Rubber hand illusion and experiences of dissociation in women with self-injury behavior

Abstract

Background: Illusory ownership over a rubber limb, as observed in the experimental paradigm the rubber hand illusion (RHI), has been reported to be correlated with self-reported dissociative symptoms in patients with current and remitted borderline personality disorder. The aim of the present study was to assess the association between RHI and dissociative symptoms in women with non-suicidal self-injury (NSSI), a patient group reporting high levels of dissociative symptoms. Methods: 41 women with NSSI and a healthy control group of 40 women were included in the study. The RHI was induced by administering tactile stimulation with a soft brush to the participants’ hand and a rubber hand. One congruent condition (synchronous brushing) and one incongruent condition (asynchronous brushing) was compared. The strength of the illusion was measured with the RHI questionnaire and proprioceptive drift. Trait dissociation was measured with the Dissociative Experience Scale-II. Results: Both the NSSI group (p < .001) and control group (p < .001) reported illusory ownership during the experiment, but there was no statistically significant difference in illusory ownership (p = .694) or proprioceptive drift (p = .219) between NSSI and controls. Illusory ownership did not correlate with trait dissociation symptoms in the NSSI group. Discussion: The RHI was induced in both groups but was not more pronounced in NSSI and did not correlate with dissociative symptoms. The results are consistent with some of the previous efforts to establish a relationship between illusory ownership and borderline personality disorder.

Keywords

• NSSI
• Rubber hand illusion
• Dissociation
• Self-harm
• Borderline traits