Physiological and Subjective Stress Responses and Their Coherence in BPD, FND, and Healthy Controls: A Preregistered Study Using the Interoceptive Approach Task
Year: 2026
Type: preprint
Abstract: This pre-registered study investigates interoceptive processes in individuals with Borderline Personality Disorder (BPD), Functional Neurological Disorder (FND), and Healthy Controls (HC) using a novel experimental paradigm: the Interoceptive Approach Task (IAT). Interoception refers to the perception and interpretation of internal bodily signals, such as changes in heart rate, respiration, muscle tension, and autonomic arousal. Contemporary theories increasingly suggest that disturbances in interoceptive processing may contribute to the development and maintenance of both psychiatric and functional neurological disorders. However, existing interoception research has predominantly relied on highly controlled laboratory tasks that assess bodily perception under static and emotionally neutral conditions. Such paradigms may have limited ecological validity and may not adequately capture the dynamic interpersonal contexts in which interoceptive processes are clinically relevant. To address this limitation, the present study introduces the Interoceptive Approach Task (IAT), a standardized interpersonal stress paradigm derived from the stop-distance tradition commonly used in psychomotor and body-oriented therapeutic settings. During the task, participants are exposed to a controlled interpersonal proximity challenge while continuous physiological data are collected. Simultaneously, participants continuously report their subjective tension using a synchronized rotary dial interface. This design allows the investigation of physiological reactivity, subjective tension, and the temporal relationship between both processes in an ecologically meaningful yet experimentally controlled setting. The primary objective of the study is to determine whether individuals with BPD, FND, and healthy controls differ in (a) physiological responses during the IAT, (b) subjective tension responses during the task, and (c) interoceptive coherence, defined as the within-person coupling between subjective tension and objectively measured physiological signals over time. Physiological measures include cardiac activity, heart rate variability, electrodermal activity, and respiration. In addition, interpersonal stopping distance during the approach task will be recorded. The study is grounded in contemporary predictive processing and active inference theories of interoception, which propose that individuals develop characteristic patterns of interpreting and responding to bodily signals throughout development. Based on previous theoretical and empirical work, BPD and FND are hypothesized to represent distinct interoceptive profiles. However, the present study is primarily designed to quantify and compare these profiles rather than to test a specific clinical intervention. A secondary objective is to explore whether transdiagnostic interoceptive phenotypes can be identified across diagnostic categories. To this end, cluster analytic techniques will be applied to physiological and subjective measures obtained during the task. This exploratory analysis aims to investigate whether naturally occurring interoceptive profiles emerge that cut across traditional diagnostic boundaries. The study will recruit 90 participants (30 BPD, 30 FND, and 30 healthy controls). Data will consist of continuous psychophysiological recordings, continuous subjective tension ratings, behavioral task measures, and self-report questionnaires assessing interoceptive sensibility, attachment, autonomy-connectedness, and childhood adversity. Expected outcomes include a more detailed characterization of interoceptive functioning in BPD and FND, the development and evaluation of a novel laboratory paradigm for studying interoception under interpersonal stress, and the generation of new insights into transdiagnostic mechanisms underlying emotional and bodily regulation. More broadly, the project aims to contribute to the growing field of interoception research by providing a dynamic and ecologically relevant approach to studying the relationship between physiological arousal and subjective bodily experience.
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7202212282