A multi-method assessment of interoception among sexual trauma survivors

Highlights

• Sexual trauma victims with better interoceptive accuracy had lower PTSD symptoms.

• More accurately perceiving interoceptive cues relates to lower PTSD symptoms.

• Better interoceptive accuracy and suggests better emotional awareness.

• Interoceptive accuracy did not mediate sexual trauma's effect on PTSD symptoms.

• Findings suggest interoceptive-sensibility and -accuracy differently predict PTSD.

Abstract

It is well established that many female sexual trauma survivors experience dissociation, particularly disconnection from the body, in the aftermath of sexual trauma. This study aims to address the open question of how sexual trauma is associated with awareness of inner body sensations (i.e., interoception). Given the important role that interoception has in emotion regulation, a process with which survivors often struggle, it is important to understand the associations between interoception and PTSD symptoms among survivors. Through multi-methods, we assessed associations between interoception, dissociation, and PTSD symptoms among 200 female sexual trauma survivors. We assessed two components of interoception: interoceptive accuracy (IAc: accurately perceiving internal body sensations; via heartbeat perception task) and interoceptive sensibility (IS: self-report perception of sensitivity to interoceptive sensations). We hypothesized that IAc and IS would be positively correlated with PTSD, with interactions between IAc/dissociation and IS/dissociation qualifying those main effects, weakening them for survivors with higher dissociation. Results showed an opposite pattern than was predicted: although IAc did explain significant PTSD variance, as IAc increased, PTSD decreased. Although IAc did explain significant variance in PTSD symptoms, interestingly, IS did not. Consistent with extant literature, dissociation predicted significant variance in PTSD. These correlational results suggest that the ability to more accurately perceive inner body sensations is related to lower PTSD symptoms. Findings provide a foundation for future research that can assess if interventions (such as yoga or exercise) that target increasing interoceptive accuracy lead to decreases in PTSD symptoms. We discuss further clinical implications, limitations and future directions.

Introduction

Exposure to sexual trauma (i.e., unwanted sexual contact experiences: touching, kissing, penetration) is harmful to survivors physically [29] and emotionally [40]. Repairing the harm is burdensome for individuals and their communities [79]. Female sexual trauma survivors (hereafter “survivors”) are frequently burdened with increased healthcare utilization [41] resulting, in part, from negative physical and mental health symptoms secondary to sexual trauma [25]. This burden is born disproportionately by women [[6], [43]], making them an important population to research.

One of the most researched outcomes following sexual trauma is posttraumatic stress disorder (PTSD). Following exposure to a traumatic event, PTSD is characterized by four symptom clusters: intrusion; avoidance; negative changes in mood and cognitions; and heightened arousal and reactivity. For diagnosis, these symptoms must be at a clinically impairing threshold and have persisted for longer than one month [3]. However, even when subthreshold diagnostically, PTSD symptoms cause distress [7]. Thus, studying the effects of sexual trauma across a range of PTSD symptomatology is essential to understand the impact of these life experiences.

By definition, sexual trauma involves violating a protective body boundary. As such, studying how sexual trauma is related to survivors’ experience of their bodies and body sensations is an important research topic, for two central reasons: emotions are embodied, and the body can become a sexual trauma reminder. Theory and empirical data suggest that emotions are embodied experiences that organize behavior, facilitating goal pursuit [[15], [39], [47], [53], [54], [64], [74]]. As such, disruption in sensing and deciphering somatic experience could promote broad regulatory dysfunction. Following sexual trauma, many survivors struggle with emotional awareness and regulation [55] and many mental health outcomes stemming from sexual trauma relate to challenges with emotion regulation [28]. Because of the critical links between body awareness, emotional awareness and regulation, it is important to assess how sexual trauma impacts survivors’ body awareness, and how those impacts are related to changes in PTSD symptoms. Such results would inform novel interventions for emotion awareness and regulation, because one possibility is that greater sensitivity and accuracy deciphering somatic experience may promote greater emotion-regulatory capacities and lower PTSD symptoms. In fact, there is already empirical evidence offering initial support of this possibility: intervention research shows that along the course of body-based interventions (e.g., yoga and exercise), self-reported awareness of inner body sensations (i.e., interoceptive sensibility) increases and PTSD symptoms decrease [57],[61]. These studies support the covariance of self-reported interoceptive sensibility and PTSD symptoms, but are limited in that they did not include an objective measure of accuracy in deciphering inner body sensations (i.e., interoceptive accuracy). Further, one study only included three participants [61], limiting the generalizability of the findings. In order to understand the links between body awareness, PTSD symptoms and emotion regulation, additional studies are needed that assess awareness of body sensations subjectively and objectively.

Notwithstanding, an alternative possibility exists: after sexual trauma, survivors’ bodies might become cues for traumatic memories, which may lead heightened awareness of body sensations and relate to increases in PTSD symptoms. One study on survivors of child sexual abuse found that distinct regions of the body, such as the inner thighs and pubic area, were rated by participants as trauma-associated, and that those body parts were associated with negative emotions [18]. It is well documented that survivors have difficulty with consensual sexual intimacy [16], neglect some aspects of physical self-care [49], report trauma reexperiencing symptoms during gynecological care [50] and engage in non-suicidal self-injury [86]. Extending from the empirical work of Dyer and colleagues [18], it is possible that such challenges may in part be because areas of the body act as cues for PTSD symptoms such as hyperarousal and hypervigillance. This relationship would suggest that increased somatic sensitivity and accuracy in deciphering somatic experience would increase posttraumatic symptoms.

Given the two aforementioned ways that body awareness and PTSD symptoms may be related, there are therefore two competing hypotheses: 1) heightened somatic sensitivity and accuracy facilitate emotion regulation, and are inversely related to PTSD symptoms; or 2) heightened sensitivity to and accurate perception of somatic sensations contribute to psychopathology, and are positively associated with increased PTSD symptoms. Empirically evaluating these hypotheses is crucial, as knowing how body awareness functions following sexual trauma could aid in the development of interventions that directly target body awareness, focusing either on increasing or decreasing it.

A potential moderating construct – dissociation – is important to account for. Dissociation, a set of processes that individuals can use to retreat psychologically from painful experiences, separates capacities that are typically integrated (e.g., cognition, perception, emotion, physiology) [[42], [67]]. Some types of dissociation are considered normative (e.g., attentional disruptions), while others are associated with clinical impairment (e.g., amnesia, depersonalization) [83]. In traumatic situations, dissociative processes are adaptive, offering some relief during victimization; however continuous post-trauma dissociation can be extremely disruptive. Dissociation can disconnect individuals from body awareness (e.g., experiencing one's body as separate from oneself), and is linked with developing other posttraumatic symptoms [48]. To adequately understand the associations between body awareness and sexual trauma exposure, it is necessary to account for dissociation's effect in the same model.

Researchers have not extensively studied survivors’ awareness of internal body sensations (i.e., interoception). Although interoception is operationalized differently throughout the literature (e.g., [[68], [56]]), we utilized Garfinkel and Critchley's [[31], [32]] definitions of interoceptive capacities. Garfinkel and Critchley separate interoception into three components, and in our study we assessed two: interoceptive accuracy (IAc) and interoceptive sensibility (IS). IAc, the objective facet of interoception, is accuracy in detecting body sensations. IAc is commonly measured with a behavioral task that involves participants monitoring bodily sensations (e.g., heartbeat) while those bodily sensations are simultaneously measured through an electrocardiogram machine. IS, the subjective facet of interoception, is the self-reported dispositional awareness of inner body sensations.

To our knowledge, there is no research on IAc among survivors, and limited research exists on interoceptive sensibility (IS) among survivors. One study comparing mixed-gender trauma to no-trauma groups showed no between-group differences in self-reported body awareness. Their results did demonstrate higher levels of body dissociation among female survivors versus females without trauma histories [67]. A second study investigated IS among physical and sexual abuse survivors with PTSD [59]. They found that higher self-reported IS (measured through the Eating Disorder Inventory-II [33]) was related to decreases in PTSD symptoms following 10-weeks of cognitive behavioral therapy for PTSD. These results are challenging to interpret given that the measure of IS (i.e., Eating Disorder Inventory-II IS subscale (EDI-II) [33]) merges two distinct constructs: IS and alexithymia. Therefore, the face validity in the EDI-II for IS is questionable [44]. Given these limited results, further research on IS and research that includes an assessment of IAc among survivors is needed.

The present study aims to build upon the current interoception research with survivors through multi-method assessment of interoception and dissociation, and to empirically evaluate whether heightened somatic sensitivity and accuracy are associated with decreased or increased PTSD symptoms. In a first model, we hypothesized that IAc and IS (analyzed separately) would be associated with increased PTSD symptoms, consistent with models of anxiety in which increased awareness of sensation exacerbates symptom intensity and frequency. We further hypothesized that dissociation would moderate these relationships, such that higher levels of dissociation would be associated with weaker relationships between IAc/IS and PTSD. In a second model, we hypothesized that IAc/IS would partially mediate the association between number of distinct types of sexual trauma and PTSD. We hypothesized that dissociation would moderate the association between IAc/IS and PTSD, and increased dissociation would diminish the relationship between IAc/IS and PTSD.