Interoceptive dysfunction: toward an integrated framework for understanding somatic and affective disturbance in depression

Brain Networks, Neurotransmitters and Psychedelics: Towards a Neurochemistry of Self-Awareness

PURPOSE OF REVIEW

Self-awareness can be defined as the capacity of becoming the object of one's own awareness and, increasingly, it has been the target of scientific inquiry. Self-awareness has important clinical implications, and a better understanding of the neurochemical basis of self-awareness may help clarifying causes and developing interventions for different psychopathological conditions. The current article explores the relationship between neurochemistry and self-awareness, with special attention to the effects of psychedelics.

RECENT FINDINGS

The functioning of self-related networks, such as the default-mode network and the salience network, and how these are influenced by different neurotransmitters is discussed. The impact of psychedelics on self-awareness is reviewed in relation to specific processes, such as interoception, body ownership, agency, metacognition, emotional regulation and autobiographical memory, within a framework based on predictive coding. Improved outcomes in emotional regulation and autobiographical memory have been observed in association with the use of psychedelics, suggesting higher-order self-awareness changes, which can be modulated by relaxation of priors and improved coping mechanisms linked to cognitive flexibility. Alterations in bodily self-awareness are less consistent, being potentially impacted by doses employed, differences in acute/long-term effects and the presence of clinical conditions. Future studies investigating the effects of different molecules in rebalancing connectivity between resting-state networks may lead to novel therapeutic approaches and the refinement of existing treatments.

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 two 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 cut-off values. Pain severity significantly predicted depressive symptoms (β =0.39, 95% bootstrap CI [0.719, 1.333]). Negative body awareness (β =0.121, 95% bootstrap CI [0.174, 0.468]) and interoceptive self-regulation (β = 0.05, 95% bootstrap CI [0.035, 0.252]) 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 two 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 mechanisms involved in the complex pain-depression cycle.

The Mediating Role of Interoceptive Sensitivity in the Relationship between Physical Activity and Depression Symptoms in College Students

A substantial body of evidence indicates that neurological, psychological, and behavioral health issues are profoundly linked to interoceptive sensitivity. The present study aimed to identify the effects of interoceptive sensitivity on the relationship between physical activity and symptoms of depression in Chinese college students. This study employed a cross-sectional design using convenience sampling. An online self-reported survey was distributed to college students in China. The participants' interoceptive sensitivity, physical activity levels, and depressive symptoms were measured using the MAIA-2, IPAQ-SF, and PHQ-9, respectively. The mediating effect was tested via regression analysis and a parallel mediation model, with bootstrap confidence intervals for indirect effects. The results showed a significant negative correlation between physical activity and depression. A significant positive correlation was observed between physical activity and seven dimensions of interoceptive sensitivity. Conversely, interoceptive sensitivity exhibited a negative correlation with depression. The bootstrap mediation analysis showed that the "not distracting" and "trusting" dimensions of interoceptive sensitivity had significant indirect effects on the relationship between physical activity and depression, suggesting that physical activity might reduce depressive symptoms via these two interoceptive sensitivity dimensions. The findings suggest that interoceptive sensitivity should be integrated into therapeutic interventions, such as physical activity interventions, in the treatment of mental illnesses, particularly depression. Increasing physical activity levels, with a specific focus on enhancing interoceptive modulation, appears to be a promising approach for addressing depression in college students.

Novel online enfacement illusion for investigating self-perception in mental disorders: an experimental study protocol

BACKGROUND

Remote research methods and interventions for mental health disorders have become increasingly important, particularly for conditions like eating disorders (EDs). Embodiment illusions, which induce feelings of ownership over another person?s body or body parts, offer valuable insights into the mechanisms underlying self-perception issues in EDs and potential interventions. However, existing research using these illusions has been limited to face-to-face settings. We illustrate a novel online protocol to induce the enfacement illusion (embodiment illusion principles applied to one's face) in an ED-based sample.

METHODS

Participants complete a 2-hr virtual session with a researcher. First, baseline trait/state ED psychopathology measures and a self-face recognition task occur. Second, participants experience two testing blocks of the enfacement illusion involving synchronously and asynchronously mimicking a pre-recorded actor's facial expressions. After each block, subjective and objective enfacement illusion measures occur alongside state ED psychopathology reassessment.

DISCUSSION

Successfully inducing enfacement illusions online could provide an affordable, accessible virtual approach to further elucidate the mechanistic role of self-perception disturbances across psychopathologies such as EDs. Moreover, this protocol may represent an innovative, remotely-delivered intervention strategy, as 'enfacement' over another face could update negative self-representations in a cost-effective, scalable manner.

Interoception in anxiety, depression, and psychosis: a review

Research has examined the relationship between interoception and anxiety, depression, and psychosis; however, it is unclear which aspects of interoception have been systematically examined, what the combined findings are, and which areas require further research. To answer these questions, we systematically searched and narratively synthesised relevant reviews, meta-analyses, and theory papers (total n = 34). Existing systematic reviews and meta-analyses (anxiety n = 2; depression n = 2; psychosis n = 0), focus on cardiac interoceptive accuracy (heartbeat perception), and indicate that heartbeat perception is not systematically impaired in anxiety or depression. Heartbeat perception might be poorer in people with psychosis, but further evidence is needed. Other aspects of interoception, such as different body systems and processing levels, have been studied but not systematically reviewed. We highlight studies examining these alternative bodily domains and levels, review the efficacy of interoception-based psychological interventions, and make suggestions for future research.

Funding

Wellcome Trust UK.

The association between urbanization and depression in the elderly: A network analysis from the complexity science perspective

IMPORTANCE

The global increase in urbanization has coincided with a rise in depression prevalence. However, the effect of urbanization on depression remains controversial, especially for the elderly.

OBJECTIVE

To clarify how urbanization impacts depression in the elderly from a network perspective.

DESIGN, SETTING, AND PARTICIPANTS

This sectional cohort study used data from China Health and Retirement Longitudinal Study (CHARLS).

MAIN OUTCOMES AND MEASURES

The occurrence of depressive symptoms in urban and rural elderly residents. Network metrics of depressive symptoms.

RESULTS

Of the 13,993 participants, lower incidence of depressive symptoms was observed in urban (26.3 %, 95 % CI, 24.7 %-27.8 %) than in rural (40.4 %, 95 % CI, 39.5 %-41.3 %, P < 0.0001) residents. However, higher incidence of depressive symptoms was observed in urban (26.3 %, 95 % CI, 25.2 %-28.4 %) than in rural (17.5 %, 95 % CI, 16.1 %-18.9 %, P < 0.0001) residents in a subset of 2898 pairs of participants after PSM. No difference in the network structure and metrics between urban and rural residents before (M = 0.071, p = 0.054, S = 0.037, p = 0.80) and after (M = 0.085, p = 0.133, S = 0.086, p = 0.47) PSM was detected. The networks structure revealed that negative affect was strongly connected to somatic symptoms and that the two anhedonic symptoms were also strongly connected.

CONCLUSIONS

The current study indicated the homogeneity of the ultimate nature of depression between rural and urban residents from the network perspective, supporting the viewpoint that urbanization might not impose influence on depression. Further researches delving deeper into the complexity of the issue may provide new insights into our understanding of depression in an urban environment among the elderly.

Bodies in action: Do contractive and expansive postures facilitate adaptive behavior?

The present study investigated the effects of expansive and contractive body displays on adaptive behavior and affective outcomes. Addressing limitations in past research, the effects were investigated in two different contexts (i.e., fear context and sadness context), compared with two types of control conditions and the moderating effects of motivational traits and symptoms of psychopathology were accounted for. A sample of 186 adults completed a fear experiment involving a mock job interview and a sadness experiment involving sad mood induction. For each experiment, participants were randomly assigned to one of four body manipulations: (1) expansive; (2) contractive; (3) active control (i.e., running in place); or 4) passive control (i.e., doing nothing). The primary outcome was adaptive behavior (i.e., appropriate job-interview behavior and positive recall bias). Secondary affective outcomes were emotions, action tendencies, and appraisals. Results revealed small, non-significant effects of body displays on primary outcomes (ds = 0.19-0.28). For secondary outcomes, significant effects were identified for positive emotions (ds = 0.33). Across secondary outcomes, pairwise comparisons revealed that expansive displays led to more favorable outcomes than contractive displays. For participants with the highest levels of depression, body display conditions led to less favorable affective outcomes than control conditions. The results suggest that body displays do not influence adaptive behavior within the investigated contexts. When compared to contractive displays, expansive displays were found to yield more favorable affective changes. Lastly, the findings indicate that further investigations into body manipulations in the context of psychopathology are warranted.

Interoceptive training impacts the neural circuit of the anterior insula cortex

Interoception is the perception of afferent information that arises from anywhere and everywhere within the body. Recently, interoceptive accuracy could be enhanced by cognitive training. Given that the anterior insula cortex (AIC) is a key node of interoception, we hypothesized that resting functional connectivity (RSFC) from AIC was involved in an effect of interoceptive training. To address this issue, we conducted a longitudinal intervention study using interoceptive training and obtained RSFC using fMRI before and after the intervention. A heartbeat perception task evaluated interoceptive accuracy. Twenty-two healthy volunteers (15 females, age 19.9 ± 2.0 years) participated. After the intervention, interoceptive accuracy was enhanced, and anxiety levels and somatic symptoms were reduced. Also, RSFC from AIC to the dorsolateral prefrontal cortex (DLPFC), superior marginal gyrus (SMG), anterior cingulate cortex (ACC), and brain stem, including nucleus tractus solitarius (NTS) were enhanced, and those from AIC to the visual cortex (VC) were decreased according to enhanced interoceptive accuracy. The neural circuit of AIC, ACC, and NTS is involved in the bottom-up process of interoception. The neural circuit of AIC, DLPFC, and SMG is involved in the top-down process of interoception, which was thought to represent the cognitive control of emotion. The findings provided a better understanding of neural underpinnings of the effect of interoceptive training on somatic symptoms and anxiety levels by enhancing both bottom-up and top-down processes of interoception, which has a potential contribution to the structure of psychotherapies based on the neural mechanism of psychosomatics.

Effect of MDMA-assisted therapy on mood and anxiety symptoms in advanced-stage cancer (EMMAC): study protocol for a double-blind, randomised controlled trial

BACKGROUND

Symptoms of anxiety and depression are common in patients with terminal illness and multiple challenges exist with timely and effective care in this population. Several centres have reported that one dose of the serotonergic psychedelic psilocybin, combined with therapeutic support, improves these symptoms for up to 6 months in this patient group. Drawing upon related therapeutic mechanisms, 3,4-methylenedioxymethamphetamine (MDMA)-assisted therapy may have the potential to achieve similar, positive mental health outcomes in this group. Preliminary evidence also supports the tolerability of MDMA-assisted therapy for anxiety and depression in advanced-stage cancer.

METHODS

Up to 32 participants with advanced-stage cancer and associated depression and anxiety will be randomised in a 1:1 ratio into one of two blinded parallel treatment arms. The intervention group will receive 120 mg (+ 60 mg optional supplemental dose) MDMA-assisted therapy. The psychoactive control group will receive 20 mg oral (+ 10 mg optional supplemental dose) methylphenidate-assisted therapy. For each medication-assisted therapy session, participants will undergo two 90-min therapeutic support sessions in the week preceding, and one 90-min support session the day after the experimental session. A battery of measures (mood, anxiety, quality of life, mystical experience, spiritual wellbeing, attitudes towards death, personality traits, holistic health and wellbeing, connectedness, demoralisation, expectations, qualitative data and safety measures) will be assessed at baseline and through to the end of the protocol. Participants will be followed up until either 12 months post-randomisation or death, whichever occurs first.

DISCUSSION

This study will examine the effect of MDMA-assisted therapy on symptoms of anxiety and depression in advanced-stage cancer. Potential therapeutic implications include establishing the safety and effectiveness of a novel treatment that may relieve mental suffering in patients with life-threatening illness.

TRIAL REGISTRATION

Trial registered on Australian New Zealand Clinical Trials Registry.

REGISTRATION NUMBER

ACTRN12619001334190p. Date registered: 30/09/2019. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378153&showOriginal=true&isReview=true.

The relationship between interoceptive emotional awareness, neuroticism, and depression, anxiety, and stress

COVID-19 has caused challenges to daily living globally, with profound implications for negative mood. A variety of state and trait-based factors can influence how a person may respond and adapt to challenges such as a global pandemic. Personality is an area impacting how a person responds to both internal and external situations (trait) and Emotional Awareness (EA) is a facet of interoception (an awareness of the mind-body connection) that determines the way an individual interprets their physiological state of the body, and the associated emotions (state-trait). Both areas have been well researched in isolation, however the body of literature exploring the relationships between both is much smaller. It would therefore be beneficial to explore the interrelationships of both state and trait factors on wellbeing to enable a more comprehensive understanding. It was hypothesised that EA would moderate the relationship between Neuroticism and Depression, Anxiety, and Stress. Participants residing in Australia during periods of imposed lockdown were included within the study (n = 838; Ages = 18-60 years) and completed an online questionnaire battery including a variety of state and trait questionnaires. A moderation analysis was conducted to explore whether Emotional Awareness changed the relationship between neuroticism and depression, anxiety, and stress utilising an alpha of < .05. EA moderated the relationship between Neuroticism and Anxiety (p = .001, 95% CI .03-.17)), and Stress (p = .02 95% CI.01-.13), but not Depression (p = .23, 95% CI .03-.13). As Neuroticism increased, negative mood increased for all levels of EA, however those high in Neuroticism and EA displayed the highest Anxiety and Stress. Interventions to increase EA, such as mindfulness, may have adverse effects for individuals high in Neuroticism, emphasising the importance of tailored interventions and supporting the assumption that high levels of Neuroticism represent increased vulnerability during a pandemic.

A three-dimensional model of neural activity and phenomenal-behavioral patterns

How phenomenal experience and behavior are related to neural activity in physiology and psychopathology represents a fundamental question in neuroscience and psychiatry. The phenomenal-behavior patterns may be deconstructed into basic dimensions, i.e., psychomotricity, affectivity, and thought, which might have distinct neural correlates. This work provides a data overview on the relationship of these phenomenal-behavioral dimensions with brain activity across physiological and pathological conditions (including major depressive disorder, bipolar disorder, schizophrenia, attention-deficit/hyperactivity disorder, anxiety disorders, addictive disorders, Parkinson's disease, Tourette syndrome, Alzheimer's disease, and frontotemporal dementia). Accordingly, we propose a three-dimensional model of neural activity and phenomenal-behavioral patterns. In this model, neural activity is organized into distinct units in accordance with connectivity patterns and related input/output processing, manifesting in the different phenomenal-behavioral dimensions. (1) An external neural unit, which involves the sensorimotor circuit/brain's sensorimotor network and is connected with the external environment, processes external inputs/outputs, manifesting in the psychomotor dimension (processing of exteroception/somatomotor activity). External unit hyperactivity manifests in psychomotor excitation (hyperactivity/hyperkinesia/catatonia), while external unit hypoactivity manifests in psychomotor inhibition (retardation/hypokinesia/catatonia). (2) An internal neural unit, which involves the interoceptive-autonomic circuit/brain's salience network and is connected with the internal/body environment, processes internal inputs/outputs, manifesting in the affective dimension (processing of interoception/autonomic activity). Internal unit hyperactivity manifests in affective excitation (anxiety/dysphoria-euphoria/panic), while internal unit hypoactivity manifests in affective inhibition (anhedonia/apathy/depersonalization). (3) An associative neural unit, which involves the brain's associative areas/default-mode network and is connected with the external/internal units (but not with the environment), processes associative inputs/outputs, manifesting in the thought dimension (processing of ideas). Associative unit hyperactivity manifests in thought excitation (mind-wandering/repetitive thinking/psychosis), while associative unit hypoactivity manifests in thought inhibition (inattention/cognitive deficit/consciousness loss). Finally, these neural units interplay and dynamically combine into various neural states, resulting in the complex phenomenal experience and behavior across physiology and neuropsychiatric disorders.

Recognition of others' interoceptive states in those with and without eating disorders

BACKGROUND

The ability to recognize one's own emotions is associated with one's ability to recognize others' emotions. Beyond the domain of emotion, however, the relationship between recognition of one's own internal states (interoception) and others' interoceptive states has not been investigated, either in the typical population or clinical groups with interoceptive difficulties (e.g. eating disorders; EDs).

METHOD

This study investigated recognition of one's own and others' internal states in adults with and without eating disorders, using a high frequency visual noise paradigm. Participants completed self-report measures of interoception, alexithymia (difficulties recognising one's own emotional internal states) and ED symptomatology, and the Heartbeat Counting Task measure of cardiac interoceptive accuracy.

RESULTS

Alexithymia was significantly negatively correlated with recognition of others' interoceptive states. EDs were not associated with difficulties recognising others' interoceptive states.

CONCLUSIONS

The ability to recognise one's own emotional internal states is associated with the recognition of others' interoceptive states, which may contribute to social skills and the ability to care for others.

Interoception, somatic symptoms, and somatization tendency in Chinese individuals with subsyndromal depression: A follow-up study

Interoception refers to the sensation and perception of internal bodily sensations, and may be related to depressive symptoms. Schemata concerning the body vary across different cultures and may influence interoception and symptom presentations of depression. This study explored the relationship between interoception, depressive symptoms, and schema of somatic focus in Chinese people with subsyndromal depression. Thirty-nine individuals with subsyndromal depression (SD) and 40 healthy controls (HCs) were assessed at baseline and after 3 months. Participants completed the self-report questionnaires for assessing interoceptive sensibility, somatic and psychological symptoms of depression, and somatization tendency. They also completed the heartbeat perception behavioral task for estimating interoceptive accuracy. The results showed that both the SD and the HC groups showed similar interoceptive accuracy, although the SD group showed heightened interoceptive sensibility. The discrepancy between interoceptive sensibility and interoceptive accuracy is termed the interoceptive trait prediction error (ITPE). The ITPE was positive in SD participants but was negative in HCs. In the entire sample, interoceptive sensibility and the ITPE were correlated with somatic symptoms rather than with psychological symptoms of depression. Interoceptive sensibility partially mediated the relationship between somatization tendency and somatic symptoms, after controlling for psychological symptoms of depression. These results remained stable after 3 months. The shortcomings of the present study were a lack of clinical interview to ascertain diagnosis and a short follow-up duration. In conclusion, our study suggests that altered interoception occurs in subsyndromal depression. Interoception is related to somatic symptoms of depression. The schema of body was related to depressive symptoms, partially through interoception, in Chinese people with subsyndromal depression.

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

The role of interoception in reducing trauma-associated distress: a feasibility study

Background: Altered interoception plays an important role in chronic stress and posttraumatic stress disorder. The aim of this study was to evaluate the feasibility of a Trauma Sensitive Yoga (TSY) intervention for improving emotional distress and psychological discomfort in women living under circumstances of social and gender vulnerability. We assessed the effect of the treatment on the interoceptive mechanisms, and whether the psychological improvements were mediated by the changes in these mechanisms.Methods: The study involved a sample of 62 women who attended public community centres dedicated to supporting women victims of gender-based violence or who were socially and economically disadvantaged because of their gender. Participants underwent a six-week TSY programme. We evaluated dropout rate, adherence, and intervention satisfaction. We measured emotional distress, psychological discomfort, interoceptive mechanisms, and two nonequivalent dependent variables to enhance internal validity. We compared pre-post differences using paired samples t-test and a structural equation model (SEM) analysis was performed to compare the changes in the outcomes with the changes in the nonequivalent dependent variables. Mediation models were adjusted to evaluate the role of changes in interoception on outcome changes.Results: Fourteen (23%) women dropped out, mainly after the first intervention session. Intervention adherence (mean attendance 5.3 over 6 sessions) and acceptability were high (mean satisfaction 3.4 over 4). We observed post-intervention improvements in anxiety, depression, psychological discomfort, body responsiveness, and interoceptive awareness. The changes in the outcomes were larger than the changes in the nonequivalent dependent variables. Additionally, we found that the changes in body responsiveness partially mediated the change in anxiety and psychological discomfort but not in depression.Conclusions: TSY could be an interesting therapeutic approach for women experiencing chronic posttraumatic stress symptomatology. Our findings underscore the role of interoceptive mechanisms in traumatic stress and emphasize the importance of addressing these aspects.

Breathing on the mind: Treating dyspnea and anxiety symptoms with biofeedback in chronic lung disease - A qualitative analysis

RATIONALE

Chronic obstructive pulmonary disease (COPD) is characterized by dysfunctional breathing patterns that contribute to impaired lung function and symptoms of dyspnea, anxiety, and abnormal carbon dioxide (CO2) levels.

OBJECTIVE

The study objective was to measure the acceptability of a new mind-body intervention we developed called Capnography-Assisted, Learned Monitored (CALM) Breathing, implemented before pulmonary rehabilitation.

METHODS

CALM Breathing is a 4-week (8-session) intervention designed to treat dyspnea and anxiety in adults with COPD by targeting dysfunctional breathing behaviors (guided by end-tidal CO2 levels). CALM Breathing consists of ten core breathing exercises, CO2 biofeedback, and motivational interviewing. Using qualitative methods and semi-structured interviews immediately post-intervention, we evaluated the acceptability and participation process of CALM Breathing. Themes were identified using constant comparative analysis.

RESULTS

Sixteen participants were interviewed after receiving CALM Breathing. Three main themes of CALM Breathing were identified: (1) Process of learning self-regulated breathing, (2) Mechanisms of a mind-body intervention, (3) Clinical and implementation outcomes.

CONCLUSIONS

Positive themes supported the acceptability of CALM Breathing and described participants' process of learning more self-regulated breathing to manage their dyspnea and anxiety. Positive signals from qualitative participant feedback provided support for CALM Breathing as an intervention for COPD, but larger scale efficacy trials are needed.

Altered reward network responses to social touch in major depression

BACKGROUND

Social touch is an integral part of social relationships and has been associated with reward. Major depressive disorder (MDD) is characterized by severe impairments in reward processing, but the neural effects of social touch in MDD are still elusive. In this study, we aimed to determine whether the neural processing of social touch is altered in MDD and to assess the impact of antidepressant therapy.

METHODS

Before and after antidepressant treatment, 53 MDD patients and 41 healthy controls underwent functional magnetic resonance imaging (fMRI) while receiving social touch. We compared neural responses to social touch in the reward network, behavioral ratings of touch comfort and general aversion to interpersonal touch in patients to controls. Additionally, we examined the effect of treatment response on those measures.

RESULTS

Clinical symptoms decreased after treatment and 43.4% of patients were classified as responders. Patients reported higher aversion to interpersonal touch and lower comfort ratings during the fMRI paradigm than controls. Patients showed reduced responses to social touch in the nucleus accumbens, caudate nucleus and putamen than controls, both before and after treatment. Contrary to our hypotheses, these effects were independent of touch velocity. Non-responders exhibited blunted response in the caudate nucleus and the insula compared to responders, again irrespective of time.

CONCLUSIONS

These findings suggest altered striatal processing of social touch in MDD. Persistent dysfunctional processing of social touch despite clinical improvements may constitute a latent risk factor for social withdrawal and isolation.

Pain experience in eating disorders: The mediating role of depression, alexithymia and interoceptive awareness

OBJECTIVE

Evidence suggests reduced sensitivity to pain due to high pain threshold in anorexia and bulimia nervosa and a possible role of depression, alexithymia and interoceptive awareness on pain experience. This study examined whether self-report and real-time evoked pain experience were mediated by depression, alexithymia and interoceptive awareness in a comprehensive sample of patients with eating disorders (ED).

METHOD

145 participants (90 ED, 55 healthy controls (HC)) underwent a real-time evoked examination of pain and completed self-report questionnaires for pain (Pain Detect Questionnaire (PD-Q), PD-Q VAS, Leeds Assessment of Neuropathic Symptoms and Signs), depression (BDI-II), interoceptive awareness Multidimensional Assessment of Interoceptive Awareness (MAIA), and alexithymia (TAS-20). Three mediation models, with ED diagnosis as independent variable, and BDI, MAIA and TAS-20 as mediators, were tested.

RESULTS

Participants with ED and HC exhibited similar pain type and intensity (self-report and real-time). Eating disorders diagnosis was associated with lower self-report pain intensity and non-neuropathic like pain experience (model 1-2). Depressive symptoms partially (model 1-2) or fully (model 3) mediated the association between ED diagnosis and pain experience, alone (model 1) or via alexithymia (model 3). Interoceptive awareness did not influence pain symptomatology.

DISCUSSION

ED diagnosis is associated with non-neuropathic and lower pain experience. However, concurrent depression and alexithymia are associated with higher pain symptoms and neuropathic features. These results could inform clinicians about the influence of psychopathology on pain experience in ED.

Early developmental risks for tobacco addiction: A probabilistic epigenesis framework

Considerable progress has been made in elucidating the relationships between early life psychobiological and environmental risk factors and the development of tobacco addiction. However, a comprehensive understanding of the heterogeneity in tobacco addiction phenotypes requires integrating research findings. The probabilistic epigenesis meta-theory offers a valuable framework for this integration, considering systemic, multilevel, developmental, and evolutionary perspectives. In this paper, we critically review relevant research on early developmental risks associated with tobacco addiction and highlight the integrative heuristic value of the probabilistic epigenesis framework for this research. For this, we propose a four-level systems approach as an initial step towards integration, analyzing complex interactions among different levels of influence. Additionally, we explore a coaction approach to examine key interactions between early risk factors. Moreover, we introduce developmental pathways to understand interindividual differences in tobacco addiction risk during development. This integrative approach holds promise for advancing our understanding of tobacco addiction etiology and informing potentially effective intervention strategies.

Beyond Gender: Interoceptive Sensibility as a Key Predictor of Body Image Disturbances

Body image disturbance (BID) involves negative attitudes towards shape and weight and is associated with lower levels of interoceptive sensibility (IS) (the subjective perceptions of internal bodily states). This association is considered a risk factor for developing eating disorders (EDs) and is linked to altered sensorimotor representations of the body (i.e., body schema). BIDs manifest across genders and are currently understudied in men. This study investigated gender-related differences in BID and its relationship to the body schema and IS. Data were collected from 86 men and 86 women. BID was assessed using questionnaires measuring self-objectification, state, and trait body dissatisfaction. IS was measured via the MAIA-2. The body schema was indexed via an embodied mental rotation task. Results showed that women reported higher BID than men across all scales. Gender differences in sub-components of interoceptive sensibility were found. Overall, both gender and interoceptive sensibility predicted BID. However, interoceptive sensibility exhibited its own unique association with BID beyond the influence of gender. BID, IS and gender were not significant predictors of performance in the body schema task. Therefore, while gender predicts differences in BID and interoceptive sensibility, there was no evidence of gender-related differences in body schema.

Impaired eating behaviors but intact metabolic hormone levels in individuals with major depressive disorder and generalized anxiety disorder

BACKGROUND

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) contribute significantly to global health burdens. Identifying disease markers for these comorbid disorders can increase understanding of pathogenesis and improve screening and intervention strategies. This study examined the association of physical health factors with MDD and MDD + GAD, across sexes.

METHODS

Two samples of participants from the Tulsa-1000 study (exploratory cohort: N = 136; confirmatory cohort: N = 185) completed body composition measurements, eating behavior (Three Factor Eating Questionnaire [TFEQ], Eating Disorder Diagnostic Scale [EDDS]), exercise questionnaires, and a blood draw. Metabolic hormone concentrations (leptin, insulin, and adiponectin) were analyzed from blood samples. Within each cohort, a two-way analysis of variance compared three groups (MDD, MDD + GAD, and healthy controls [HC]), sex, and their interaction on dependent variables. Hedges g was calculated to reflect effect size magnitude.

RESULTS

Medium-to-large group main effects across cohorts indicated that compared to HC: (1) MDD (g = 1.71/0.57) and MDD + GAD (g = 0.93/0.69) reported higher TFEQ Disinhibition scores; (2) MDD endorsed higher TFEQ Hunger scores (g = 0.66/0.48); and (3) MDD (g = 1.60/1.30) and MDD + GAD (g = 0.92/1.72) reported greater EDDS scores. Large sex main effects across cohorts indicated that females exhibited higher levels than males for percent body fat (g = 1.07/1.17), leptin (g = 1.27/1.12), and adiponectin (g=0.82/0.88).

LIMITATIONS

The power to detect group*sex interactions was limited due to a greater number of females (than males) in the study, and over half of clinical participants were taking medications.

CONCLUSIONS

Individuals with MDD and MDD + GAD demonstrate difficulties in regulating eating behaviors, potentially contributing to functional impairment and increased disease burden.

Neuroanatomy of post-stroke depression: the association between symptom clusters and lesion location

Post-stroke depression affects about 30% of stroke patients and often hampers functional recovery. The diagnosis of depression encompasses heterogeneous symptoms at emotional, motivational, cognitive, behavioural or somatic levels. Evidence indicates that depression is caused by disruption of bio-aminergic fibre tracts between prefrontal and limbic or striatal brain regions comprising different functional networks. Voxel-based lesion-symptom mapping studies reported discrepant findings regarding the association between infarct locations and depression. Inconsistencies may be due to the usage of sum scores, thereby mixing different symptoms of depression. In this cross-sectional study, we used multivariate support vector regression for lesion-symptom mapping to identify regions significantly involved in distinct depressive symptom domains and global depression. MRI lesion data were included from 200 patients with acute first-ever ischaemic stroke (mean 0.9 ± 1.5 days of post-stroke). The Montgomery-Åsberg Depression Rating interview assessed depression severity in five symptom domains encompassing motivational, emotional and cognitive symptoms deficits, anxiety and somatic symptoms and was examined 8.4 days of post-stroke (±4.3). We found that global depression severity, irrespective of individual symptom domains, was primarily linked to right hemispheric lesions in the dorsolateral prefrontal cortex and inferior frontal gyrus. In contrast, when considering distinct symptom domains individually, the analyses yielded much more sensitive results in regions where the correlations with the global depression score yielded no effects. Accordingly, motivational deficits were associated with lesions in orbitofrontal cortex, dorsolateral prefrontal cortex, pre- and post-central gyri and basal ganglia, including putamen and pallidum. Lesions affecting the dorsal thalamus, anterior insula and somatosensory cortex were significantly associated with emotional symptoms such as sadness. Damage to the dorsolateral prefrontal cortex was associated with concentration deficits, cognitive symptoms of guilt and self-reproach. Furthermore, somatic symptoms, including loss of appetite and sleep disturbances, were linked to the insula, parietal operculum and amygdala lesions. Likewise, anxiety was associated with lesions impacting the central operculum, insula and inferior frontal gyrus. Interestingly, symptoms of anxiety were exclusively left hemispheric, whereas the lesion-symptom associations of the other domains were lateralized to the right hemisphere. In conclusion, this large-scale study shows that in acute stroke patients, differential post-stroke depression symptom domains are associated with specific structural correlates. Our findings extend existing concepts on the neural underpinnings of depressive symptoms, indicating that differential lesion patterns lead to distinct depressive symptoms in the first weeks of post-stroke. These findings may facilitate the development of personalized treatments to improve post-stroke rehabilitation.

Development of a Scale to Examine Responses to Bodily Sensations

OBJECTIVE

Individual differences in the perception of bodily sensations is known to be associated with affective symptomatology. However, the way people psychologically respond to everyday bodily sensations has not been examined in a systematic and balanced way. Thus, we developed the Bodily Sensations Response Scale (BSRS) to evaluate participants' self-reported cognitive, emotional, and behavioral responses to their bodily sensations. We investigated the scale's factor structure and its psychometric properties in two studies.

METHOD

In Study 1, 297 participants completed the 50-item BSRS and exploratory factor analysis (EFA) was performed on the responses. In Study 2 (N = 284), confirmatory factor analysis (CFA) was used to confirm the factor structure of the 32-item BSRS identified in Study 1.

RESULTS

In Study 1, the EFA identified a 32-item three-factor solution as the best fit for the data. Factor 1 described a defeat response to bodily sensations, Factor 2 described an acceptance response, and Factor 3 described a sensitization response. In Study 2, the three-factor solution was shown not to be parsimonious. Rather, CFA identified that the 27-item BSRS had two interpretable factors (Defeat and Acceptance) that explained participants' psychological responses to bodily sensations. The Defeat subscale was moderately to strongly correlated with awareness of bodily sensations (i.e., Body Perception Questionnaire-Short Form scores) and depression, anxiety, and stress symptom severity (i.e., Depression Anxiety Stress Scales-21 scores), whereas the Acceptance subscale was unrelated or only slightly negatively correlated to awareness of bodily sensations and depression, anxiety, and stress symptoms.

CONCLUSION

The 27-item BSRS provides a psychometrically robust assessment of the way in which people psychologically respond to everyday bodily sensations. The measure can assist researchers to better understand how people psychologically process their salient bodily sensations and how this is linked to psychopathology.

Insular dysfunction of interoception in major depressive disorder: from the perspective of neuroimaging

Interoception plays a crucial role in maintaining bodily homeostasis and promoting survival, and is considered the basis of human emotion, cognition, and self-formation. A malfunction of interoception is increasingly suggested to be a fundamental component of different mental health conditions, and depressive disorders have been especially closely associated. Interoceptive signaling and processing depends on a system called the "interoceptive pathway," with the insula, located in the deep part of the lateral fissure, being the most important brain structure in this pathway. Neuroimaging studies have revealed alterations in the structure and function of the insula in a large number of individuals with depression, yet the precise relationship between these alterations and interoceptive dysfunction remains unclear. The goal of this review is to examine the evidence that exists for dysfunction of interoception in people with Major Depressive Disorder (MDD), and to determine the associated specific alterations in the structure and function of the insula revealed by neuroimaging. Overall, three aspects of the potential relationship between interoceptive dysfunction and alterations in insular function in people with depression have been assessed, namely clinical symptoms, quantitative measures of interoceptive function and ability, and interoceptive modulation. To conclude, several specific limitations of the published studies and important lines of enquiry for future research are offered.

Dysfunctional self-reported interoception predicts residual symptom burden of fatigue in major depressive disorder: an observational study

BACKGROUND

Fatigue is a core symptom of major depressive disorder (MDD) and is frequently refractory to antidepressant treatment, leading to unfavorable clinical/psychosocial outcomes. Dysfunctional self-reported interoception (i.e., maladaptive focus on the body's physiological condition) is prevalent in MDD and could contribute to residual symptom burden of fatigue. Therefore, we explored (a.) cross-sectional correlations between both dimensions and investigated (b.) prospective associations between interoceptive impairments at admission and symptom severity of fatigue at the end of hospitalization.

METHODS

This observational, exploratory study included 87 patients suffering from MDD who completed self-rating scales, the Multidimensional Assessment of Interoceptive Awareness, Version 2 (MAIA-2), and the Multidimensional Fatigue Inventory (MFI-20), at the beginning and end of hospitalization. Bivariate correlations (r) and hierarchical regression analyses were performed.

RESULTS

The cross-sectional analysis showed moderate to large negative correlations between the MAIA-2 and MFI-20 dimensions except for the Not-Distracting scale. Symptoms of general, physical, and mental fatigue at the end of hospitalization were predicted by reduced body Trusting (β = -.31, p = .01; β = -.28, p = .02; β = -.31, p = .00, respectively). Increased Body Listening (β = .37, p = .00), Not-Worrying (β = .26, p = .02), and diminished Attention Regulation (β = -.32, p = .01) predicted higher mental fatigue.

CONCLUSIONS

Diminished body confidence at baseline identified patients at risk for post-treatment fatigue and could therefore serve as a target for improving antidepressant therapy. Body-centered, integrative approaches could address treatment-resistant fatigue in MDD. However, clinicians may also consider the potential adverse effect of increased Body Listening and Not-Worrying on mental fatigue in psychotherapeutic and counselling approaches. Due to the exploratory nature of this study, the results are preliminary and need to be replicated in pre-registered trials with larger sample sizes.

Characteristics and correlation of gray matter volume and somatic symptoms in adolescent patients with depressive disorder

Background

Adolescent patients with depressive disorders commonly exhibit somatic symptoms, which have a significant negative impact on their treatment and prognosis. Despite this, specific brain imaging characteristics of these symptoms have been poorly studied.

Methods

The Hamilton Depression Rating scale (HAMD-17), Children's Functional Somatization scale (CSI), and Toronto Alexithymia scale (TAS) were used to evaluate the clinical symptoms of adolescent depression. We analyzed the correlation between brain gray matter volume (GMV) and clinical symptoms in adolescent patients with depression and somatic symptoms.

Results

The depression subgroups with and without functional somatic symptoms (FSS) had higher scores on the HAMD-17, CSI, and TAS than the normal control group. The group with FSS had higher HAMD-17, CSI, and TAS scores than the depression group without FSS (p < 0.05). CSI and TAS scores were positively correlated (r = 0.378, p < 0.05). The GMV of the right supplementary motor area was higher in the depression groups with and without FSSs than in the normal control group, and the GMV was higher in the group without FSS than in the group with FSS (F = 29.394, p < 0.05). The GMV of the right supplementary motor area was negatively correlated with CSI in the depressed group with FSS (r = -0.376, p < 0.05). In the group with depression exhibiting FSS, CSI scores were positively correlated with GMV of the middle occipital gyrus (pr = 0.665, p = 0.0001), and TAS scores were positively correlated with GMV of the caudate nucleus (pr = 0.551, p = 0.001).

Conclusion

Somatic symptoms of adolescent depressive disorder are associated with alexithymia; moreover, somatic symptoms and alexithymia in adolescent patients with depressive disorders are correlated with GMV changes in different brain regions.

Altered brain dynamic in major depressive disorder: state and trait features

Temporal neural synchrony disruption can be linked to a variety of symptoms of major depressive disorder (MDD), including mood rigidity and the inability to break the cycle of negative emotion or attention biases. This might imply that altered dynamic neural synchrony may play a role in the persistence and exacerbation of MDD symptoms. Our study aimed to investigate the changes in whole-brain dynamic patterns of the brain functional connectivity and activity related to depression using the hidden Markov model (HMM) on resting-state functional magnetic resonance imaging (rs-fMRI) data. We compared the patterns of brain functional dynamics in a large sample of 314 patients with MDD (65.9% female; age (mean ± standard deviation): 35.9 ± 13.4) and 498 healthy controls (59.4% female; age: 34.0 ± 12.8). The HMM model was used to explain variations in rs-fMRI functional connectivity and averaged functional activity across the whole-brain by using a set of six unique recurring states. This study compared the proportion of time spent in each state and the average duration of visits to each state to assess stability between different groups. Compared to healthy controls, patients with MDD showed significantly higher proportional time spent and temporal stability in a state characterized by weak functional connectivity within and between all brain networks and relatively strong averaged functional activity of regions located in the somatosensory motor (SMN), salience (SN), and dorsal attention (DAN) networks. Both proportional time spent and temporal stability of this brain state was significantly associated with depression severity. Healthy controls, in contrast to the MDD group, showed proportional time spent and temporal stability in a state with relatively strong functional connectivity within and between all brain networks but weak averaged functional activity across the whole brain. These findings suggest that disrupted brain functional synchrony across time is present in MDD and associated with current depression severity.

Relationship Between Interoception and Autistic Traits: A Resting-State Functional Connectivity Study

Interoception, the sense of the physiological condition of our body, is impaired in individuals with autism spectrum disorders. Evidence suggests that subclinical autistic traits are mild manifestations of autistic symptoms, present in the general population. We examined the resting-state functional connectivity (rsFC) associating with interoception and autistic traits in 62 healthy young adults. Autistic traits correlated negatively with the rsFC between the lateral ventral anterior insula and anterior cingulate cortex. Interoceptive accuracy and sensibility correlated positively with the rsFC between interoceptive brain networks and the cerebellum, supplementary motor area, and visual regions. The results suggest that a negative relationship between interoception and autistic traits is largely accounted for by both self-report measures and decreased rsFC amongst the interoceptive brain network.

Neurofeedback as neuroempowerment technique for affective regulation and interoceptive awareness in adolescence: preliminary considerations applied to a psychogenic pseudosyncope case

Revisions of classical models of acute stress response spectrum and defence cascade process might represent a valuable background for the interpretation of the link between affective reactions, traumatic experiences, and Psychogenic pseudosyncope (PPS) events in childhood and across the lifespan. Indeed, associations between subjective emotional life, early exposure to distressing and/or traumatic events, and PPS have fuelled a debate on potential causes of occurrence and recurrence of such a peculiar clinical manifestation. At the same time, such background suggests that empowering stress management and affective regulation skills could be the target for neurorehabilitation interventions aiming at reducing the severity of symptomatology and/or improving awareness and management of pseudosyncopal spells. Specifically, neuro/biofeedback-based empowerment of self-regulation skills, associated to an increased interoceptive increased awareness, could be a promising complement to classical psychological therapies. Starting from the presentation of a paediatric PPS clinical case, the present work discusses the relevance of assessing affective appraisal and autonomic reactivity in individuals suffering from PPS episodes and introduces a novel potential neuroempowerment protocol aimed at improving self-regulation and stress management skills in adolescence based on a combined neurofeedback and embodied-awareness intervention. By capitalizing available evidence of the effects of neuromodulation and embodied practices on self-awareness/regulation across the life-span, the proposed protocol is based on neurofeedback-supported affective management training, as well as both contemplative and informal awareness exercises devised to be appealing and challenging even for younger patients.

Invasive Computational Psychiatry

Computational psychiatry, a relatively new yet prolific field that aims to understand psychiatric disorders with formal theories about the brain, has seen tremendous growth in the past decade. Despite initial excitement, actual progress made by computational psychiatry seems stagnant. Meanwhile, understanding of the human brain has benefited tremendously from recent progress in intracranial neuroscience. Specifically, invasive techniques such as stereotactic electroencephalography, electrocorticography, and deep brain stimulation have provided a unique opportunity to precisely measure and causally modulate neurophysiological activity in the living human brain. In this review, we summarize progress and drawbacks in both computational psychiatry and invasive electrophysiology and propose that their combination presents a highly promising new direction-invasive computational psychiatry. The value of this approach is at least twofold. First, it advances our mechanistic understanding of the neural computations of mental states by providing a spatiotemporally precise depiction of neural activity that is traditionally unattainable using noninvasive techniques with human subjects. Second, it offers a direct and immediate way to modulate brain states through stimulation of algorithmically defined neural regions and circuits (i.e., algorithmic targeting), thus providing both causal and therapeutic insights. We then present depression as a use case where the combination of computational and invasive approaches has already shown initial success. We conclude by outlining future directions as a road map for this exciting new field as well as presenting cautions about issues such as ethical concerns and generalizability of findings.

[Mother brain: Bayesian theory of maternal interoception during pregnancy and postpartum]

The perinatal period, including pregnancy and postpartum, causes major morphological, endocrinal, and thermal transitions in women. As the fetus grows, abdominal muscle fibers stretch, internal organs such as the bladder or colon move, and the uterine anatomy changes. Many of these changes involve interoception, the perception of internal body signals such as muscle and visceral sensations. Despite the importance of these interoceptive signals, few studies have explored perinatal interoception. We propose an innovative theory of maternal interoception based on recent findings in neuroscience. We show that interoceptive signals processing during pregnancy is crucial for understanding perinatal phenomenology and psychopathology, such as maternal perception of fetal movements, maternal-infant bonding, denial of pregnancy, phantom fetal movements after childbirth, pseudocyesis or even puerperal delusion. Knowing the importance of these interoceptive mechanisms, clinicians in obstetrics, gynecology and mental health should be particularly vigilant to maternal interoception during the perinatal period.

Pilot Study About the Effects of the Soma Experiencing Motion (Soma e-Motion) Program on Interoceptive Awareness and Self-Compassion

OBJECTIVE

The purpose of this study was to examine the effects of the Soma experiencing motion (Soma e-motion) program on interoceptive awareness and self-compassion among novices.

METHODS

A total of 19 adults (clinical group=9, non-clinical group=10) participated in the intervention. Psychological and physical changes after program were qualitatively analyzed using in-depth interviews. The Korean Multidimensional Assessment of Interoceptive Awareness (K-MAIA) and the Korean version of the Self-Compassion Scale (K-SCS) were used as quantitative measures.

RESULTS

The non-clinical group showed statistically significant differences in the K-MAIA scores (z=-2.805, p<0.01) and K-SCS scores (z=-2.191, p<0.05); however, the clinical group showed no significant differences (K-MAIA: z=-0.652, p>0.05; K-SCS: z=-0.178, p>0.05). According to the in-depth interviews, the results of the qualitative analysis were categorized into five dimensions (psychological and emotional, physical, cognitive, behavioral, and aspects participants found challenging and needs improvement).

CONCLUSION

The Soma e-motion program was feasible for improving interoceptive awareness and self-compassion in the non-clinical group. However, further research is needed to investigate the clinical efficacy of the Soma e-motion program for clinical group.

Exploring Associations between C-Reactive Protein and Self-Reported Interoception in Major Depressive Disorder: A Bayesian Analysis

Major depressive disorder (MDD) is associated with dysfunctional self-reported interoception (i.e., abnormal perception of the body's physiological state) and systemic inflammation, both of which adversely affect treatment response. In this study, we explored associations between C-reactive protein (CRP) and self-reported interoception, to gain more insight into the pathophysiology of interoceptive impairments in MDD. We also aimed to replicate previous findings on the associations of depression and fatigue severity with CRP. The study included 97 depressed individuals, who completed self-administered questionnaires (Multidimensional Assessment of Interoceptive Awareness (MAIA-2); Beck Depression Inventory-II, Multidimensional Fatigue Inventory). CRP concentrations were analyzed in the serum using a particle-enhanced turbidimetric immunoassay. We applied Bayesian inference to estimate robust effect parameters from posterior distributions based on MCMC sampling, and computed Bayes factors (BF₁₀) as indices of relative evidence. The bivariate analysis supported evidence against associations between CRP and self-reported interoception (BF₁₀ ≤ 0.32), except for one dimension (Not-Distracting: r = 0.11, BF₁₀ > 0.43, absence of evidence). Positive correlations with overall depression (r = 0.21, BF₁₀ = 3.19), physical fatigue (r = 0.28, BF₁₀ = 20.64), and reduced activity (r = 0.22, BF₁₀ = 4.67) were found. The multivariate analysis showed moderate evidence that low-grade inflammation predicted higher scores on the MAIA-2 Not-Worrying scale (β = 0.28, BF₁₀ = 3.97), after controlling for relevant confounders. Inflammatory responses, as measured by CRP, may not be involved in the pathophysiology of dysfunctional self-reported interoception. However, systemic low-grade inflammation could potentially exert a protective effect against worries about pain or discomfort sensations. An immunological involvement in interoceptive impairments cannot be ruled out until future studies considering additional biomarkers of inflammation replicate our findings.

Abnormal cortical-striatal-thalamic-cortical circuit centered on the thalamus in MDD patients with somatic symptoms: Evidence from the REST-meta-MDD project

OBJECTIVE

Somatic symptoms are common comorbidities of major depressive disorder (MDD), and negatively impact the course and severity of the disease. In order to enrich the understanding of the pathological mechanism and clarify the neurobiological basis of somatic symptoms in depression, we attempted to explore the changes of brain structure and function in a large sample between depression with and without somatic symptoms.

METHODS

Structure magnetic resonance imaging (MRI) data were collected from 342 patients with somatic symptoms (SD), 208 patients without somatic symptoms (NSD), and 510 healthy controls (HCs) based on the REST-meta-MDD project. We analyzed the whole brain VBM maps of the three groups, and combined with weight degree centrality (DC) index, we investigated whether the brain regions with gray matter volume (GMV) and gray matter density (GMD) abnormalities in MDD patients with somatic symptoms had corresponding brain functional abnormalities.

RESULTS

Between depression with and without somatic symptoms, we found that there are extensive GMV and GMD differences involving cortical regions such as the temporal lobe, occipital lobe, and insula, as well as subcortical brain regions such as thalamus and striatum. The comparison results of weight DC signals of GMV and GMD abnormal clusters between the SD and NSD groups were basically consistent with the GMV and GMD abnormal clusters.

CONCLUSION

The results indicate that the structure and function of cortical-striatal-thalamic-cortical (CSTC) circuit centered on the thalamus were abnormal in MDD patients with somatic symptoms. This may be the neurobiological basis of somatic symptoms in MDD.

Effects of emotional contexts on respiratory attention task performance

Negative emotions have been found associated with high prevalence of respiratory disease and increased subjective feelings of dyspnea, while positive emotional stimulus has been suggested to alleviate dyspneic feelings. However, the extent to which different emotional contexts affect individuals' respiratory interoceptive attention was not clear. Therefore, the purpose of this study was to investigate the influences of emotional contexts on respiratory interoceptive accuracy, and the relationships between respiratory interoceptive accuracy and negative emotions as well as respiratory symptoms. Fifty-six healthy participants completed the self-reported questionnaires of depression, anxiety, and respiratory symptoms. During the experiment, the participants were instructed to watch one neutral and one positive affective picture series and mentally count the number of perceived occlusions (reported at the end of the trials). The Wilcoxon Signed-Rank test and Spearman's correlations were used to examine the effect of the emotional pictures and to explore the relationships between the level of emotional status or respiratory symptoms and respiratory interoceptive task performance. The significance level was set at p < 0.05. Our results did not show a significant difference in participants' occlusion counting task performance between the neutral and positive emotional context. However, Spearman's Rho correlation analysis revealed that depression level was negatively correlated with accuracy of the task performance in the neutral emotional context, and this relationship diminished in the positive emotional context. In summary, our study demonstrated that negative emotional status, especially depression, may lead to decreased respiratory interoceptive accuracy. Future studies are recommended to test the effect of positive emotional context on respiratory interoceptive task performance in individuals with clinical depression and anxiety.

The Role of Lifestyle on Adherence to Treatment in a Sample of Patients with Unipolar and Bipolar Depression

Introduction: Poor adherence to treatment is currently stated to be one of the causes of depression relapse and recurrence. The aim of the present study is to assess potential differences in terms of clinical and lifestyle features related to adherence to treatment in a sample of patients with unipolar and bipolar depression. Methods: One hundred and eight patients with a diagnosis of unipolar or bipolar depressive episode were recruited from January 2021 to October 2022. Adherence to psychopharmacological treatment was assessed using the clinician rating scale. Descriptive and association analyses were performed to compare subgroups based on adherence to treatment. Results: Lower levels of adherence to treatment were associated with fewer years of education, work impairment, manic prevalent polarity lifetime, and greater comorbidity with alcohol and drug abuse. The majority of patients with positive adherence did not report any hospitalization and involuntary commitment lifetime. Conclusions: Patients with a positive treatment adherence showed significant differences in terms of lifestyle and clinical features compared to non-adherent patients. Our results may help to identify patients more likely to have poor medication adherence, which seem to lead to a worse disease course and quality of life.

Interoceptive hunger, eating attitudes and beliefs

Interoceptive individual differences have garnered interest because of their relationship with mental health. One type of individual difference that has received little attention is variability in the sensation/s that are understood to mean a particular interoceptive state, something that may be especially relevant for hunger. We examined if interoceptive hunger is multidimensional and idiosyncratic, if it is reliable, and if it is linked to dysfunctional eating and beliefs about the causes of hunger. Participants completed a survey just before a main meal, with most retested around 1 month later. We found that interoceptive hunger has 11 dimensions, and while people differ considerably in their combinations of interoceptive hungers, these represent only 4% of all possible permutations. Hunger reports were reliable. We found relationships between variability in hunger interoception and dysfunctional eating, especially for uncontrolled eating. We also found that hunger beliefs were in some cases strongly related to aspects of hunger interoception. The implications of these findings are discussed.

A systematic review on the potential use of machine learning to classify major depressive disorder from healthy controls using resting state fMRI measures

BACKGROUND

Major Depressive Disorder (MDD) is a psychiatric disorder characterized by functional brain deficits, as documented by resting-state functional magnetic resonance imaging (rs-fMRI) studies.

AIMS

In recent years, some studies used machine learning (ML) approaches, based on rs-fMRI features, for classifying MDD from healthy controls (HC). In this context, this review aims to provide a comprehensive overview of the results of these studies.

DESIGN

The studies research was performed on 3 online databases, examining English-written articles published before August 5, 2022, that performed a two-class ML classification using rs-fMRI features. The search resulted in 20 eligible studies.

RESULTS

The reviewed studies showed good performance metrics, with better performance achieved when the dataset was restricted to a more homogeneous group in terms of disease severity. Regions within the default mode network, salience network, and central executive network were reported as the most important features in the classification algorithms.

LIMITATIONS

The small sample size together with the methodological and clinical heterogeneity limited the generalizability of the findings.

CONCLUSIONS

In conclusion, ML applied to rs-fMRI features can be a valid approach to classify MDD and HC subjects and to discover features that can be used for additional investigation of the pathophysiology of the disease.

Exploring the contributions of affective constructs and interoceptive awareness to feeling fat

PURPOSE

Feeling fat, a subjective feeling of being overweight that does not always correspond to actual body weight, is commonly reported in patients with an eating disorder. Research suggests that feeling fat relates to deficits in interoceptive awareness, the perception and integration of signals related to body states. Relatedly, recent work has linked feeling fat to affective constructs, such as depressive symptoms and guilt. The current study explores the unique relationships between feeling fat, self-reported, and objective IA, guilt, alexithymia, and depressive symptoms.

METHOD

Female undergraduates (N = 128) completed the 11th item of the Eating Disorder Examination Questionnaire, the Toronto Alexithymia Scale, the Guilt subscale of the Positive and Negative Affect Schedule, and the Beck Depression Inventory-II. Participants also completed two IA measures: a heartbeat perception task and the Multidimensional Assessment of Interoceptive Awareness.

RESULTS

All collected measures explained 56% of the variability in feeling fat. Depressive symptoms, self-reported IA, and BMI accounted for significant variability in feeling fat. Relative weights analyses revealed that depressive symptoms accounted for the most variability in feeling fat (19%). This finding remained significant after controlling for BMI, which also accounted for significant variability in feeling fat (25%).

CONCLUSIONS

Our results replicate previous findings that depressive symptoms relate significantly to feeling fat and extend this work by incorporating the role of interoceptive awareness, guilt, and alexithymia. Endorsement of feeling fat during an intake assessment may alert clinicians to assess for depressive symptoms, and focusing on depressive symptoms in treatment may improve feeling fat.

LEVEL OF EVIDENCE

Level I Evidence obtained from an experimental study.

Increased insula response to interoceptive attention following mindfulness training is associated with increased body trusting among patients with depression

Interoceptive dysfunction is often present in anxiety and depression. We investigated the effects of an 8-week intervention, Mindfulness Training for Primary Care (MTPC), on brain mechanisms of interoceptive attention among patients with anxiety and/or depression. We hypothesized that fMRI brain response to interoception in the insula, a region known for interoceptive processing, would increase following the MTPC intervention, and that such increases would be associated with post-intervention changes in self-reported measures of interoceptive awareness. Adults (n = 28) with anxiety and/or depression completed baseline and post-intervention fMRI visits, including a task in which they alternated between focusing on their heartbeat (interoception (INT)) and a control visual attention task (exteroception (EXT)). Following MTPC, we observed increased evoked fMRI response (relative to baseline) in left anterior insula during the INT-EXT task contrast (z > 3.1, p < 0.001 corrected). In patients with moderate-to-severe depression as defined by the Patient Reported Outcomes Measurement Information System (PROMIS), increased post-intervention insula response was associated with increased Body Trusting, a subscale of the Multidimensional Assessment of Interoceptive Awareness (z > 3.1, p = 0.007 corrected). This study demonstrates that patients with mood disorders may respond differentially to mindfulness-based treatment depending on depression severity, and that among those who are more depressed, increased trusting in one's own body sensations and experiencing the body as a safe place to attend to may be necessary components of positive responses to mindfulness-based interventions.

Anterior Insula Activation During Cardiac Interoception Relates to Depressive Symptom Severity in HIV-Positive and HIV-Negative Postmenopausal Women

OBJECTIVE

This study aimed to determine whether subclinical symptoms of depression in postmenopausal women are associated with blood oxygen level-dependent (BOLD) activity within the anterior insula during cardiac interoceptive awareness and whether this association differs for persons living with the human immunodeficiency virus (PWH).

METHOD

Twenty-three postmenopausal (mean [standard deviation] age = 56.5 [4.8] years) and 27 HIV-negative women (mean [standard deviation] age = 56.4 [8.0]) underwent functional magnetic resonance imaging while performing a heartbeat detection task. BOLD activation within the bilateral anterior insula based on the contrast of a heartbeat detection condition with and without a distracting tone was entered along with age, HIV status, and psychological stress into two multivariate regression models with self-reported depressive symptom severity as the outcome.

RESULTS

Depressive symptoms did not vary by HIV status, nor was there a main effect or interaction for PWH on insula BOLD activation. Depressive symptoms were positively associated with psychological stress for the left ( β = 0.310, t (49) = 2.352, p = .023) and right brain models ( β = 0.296, t (49) = 2.265, p = .028) as well as the magnitude of BOLD activation in the left insula ( β = 0.290, t (49) = 2.218, p = .032) and right insula ( β = 0.318, t (49) = 2.453, p = .018), respectively. Exploratory analyses revealed that greater magnitude of BOLD activation attributed to exteroceptive noise (tone) was also correlated with self-reported distrust and preoccupation with interoceptive sensations.

CONCLUSIONS

Results support an active interference model for interoceptive awareness wherein greater BOLD signal in the anterior insula in the presence of distracting exteroceptive stimuli may reflect greater prediction error, a feature of depression.

Predictive processing in depression: Increased prediction error following negative valence contexts and influence of recent mood-congruent yet irrelevant experiences

BACKGROUND

Novel theoretical models of depression have recently emerged based on an influential new perspective in neuroscience known as predictive processing. In these models, depression may be understood as an imbalance of predictive signals in the brain; more specifically, a dominance of predictions leading to a relative insensitivity to prediction error. Despite these important theoretical advances, empirical evidence remains limited, and how expectations are generated and used dynamically in individuals with depression remains largely unexplored.

METHODS

In this study, we induced facial expression predictions using emotion contexts in 34 individuals with depression and 34 healthy controls.

RESULTS

Compared to controls, individuals with depression perceived displayed facial expressions as less similar to their expectations (i.e., increased difference between expectations and actual sensory input) following contexts evoking negative valence emotions, indicating that depressed individuals have increased prediction error in such contexts. This effect was amplified by recent mood-congruent yet irrelevant experiences.

LIMITATIONS

The clinical sample included participants with comorbid psychopathology and taking medication. Additionally, the two groups were not evaluated in the same setting, and only three emotion categories (fear, sadness, and happiness) were explored.

CONCLUSIONS

Our results shed light on potential mechanisms underlying processing abnormalities regarding negative information, which has been consistently reported in depression, and may be a relevant point of departure for exploring transdiagnostic vulnerability to mental illness. Our data also has the potential to improve clinical practice through the implementation of novel diagnostic and therapeutic tools based on the assessment and modulation of predictive signals.

Body image dissatisfaction and interoceptive sensibility significantly predict postpartum depressive symptoms

BACKGROUND

During pregnancy women experience rapid and unique changes in body weight, shape and size over a relatively short time period. While research focused on the role of external bodily modifications during pregnancy, research on internal bodily variations is missing.

METHODS

In a longitudinal study, we recruited healthy pregnant women and measured whether and how depressive symptoms, body image dissatisfaction and the subjective tendency to focus on one's own internal bodily sensations, i.e., interoceptive sensibility, changed during pregnancy and postpartum. Pregnant women filled online self-report questionnaires during pregnancy (i.e. second and third trimester) and after (i.e. six weeks) the delivery, including the Body Areas Satisfaction Scale, the Multidimensional Assessment of Interoceptive Awareness, and the Edinburgh Postnatal Depression Scale.

RESULTS

While depressive symptoms remained stable in the peripartum, body image dissatisfaction increased in the postpartum compared to the pregnancy period, and interoceptive sensibility increased over pregnancy. Findings showed that the increase of body dissatisfaction through the peripartum and the levels of interoceptive sensibility in the early phase of pregnancy predicted depressive symptoms in the postpartum.

LIMITATIONS

Interoception was evaluated as a subjective measure (i.e., interoceptive sensibility). Future studies may include objective measures of interoceptive accuracy and interoceptive awareness.

CONCLUSIONS

The current study supports the importance of body image dissatisfaction and interoceptive sensibility in the development of postpartum depressive symptoms. Future studies need to investigate if interventions aimed to increase interoceptive sensibility might be useful in preventing depressive symptoms and identify the mechanisms that can lead to these changes.

Understanding the neurobiological basis of anhedonia in major depressive disorder - evidence for reduced neural activation during reward and loss processing

BACKGROUND

Anhedonia is a key symptom of major depressive disorder (MDD). Anhedonia is associated with aberrant reward processing, but whether it might interfere similarly with the neural processing of aversive stimuli, such as monetary loss, remains unknown. We aimed to investigate potential associations between anhedonia and neural response during reward and loss processing in patients with MDD.

METHODS

We investigated blood-oxygen-level-dependent response in the orbitofrontal cortex, cingulate cortex, insula and basal ganglia during monetary reward and loss processing in 182 patients with MDD, using a card-guessing paradigm. We measured anhedonia with the Social and Physical Anhedonia Scale (SASPAS), and we tested for the main and interaction effects of SASPAS scores and the experimental condition (reward or loss) in a full factorial model.

RESULTS

We detected a negative main effect of anhedonia, as well as a significant interaction effect of anhedonia and the experimental condition, on orbitofrontal and insular neural response. Post hoc analyses revealed that the interaction was driven by a significant association between higher anhedonia scores and hypoactivation during loss processing. We observed no significant association between anhedonia and neural response during reward processing.

LIMITATIONS

This study had a cross-sectional design.

CONCLUSION

Our findings confirmed that altered neural processing in the orbitofrontal cortex and insula is a neurobiological feature of anhedonic symptomatology in people with MDD. The pronounced association between anhedonia and blunted neural response during loss processing supports a broader concept for the neurobiological basis of anhedonia. Hence, MDD with anhedonic features might be characterized by reduced neural response to external stimuli, potentially because of amotivation.

Static and treatment-responsive brain biomarkers of depression relapse vulnerability following prophylactic psychotherapy: Evidence from a randomized control trial

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A prospective study of neural biomarkers of relapse in remitted depressed patients.

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Assessed neural response to dysphoric mood-induction before and after psychotherapy.

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Relapse over a 2-year follow-up linked to dysphoria-evoked sensory inhibition.

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Relapse risk was lower when dorsolateral prefrontal reactivity decreased over time.

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Depression prophylaxis may involve reducing dysphoria-evoked sensory inhibition.

Background

Neural reactivity to dysphoric mood induction indexes the tendency for distress to promote cognitive reactivity and sensory avoidance. Linking these responses to illness prognosis following recovery from Major Depressive Disorder informs our understanding of depression vulnerability and provides engagement targets for prophylactic interventions.

Methods

A prospective fMRI neuroimaging design investigated the relationship between dysphoric reactivity and relapse following prophylactic intervention. Remitted depressed outpatients (N = 85) were randomized to 8 weeks of Cognitive Therapy with a Well-Being focus or Mindfulness Based Cognitive Therapy. Participants were assessed before and after therapy and followed for 2 years to assess relapse status. Neural reactivity common to both assessment points identified static biomarkers of relapse, whereas reactivity change identified dynamic biomarkers.

Results

Dysphoric mood induction evoked prefrontal activation and sensory deactivation. Controlling for past episodes, concurrent symptoms and medication status, somatosensory deactivation was associated with depression recurrence in a static pattern that was unaffected by prophylactic treatment, HR 0.04, 95% CI [0.01, 0.14], p < .001. Treatment-related prophylaxis was linked to reduced activation of the left lateral prefrontal cortex (LPFC), HR 3.73, 95% CI [1.33, 10.46], p = .013. Contralaterally, the right LPFC showed dysphoria-evoked inhibitory connectivity with the right somatosensory biomarker

Conclusions

These findings support a two-factor model of depression relapse vulnerability, in which: enduring patterns of dysphoria-evoked sensory deactivation contribute to episode return, but vulnerability may be mitigated by targeting prefrontal regions responsive to clinical intervention. Emotion regulation during illness remission may be enhanced by reducing prefrontal cognitive processes in favor of sensory representation and integration.

Effects of mindfulness-based intervention programs on sleep among people with common mental disorders: A systematic review and meta-analysis

BACKGROUND

Sleep problems are particularly prevalent in people with depression or anxiety disorder. Although mindfulness has been suggested as an important component in alleviating insomnia, no comprehensive review and meta-analysis has been conducted to evaluate the effects of different mindfulness-based intervention (MBI) programs on sleep among people with depression or anxiety disorder.

AIM

To compare the effects of different MBI programs on sleep among people with depression or anxiety disorder.

METHODS

Related publications in Embase, Medline, PubMed and PsycINFO databases were systematically searched from January 2010 to June 2020 for randomised controlled trials. Data were synthesized using a random-effects or a fixed-effects model to analyse the effects of various MBI programs on sleep problems among people with depression or anxiety disorder. The fixed-effects model was used when heterogeneity was negligible, and the random-effects model was used when heterogeneity was significant to calculate the standardised mean differences (SMDs) and 95% confidence intervals (CIs).

RESULTS

We identified 397 articles, of which 10 randomised controlled trials, involving a total of 541 participants, were included in the meta-analysis. Studies of internet mindfulness meditation intervention (IMMI), mindfulness meditation (MM), mindfulness-based cognitive therapy (MBCT), mindfulness-based stress reduction (MBSR) and mindfulness-based touch therapy (MBTT) met the inclusion criteria. The greatest effect sizes are reported in favour of MBTT, with SMDs of -1.138 (95%CI: -1.937 to -0.340; P = 0.005), followed by -1.003 (95%CI: -1.645 to -0.360; P = 0.002) for MBCT. SMDs of -0.618 (95%CI: -0.980 to -0.257; P = 0.001) and -0.551 (95%CI: -0.842 to -0.260; P < 0.0001) were reported for IMMI and MBSR in the pooling trials, respectively. Significant effects on sleep problem improvement are shown in all reviewed MBI programs, except MM, for which the effect size was shown to be non-significant.

CONCLUSION

All MBI programs (MBTT, MBCT, IMMI and MBSR), except MM, are effective options to improve sleep problems among people with depression or anxiety disorder.

Interoception Dysfunction Contributes to the Negative Emotional Bias in Major Depressive Disorder

Background

Previous research studies have demonstrated that impaired interoception is involved in emotional information processing in major depressive disorder (MDD). Heartbeat-evoked potential (HEP) amplitudes, an index for interoception, could be manipulated by emotional faces in healthy people. Considering negative emotional bias is the core characteristic in MDD, we hypothesized that interoception dysfunction was associated with the negative emotional bias in MDD.

Methods

An electroencephalogram (EEG) study under an emotional faces task was applied to explore the relationship between interoception and emotional bias. HEPs before emotional faces stimuli were used to predict the late positive potential (LPP) amplitudes and it worked as an index of emotional bias. Twenty-seven patients with MDD and 27 healthy controls (HCs) participated in this study. Source analysis gave an auxiliary description for results in sensory level.

Results

Major depressive disorders (MDDs) had poor performance in the heartbeat count task (HCT) and attenuate HEP average amplitudes (455-550 ms). Compared with HCs, cluster-based permutation t-tests revealed that MDDs had attenuated LPP amplitudes (300-1,000 ms) over centroparietal regions and enhanced LPP amplitudes over frontocentral regions. Furthermore, abnormal attenuated HEPs could predict aberrant LPPs under sad face stimuli in MDDs, which could be associated with the dysfunction of the anterior cingulate cortex (ACC) and right insula.

Conclusion

Mediated by ACC and insula, interoception dysfunction contributes to the negative emotional bias of MDD, highlighting the importance of interoception in the disorder.

Implicit Associations of Nonsuicidal Self-Injury with Relief in Posttraumatic Stress and Depressive Disorders

OBJECTIVE

Although once considered a defining feature of borderline personality disorder, research has found high rates of NSSI among individuals with other psychiatric disorders, particularly posttraumatic stress disorder (PTSD) and depressive disorders. A recent study from our research team found that lifetime PTSD and depressive disorders were associated with unique self-reported NSSI motives. Given well-established limitations of assessing motives via self-report measures, the present study sought to extend this line of research by using a novel laboratory measure of the implicit NSSI-relief association to examine NSSI emotional relief motives.

METHOD

A subset of participants from our previous study (N = 109) completed diagnostic interviews and the laboratory-based DSH-Relief Implicit Association Test (IAT).

RESULTS

Findings indicated that individuals with lifetime PTSD evidenced stronger NSSI-relief associations than those without PTSD. Further, this main effect was qualified by a PTSD by depressive disorder interaction, such that stronger NSSI-relief associations were found among individuals with lifetime PTSD but no lifetime depressive disorder than among individuals without a history of either PTSD or a depressive disorder.

CONCLUSIONS

Results highlight the importance of investigating NSSI motives associated with different symptom profiles using a multi-method approach.

Impact of serotonergic medication on interoception in major depressive disorder

Unmedicated individuals with major depressive disorder (MDD) show abnormal interoception, but it is unclear whether antidepressant treatment via serotonergic medication alters this relationship. The current cross-sectional study examined associations between neural and behavioral indices of interoceptive processing and chronic serotonergic medication administration in MDD. 47 selective serotonin reuptake inhibitor (SSRI)-medicated MDD (MDD-SSRI) individuals were propensity-matched with 48 unmedicated current MDD (MDD-UnMed) and 41 healthy comparison (HC) participants on demographics including age, sex, body mass index, education, as well as on dimensional scales of symptom severity including depression and anxiety. All participants completed an interoceptive attention task during functional magnetic resonance imaging, and a behavioral heartbeat tapping task under three conditions: Guessing, No Guessing, and Breath Hold. Relative to HC, both MDD groups: (1) exhibited lower mid-insula, amygdala, putamen, and caudate activation during interoceptive versus exteroceptive attention; and (2) showed poorer heartbeat tapping performance during the Breath Hold condition. However, the MDD-SSRI group reported higher intensity ratings of heartbeat and stomach sensations than MDD-UnMed and HC during the interoceptive attention task. These findings suggest that the attenuated patterns of neural activation observed in depressed individuals during interoceptive attention are not ameliorated by the chronic administration of serotonergic medications. However, amplified interoceptive sensation ratings suggest a potential impact of chronic serotonergic medication on conscious experiences of internal body states. Future investigations will need to determine the extent to which serotonergic medications acutely influence interoceptive processing, and whether such changes play a role in therapeutic responses during treatment initiation.