interoceptive accuracy (IAc) and time-perceiving (TA) skills of 57 COVID-19 survivors one month after hospital discharge through, respectively, a heartbeats perception task and a time duration task. Each participant was assessed about his interoceptive awareness (IAw) through Multidimensional Assessment of Interoceptive Awareness questionnaire (MAIA) and then, screened for post-traumatic (Impact of Events Scale - IES-R), anxious (State-Trait Anxiety Inventory - STAI-Y1) and depressive (Zung Self-Rating Depression Scale - ZSDS; Beck Depression Inventory - BDI-13) symptoms. Biomarkers of inflammation (platelet count, PC; mean platelet volume, MPV and systemic immune-inflammation index, SII) were obtained in a subsample of 40 survivors by a blood sampling conducted at admission and discharge time from the hospital. Correlational, GLM, GLMZ, and mediation analyses were performed.

RESULTS

IAc did not correlate with TA confirming the reliability of interoceptive measure. IAc positively predicts MAIA's Trusting subscale and negatively predicts anxious psychopathology which fully mediates the effect of IAc on Trusting.PC at hospital admission predicts anxiety at one month after recovery. Again, a higher decrease of SII during hospitalization predicts higher IAc skill and lower anxiety state at one month. The link between SII change and anxiety is fully mediated by IAc.

CONCLUSIONS

Our results unveil a potential key role of interoception and brain-body interchange in the exacerbation and maintenance of anxiety psychopathology in COVID-19 survivors.

Discrepancies in the Definition and Measurement of Human Interoception: A Comprehensive Discussion and Suggested Ways Forward

Interoception has been the subject of renewed interest over the past 2 decades. The involvement of interoception in a variety of fundamental human abilities (e.g., decision-making and emotional regulation) has led to the hypothesis that interoception is a central transdiagnostic process that causes and maintains mental disorders and physical diseases. However, interoception has been inconsistently defined and conceptualized. In the first part of this article, we argue that the widespread practice of defining interoception as the processing of signals originating from within the body and limiting it to specific physiological pathways (lamina I spinothalamic afferents) is problematic. This is because, in humans, the processing of internal states is underpinned by other physiological pathways generally assigned to the somatosensory system. In the second part, we explain that the consensual dimensions of interoception are empirically detached from existing measures, the latter of which capture loosely related phenomena. This is detrimental to the replicability of findings across measures and the validity of interpretations. In the general discussion, we discuss the main insights of the current analysis and suggest a more refined way to define interoception in humans and conceptualize its underlying dimensions.

Gender Differences in the Association Between Anxiety and Interoceptive Insight

Anxiety is one of the most common and debilitating mental health disorders, and is related to changes in interoception (perception of bodily states). While anxiety is more prevalent in women than men, gender differences in interoception-anxiety associations are often overlooked. Here, we examined gender-specific relationships between anxiety and interoception in the breathing domain, utilising multicentre data pooled from four study sites (N = 175; 51% women). State anxiety scores were quantified via the Spielberger State-Trait Anxiety Inventory, and breathing-related interoceptive dimensions via an inspiratory load task to quantify sensitivity, decision bias, metacognitive bias (confidence in interoceptive decisions), and metacognitive insight (congruency between performance and confidence). Regression analyses revealed a significant negative relationship between state anxiety and metacognitive bias (β = -0.28; p = 0.01) and insight (β = -0.09; 95% highest density interval [HDI] in a hierarchical Bayesian regression = [-0.18, -0.004]) across the whole sample, while state anxiety did not relate to interoceptive sensitivity nor decision bias. While no mean interoceptive effects relating to gender were observed, the relationship between anxiety and metacognitive insight towards breathing was driven by women (women: β = -0.18; HDI = [-0.31, -0.05]; men: β = 0.02; HDI = [-0.12, 0.15]) with a significant interaction effect (β difference = -0.20; HDI = [-0.37, -0.01]), which did not hold for trait anxiety nor depression measures. In summary, state anxiety was associated with decreased metacognitive bias across all participants, while decreased interoceptive insight was only associated with anxiety in women but not men. Therefore, treatment programmes focusing on interoceptive metacognitive bias may be useful for all anxiety patients, while interoceptive insight might represent a specific treatment target for women with anxiety.

Attention to the body! Comparing the connection between interoceptive abilities and somatic complaints of women with and without history of intimate partner violence

BACKGROUND

Somatic complaints are a critical burden to women, particularly to those women who survived intimate partner violence (IPV). The way women feel, perceive, and relate to their own body, that is, interoception, seems to have a significant role in the pathway to somatic complaints. However, to the best of our knowledge, no study has yet explored the relationship between interoception and somatic complaints of women survivors of IPV.

OBJECTIVES

To deepen the understanding of the underlying interoceptive mechanisms of somatic complaints experienced by women survivors of IPV.

DESIGN

Cross-sectional study.

METHOD

Women with (N = 44) and without (N = 52) history of IPV were assessed regarding interoceptive accuracy, interoceptive sensibility, and somatic complaints. Associations between both variables in each group were examined, and a hierarchical regression analysis assessed to what extent somatic complaints were explained by the interoceptive abilities, with the mediating role of IPV group membership.

RESULTS

Women survivors of IPV reported more somatic complaints (p < 0.001), which were negatively associated with interoceptive attention regulation. The opposite association was found in women who have never experienced IPV. For the IPV group, the interoceptive attention regulation, added to age and the index of the violence suffered, explains 43% of the variance in somatic complaints.

CONCLUSION

The findings suggest that for women with history of IPV, but not for those without, the ability to regulate the attention given to bodily sensations is a mediator of women' somatic complaint. Thereby we suggest that interoceptive attention regulation can be a promising therapeutic aim, for women recovering from IPV.

Allostatic Interoceptive Overload Across Psychiatric and Neurological Conditions

Emerging theories emphasize the crucial role of allostasis (anticipatory and adaptive regulation of the body's biological processes) and interoception (integration, anticipation, and regulation of internal bodily states) in adjusting physiological responses to environmental and bodily demands. In this review, we explore the disruptions in integrated allostatic interoceptive mechanisms in psychiatric and neurological disorders, including anxiety, depression, Alzheimer's disease, and frontotemporal dementia. We assess the biological mechanisms associated with allostatic interoception, including whole-body cascades, brain structure and function of the allostatic interoceptive network, heart-brain interactions, respiratory-brain interactions, the gut-brain-microbiota axis, peripheral biological processes (inflammatory, immune), and epigenetic pathways. These processes span psychiatric and neurological conditions and call for developing dimensional and transnosological frameworks. We synthesize new pathways to understand how allostatic interoceptive processes modulate interactions between environmental demands and biological functions in brain disorders. We discuss current limitations of the framework and future transdisciplinary developments. This review opens a new research agenda for understanding how allostatic interoception involves brain predictive coding in psychiatry and neurology, allowing for better clinical application and the development of new therapeutic interventions.

Effects of a Footbathing Intervention on Physiological, Endocrine, and Psychological Status in Japanese University Students: A Randomized Controlled Trial

The present pilot study examined effectiveness of a 2-week footbathing intervention on physiological, endocrine, and psychological status in healthy Japanese university students. A total of 51 participants were randomly assigned to a footbathing or normal bathing group. Participants in both groups provided daily free descriptions of their physical and mental states during the intervention period. Participants also underwent measurements of autonomic nervous system activities and salivary cortisol, and completed questionnaires in the pre- and post-intervention periods, as well as in the follow-up period. Neither the footbathing group nor the normal bathing group showed significant changes in deep body temperature, blood pressure, or salivary cortisol through the intervention period. Significant increases in dispositional mindfulness and interoceptive awareness, and significant decrease in trait anxiety were observed regardless of the groups. Nevertheless, an awareness of changes in bodily sensations and mood by footbathing mentioned in the participants' free descriptions was significantly associated with increased deep body temperature, dispositional mindfulness, interoceptive awareness, and subjective well-being from the pre- to post-intervention periods. These results suggest that the period of intervention and sample size might have been insufficient to induce significant changes in baseline psychophysiological status, but that awareness of changes in psychophysiological states may potentially be involved in the mechanism of footbathing.

Aberrant Cardiac Interoception in Psychosis

BACKGROUND AND HYPOTHESIS

There is mounting evidence that cardiac interoception, the perception of one's heartbeat, is central to affective experiences. It has been proposed that symptoms of psychosis could arise from interoceptive dysfunction. Here we hypothesized that people with psychotic disorders would have a specific impairment in cardiac interoception, over and above broader perceptual deficits.

STUDY DESIGN

43 adults with a history of psychosis (31 schizophrenia, 12 schizoaffective disorder) and 41 matched control participants completed a heart rate discrimination task. Participants responded to whether they perceived a sequence of auditory tones to be faster or slower than their heart rate. By trialing a range of auditory tone rates, we estimated a threshold for each participant, the difference between perceived heart rate and actual heart rate. To test whether differences were specific to interoception, participants completed an exteroceptive control condition, testing their discrimination of the rate of 2 sets of audible sounds instead of heart rate.

STUDY RESULTS

Participants with a history of psychosis had greater absolute differences between perceived and actual heart rate, indicating over- or under-estimation of heart rate compared to healthy controls. This difference was specific to the interoceptive condition, and not explained by group differences in exteroceptive perception.

CONCLUSIONS

Psychotic disorders are associated with misestimation of heart rate. Further research may elucidate whether interoceptive abnormalities contribute to specific symptoms such as somatic delusions or affective features, and whether interoception could be a treatment target in psychotic disorders.

Heterogeneous appetite patterns in depression: computational modeling of nutritional interoception, reward processing, and decision-making

Accurate interoceptive processing in decision-making is essential to maintain homeostasis and overall health. Disruptions in this process have been associated with various psychiatric conditions, including depression. Recent studies have focused on nutrient homeostatic dysregulation in depression for effective subtype classification and treatment. Neurophysiological studies have associated changes in appetite in depression with altered activation of the mesolimbic dopamine system and interoceptive regions, such as the insular cortex, suggesting that disruptions in reward processing and interoception drive changes in nutrient homeostasis and appetite. This study aimed to explore the potential of computational psychiatry in addressing these issues. Using a homeostatic reinforcement learning model formalizing the link between internal states and behavioral control, we investigated the mechanisms by which altered interoception affects homeostatic behavior and reward system activity via simulation experiments. Simulations of altered interoception demonstrated behaviors similar to those of depression subtypes, such as appetite dysregulation. Specifically, reduced interoception led to decreased reward system activity and increased punishment, mirroring the neuroimaging study findings of decreased appetite in depression. Conversely, increased interoception was associated with heightened reward activity and impaired goal-directed behavior, reflecting an increased appetite. Furthermore, effects of interoception manipulation were compared with traditional reinforcement learning parameters (e.g., inverse temperature β and delay discount γ), which represent cognitive-behavioral features of depression. The results suggest that disruptions in these parameters contribute to depressive symptoms by affecting the underlying homeostatic regulation. Overall, this study findings emphasize the importance of integrating interoception and homeostasis into decision-making frameworks to enhance subtype classification and facilitate the development of effective therapeutic strategies.

Fears Worth Testing Out: A Systematic Review of the Neural Mechanisms of Treatment Outcome for Anxiety-Related Disorders

With the advent of human neuroimaging, researchers were drawn to the idea that by better understanding the human brain, more effective mental health interventions could be developed. It has been more than 20 years since the first functional magnetic resonance imaging (fMRI) studies were conducted to examine changes in brain activation with anxiety-related treatments and more than 60 studies have since been published in this vein. For the current review, we conduct a systematic review of this literature, focusing on adult studies using task-based fMRI to measure brain activation changes with pharmacologic or psychotherapy interventions for phobia, social anxiety disorder, panic disorder, generalized anxiety disorder, posttraumatic stress disorder, and obsessive-compulsive disorder. Neuroscientific theories of anxiety-related disorders and their treatment have focused on prefrontal-insula-amygdala networks. Treatment-related decreases in amygdala and/or anterior insula activation were identified as the most consistent finding across disorders, with the most consistent results reported for specific phobia. Directionality of change and specific regions implicated in the prefrontal cortex were inconsistent across studies. The potential importance for probing other networks and processes as mechanisms of anxiety treatment was recognized, such as striatal regions underlying inhibitory learning or reward responsivity. Future treatment-fMRI research related to anxiety disorders would benefit from larger sample sizes, use of more nuanced computational approaches, and increased focus on replication. There is continued promise that fMRI research will enhance our understanding of how treatments work and inform the evolution of more effective or personalized mental health treatment.

Nature heals: An informational entropy account of self-organization and change in field psychotherapy

This paper reviews biophysical models of psychotherapeutic change based on synergetics and the free energy principle. These models suggest that introducing sensory surprise into the patient-therapist system can lead to self-organization and the formation of new attractor states, disrupting entrenched patterns of thoughts, emotions, and behaviours. We propose that the therapist can facilitate this process by cultivating epistemic trust and modulating embodied attention to allow surprising affective states to enter shared awareness. Transient increases in free energy enable the update of generative models, expanding the range of experiences available within the patient-therapist phenomenal field. We hypothesize that patterns of disorganization at behavioural and physiological levels, indexed by increased entropy, complexity, and lower determinism, are key markers and predictors of psychotherapeutic gains. Future research should investigate how the therapist's openness to novelty shapes therapeutic outcomes.

The SARS-CoV-2 pandemic causes a dysfunctional dietary behavior: A German cross-sectional study

Background: Since the COVID-19 pandemic has been affected our daily lives, the global population has been exposed to permanent concerns and thus might suffer from the psychological burden. It is well known that psychological burdens can affect dietary behavior. Aim: The impact of a psychological burden on people, and in particular on their dietary patterns was investigated in this nationawide cross-sectional study. Methods: 7525 participants responded to the questionnaire regarding the psychological burden concerning the COVID-19 pandemic and their current dietary structure with changes in the pattern and food amount (between November 2020 and March 2021). Results: A pandemic-related dysfunction of dietary behavior was found. Some participants reported restrictive (conscious) food intake and as well impulsive food intake, which can be described as dysfunctional eating behaviors. In particular, younger persons and individuals who claimed an increased psychological burden reported dysfunctional dietary behavior. Data clearly show that psychological burdens affect an individual's dietary behavior. Conclusion: Public health strategies have to be developed to support individuals at risk to improve coping strategies. The long-term aim should be avoiding the maintenance of dysfunctional dietary behavior.

Change starts with the body: Interoceptive appreciation mediates the effect of mindfulness training on behavior change - an effect moderated by depression severity

Mindfulness catalyzes health behavior change. Yet, interoception is dysregulated in depression, potentially impairing behavioral activation. We examined the mediating role of interoceptive appreciation, as measured by how much one trusts and listens to internal bodily signals, on behavior change. Primary care patients with depression, anxiety, or stress disorders related to chronic illness were randomized to Mindfulness Training for Primary Care (MTPC) using the Mindful Behavior Change curriculum or a low-dose mindfulness comparator. Participants (N = 274) completed the Multidimensional Assessment of Interoceptive Awareness (MAIA) at 0 and 8 weeks. At week 7, participants chose a health behavior action plan. During weeks 8-10, participants reported their action plan initiation (API) level. We investigated the effect of MTPC on API level (MTPC-API), the mediating role of interoceptive appreciation (Body Listening [MAIA-BL] + Trusting [MAIA-T]), and baseline depression severity as a moderator. MTPC had a significant direct effect on API. Interoceptive appreciation (MAIA-BL + MAIA-T) had a significant indirect effect on API (CI=0.15-0.56). Without depression (n = 76), MAIA-BL partially mediated MTPC-API (CI=0.02-0.87). With moderate-to-severe depression (n = 132), MAIA-T partially mediated MTPC-API (CI=0.01-0.85). Interoceptive appreciation helps people listen to motivating bodily signals. In depression, regaining body trust may be an important step on a mindful path towards change.

Changes in hoarding-related beliefs and associated neural changes during a simulated discarding task after cognitive-behavioral treatment for hoarding disorder

Hoarding disorder (HD) is maintained by maladaptive beliefs about possessions, and recent research has demonstrated that changes in these beliefs partially mediate improvement in cognitive-behavioral therapy (CBT) for hoarding. It is not yet known whether changes in neural activity, particularly when discarding possessions, are associated with cognitive change during CBT for HD. Adults who completed group CBT for HD (N = 58) participated in a simulated discarding task before and after CBT. Neural activity was measured using functional magnetic resonance imaging (fMRI) as participants made simulated discarding decisions. At baseline, activity in the left middle insula and left anterior cingulate cortex was significantly associated with hoarding-related beliefs. After receiving CBT for HD, decreases in maladaptive hoarding-related beliefs were significantly associated with increased activity compared to baseline in the right anterior ventral insula, along the left middle frontal gyrus and bilateral inferior temporal lobe, and in visuospatial areas. These results demonstrate that maladaptive beliefs in HD are associated with activation of specific neural regions during discarding decisions and that reduction in beliefs over a course of CBT for HD is associated with specific changes in neural activity.

What can the psychoneuroimmunology of yoga teach us about depression's psychopathology?

Depression, the most prevailing mental health condition, remains untreated in over 30% of patients. This cluster presents with sub-clinical inflammation. Investigations trialling anti-inflammatory medications had mixed results. The lack of results may result from inflammation's complexity and targeting only a few of depression's abnormal pathways. Mind-body therapies' biological and neuro-imaging studies offer valuable insights into depression psychopathology. Interestingly, mind-body therapies, like yoga, reverse the aberrant pathways in depression. These aberrant pathways include decreased cognitive function, interoception, neuroplasticity, salience and default mode networks connectivity, parasympathetic tone, increased hypothalamic-pituitary-adrenal (HPA) axis activity, and metabolic hyper/hypofunction. Abundant evidence found yogic techniques improving self-reported depressive symptoms across various populations. Yoga may be more effective in treating depression in conjunction with pharmacological and cognitive therapies. Yoga's psychoneuroimmunology teaches us that reducing allostatic load is crucial in improving depressive symptoms. Mind-body therapies promote parasympathetic tone, downregulate the HPA axis, reduce inflammation and boost immunity. The reduced inflammation promotes neuroplasticity and, subsequently, neurogenesis. Improving interoception resolves the metabolic needs prediction error and restores homeostasis. Additionally, by improving functional connectivity within the salience network, they restore the dynamic switching between the default mode and central executive networks, reducing rumination and mind-wandering. Future investigations should engineer therapies targeting the mechanisms mentioned above. The creation of multi-disciplinary health teams offering a combination of pharmacological, gene, neurofeedback, behavioural, mind-body and psychological therapies may treat treatment-resistant depression.

Neural Interoceptive Processing Is Modulated by Deep Brain Stimulation to Subcallosal Cingulate Cortex for Treatment-Resistant Depression

BACKGROUND

Symptoms of depression are associated with impaired interoceptive processing of bodily sensation. The antidepressant effects of subcallosal cingulate deep brain stimulation (SCC DBS) include acute change in bodily sensation, and the SCC target is connected to cortical regions critically involved in interoception. This study tested whether cortical interoceptive processing is modulated by SCC DBS for treatment-resistant depression.

METHODS

In 8 patients receiving SCC DBS for treatment-resistant depression, we used electroencephalography to measure the heartbeat-evoked potential (HEP), a putative readout of neural interoception, before surgery and over 6 months of treatment with DBS. We also examined the immediate effect of DBS on the HEP and correlated HEP change over time with outcomes of treatment for depression.

RESULTS

HEP amplitude increased from baseline to 6 months of DBS treatment, and this increase was associated with faster antidepressant response. Recording with stimulation on (vs. off) had an immediate effect on HEP in the laboratory. Overall, modulation of the HEP was most pronounced in sensors over the left parietal cortex.

CONCLUSIONS

Brain-based evidence implies an interoceptive element in the mechanism of treatment efficacy with DBS for treatment-resistant depression and substantiates a theorized connection between interoception and depression.

Interoceptive Ability and Emotion Regulation in Mind-Body Interventions: An Integrative Review

It is increasingly recognized that interoceptive ability, the capacity to detect, interpret, and consciously integrate signals related to the physiological condition of the body, is central to emotion experience and regulation. Interoceptive ability can be trained and improved through mind-body interventions. This article attempts to provide an integrative review of the link between interoceptive ability and emotion regulation in mind-body interventions. To this aim, (1) we address the constructs of interoceptive ability and mind-body interventions in relation to the double pathway of emotion regulation, and (2) we include a review of selected empirical and qualitative studies. These show that mindfulness meditation affects the brain-body axis through top-down processing, improving both interoceptive ability and emotion regulation. Interventions based on bottom-up processing through body movement and emotional expression are illustrated, but it is argued that they are still under-investigated. In light of the literature reviewed, we contend that interoceptive ability is a crucial aspect associated with the effects of mind-body interventions on emotion regulation. Additionally, we suggest that if studied through both quantitative and qualitative methods, interoceptive ability may serve as a general construct that allows a more integrated view of the polarities related to the spectrum of embodied experience: top-down and bottom-up emotion processing, observational and non-observational body awareness, conscious and unconscious level of interoception.

Exploring the relationship between cardiac awareness and balance

Postural balance requires the interplay between several physiological signals. Indirect evidence suggests that the perception of signals arising from the autonomic nervous system might play a role (e.g. cardiac awareness). Here, we tested this hypothesis by investigating the relationship between postural control and cardiac awareness (i.e. interoception) in a sample of N = 70 healthy individuals. Postural control was measured using a medical robotic device, while cardiac awareness was evaluated using the heartbeat counting task. A within-subject design included two platform configurations (static, unstable) and two visual feedback conditions (eyes open, eyes closed). For each condition, we measured the sway area and the range of oscillation of the platform, as well as the range of oscillation and the quantity of movement of participants' trunk. In the "platform unstable, eyes closed" condition, participants with higher cardiac awareness demonstrated a significantly smaller sway area and reduced oscillations of both the platform and their trunk. These findings hint at a potential link between interoception and postural control, suggesting that the perception of internal body signals might sustain balance.

A systematic review and meta-analysis of the relationship between subjective interoception and alexithymia: Implications for construct definitions and measurement

Although research indicates that self-reported interoception is associated with deficits in identifying and describing emotional experience, and externally oriented thinking styles (alexithymia), this relationship appears moderated by how interoception is measured. A systematic review and meta-analyses examined the association between self-reported interoception and alexithymia, investigating how different interoceptive questionnaires relate to alexithymia at global and facet levels. PsychINFO, PubMed, Scopus, and Web of Science databases were searched with predefined terms related to self-reported interoception and alexithymia. Three reviewers independently assessed articles, extracted data, and undertook risk of bias assessment. Thirty-two cross-sectional studies published between 1996 and 2023 were included. Random-effects meta-analyses and narrative synthesis indicated that global alexithymia was positively associated with measures of interoceptive confusion, autonomic nervous system reactivity, and heightened interoceptive attention, and inversely associated with interoceptive accuracy and adaptive interoception, indexed by composite Multidimensional Assessment of Interoceptive Awareness scores, but particularly interoceptive trusting, self-regulation, and attention regulation. These patterns were observed for alexithymic facets and stronger in magnitude for difficulty identifying feelings and difficulty describing feelings, relative to externally oriented thinking. Overall, results suggested that the association between self-reported interoception and alexithymia differs as a function of the interoceptive self-report. The review highlighted issues with construct definition and operationalisation and determined that existing interoceptive self-reports broadly capture maladaptive and adaptive sensing, attention, interpretation, and memory. The findings underscore the importance of specifying interoceptive constructs and using appropriate assessments to improve convergence between constructs and measurements, further suggesting potential clinical utility in using existing self-reports to measure interoception and alexithymia, facilitating interventions targeting mind-body connections.

Applying an osteopathic intervention to improve mild to moderate mental health symptoms: a mixed-methods feasibility randomised trial

BACKGROUND

The increasing prevalence of mental health disorders in the United Kingdom necessitates the exploration of novel treatment modalities. This study aimed to assess the feasibility and acceptability of conducting a randomised controlled trial (RCT) evaluating the efficacy of four osteopathic interventions on psychophysiological and mental health outcomes.

METHODS

A mixed-methods feasibility study with an explanatory sequential design was implemented. The quantitative phase involved randomising 42 participants into four intervention groups: (1) high-velocity and articulation techniques (HVAT), (2) soft-tissue massage (STM), (3) craniosacral therapy (CST), and (4) a combination approach. Primary outcome measures encompassed recruitment rate, assessment duration, questionnaire completion, intervention attrition, and adverse events. Secondary outcomes included validated assessments of depression, anxiety, stress, psychological flexibility, heart rate variability (HRV), and interoception, administered pre- and post-intervention. Analysis of variance (ANOVA) was employed to evaluate pre-post intervention changes. The qualitative phase comprised semi-structured interviews analysed using thematic analysis.

RESULTS

The study achieved a recruitment rate of 21 eligible participants per month, with 54.8% of respondents meeting eligibility criteria. All 33 participants who completed the study underwent interventions and assessments within the allocated one-hour timeframe, with full questionnaire completion. The attrition rate was 21%. No adverse events were reported. Qualitative analysis revealed positive participant experiences, with themes highlighting good practitioner communication, intervention accessibility, and increased bodily awareness. Some participants found the questionnaire battery burdensome. Exploratory quantitative analyses showed variations in effects across interventions for heart rate variability, interoceptive accuracy, and mental health measures, but these results should be interpreted cautiously due to the small sample size.

CONCLUSIONS

This study provides evidence supporting the feasibility and acceptability of a larger-scale RCT investigating osteopathic interventions for individuals presenting with mild psychological symptoms. The preliminary findings suggest potential efficacy in improving mental health outcomes, warranting further investigation. Trial registration NCT05674071, registered 06/01/2023.

Pain Severity and Depressive Symptoms in Endometriosis Patients: Mediation of Negative Body Awareness and Interoceptive Self-Regulation

Endometriosis-related pain may be associated with depressive symptoms. Although a growing body of evidence supports this association, the underlying mechanisms are still largely unclear. Impaired perceptions of bodily external and internal stimuli may be involved in this process. This study aims to assess the mediating role of 2 facets of interoception-the awareness of negative body signals and interoceptive self-regulation-in the association between pain severity and depressive symptoms among women with endometriosis. A total of 301 patients who reported a diagnosis of endometriosis were recruited from an endometriosis and chronic pelvic pain outpatient university clinic and through patient associations and completed self-reported instruments. A parallel mediation analysis was conducted. Almost half of women (48.2%) reported depressive symptoms above the self-rating scale cutoff values. Pain severity significantly predicted depressive symptoms (β = .39, 95% bootstrap confidence interval [CI] [.719, 1.333]). Negative body awareness (β = .121, 95% bootstrap CI [.174, .468]) and interoceptive self-regulation (β = .05, 95% bootstrap CI [.035, .252]) partially mediated this relationship. Our findings indicated that pain may interfere with the perception of the body as a source of calmness and safety, limiting the individual's ability to effectively regulate emotions. Future research should further explore these mechanisms and evaluate the efficacy of interventions focusing on interoceptive sensibility to enhance the psychological well-being of endometriosis patients. PERSPECTIVE: This article investigates for the first time the potential role of 2 facets of interoceptive sensibility in the relationship between pain severity and depressive symptoms in women with endometriosis. These findings may contribute to advancing knowledge about the mechanisms involved in the complex pain-depression cycle.

WACARDIA: Graphical MATLAB software for Wireless Assessment of CARDiac Interoceptive Accuracy

Many theories of psychological function emphasize the importance of bodily sensations and the ability to accurately detect them, known as interoceptive accuracy. The most common measure of interoceptive accuracy uses heartbeat detection tasks such as the Whitehead Task, yet to our knowledge there are no freely accessible programs to conduct this task. In this paper, we present novel software called WACARDIA (Wireless Assessment of CARDiac Interoceptive Accuracy), which is free, open-source software that conducts the heartbeat detection task using Matlab and Psychtoolbox. WACARDIA contains several key features supporting participant engagement, operator convenience, and measurement accuracy. First, the program includes an optional practice trial of unlimited duration, a participant-facing graphical interface, and the ability to perform heartbeat detection training. Second, the operator is provided with a graphical user interface, live trial feedback, an accurate wireless electrocardiogram device, and a separate program to conduct the related Heartbeat Tracking task. Finally, the program ensures the accuracy of collected data by scheduling the delivery of tones with high precision and implementing fail-safes to automatically reset erroneous measurements. This paper includes flowcharts that help create transparency by describing our algorithm. We also outline customizable aspects of the program with the intent to have WACARDIA's algorithm expanded to accommodate more situations and applications. With this paper, we hope to encourage the practice of publicizing research software to contribute to the transparency, rigor, and reproducibility of scientific studies. WACARDIA and video tutorials are available at www.github.com/iankleckner/wacardia and http://wacardia.iankleckner.com.

He Who Seeks Finds (Bodily Signals): German Validation of the Interoceptive Attention Scale (IATS) and its Relationship with Subclinical Psychopathology

Alterations in interoception have been linked to psychopathology. Recent findings suggest that both the attention to and the accuracy of, interoceptive perceptions may be oppositely related to subclinical symptomatology. Thus, providing well-validated tools that tap into these interoceptive processes is crucial for understanding the relation between interoceptive processing and subclinical psychopathology. In the current study (N = 642), we aimed to (1) validate the German version of the Interoceptive Attention Scale (IATS; Gabriele et al., 2022), and (2) test the differential association of self-reported interoceptive attention and accuracy with subclinical symptomatology, including alexithymia, depressive, and anxious symptomatology. We observed that a one-factor solution is a well-fitting model for the IATS. Further, the IATS showed good internal consistency, convergent, and divergent validity, but poor test-retest reliability. Self-reported interoceptive attention and accuracy were unrelated to each other. However, IATS scores were positively related to all measures of psychopathology (except depressive symptomatology), whereas self-reported interoceptive accuracy scores showed negative or nonsignificant relations with these. Our data suggest that the IATS is a good instrument to measure self-report interoceptive attention in the German population. Further, we highlight the need to distinguish between constructs of interoception to better understand the relation between interoception and psychopathology.

Computational Mechanisms of Learning and Forgetting Differentiate Affective and Substance Use Disorders

Depression and anxiety are common, highly co-morbid conditions associated with a range of learning and decision-making deficits. While the computational mechanisms underlying these deficits have received growing attention, the transdiagnostic vs. diagnosis-specific nature of these mechanisms remains insufficiently characterized. Individuals with affective disorders (iADs; i.e., depression with or without co-morbid anxiety; N=168 and 74, respectively) completed a widely-used decision-making task. To establish diagnostic specificity, we also incorporated data from a sample of individuals with substance use disorders (iSUDs; N=147) and healthy comparisons (HCs; N=54). Computational modeling afforded separate measures of learning and forgetting rates, among other parameters. Compared to HCs, forgetting rates (reflecting recency bias) were elevated in both iADs and iSUDs (p = 0.007, η 2 = 0.022). In contrast, iADs showed faster learning rates for negative outcomes than iSUDs (p = 0.027, η 2 = 0.017), but they did not differ from HCs. Other model parameters associated with learning and information-seeking also showed suggestive relationships with early adversity and impulsivity. Our findings demonstrate distinct differences in learning and forgetting rates between iSUDs, iADs, and HCs, suggesting that different cognitive processes are affected in these conditions. These differences in decision-making processes and their correlations with symptom dimensions suggest that one could specifically develop interventions that target changing forgetting rates and/or learning from negative outcomes. These results pave the way for replication studies to confirm these relationships and establish their clinical implications.

Changes in interoception before and after treatment in patients with alcohol use disorder

AIMS

To investigate the factors associated with interoception in patients with alcohol use disorder and determine whether treatment causes changes in their interoception.

METHODS

The Body Perception Questionnaire-Body Awareness ultra-short version Japanese version (BPQ-BAVSF-J) was used to measure interoception in 50 alcohol-dependent participants (27 in the inpatient group and 23 in the outpatient group). The BPQ-BAVSF-J was administered and data on aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (γ-GTP), mean corpuscular volume, platelet count, and Fib-4 index were extracted at admission and immediately before discharge for the inpatient group and at the first outpatient visit and approximately 3 months after the visit for the outpatient group.

RESULTS

The mean age of the 50 participants was 51.0 ± 12.3 years. Significant associations were found between the BPQ-BAVSF-J and Fib-4 index and AST. The BPQ-BAVSF-J score significantly decreased at discharge in the inpatient group. AST, ALT, γ-GTP, and Fib-4 index of liver function were also significantly lower at discharge. In contrast, in the outpatient group, there were no significant changes in the BPQ-BAVSF-J score, AST level, ALT level, γ-GTP level, and Fib-4 index between at the first outpatient visit and approximately 3 months after the visit.

CONCLUSIONS

Interoception in patients with alcohol use disorder increased with worsening liver function and decreased with improvement in liver function owing to treatment. This suggests that the BPQ-BAVSF-J score, an easily accessible scale, may be used to detect early deterioration of liver function through regular administration.

Interoception mediates the association between social support and sociability in patients with major depressive disorder

BACKGROUND

Interoception dysfunction has an important impact on the onset and development of major depressive disorder (MDD). Social support serves as a protective factor against MDD, and sociability also plays a significant role in this condition. These interconnected constructs-social support and sociability-play pivotal roles in MDD. However, no research on the mechanisms underlying the associations between social support and sociability, particularly the potential role of interoception, have been reported.

AIM

To investigate the mediating effect of interoception between social support and social ability and to explore the independent role of social support in sociability.

METHODS

The participants included 292 patients with MDD and 257 healthy controls (HCs). The patient health questionnaire 9, the multidimensional assessment of interoception awareness, version 2 (MAIA-2), the social support rating scale (SSRS), and the Texas social behavior inventory (TSBI) were used to assess depression, interoception, social support, and sociability, respectively. A mediation analysis model for the eight dimensions of interoception (noticing, not distracting, not worrying, attention regulation, emotional awareness, self-regulation, body listening, and trust), social support, and sociability were established to evaluate the mediating effects.

RESULTS

A partial correlation analysis of eight dimensions of the MAIA-2, SSRS, and TSBI scores, with demographic data as control variables, revealed pairwise correlations between the SSRS score and both the MAIA-2 score and TSBI score. In the major depression (MD) group, the SSRS score had a positive direct effect on the TSBI score, while the scores for body listening, emotional awareness, self-regulation, and trust in the MAIA-2C had indirect effects on the TSBI score. In the HC group, the SSRS score had a positive direct effect on the TSBI score, and the scores for attention regulation, emotional awareness, self-regulation, and trust in the MAIA-2C had indirect effects on the TSBI score. The proportion of mediators in the MD group was lower than that in the HC group.

CONCLUSION

Interoceptive awareness is a mediating factor in the association between social support and sociability in both HCs and depressed patients. Training in interoceptive awareness might not only help improve emotional regulation in depressed patients but also enhance their social skills and support networks.

Heartbeat-related spectral perturbation of electroencephalogram reflects dynamic interoceptive attention states in the trial-by-trial classification analysis

Attending to heartbeats for interoceptive awareness initiates distinct electrophysiological responses synchronized with the R-peaks of an electrocardiogram (ECG), such as the heartbeat-evoked potential (HEP). Beyond HEP, this study proposes heartbeat-related spectral perturbation (HRSP), a time-frequency map of the R-peak locked electroencephalogram (EEG), and explores its characteristics in identifying interoceptive attention states using a classification approach. HRSPs of EEG brain components specified by independent component analysis (ICA) were used for the offline and online classification of interoceptive states. A convolutional neural network (CNN) designed specifically for HRSP was applied to publicly available data from a binary-state experiment (attending to self-heartbeats and white noise) and data from our four-state classification experiment (attending to self-heartbeats, white noise, time passage, and toe) with diverse input feature conditions of HRSP. From the dynamic state perspective, we evaluated the primary frequency bands of HRSP and the minimal number of averaging epochs required to reflect changing interoceptive attention states without compromising accuracy. We also assessed the utility of group ICA and models for classifying HRSP in new participants. The CNN for trial-by-trial HRSP with actual R-peaks demonstrated significantly higher classification accuracy than HRSP with sham, i.e., randomly positioned, R-peaks. Gradient-weighted class activation mapping highlighted the prominent role of theta and alpha bands between 200-600 ms post-R-peak-features absent in classifications using sham HRSPs. Online classification benefits from employing a group ICA and classification model, ensuring reliable accuracy without individual EEG precollection. These results suggest HRSP's potential to reflect interoceptive attention states, proposing transformative implications for clinical applications.

Anxiety and restrained eating in everyday life: An ecological momentary assessment study

BACKGROUND

Restrained eating has been related to psychological distress like anxiety and eating disorder symptomatology, but little is known about this relationship in daily life in non-clinical populations. We aimed to understand concurrent and temporal associations between momentary anxiety and restrained eating in everyday life within and across persons in a non-clinical sample, and examined whether this association remains after controlling for eating disorder symptomatology.

METHODS

We used a 10-day ecological momentary assessment (EMA) protocol. Participants (n = 123) completed a baseline survey with demographics and eating disorder symptomatology questions, and three EMA surveys per day reporting anxiety and restrained eating intentions. We applied mixed-effects and random intercept cross-lagged models to analyze the data.

RESULTS

Momentary anxiety and restrained eating were concurrently significantly positively associated within and between persons. When participants had more anxiety than was typical for them, they were more likely to intend to restrain eating, and people with overall higher anxiety symptoms tended to report greater restrained eating over the study period. These associations remained significant after adjusting for eating disorder symptomatology. There were no significant temporal cross-lagged effects. Anxiety-restrained eating association did not spill over into the next assessment window.

LIMITATIONS

The time window between prompts may have been too long to capture potential temporal effects, and we did not examine actual behavioral food restrictions.

CONCLUSION

Daily-life anxiety may be related to concurrent restrained eating intentions, above and beyond baseline eating disorder symptomatology. Research is needed exploring daily-life anxiety as a potential intervention target to address restrained eating.

Interoception primes negative emotion processing during cognitive reappraisal: Electroencephalographical evidence

Interoception, which refers to sensing, interpreting, and integrating internal bodily signals, has been suggested to be associated with emotion regulation. Previous research has demonstrated individual differences in interoception and its impact on emotion regulation. However, the priming effect of interoception on emotion regulation and the underlying neural mechanisms remain unknown. This study aims to examine how interoception primes different strategies of cognitive reappraisal, using electroencephalography (EEG). Thirty-seven healthy participants completed an interoceptive priming task. We found that interoception increased the amplitudes of the late positive potential (LPP) during both interpretation and detachment strategies. The priming effect of interoception in enhancing LPP amplitudes lasted longer for interpretation than for detachment. A decrease in alpha power during reinterpretation was observed after interoceptive priming, but not during detachment. The results revealed that interoception enhanced attention to bodily signals associated with negative emotions during cognitive reappraisal. Interoception showed distinct effects on different strategies of cognitive reappraisal, with different underlying neural mechanisms. Interoception-based programs may be an effective way to enhance the capacity for cognitive reappraisal.

Disembodiment and Affective Resonances in Esketamine Treatment of Depersonalized Depression Subtype: Two Case Studies

INTRODUCTION

Dissociative experiences are considered undesirable ketamine's adverse events. However, they might be crucial for ketamine's antidepressant effects, at least in some depression subtypes. Current understandings of ketamine's therapeutic potentials converge on the so-called "relaxed prior hypothesis," suggesting that glutamatergic blockage up-weights bottom-up surprising somatosensory/affective states. As a result, ketamine improves short-term plasticity in depression by enhancing sensitivity to interoceptive signals.

METHODS

We selected 2 case studies for their paradigmatic description of "depersonalized depression" (Entfremdungsdepression) symptoms. Patients were included in a 6-month-long esketamine program for treatment resistant depression, during which we collected their spontaneous experience with esketamine. According to a neurophenomenological approach, we combined subjective reports from unstructured clinical interviews and the review of previous objective neuroimaging results and neurocomputational models to unveil the relation between esketamine antidepressant effects and interoceptive sensitivity.

RESULTS

According to our clinical observations, esketamine-induced dissociation might be particularly effective in the depersonalized depression subtype, in which interoceptive awareness and interaffectivity are particularly compromised. Ketamine and esketamine's dissociative effects and particularly disembodiment might suspend previously acquired patterns of feeling, sensing, and behaving.

CONCLUSIONS

Coherently with previous research, we suggest that esketamine-induced disembodiment allows for a transient window of psychological plasticity and enhanced sensitivity, where the body recovers its permeability to affective affordances.