The Bodily Self from Psychosis to Psychedelics
preprint DOI: 10.31234/osf.io/5e4q6
Summary
The study examined how the sense of bodily self differs among patients with psychosis, individuals with psychedelic experiences, and control participants. It found that psychosis patients exhibited reduced Body Ownership and Sense of Agency during actions. While those with psychedelic experiences reported lasting changes in their sense of self, no significant differences were observed between them and control participants regarding bodily self. The findings indicate that psychedelics may alter self-perception without affecting bodily self-processing.
Study at a glance
| Sample size | 75 |
|---|---|
| Population | patients with psychosis, participants with a history of substantial psychedelic experiences, and control participants |
| Key finding | Psychosis patients showed reduced Body Ownership and Sense of Agency, while psychedelic users reported lasting changes in self-perception without differences in bodily self compared to controls. |
Abstract
The sense of self is a foundational element of neurotypical human consciousness. We normally experience the world as embodied agents, with the unified sensation of our selfhood being nested in our body. Critically, the sense of self can be altered in psychiatric conditions such as psychosis and altered states of consciousness induced by psychedelic compounds. The similarity of phenomenological effects across psychosis and psychedelic experiences has given rise to the “psychotomimetic” theory suggesting that psychedelics simulate psychosis-like states. Moreover, psychedelic-induced changes in the sense of self have been related to reported improvements in mental health. Here we investigated the bodily self in psychedelic, psychiatric, and control populations. Using the Moving Rubber Hand Illusion, we tested (N=75) patients with psychosis, participants with a history of substantial psychedelic experiences, and control participants to see how psychedelic and psychiatric experience impacts the bodily self. Results revealed that psychosis patients had reduced Body Ownership and Sense of Agency during volitional action. The psychedelic group reported subjective long-lasting changes to the sense of self, but no differences between control and psychedelic participants were found. Our results suggest that while psychedelics induce both acute and enduring subjective changes in the sense of self, these are not manifested at the level of the bodily self. Furthermore, our data show that the bodily self-processing, related to volitional action, is disrupted in psychosis patients. We discuss these findings in relation to anomalous self-processing across psychedelic and psychotic experiences.