Interoceptive deficits, non-suicidal self-injury, and suicide risk: a multi-sample study of indirect effects

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.

Testing replicability of the relationship between weight suppression and binge eating in three non-clinical samples varying in lifetime weight history

OBJECTIVE

Increased weight suppression, the difference between an individual's highest and current weight at present height, predicts binge eating among eating disorder samples. Less is known about this relationship in non-clinical samples of individuals with a history of higher weight.

METHODS

Lifetime highest BMI was tested as a moderator of the relationship between weight suppression and binge eating in three independent samples (N = 1740).

RESULTS

At the bivariate level, weight suppression was not associated with binge eating in any sample (p's ≥ 0.20). Lifetime highest BMI moderated the relationship between weight suppression and binge eating in Sample 1 (p = .04), such that greater weight suppression was associated with lower binge eating among those with a history of higher weight (i.e., BMI = 40 kg/m2). In Samples 2 and 3, the lifetime highest BMI by weight suppression interaction term was not significant and dropped from the model (p's = 0.10-0.12). Accounting for age, gender, and lifetime highest BMI, greater weight suppression was associated with lower binge eating scores (p's < 0.04). A meta-analysis combining results revealed a small but significant interaction effect (r = 0.07, p = .02).

CONCLUSIONS

Findings highlight the importance of investigating the generalizability of eating disorder risk and maintenance theories across the weight spectrum. Weight loss may not increase risk for binge eating among those with a history of higher weight. Future work should replicate and extend this finding using longitudinal designs. More research is needed to elucidate which weight loss motivations and/or behaviors are most closely linked to binge eating.

Interoceptive deficits moderate the relationship between bulimia symptoms and suicide risk

Objective: Interoceptive deficits have been linked to suicidality and eating disorders. The relationship between disordered eating symptoms and suicidality may depend on the level of interoceptive deficits. It was expected that interoceptive deficits would moderate the relationship between disordered eating symptoms (oral control, dieting, and bulimia) and suicidality (suicide attempts, ideation, and communication) when interoceptive deficits were high. Methods: University students (N = 417, Mage = 19.75, 78.2% white, 72.4% female) completed self-report measures that assessed disordered eating, interoceptive deficits, and suicide history. Results: Interoceptive deficits emerged as a significant moderator only in the association between bulimia symptoms and suicidality, when interoceptive deficits were high. Conclusions: The results of this study indicate that bulimia symptoms may have a unique interaction with interoceptive deficits and suicidality. Future research should focus on targeting interoceptive deficits in treatment to help reduce disordered eating symptoms and suicide risk, particularly for students with bulimia symptoms.

Disrupted interoception in Military Service Members and Veterans with a history of suicidality

INTRODUCTION

This project tested whether Service Members (SM) and Veterans with current suicidal ideation or a history of suicide attempt had greater interoceptive dysfunction than SM and Veterans with past or no suicidal ideation.

METHOD

Participants (N = 195; 69% male) were SM (62%) and Veterans (38%) who completed measures of suicidal thoughts and behaviors and subjective and objective interoceptive dysfunction. Participants were split into the following suicide groups: no suicidality, lifetime ideation, current ideation, and past attempt. Planned orthogonal contrasts tested for differences.

RESULTS

The combined suicidality group (lifetime ideation, current ideation, or past attempt) had worse body trust relative to the no suicidality group, and the current ideation group had worse body trust relative to those with lifetime ideation. Those with a history of suicide attempt had worse body appreciation than the combined group of ideators, and those with current ideation had worse body appreciation relative to those with lifetime ideation. The groups did not differ on objective interoception.

CONCLUSION

Interoception is disrupted among individuals with suicidality histories within a predominantly male-identified military sample. Individuals with current suicidal ideation had both worse body trust and appreciation relative to those with past ideation. Suicide risk assessments may benefit from including questions related to body trust.

Peripheral and neural correlates of self-harm in children and adolescents: a scoping review

BACKGROUND

Self-harm in children and adolescents is difficult to treat. Peripheral and neural correlates of self-harm could lead to biomarkers to guide precision care. We therefore conducted a scoping review of research on peripheral and neural correlates of self-harm in this age group.

METHODS

PubMed and Embase databases were searched from January 1980-May 2020, seeking English language peer-reviewed studies about peripheral and neural correlates of self-harm, defined as completed suicide, suicide attempts, suicidal ideation, or non-suicidal self-injury (NSSI) in subjects, birth to 19 years of age. Studies were excluded if only investigating self-harm in persons with intellectual or developmental disability syndromes. A blinded multi-stage assessment process by pairs of co-authors selected final studies for review. Risk of bias estimates were done on final studies.

RESULTS

We screened 5537 unduplicated abstracts, leading to the identification of 79 eligible studies in 76 papers. Of these, 48 investigated peripheral correlates and 31 examined neural correlates. Suicidality was the focus in 2/3 of the studies, with NSSI and any type of self-harm (subjects recruited with suicidality, NSSI, or both) investigated in the remaining studies. All studies used observational designs (primarily case-control), most used convenience samples of adolescent patients which were predominately female and half of which were recruited based on a disorder. Over a quarter of the specific correlates were investigated with only one study. Inter-study agreement on findings from specific correlates with more than one study was often low. Estimates of Good for risk of bias were assigned to 37% of the studies and the majority were rated as Fair.

CONCLUSIONS

Research on peripheral and neural correlates of self-harm is not sufficiently mature to identify potential biomarkers. Conflicting findings were reported for many of the correlates studied. Methodological problems may have produced biased findings and results are mainly generalizable to patients and girls. We provide recommendations to improve future peripheral and neural correlate research in children and adolescents, ages 3-19 years, with self-harm.

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.

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.

Clarifying the Relationship of Dissociative Experiences to Suicide Ideation and Attempts: A Multimethod Examination in Two Samples

Fears of pain, injury, and death may represent key barriers to acting on suicidal thoughts. Dissociation, which involves a disconnection from one's body, may reduce fears and sensations of pain associated with harming the body, in turn facilitating suicide attempts. This study examined whether dissociation differentiated individuals with a history of suicide attempts from those with a history of suicide ideation, and investigated whether other relevant constructs explain this relationship. Sample 1 included 754 undergraduates (M_age = 21, 79% female) who completed a battery of self-report measures. Sample 2 included 247 undergraduates (M_age = 19, 74% female) who completed a self-report measure of dissociation, a clinical interview regarding suicide history, and four counterbalanced behavioral pain tolerance tasks. In both samples, dissociation was elevated in lifetime attempters compared to ideators (d = 0.28; d = 0.46; ps = 0.01) and slightly elevated in lifetime ideators compared to nonsuicidal individuals (d = 0.19, p = .02; d = 0.24, p = .47), though this effect was non-significant in the latter sample. In Sample 1, dissociation no longer differentiated attempters from ideators after controlling for clinical covariates. In Sample 2, dissociation was unrelated to behavioral pain tolerance tasks, and these tasks did not account for the association between dissociation and attempts. Overall, dissociation differentiated individuals with a history of suicide attempts from those with ideation alone in both samples. Pain tolerance did not explain this association; instead, it is possible that the relationship of dissociation to suicide attempts is due to "third variables" associated with both phenomena, such as symptoms of borderline personality disorder or posttraumatic stress disorder.

Body Investment as a Protective Factor in the Relationship Between Acquired Capability for Suicide and Suicide Attempts

Acquired capability for suicide is associated with increased suicide risk and behaviors, but little research has examined factors that may qualify this relationship. Body investment is proposed as one such factor, as it may engage self-preservation instincts and serve as a buffer to capability for suicide. It was expected that facets of body investment (body feelings, body care, comfort with touch, and body protection) would moderate the relationship between acquired capability for suicide and suicide attempts. The current study included a sample of 1,150 undergraduate students with a mean age of 19.74 (3.44). The majority of the sample identified as female (71%) and White/Caucasian (78%). Participants completed self-report measures of body investment (Body Investment Scale [BIS]), acquired capability (Acquired Capability for Suicide Scale [ACSS]), suicide thoughts and attempt history (Self-Harm Behavior Questionnaire [SHBQ]), and demographic information. Four moderation analyses were run using the PROCESS macro; one for each body investment subscale. All facets of body investment showed significant moderation except for body care. Acquired capability was significantly associated with suicide attempts when body feelings, comfort with touch, and body protection were low, but not when they were high. Results indicate that fostering aspects of body investment may be important for suicide prevention.

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.

Self-Reported Interoceptive Sensibility Does Not Moderate the Relationship Between Eating Disorder Symptoms and Suicidal Thoughts and Behaviors

Past research has demonstrated a strong relationship between eating disorders (EDs) and suicidality (i.e., suicidal thoughts, plans, and attempts), and preliminary work within the framework of the interpersonal psychological theory of suicide (Joiner, 2007) suggests that potentially painful ED behaviors (binge eating, purging, fasting, excessive exercise) may contribute to increased risk of suicide through heightened pain tolerance and increased capability of suicide. However, additional explanations are needed for why only some individuals with EDs actually engage in suicidal behaviors (i.e., attempt suicide), whereas others do not. A growing body of literature suggests that interoceptive deficits (a disconnection from one's own bodily sensations and emotions; IDs) might be a factor linking eating disorders and suicide. To better understand this relationship, the current study tests the moderating effects of self-reported IDs on the relations between ED behaviors and suicidality and past suicide attempts in a transdiagnostic ED sample (N = 181). We hypothesized that ED behaviors would directly relate to suicidality, but that IDs would moderate the relationship between ED behaviors and past suicide attempts, such that those high in IDs would demonstrate a stronger relationship between ED behaviors and suicide attempts. Contrary to our hypothesis, IDs did not moderate the relationship; instead, fasting and purging had significant and strong main effects on suicidality and past suicide attempts without moderation effects. Results suggest that fasting and purging may be important ED behaviors to consider in the relationship between EDs and suicidality. Future directions include further examining the relationship between IDs, suicidality, and EDs using measures of IDs that better encompass physical (as opposed to emotional) aspects of IDs.

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.

Learning From Artemisia's Lucretia: Embodied Suffering and Interoception in Suicide

In the painting "Lucretia," Artemisia Gentileschi, one of the major painters of the 17^th century, depicts Lucretia's suicide. This artwork empathic vision offers the spectator the apprehension of a unique phenomenon where psychological pain is transformed into self-aggression. To understand why the body becomes an object to attack, it is important to study the role of interoception and self-awareness in the suicidal process. This essay discusses how bodily representations are crucial for interacting efficiently and safely with the outside world and for establishing the sense of self. It presents some of the available evidence showing that alterations in the body representation and in the sensations perceived by it contribute to suicide. Indeed, neuroimaging studies show that social environmental factors and their biological consequences in the body (e.g., increased neuroinflammation) can alter the neural networks of suicidal behavior by increasing the sensitivity to psychological pain and the disconnection from self-awareness. Therefore, body image, sensations and awareness as well as psychological pain should be examined to improve the understanding of the dynamic interactions between body, brain, and mind that underly suicidal behavior. This conceptualization brings clinical and therapeutic perspectives in a domain where they are urgently needed.

Sense it and use it: interoceptive accuracy and sensibility in suicide ideators

BACKGROUND

Interoceptive deficits have been found to be associated with suicidal ideation and behavior. However, an objective measure of interoceptive accuracy has not been investigated in participants with suicide ideation, by now. This study aimed at investigating interoceptive accuracy and sensibility in persons with and without suicide ideation (SI) while controlling for severity of depressive symptoms.

METHOD

Ninety-five participants (age: M = 34.8, SD = 11.6, n = 56 female [58.9%]; n = 51 patients with a Major Depressive Disorder and n = 44 healthy participants) were assessed for interoceptive accuracy and sensibility, depression and SI.

RESULTS

Twenty-five participants (26%) reported SI. They showed interoceptive accuracy comparable to persons without SI (t = -.81, p = .422), but significantly lower interoceptive sensibility. After controlling for severity of depressive symptoms in a hierarchical linear regression analysis, most associations between interoceptive sensibility and SI disappeared.

CONCLUSION

Results suggest that suicide ideators do not lack the ability to perceive their own bodily signals but they feel less able to use them in a way that is advantageous for them. Differences between suicide ideators and non-ideators appear to be largely driven by depressive symptoms (depression bias).