Induced illusory body ownership in borderline personality disorder

Abstract

One aspect of selfhood that may have relevance for borderline personality disorder (BPD) is variation in sense of body ownership. We employed the rubber hand illusion to manipulate sense of body ownership in BPD. We extended previous research on illusory body ownership in BPD by testing: (i) two illusion conditions: asynchronous and synchronous stimulation, (ii) relationship between illusion experience and BPD symptoms, and (iii) relationship between illusion experience and maladaptive personality traits. We measured illusion strength (questionnaire responses), proprioceptive drift (perceived shift in physical hand position), BPD symptoms (Revised Diagnostic Interview for Borderlines score), and maladaptive personality traits (Personality Inventory for DSM-5) in 24 BPD and 21 control participants. For subjective illusion strength, we found main effects of group (BPD > healthy control, F(1, 43) = 11.94, P = 0.001) and condition (synchronous > asynchronous, F(1, 43) = 22.80, P < 0.001). There was a group × condition interaction for proprioceptive drift (F(1, 43) = 6.48, P = 0.015) such that people with BPD maintained illusion susceptibility in the asynchronous condition. Borderline symptom severity correlated with illusion strength within the BPD group, and this effect was specific to affective (r = 0.45, P < 0.01) and cognitive symptoms (r = 0.46, P < 0.01). Across all participants, trait psychoticism correlated with illusion strength (r = 0.44, P < 0.01). People with BPD are more susceptible to illusory body ownership than controls. This is consistent with the clinical literature describing aberrant physical and emotional experiences of self in BPD. A predictive coding framework holds promise to develop testable mechanistic hypotheses for disrupted bodily self in BPD.

The Cognitive, Ecological, and Developmental Origins of Self-disturbance in Borderline Personality Disorder

“…Only two studies have investigated RHI in BPD patients. Both studies report an increased illusory limb ownership in adult women with BPD compared to healthy controls (Bekrater-Bodmann et al, 2016;Neustadter et al, 2019). Interestingly, one of these studies showed that this increased illusion occured not only in the synchronous condition, but also in the asynchronous condition (Neustadter et al, 2019).…”

“…With respect to proprioceptive drift, both studies report similar drift toward the rubber hand in the synchronous condition in BPD and healthy controls groups. Nonetheless, BPD participants also showed a sustained proprioceptive drift during the asynchronous condition in one study (Neustadter et al, 2019). In addition, Bekrater-Bodmann and colleagues showed that state and trait dissociations were both associated with illusory limb ownership but not significantly associated with proprioceptive drift (Bekrater-Bodmann et al, 2016).…”

“…Abnormal illusory experience through RHI have also been shown in schizophrenia as well as during ketamine challenge (Neustadter et al, 2019). Increased illusory limb ownership have also been associated with Body Dysmorphic Disorder and eating disorders, and appears to be related to what Neustadter and colleagues call a transdiagnostic "psychosis-proneness" (Neustadter et al, 2019).…”

“…Abnormal illusory experience through RHI have also been shown in schizophrenia as well as during ketamine challenge (Neustadter et al, 2019). Increased illusory limb ownership have also been associated with Body Dysmorphic Disorder and eating disorders, and appears to be related to what Neustadter and colleagues call a transdiagnostic "psychosis-proneness" (Neustadter et al, 2019). As a result, RHI (Bekrater-Bodmann et al, 2016) as well as broader body ownership experiences, have been associated with state and trait dissociation (Löffler et al, 2020) and trait psychoticism (Neustadter et al, 2019) in BPD subjects.…”

Improving Research Practice for Studying Borderline Personality Disorder: Lessons From the Clinic

“…And indeed, people with BPD, who are highly influenced by social cues, have increased susceptibility even to the canonically less illusion-inducing asynchronous condition of the rubber hand illusion task. 43 Therefore, the hypothesis put forth by Lush et al. that direct measurement of hypnotizability may help to control for the contribution of high phenomenological control in participant responses may also have particular relevance for research in people with BPD.…”