Diminished responses to bodily threat and blunted interoception in suicide attempters

Clinical, behavioral, and electrophysiological profiles along a continuum of suicide risk: evidence from an implicit association task

BACKGROUND

An urgent need exists to identify neural correlates associated with differing levels of suicide risk and develop novel, rapid-acting therapeutics to modulate activity within these neural networks.

METHODS

Electrophysiological correlates of suicide were evaluated using magnetoencephalography (MEG) in 75 adults with differing levels of suicide risk. During MEG scanning, participants completed a modified Life-Death Implicit Association Task. MEG data were source-localized in the gamma (30-58 Hz) frequency, a proxy measure of excitation-inhibition balance. Dynamic causal modeling was used to evaluate differences in connectivity estimates between risk groups. A proof-of-concept, open-label, pilot study of five high risk participants examined changes in gamma power after administration of ketamine (0.5 mg/kg), an NMDAR antagonist with rapid anti-suicide ideation effects.

RESULTS

Implicit self-associations with death were stronger in the highest suicide risk group relative to all other groups, which did not differ from each other. Higher gamma power for self-death compared to self-life associations was found in the orbitofrontal cortex for the highest risk group and the insula and posterior cingulate cortex for the lowest risk group. Connectivity estimates between these regions differentiated the highest risk group from the full sample. Implicit associations with death were not affected by ketamine, but enhanced gamma power was found for self-death associations in the left insula post-ketamine compared to baseline.

CONCLUSIONS

Differential implicit cognitive processing of life and death appears to be linked to suicide risk, highlighting the need for objective measures of suicidal states. Pharmacotherapies that modulate gamma activity, particularly in the insula, may help mitigate risk.Clinicaltrials.gov identifier: NCT02543983, NCT00397111.

The Neurophysiology of Interoceptive Disruptions in Trauma-Exposed Populations

In the aftermath of psychological trauma, many individuals experience perturbations in interoception, a term that broadly references the ability to accurately detect body signals and integrate these signals with emotional states. These interoceptive disruptions can manifest in different ways, including blunting or amplification of sensitivity to internal physiological signals. In this chapter we review extant neurophysiological research on interoception in trauma-exposed populations, with a particular focus on the effects of chronic interpersonal trauma, such as childhood maltreatment and racial discrimination. We explore research that used different types of interoceptive assays, from self-report measures to electrophysiological and neuroimaging tools to characterize the disruptions in pain perception, interoceptive acuity, and physiological responses that may arise after a traumatic event. Finally, we discuss interventions that are designed to target interoceptive mechanisms, from exposure-based therapies to mindfulness-based practices, as well as future directions in trauma interoception research.

Exploring the role of neuronal-enriched extracellular vesicle miR-93 and interoception in major depressive disorder

Major depressive disorder (MDD) is associated with interoceptive processing dysfunctions, but the molecular mechanisms underlying this dysfunction are poorly understood. This study combined brain neuronal-enriched extracellular vesicle (NEEV) technology and serum markers of inflammation and metabolism with Functional Magnetic Resonance Imaging (fMRI) to identify the contribution of gene regulatory pathways, in particular micro-RNA (miR) 93, to interoceptive dysfunction in MDD. Individuals with MDD (n = 41) and healthy comparisons (HC; n = 35) provided blood samples and completed an interoceptive attention task during fMRI. EVs were separated from plasma using a precipitation method. NEEVs were enriched by magnetic streptavidin bead immunocapture utilizing a neural adhesion marker (L1CAM/CD171) biotinylated antibody. The origin of NEEVs was validated with two other neuronal markers - neuronal cell adhesion molecule (NCAM) and ATPase Na+/K+ transporting subunit alpha 3 (ATP1A3). NEEV specificities were confirmed by flow cytometry, western blot, particle size analyzer, and transmission electron microscopy. NEEV small RNAs were purified and sequenced. Results showed that: (1) MDD exhibited lower NEEV miR-93 expression than HC; (2) within MDD but not HC, those individuals with the lowest NEEV miR-93 expression had the highest serum concentrations of interleukin (IL)-1 receptor antagonist, IL-6, tumor necrosis factor, and leptin; and (3) within HC but not MDD, those participants with the highest miR-93 expression showed the strongest bilateral dorsal mid-insula activation during interoceptive versus exteroceptive attention. Since miR-93 is regulated by stress and affects epigenetic modulation by chromatin re-organization, these results suggest that healthy individuals but not MDD participants show an adaptive epigenetic regulation of insular function during interoceptive processing. Future investigations will need to delineate how specific internal and external environmental conditions contribute to miR-93 expression in MDD and what molecular mechanisms alter brain responsivity to body-relevant signals.

Body Awareness as a Protective Factor against Suicidal Orientations in College Students

In this study, binary logistic regression and linear regression analyses were used to examine the relationship between interoceptive body awareness and suicidal orientation among Colombian university students. Additionally, the bootstrap technique was employed to resample and estimate the distribution of the data. The results support the idea that greater interoceptive awareness may protect against suicidal orientation by improving emotional regulation. An inverse relationship was found between interoceptive awareness and suicidal ideation. These findings align with previous literature emphasizing the importance of body awareness for emotional well-being. Further longitudinal research is needed to explore this relationship more deeply.

Clinical and electrophysiological correlates of hopelessness in the context of suicide risk✰

Hopelessness is a key risk factor for suicide. This analysis explored whether hopelessness indicates a recent suicide crisis state and is linked with magnetoencephalography (MEG) oscillatory power and effective connectivity differences. Change in hopelessness ratings and effective connectivity post-ketamine were also evaluated in a subsample of high-risk individuals to evaluate correlates of dynamic changes over time. Participants (66F;44 M;1 transgender) included individuals with suicide crisis in the last two weeks (High Risk (HR), n = 14), those with past suicide attempt but no recent suicide ideation (SI) (Low Risk (LR), n = 37), clinical controls (CC, n = 33), and healthy volunteers at minimal risk (MinR, n = 27). MEG oscillatory power and clinical hopelessness ratings (via the Beck Hopelessness Scale (BHS)) were evaluated across groups. Dynamic casual modeling (DCM) evaluated connectivity within and between the anterior insula (AI) and anterior cingulate cortex (ACC). A subsample of HR individuals who received ketamine (n = 10) were evaluated at Day 1 post-infusion. The HR group reported the highest levels of hopelessness, even when adjusting for SI. MEG results linked hopelessness with reduced activity across frequency bands in salience network regions, with no group or group-by-interaction effects. Using DCM, the HR group had reduced intrinsic drive from granular Layer IV stellate cells to superficial pyramidal cells in the ACC and AI. In the pilot HR study, reduced hopelessness was linked with increased drive for this same connection post-ketamine. Hopelessness is a possible proxy for suicide risk. Electrophysiological targets for hopelessness include widespread reductions in salience network activity, particularly in the ACC and AI.

To be or not to be: The active inference of suicide

Suicide presents an apparent paradox as a behavior whose motivation is not obvious since its outcome is non-existence and cannot be experienced. To address this paradox, we propose to frame suicide in the integrated theory of stress and active inference. We present an active inference-based cognitive model of suicide as a type of stress response hanging in cognitive balance between predicting self-preservation and self-destruction. In it, self-efficacy emerges as a meta-cognitive regulator that can bias the model toward either survival or suicide. The model suggests conditions under which cognitive homeostasis can override physiological homeostasis in motivating self-destruction. We also present a model proto-suicidal behavior, programmed cell death (apoptosis), in active inference terms to illustrate how an active inference model of self-destruction can be embodied in molecular mechanisms and to offer a hypothesis on another puzzle of suicide: why only humans among brain-endowed animals are known to practice it.

Neural correlates of automatic emotion regulation and their association with suicidal ideation in adolescents during the first 90-days of residential care

BACKGROUND

Suicide is the second leading cause of death for adolescents in the United States. However, relatively little is known about the forms of atypical neuro-cognitive function that are correlates of suicidal ideation (SI). One form of cognitive/affective function that, when dysfunctional, is associated with SI is emotion regulation. However, very little work has investigated the neural correlates of emotion dysregulation in adolescents with SI.

METHODS

Participants (N = 111 aged 12-18, 32 females, 31 [27.9%] reporting SI) were recruited shortly after their arrival at a residential care facility where they had been referred for behavioral and mental health problems. Daily reports of SI were collected during the participants' first 90-days in residential care. Participants were presented with a task-fMRI measure of emotion regulation - the Affective Number Stroop task shortly after recruitment. Participants were divided into two groups matched for age, sex and IQ based on whether they demonstrated SI.

RESULTS

Participants who demonstrated SI showed increased recruitment of regions including dorsomedial prefrontal cortex/supplemental motor area and parietal cortex during task (congruent and incongruent) relative to view trials in the context of emotional relative to neutral distracters.

CONCLUSIONS

Participants with SI showed increased recruitment of regions implicated in executive control during the performance of a task indexing automatic emotion regulation. Such data might suggest a relative inefficiency in the recruitment of these regions in individuals with SI.

Predicting suicidality in late-life depression by 3D convolutional neural network and cross-sample entropy analysis of resting-state fMRI

BACKGROUND

Predicting suicide is a pressing issue among older adults; however, predicting its risk is difficult. Capitalizing on the recent development of machine learning, considerable progress has been made in predicting complex behavior such as suicide. As depression remained the strongest risk for suicide, we aimed to apply deep learning algorithms to identify suicidality in a group with late-life depression (LLD).

METHODS

We enrolled 83 patients with LLD, 35 of which were non-suicidal and 48 were suicidal, including 26 with only suicidal ideation and 22 with past suicide attempts, for resting-state functional magnetic resonance imaging (MRI). Cross-sample entropy (CSE) analysis was conducted to examine the complexity of MRI signals among brain regions. Three-dimensional (3D) convolutional neural networks (CNNs) were used, and the classification accuracy in each brain region was averaged to predict suicidality after sixfold cross-validation.

RESULTS

We found brain regions with a mean accuracy above 75% to predict suicidality located mostly in default mode, fronto-parietal, and cingulo-opercular resting-state networks. The models with right amygdala and left caudate provided the most reliable accuracy in all cross-validation folds, indicating their neurobiological importance in late-life suicide.

CONCLUSION

Combining CSE analysis and the 3D CNN, several brain regions were found to be associated with suicidality.

Exploring the Link between Interoceptive Body Awareness and Suicidal Orientation in University Students: A Cross-Sectional Study

INTRODUCTION

The transition to college life can impact the mental health of students. There are mental health care strategies that promote connection with the body's internal signals, which can help to improve mental well-being, manage emotions, and reduce the risk of suicide in university students.

AIM

This study aimed to examine the association between interoceptive body awareness variables and suicidal orientation in a sample of 169 undergraduate students in Colombia.

METHODS

An observational, cross-sectional study was conducted in 2023 with Colombian students as the participants.

RESULTS

The findings revealed a significant and moderately negative correlation between the Multidimensional Assessment of Interoceptive Awareness (MAIA) total score and the Inventory of Suicide Orientation (ISO-30) total score (r = -0.54, p < 0.001). Confidence and self-regulation were identified as the most influential factors in the relationship between MAIA and ISO-30. Significant correlations were observed (p < 0.001), indicating moderate correlation values ranging from -0.43 to -0.57.

DISCUSSION

Our findings support the existence of a negative correlation between interoceptive body awareness and suicidal orientation. Further research is needed to better understand this relationship and to develop specific interventions based on body awareness to prevent suicide orientation.

CONCLUSION

There are practical implications associated with recognizing the importance of body awareness in relation to decreasing suicidal orientation, and multidisciplinary teams addressing mental health can incorporate this knowledge.

Associations Between Suicidality and Interoception in Obsessive-Compulsive Disorder

Background

Individuals with obsessive-compulsive disorder (OCD) are at increased risk for suicide. One potential risk factor is interoceptive sensibility (IS), which is one's subjective experience of bodily sensations. The current study examined the relationship between IS and current suicidal ideation and lifetime history of suicide attempt, controlling for relevant covariates.

Methods

Participants (N = 145) were a clinical sample of individuals with OCD from the New York City area. A clinical rater administered a diagnostic interview and an OCD severity assessment, and participants completed questionnaires about demographics, IS, and suicidality.

Results

Current suicidal ideation was associated with reduced trusting of the body, and lifetime history of suicide attempt was related to greater general awareness of sensation. These associations remained significant after controlling for covariates.

Conclusions

These results suggest that specific facets of IS may be associated with specific domains of suicidality. Decreased body trusting may represent a feeling of disconnection from the body that facilitates desire for death. Increased noticing of bodily sensations may lead to greater mental pain, which could interact with deficits in emotion regulation to increase risk for suicide attempt. Further research on the relationships between IS and suicidality in OCD is warranted.

Potential neuropsychological mechanism involved in the transition from suicide ideation to action - a resting-state fMRI study implicating the insula

BACKGROUND

Understanding the neural mechanism underlying the transition from suicidal ideation to action is crucial but remains unclear. To explore this mechanism, we combined resting-state functional connectivity (rsFC) and computational modeling to investigate differences between those who attempted suicide(SA) and those who hold only high levels of suicidal ideation(HSI).

METHODS

A total of 120 MDD patients were categorized into SA group (n=47) and HSI group (n=73). All participants completed a resting-state functional MRI scan, with three subregions of the insula and the dorsal anterior cingulate cortex (dACC) being chosen as the region of interest (ROI) in seed-to-voxel analyses. Additionally, 86 participants completed the balloon analogue risk task (BART), and a five-parameter Bayesian modeling of BART was estimated.

RESULTS

In the SA group, the FC between the ventral anterior insula (vAI) and the superior/middle frontal gyrus (vAI-SFG, vAI-MFG), as well as the FC between posterior insula (pI) and MFG (pI-MFG), were lower than those in HSI group. The correlation analysis showed a negative correlation between the FC of vAI-SFG and psychological pain avoidance in SA group, whereas a positive correlation in HSI group. Furthermore, the FC of vAI-MFG displayed a negative correlation with loss aversion in SA group, while a positive correlation was found with psychological pain avoidance in HSI group.

CONCLUSION

In current study, two distinct neural mechanisms were identified in the insula which involving in the progression from suicidal ideation to action. Dysfunction in vAI FCs may gradually stabilize as individuals experience heightened psychological pain, and a shift from positive to negative correlation patterns of vAI-MFC may indicate a transition from state to trait impairment. Additionally, the dysfunction in PI FC may lead to a lowered threshold for suicide by blunting the perception of physical harm.

Decreased gray matter volume in regions associated with affective pain processing in unmedicated individuals with nonsuicidal self-injury

Nonsuicidal self-injury (NSSI) has been consistently associated with a reduced aversion to physical pain. Yet, little research has been done to investigate the brain structures related to pain in individuals with NSSI. This study examined gray matter volume patterns of pain processing regions in participants engaging in NSSI (n = 63) and age-, sex-, and handedness-matched healthy controls (n = 63). Voxel-based morphometry was performed to explore gray matter volume in regions of interest (ROIs) and partial correlation analyses were conducted to identify their associations with the frequency, versatility, duration, functions, and pain intensity of self-injury. As a result, significant volume decreases were found in the right anterior insula, bilateral secondary somatosensory cortex (SII), and left inferior frontal gyrus. Moreover, individuals with smaller anterior insula and SII volume showed a higher likelihood of endorsing affect-regulation and sensation-seeking functions of NSSI, as well as engaging in self-injury with a greater perceived intensity of pain. Our results provide the first empirical evidence that individuals with NSSI may exhibit distinct characteristics in brain regions associated with the affective component of pain processing. These neurobiological changes may be associated with their maladaptive response to noxious and painful NSSI experiences.

Sensitivity to ostracism is blunted in suicide attempters only when they report suicidal ideation

BACKGROUND

Modified pain perception is at the core of many theories on suicide; however, studies on the relationship between pain perception and suicidal behavior (attempt) have produced contradictory results. In this experimental study, we investigated whether physical pain and social pain are concomitantly influenced by suicidal ideation (SI) and past suicidal behavior.

METHODS

155 inpatients with depression (90 with and 65 without past history of suicide attempt) were included. They underwent thermal stimulation of the skin to assess physical pain tolerance and played the Cyberball game to assess their sensitivity to ostracism (social pain). Participants self-assessed current SI through the specific item in the Beck Depression Inventory.

RESULTS

Pain tolerance was not associated with history of suicide attempt, current SI, and their interaction. Social pain was associated with the interaction between history of suicide attempt and current SI. Social pain was decreased in suicide attempters, compared with non-attempters, only when they reported current SI.

LIMITATIONS

Cyberball game may not be representative of everyday stress and ecological social context.

CONCLUSIONS

Unlike what suggested by many theories, pain tolerance does not seem to be necessary to attempt suicide. Suicide attempters with current SI displayed blunted sensitivity to ostracism and could be less willing to restore social affiliation compared with non-attempters.

Resting-state neural mechanisms of capability for suicide and their interaction with pain - A CAN-BIND-05 Study

BACKGROUND

Suicidal ideation is highly prevalent in Major Depressive Disorder (MDD). However, the factors determining who will transition from ideation to attempt are not established. Emerging research points to suicide capability (SC), which reflects fearlessness of death and increased pain tolerance, as a construct mediating this transition. This Canadian Biomarker Integration Network in Depression study (CANBIND-5) aimed to identify the neural basis of SC and its interaction with pain as a marker of suicide attempt.

METHODS

MDD patients (n = 20) with suicide risk and healthy controls (n = 21) completed a self-report SC scale and a cold pressor task measuring pain threshold, tolerance, endurance, and intensity at threshold and tolerance. All participants underwent a resting-state brain scan and functional connectivity was examined for 4 regions: anterior insula (aIC), posterior insula (pIC), anterior mid-cingulate cortex (aMCC) and subgenual anterior cingulate cortex (sgACC).

RESULTS

In MDD, SC correlated positively with pain endurance and negatively with threshold intensity. Furthermore, SC correlated with the connectivity of aIC to the supramarginal gyrus, pIC to the paracingulate gyrus, aMCC to the paracingulate gyrus, and sgACC to the dorsolateral prefrontal cortex. These correlations were stronger in MDD compared to controls. Only threshold intensity mediated the correlation between SC and connectivity strength.

LIMITATIONS

Resting-state scans provided an indirect assessment of SC and the pain network.

CONCLUSIONS

These findings highlight point to a neural network underlying SC that is associated with pain processing. This supports the potential clinical utility of pain response measurement as a method to investigate markers of suicide risk.

The unique face of comorbid anxiety and depression: increased interoceptive fearfulness and reactivity

Anxiety and depression commonly co-occur, yet the underlying brain and behavioral processes are poorly understood. Here we examined the hypothesis that individuals with comorbid anxiety and depression would show increased fearful reactivity to an aversive interoceptive perturbation relative to depressed-only individuals. One-hundred and eighty anxious and/or depressed participants from the Tulsa 1000 study completed multi-level behavioral or functional magnetic resonance imaging assessments of interoception and nociception including breath-hold and cold-pressor challenges, and heartbeat perception and interoceptive attention tasks. One-hundred and four individuals with comorbid depression and anxiety disorders (Dep+Anx) were propensity matched with 52 individuals with depression-only (Dep). Data were analyzed using mixed-effects linear regression. The Dep+Anx group showed significantly greater self-reported fear of suffocation during breath holding (Wilcoxon r = 0.23) and reduced cold pain tolerance (R ² = 0.027) signified by hand removal during immersion. However, these groups did not differ with respect to neutrally-valenced behavioral indices of heartbeat perception or neural indices of interoceptive attention. Individuals with comorbid depression and anxiety, vs. those with only depression, show increased respiratory fearfulness and nociceptive reactivity during perturbations of these signals, whilst showing similar interoceptive awareness in the absence of perturbation. Our findings suggest that individuals with comorbid anxiety and depression process aversive interoceptive and nociceptive signals differently than those with depression alone, providing support for a process model of increased threat sensitivity and hyperarousal in anxious depression.

Cardiac and Gastric Interoceptive Awareness Have Distinct Neural Substrates

Interoceptive awareness, an awareness of the internal body state, guides adaptive behavior by providing ongoing information on body signals, such as heart rate and energy status. However, it is still unclear how interoceptive awareness of different body organs are represented in the human brain. Hence, we directly compared the neural activations accompanying attention to cardiac (related to heartbeat) and gastric (related to stomach) sensations, which generate cardiac and gastric interoceptive awareness, in the same population (healthy humans, N = 31). Participants were asked to direct their attention toward heart and stomach sensations and become aware of them in a magnetic resonance imaging (MRI) scanner. The results indicated that the neural activations underlying gastric attention encompassed larger brain regions, including the occipitotemporal visual cortices, bilateral primary motor cortices, primary somatosensory cortex, left orbitofrontal cortex, and hippocampal regions. Cardiac attention, however, selectively activated the right anterior insula extending to the frontal operculum compared with gastric attention. Moreover, our detailed analyses focusing on the insula, the most relevant region for interoceptive awareness, revealed that the left dorsal middle insula encoded cardiac and gastric attention via different activation patterns, but the posterior insula did not. Our results demonstrate that cardiac and gastric attention evoke different brain activation patterns; in particular, the selective activation may reflect differences in the functional roles of cardiac and gastric interoceptive awareness.

Diminished body trust uniquely predicts suicidal ideation and nonsuicidal self-injury among people with recent self-injurious thoughts and behaviors

INTRODUCTION

Self-injurious thoughts and behaviors (SITBs) are difficult to predict, and novel risk factors must be identified. While diminished interoception is associated with SITBs cross-sectionally, the current study assesses whether multiple measures of interoception predict future SITBs.

METHODS

Adults (N = 43) with recent SITBs completed assessments of interoception during a baseline visit. Participants then completed biweekly assessments for 6 months in which they reported the presence and severity/frequency of suicidal ideation and nonsuicidal self-injury (NSSI).

RESULTS

Multilevel models were performed, where baseline interoceptive measures predicted presence and severity/frequency of suicidal ideation and NSSI at follow-up. The Multidimensional Assessment of Interoceptive Awareness (MAIA) Trusting subscale was the only significant predictor of the presence/severity of suicidal ideation. The MAIA Trusting, Emotional Awareness, and Body Listening subscales significantly predicted the presence of NSSI. The MAIA Emotional Awareness subscale and the Body Perception Questionnaire significantly predicted NSSI frequency.

DISCUSSION

Diminished body trust predicted both suicidal ideation and NSSI, indicating a potential shared risk pathway. However, two interoception measures (Body Listening subscale and Body Perception Questionnaire) were associated with NSSI only, indicating potentially unique risk pathways. Given the differential associations between interoception measures and SITBs, results highlight the importance of clearly defining how interoception is measured.

Suicide capability within the ideation-to-action framework: A systematic scoping review

Suicide capability is theorised to facilitate the movement from suicidal ideation to suicide attempt. Three types of contributors are posited to comprise suicide capability: acquired, dispositional, and practical. Despite suicide capability being critical in the movement from ideation-to-attempt, there has been no systematic synthesis of empirical evidence relating to suicide capability that would enable further development and refinement of the concept. This study sought to address this synthesis gap. A scoping review was conducted on suicide capability studies published January 2005 to January 2022. Eleven electronic databases and grey literature sources were searched returning 5,212 potential studies. After exclusion criteria application, 90 studies were included for final analysis. Results synthesis followed a textual narrative approach allocating studies based on contributors of suicide capability. Most studies focused on investigating only one factor within contributors. Painful and provocative events appear to contribute to acquired capability more so than fearlessness about death. Whilst emerging evidence for dispositional and practical contributors is promising, the small number of studies prevents further conclusions from being drawn. An unexpected additional cognitive contributor was identified. The focus of a single factor from most studies and the limited number of studies on contributors other than acquired capability limits the theoretical development and practical application of suicide capability knowledge. Given that suicide is a complex and multifaceted behaviour, future research that incorporates a combination of contributors is more likely to advance our understandings of suicide capability.

A Systematic Review of Behavior-Outcome Psychological Assessments as Correlates of Suicidality

AIM

Identifying correlates of suicidality is an important goal for suicide researchers because these correlates may predict suicidal behaviors. Psychological tasks that assess sensitivity to the outcomes of actions (i.e., consequence-based learning) have been commonly used by researchers seeking to identify correlates of suicidality. This is likely due to the straightforward integration of the tasks within most theoretical frameworks for understanding suicidality. Contextual factors have been shown to have a substantial effect on responding in behavior-outcome tasks. However, the direct relevance of these factors as determinants of behavior in suicide research is not clear. Thus, the purpose of this review was to assess the role of context in tasks involving behavior-outcome relations in suicide research.

METHODS

Four databases were searched using terms from general learning theory. Articles that featured evaluation of tasks with hypothetical or real outcomes to differentiate suicidality were included.

RESULTS

Eighty-two studies met inclusion criteria. Across studies there were 27 different tasks. Most instances of tasks across studies involved rewards (76.9%), while others emphasized punishment (15.7%), social (5.6%), or virtual suicide (1.8%) outcomes. Differentiation of suicidality was detected by 43.4%, 64.7%, 83.3%, and 50% of tasks featuring reward, punishment, social contexts, and virtual suicide respectively. All but five studies were retrospective.

CONCLUSION

Tasks that more closely mimic contexts and outcomes related to suicide appear to produce more pronounced differentiation of people with suicidality from people without suicidality. The lack of prospective designs is an important limitation of the literature.HIGHLIGHTSTasks that involve punishment or social outcomes better discriminate suicidality.Reward-based tasks are overused in suicide research.The conditioning hypothesis of suicidality is closely aligned with the literature.Only 5 of 82 studies incorporated prospective measures.

An insula-based network mediates the relation between rumination and interoceptive sensibility in the healthy population

BACKGROUND

Individuals sometimes continuously centered their attention on the same thoughts. When such process tends to be negative and self-referential, we delineated this mental state as rumination, which may undermine body's perception of endogenous signal, but little is known about the certainly relationship and the potential neural mechanisms.

METHODS

Rumination and interoceptive sensibility were measured by questionnaires, then insula-related network of rumination dimensions were examined by the whole brain resting-state functional connectivity (FC) in 479 college students, and whether the insula-based network mediate the relationship between rumination and interoceptive sensibility were tested.

RESULTS

Rumination (including brooding reflective pondering) and interoceptive sensibility showed positive correlations. The neural mechanisms of brooding and reflective pondering were all related to the insula-networks, to be specific, brooding was positively correlated with the FC between the left posterior insula (PI) and left parahippocampal gyrus/ hippocampus (PHG), reflective pondering were positively correlated with the FC between the insula subregion and the dorsolateral prefrontal cortex. Moreover, the relationship between brooding and interoceptive sensibility was mediated by the FC between left PI and left PHG.

LIMITATIONS

We just tested the relationship between rumination and interoceptive sensibility at a cross-sectional level, but it is unclear that whether the longitudinal relationship would be predicted by the related network.

CONCLUSIONS

Our findings provided new insights into neural mechanisms of brooding and reflective pondering, also the integration of brooding and interoceptive sensibility. The insula-related networks may contribute crucially to rumination and interoception.

A specific association between laxative misuse and suicidal behaviours in patients with anorexia nervosa and bulimia nervosa

OBJECTIVE

Eating disorders (ED) are associated with an in increased risk of suicidal behaviours. Laxative abuse might alter the gut-brain axis signaling, that might be implicated in the pathophysiology of suicide. This study aims to determine the association between laxative misuse and suicide attempt (SA) and suicidal ideation (SI) in patients with ED.

METHODS

277 patients with ED were recruited from an Eating Disorder Unit of Lapeyronie Academic Hospital, Montpellier, France. Sociodemographic and clinical data were collected. Chi-square and t test were used, with Bonferroni corrections where required. Multiple regression models assessed the relationships between laxative misuse, SA, and SI.

RESULTS

62 (22.4%) patients reported lifetime laxative misuse. They were more likely to have a history of SA than non-misusers [43.83 vs 19.9%, p < 0.001, odds ratio (OR) 3.68]. In the multivariate model, adjusted for other confounders, lifetime laxative misuse remained associated with SA (adjusted OR 3.79, p = 0.041). In past 28 days, patients with SA history reported misusing laxatives for more days than patients without SA history (6 vs 1.5 days, p = 0.01, adjusted for vomiting and ED severity). Laxative use days during past 28 days was associated with current SI, adjusted for vomiting in the same period (p = 0.017).

CONCLUSIONS

Current and lifetime laxative misuse were associated with SA history and current SI in patients with ED, at least in part independently of other suicide-related factors.

LEVEL OF EVIDENCE

Level III cohort, cross-sectional study.

Interoceptive dysfunction indicates presence and severity of self-injurious behaviors in a clinically severe transdiagnostic sample

Interoceptive dysfunction (ID) is associated with self-injurious behaviors, as disconnection from the body is thought to enable bodily harm. This study tested differences in ID among those with and without history of self-injurious behaviors, as well as the relationship between ID and lethality of past suicide attempts. Adults (N = 344; 61.3% female; mean age 27.68) seeking psychological treatment completed self-report measures and clinical interviews during intake at a community-based clinic. Overall symptom severity was substantial (e.g., approximately 40% reported current suicidal ideation and two-thirds met a clinical cut-off score of ≥ 16 on the Beck Depression Inventory). Orthogonal contrasts were used to test whether mean levels of ID differed across lifetime self-injurious behavior groups. Attempt lethality was regressed on interoceptive dysfunction, covarying depressive symptom severity, age, and gender. Participants with suicide attempt history demonstrated greater ID than those without. Participants who had engaged in non-suicidal self-injury demonstrated greater ID than those with no history of self-injurious behaviors. Greater ID was associated with higher lethality of past suicide attempt, above demographic and clinical covariates. ID may have transdiagnostic relevance for risk assessment and management of self-injurious behaviors.

Nonsuicidal Self-Injury Is Associated With Attenuated Interoceptive Responses to Self-Critical Rumination

Nonsuicidal self-injury (NSSI) is a prevalent and dangerous behavior. Those with a history of NSSI often report high levels of self-critical rumination (SCR), a form of negatively valenced introspective self-referential processing. It is plausible that this overly analytical style of relating to the self might hinder the ability to process interoceptive signals, thereby increasing the capacity to engage in behaviors that cause bodily harm. Two studies investigated whether trait or state SCR influenced aspects of interoception in those with and without a history of NSSI. In Study 1 (N = 180), irrespective of NSSI history, trait SCR was associated with finding attending to the heartbeat unpleasant. However, no associations were observed for interoceptive confidence, or metacognitive insight into their interoceptive abilities (confidence-accuracy correspondence). Trait SCR was associated with having higher interoceptive accuracy, but only in those without a history of NSSI. In Study 2 (N = 98), irrespective of NSSI history, state self-criticism led to a more negative interoceptive valence, and reduced participants' metacognitive insight. In those without a history of NSSI, state self-criticism also increased interoceptive accuracy-an effect attenuated in those with NSSI. These findings suggest that those with NSSI are characterized by a blunted interoceptive response to negatively valenced self-focused attention.

Interoceptive Abnormalities and Suicidality: A Systematic Review

Dysfunction of interoception (i.e., difficulties sensing the physiological state of one's own body) is increasingly linked to different mental health disorders and suicidal outcomes. The aim of this study was to systematically review the literature on the association between suicidality and interoception, as well as identify potential confounders and mediators of the relationship. We conducted a systematic review of four databases, allowing for critical examination of the role of different measures of interoception (accuracy, sensibility, awareness, cognitive/emotional evaluation) across the suicide continuum (ideation, plans, attempts, deaths). The search strategy identified 22 studies (14,988 participants). Preliminary but limited evidence was found for impaired interoceptive accuracy among those reporting suicide attempt histories. We found evidence of interoceptive sensibility disturbances across the suicide continuum, including experiences of not trusting one's own body sensations and impaired abilities to sustain and control attention to such sensations. Consistent evidence was also reported for disturbances related to cognitive and emotional evaluations of interoceptive sensations. The latter was particularly pronounced for those reporting suicide attempts, relative to those reporting suicidal thinking or planning alone. Overall, this review's results suggest that interoceptive abnormalities are potentially important indicators of risk for suicidal thinking, intentions, and behaviors. However, due to the inconsistent adjustment for variables of interest, and cross-sectional designs, it is unclear whether interoceptive changes and disturbances have a direct role, or whether the association is explained and mediated by key third variables (e.g. depression, disordered eating, emotional dysregulation). We discuss the implications with respect to suicidal risk and therapeutic interventions.

Reconnecting to Internal Sensation and Experiences: A Pilot Feasibility Study of an Online Intervention to Improve Interoception and Reduce Suicidal Ideation

Risk factors that are strongly associated with suicide and are amenable to intervention are in need of discovery. This three-study investigation demonstrates that an intervention designed to improve interoception-one potential suicide risk factor-may reduce suicide-related outcomes. Study 1 included 136 undergraduate participants and found that relative to a control condition, participating in a progressive muscle relaxation exercise was associated with reduced implicit identification with suicide through greater body trust, which is one domain of interoception that is consistently linked to suicide-related outcomes. Study 2 included 97 MTurk participants and found that relative to a control condition, participating in a body functionality writing exercise was associated with greater awareness of the body as a whole. Study 3 was a pilot study of a four-session online intervention designed to increase interoception. Study 3 included a sample of 22 clinical participants who completed pre- and postintervention assessments. Participants rated the intervention as highly acceptable and moderately effective. Moreover, the intervention was associated with improvements in interoception and reductions in suicidal ideation, general psychological symptoms, and disordered-eating symptoms. Overall, these findings indicate that our online interoceptive awareness training is acceptable and may be associated with improvements in clinical outcomes. Randomized controlled trials are needed to explore whether the intervention's purported mechanism-improved interoception-leads to changes in clinical outcomes.

Interoception, Pain Tolerance, and Self-Injurious Behaviors: A Multidimensional Assessment

Impairments in interoception have been linked to self-injurious behaviors, and capability for suicide may account for this relationship. However, past studies have relied primarily on self-report and unidimensional measures. The present study aimed to replicate and extend previous findings by examining the relationship between interoceptive dysfunction, pain tolerance, and self-injurious behaviors using a multidimensional and multi-method approach. A sample of 245 undergraduate students (M_age = 19.27 years, SD = 2.81; 73.7% female, 72.% White/European American), who reported lifetime suicidal ideation on a screening survey completed a battery of self-report measures, four counterbalanced pain tolerance tasks, and a clinical interview assessing their self-injurious behaviors. A tendency to stay attuned to bodily sensations was significantly related to decreased pain tolerance. Only trust in one's body was significantly related to decreased presence of lifetime suicide attempts. No other facets of interoception or pain tolerance were significantly associated with self-injurious behaviors. Overall, these findings contrast with previous findings that capability for suicide may account for relations between interoceptive dysfunction and self-injurious behaviors. Nonetheless, the results of this study provide important information on the factor structure of interoceptive dysfunction and pain tolerance, and highlight the importance of careful selection of measures and operationalization of key constructs, particularly interoceptive dysfunction and pain tolerance.

Suicidal Ideation and Eating Disorder Symptoms in Adolescents: The Role of Interoceptive Deficits

Eating disorder symptoms and suicidal ideation are relatively common, and often begin to emerge in adolescence. Interoceptive deficits, or the inability to perceive and accurately identify the physiological condition of the body, is an established risk factor for both eating disorders and suicidal thoughts and behaviors. Despite this, longitudinal research examining the temporal dynamics between these variables is scarce, especially within adolescent samples. Using a three-wave longitudinal design, the present study tested bidirectional relationships between interoceptive deficits, eating disorder symptoms, and suicidal ideation to examine whether interoceptive deficits predicted eating disorder symptoms and suicidal ideation over the course of a year among a sample of adolescents. Participants were 436 community adolescents recruited from local middle- and high-schools. Data were collected at baseline, 6-month follow-up, and 12-month follow-up. Study measures assessed current suicidal ideation, eating disorder symptom severity, and interoceptive deficits. Autoregressive cross-lagged modeling was conducted in MPlus. We found baseline eating disorder symptoms significantly predicted suicidal ideation at 6-month follow-up when controlling for baseline suicidal ideation. Baseline interoceptive deficits significantly predicted eating disorder symptoms 6-months later, while 6-month follow-up interoceptive deficits significantly predicted 12-month follow-up suicidal ideation. Our findings highlight the need for early and regular assessment of suicidal ideation and eating disorder symptoms in adolescents. Given that interoceptive deficits was a shared risk factor for both conditions within this sample, these results underscore the need for targeted interventions aimed at improving interoception.

A Transdiagnostic Multilevel Examination of Interoceptive Processing in Individuals With a Remote History of Suicidal Behavior

A developing area of research suggests that there may be a relationship between interoception and suicidal behavior. For example, it was recently reported that individuals who made a suicide attempt within the previous 5 years exhibit behavioral and neural abnormalities across multiple domains of interoception relative to nonattempters. This included increased tolerance for aversive sensations of pain and dyspnea, reduced heartbeat-perception accuracy, and blunted insula activity during attention to cardiac sensations. However, the degree to which interoceptive deficits persist following a suicidal attempt is unknown. In the current study, we examined differences between individuals with a remote history of suicide attempts (greater than 5 years ago; N = 56) versus those with no history of attempts (N = 240). We found that remote suicide attempters demonstrated greater pain tolerance and lower ratings of stress during a cold-pressor challenge and lower ratings of suffocation during a breath-hold challenge, as compared to nonattempters. In contrast, there were no group differences in breath-hold duration, interoceptive accuracy on a heartbeat-tapping task, or insula activation during cardiac attention. An exploratory resting-state functional connectivity analysis of individuals with suicide attempts in the past 5 years (N = 23), individuals with more remote histories of suicide attempts (N = 39), and nonattempters (N = 232) revealed preliminary and subtle evidence of differences in insula connectivity with areas of the temporal cortex in remote suicide attempters. Taken together, these findings suggest that blunted affective responses to aversive interoceptive sensations is an enduring characteristic of suicide attempters, even when assessed many years after a suicide attempt, whereas differences in the experience of nonaversive interoceptive sensations may be less persistent.

A multi-measure examination of interoception in people with recent nonsuicidal self-injury

OBJECTIVE

Self-injurious behaviors (SIB) are highly dangerous, yet prediction remains weak. Novel SIB correlates must be identified, such as impaired interoception. This study examined whether two forms of interoceptive processing (accuracy and sensibility) for multiple sensations (general, cardiac, and pain) differed between people with and without recent nonsuicidal self-injury (NSSI).

METHOD

Participants were adults with recent (n = 48) NSSI and with no history of SIBs (n = 55). Interoceptive sensibility was assessed with self-reports. Interoceptive accuracy for cardiac sensations was assessed using the heartbeat tracking task. Interoceptive accuracy for pain was assessed with a novel metric that mirrored the heartbeat tracking test.

RESULTS

Participants with recent NSSI reported significantly lower interoceptive sensibility for general sensations relative to people without SIBs. Groups did not differ on interoceptive sensibility for cardiac sensations or pain. Groups also did not differ on interoceptive accuracy for cardiac sensations. The NSSI group exhibited significantly lower interoceptive accuracy for pain compared with the No SIB group.

CONCLUSIONS

Interoceptive impairment in people with NSSI may vary by interoceptive domain and sensation type. Diminished interoceptive accuracy for sensations relevant to the pathophysiology of self-injury may be a novel SIB correlate.

Listen to Your Heart-Ecological Momentary Assessment of Interoceptive Accuracy, Awareness and Sensibility: A Pilot Study

Background: Interoception is a multi-facetted phenomenon including interoceptive accuracy, awareness and sensibility. Deficits in interoception have been associated with psychological distress. However, little is known about the course of interoception over time. The present study aimed at examining interoception in an ecological momentary assessment (EMA)-setting. Methods: A seven-day smartphone-based EMA was conducted in a community sample of sixty-one participants (age: M = 24.1, SD = 7.00, n = 54 female (88.5%)). To control for potential practice effects of repeated assessments during the EMA phase, participants were randomly assigned to a control (n = 30) and an interoception (n = 31) group. The latter was assessed for interoceptive accuracy, awareness and sensibility. Before and after the EMA phase, all participants were assessed for interoception in the laboratory. Results: Multilevel analyses revealed significant fluctuations for all three interoceptive facets, around 50% of variance was due to within-person variability. There were only practice effects for the subscale "Attention Regulation", measuring interoceptive sensibility. Conclusion: The facets of interoception can be assessed in an EMA-setting. Repeated interoceptive assessments do not necessarily lead to an improvement of participants' interoceptive abilities. It could be shown that all interoceptive facets fluctuate, which should be considered in future research.

Examination of structural brain changes in recent suicidal behavior

We aimed to identify brain structural changes in cortical and subcortical regions linked to recent suicidal behavior. We performed secondary analyses of structural MRI data of two independent studies, namely the Establishing Moderators/Biosignatures of Antidepressant Response - Clinical Care (EMBARC) study and a Little Rock study on acute suicidal behavior. Study 1 (EMBARC, N = 187), compared individuals with remote suicide attempts (Remote-SA), individuals with lifetime suicide ideation but no attempts (Lifetime-SI only), and depressed individuals without lifetime suicide ideation or attempts (non-suicidal depressed). Study 2 (Little Rock data, N = 34) included patients recently hospitalized for suicide ideation or attempt constituted by: patients who recently attempted suicide (Recent-SA), individuals with remote suicide attempts (Remote-SA), and Lifetime-SI only. Study 3 combined the EMBARC and Little Rock datasets including Recent-SA, Remote-SA, Lifetime-SI only and non-suicidal depressed individuals. In Study 1 and Study 2, no significant differences were observed between groups. In Study 3, significantly lower middle temporal gyrus thickness, insular surface area, and thalamic volume and higher volume in the nucleus accumbens were observed in Recent-SA. This pattern of structural abnormalities may underlie pain and emotion dysregulation, which have been linked to the transition from suicidal thoughts to action.

Heart Rate Variability Modulates Interoceptive Accuracy

Our emotional experiences depend on our interoceptive ability to perceive and interpret changes in our autonomous nervous system. An inaccurate perception and interpretation of autonomic changes impairs our ability to understand and regulate our emotional reactions. Impairments in emotion understanding and emotion regulation increase our risk for mental disorders, indicating that interoceptive deficits play an important role in the etiology and pathogenesis of mental disorders. We, thus, need measures to identify those of us whose interoceptive deficits impair their emotion understanding and emotion regulation. Here, we used cardiac measures to investigate how our ability to engage prefrontal and (para-)limbic brain region regions affects our ability to perceive and interpret cardiac changes. We administered a heartbeat detection task to a sample of healthy individuals (n = 113) whose prefrontal-(para-) limbic engagement had been determined on basis of a heart rate variability recording. We found a positive association between heartbeat detection and heart rate variability, implying that individuals with higher heart rate variability were more accurate in heartbeat detection than individuals with lower heart rate variability. These findings suggest that our interoceptive accuracy depends on our prefrontal-(para-)limbic engagement during the perception and interpretation of cardiac changes. Our findings also show that cardiac measures may be useful to investigate the association between interoceptive accuracy and prefrontal-(para-)limbic engagement in a time- and cost-efficient manner.

Greater decision uncertainty characterizes a transdiagnostic patient sample during approach-avoidance conflict: a computational modelling approach

BACKGROUND

Imbalances in approach-avoidance conflict (AAC) decision-making (e.g., sacrificing rewards to avoid negative outcomes) are considered central to multiple psychiatric disorders. We used computational modelling to examine 2 factors that are often not distinguished in descriptive analyses of AAC: decision uncertainty and sensitivity to negative outcomes versus rewards (emotional conflict).

METHODS

A previously validated AAC task was completed by 478 participants, including healthy controls (n = 59), people with substance use disorders (n = 159) and people with depression and/or anxiety disorders who did not have substance use disorders (n = 260). Using an active inference model, we estimated individual-level values for a model parameter that reflected decision uncertainty and another that reflected emotional conflict. We also repeated analyses in a subsample (59 healthy controls, 161 people with depression and/or anxiety disorders, 56 people with substance use disorders) that was propensity-matched for age and general intelligence.

RESULTS

The model showed high accuracy (72%). As further validation, parameters correlated with reaction times and self-reported task motivations in expected directions. The emotional conflict parameter further correlated with self-reported anxiety during the task (r = 0.32, p < 0.001), and the decision uncertainty parameter correlated with self-reported difficulty making decisions (r = 0.45, p < 0.001). Compared to healthy controls, people with depression and/or anxiety disorders and people with substance use disorders showed higher decision uncertainty in the propensity-matched sample (t = 2.16, p = 0.03, and t = 2.88, p = 0.005, respectively), with analogous results in the full sample; people with substance use disorders also showed lower emotional conflict in the full sample (t = 3.17, p = 0.002).

LIMITATIONS

This study was limited by heterogeneity of the clinical sample and an inability to examine learning.

CONCLUSION

These results suggest that reduced confidence in how to act, rather than increased emotional conflict, may explain maladaptive approach-avoidance behaviours in people with psychiatric disorders.

Greater decision uncertainty characterizes a transdiagnostic patient sample during approach-avoidance conflict: a computational modelling approach

BACKGROUND

Imbalances in approach-avoidance conflict (AAC) decision-making (e.g., sacrificing rewards to avoid negative outcomes) are considered central to multiple psychiatric disorders. We used computational modelling to examine 2 factors that are often not distinguished in descriptive analyses of AAC: decision uncertainty and sensitivity to negative outcomes versus rewards (emotional conflict).

METHODS

A previously validated AAC task was completed by 478 participants, including healthy controls (n = 59), people with substance use disorders (n = 159) and people with depression and/or anxiety disorders who did not have substance use disorders (n = 260). Using an active inference model, we estimated individual-level values for a model parameter that reflected decision uncertainty and another that reflected emotional conflict. We also repeated analyses in a subsample (59 healthy controls, 161 people with depression and/or anxiety disorders, 56 people with substance use disorders) that was propensity-matched for age and general intelligence.

RESULTS

The model showed high accuracy (72%). As further validation, parameters correlated with reaction times and self-reported task motivations in expected directions. The emotional conflict parameter further correlated with self-reported anxiety during the task (r = 0.32, p < 0.001), and the decision uncertainty parameter correlated with self-reported difficulty making decisions (r = 0.45, p < 0.001). Compared to healthy controls, people with depression and/or anxiety disorders and people with substance use disorders showed higher decision uncertainty in the propensity-matched sample (t = 2.16, p = 0.03, and t = 2.88, p = 0.005, respectively), with analogous results in the full sample; people with substance use disorders also showed lower emotional conflict in the full sample (t = 3.17, p = 0.002).

LIMITATIONS

This study was limited by heterogeneity of the clinical sample and an inability to examine learning.

CONCLUSION

These results suggest that reduced confidence in how to act, rather than increased emotional conflict, may explain maladaptive approach-avoidance behaviours in people with psychiatric disorders.

A Bayesian computational model reveals a failure to adapt interoceptive precision estimates across depression, anxiety, eating, and substance use disorders

Recent neurocomputational theories have hypothesized that abnormalities in prior beliefs and/or the precision-weighting of afferent interoceptive signals may facilitate the transdiagnostic emergence of psychopathology. Specifically, it has been suggested that, in certain psychiatric disorders, interoceptive processing mechanisms either over-weight prior beliefs or under-weight signals from the viscera (or both), leading to a failure to accurately update beliefs about the body. However, this has not been directly tested empirically. To evaluate the potential roles of prior beliefs and interoceptive precision in this context, we fit a Bayesian computational model to behavior in a transdiagnostic patient sample during an interoceptive awareness (heartbeat tapping) task. Modelling revealed that, during an interoceptive perturbation condition (inspiratory breath-holding during heartbeat tapping), healthy individuals (N = 52) assigned greater precision to ascending cardiac signals than individuals with symptoms of anxiety (N = 15), depression (N = 69), co-morbid depression/anxiety (N = 153), substance use disorders (N = 131), and eating disorders (N = 14)-who failed to increase their precision estimates from resting levels. In contrast, we did not find strong evidence for differences in prior beliefs. These results provide the first empirical computational modeling evidence of a selective dysfunction in adaptive interoceptive processing in psychiatric conditions, and lay the groundwork for future studies examining how reduced interoceptive precision influences visceral regulation and interoceptively-guided decision-making.