The sense of self, normally experienced as unified and embodied, can be altered in psychosis and by psychedelic compounds. Using the Moving Rubber Hand Illusion with 75 participants—psychosis patients, people with substantial psychedelic experience, and controls—the study found 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. The results suggest that psychedelics induce acute and enduring subjective changes in the sense of self that are not manifested at the level of the bodily self, while bodily self-processing related to volitional action is disrupted in psychosis.
The sense of self is a core part of normal human consciousness, but it can be altered in psychiatric conditions like psychosis and in altered states induced by psychedelics. Using the Moving Rubber Hand Illusion with 75 participants—patients with psychosis, people with substantial psychedelic experience, and controls—the study tested how these experiences affect the bodily self. Psychosis patients showed reduced Body Ownership and Sense of Agency during voluntary movement. The psychedelic group reported long-lasting subjective changes to selfhood, but no differences from controls appeared on the bodily-self measures. Thus, while psychedelics alter the subjective sense of self, these changes do not manifest at the bodily level, whereas bodily self-processing linked to voluntary action is disrupted in psychosis.