Lost in time and space? Multisensory processing of peripersonal space and time perception in people with frequent experiences of depersonalisation.

Perception of one's own body in time and space is a fundamental aspect of self-consciousness. It scaffolds our subjective experience of being present, in the here and now, a vital condition for our survival and well-being. Depersonalisation (DP) is characterized by a distressing feeling of being 'spaced out', detached from one's self, as well as atypical 'flat' time perception. Using an audio-tactile paradigm, we conducted a study looking at the effect of DP experiences on peripersonal space (PPS) - the space close to the body - and time perception. Strikingly, we found no difference in PPS perception in people with higher DP experiences (High DPe) versus low occurrences of DP experiences (Low DPe). To assess time perception, we used the Mental Time Travel (MTT) task measuring the individuals' capacity to take one's present as a reference point for situating personal versus general events in the past and the future. We found an overall poorer performance in locating events in time relative to their present reference point in High DPe. By contrast, Low DPe showed significant variation in performance when answering to relative past events, while High DPe did not. Our study sheds light on the close link between altered sense of self and egocentric spatiotemporal perception in individuals with DP experiences, the third most common psychological symptom in the general population.