Psilocybin's Mechanisms Behind Touch and Body Perception Could Treat Certain Mental Health Conditions

A recent study has found that psilocybin can alter the brain’s response to unexpected touch, impacting certain regions responsible for sensory processing and self-perception. This research, conducted by a team at the University Hospital for Psychiatry Zurich, suggests that psilocybin could be used as a potential treatment for certain mental health disorders involving altered body perception.

Study background

The placebo-controlled, double-blind study involved administering psilocybin to fifteen adult volunteers aged 20 to 40. Before the study, the volunteers went through a medical screening to confirm that they had no history of any major psychiatric or neurological disorders.

Each participant received a dose of psilocybin and a placebo in two separate sessions at least two weeks apart to ensure that any observed effects were directly from psilocybin rather than outside variables. Following consumption, participants underwent a tactile stimulation test that involved sending mild electrical pulses of varying intensities to the median nerve in the left forearm, creating a sequence of predictable and unexpected stimuli. EEG and fMRI tests were given simultaneously to capture both the timing and the location of brain activity in response to the stimuli presented to participants. 

Major findings

The study found that psilocybin can significantly change how the brain responds to unexpected touch. EEG results indicated that participants under the influence of psilocybin had a reduced mismatch negativity response (MMN), a brain signal that indicates the detection of unexpected events. These results suggest that psilocybin reduces the brain’s capability of detecting surprising touch sensations. 

The fMRI results showed decreased activity in key brain regions used for processing touch (frontal cortex, visual cortex, and cerebellum). Since these regions are critical for integrating sensory information and maintaining body awareness, their reduced activity under psilocybin indicated a disruption in the normal processing of touch information.

Participants also reported significant changes in how they perceived their bodies and self-awareness while on psilocybin. These subjective experiences match the observed changes in brain activity, showing that psilocybin’s effect on sensory processing is closely linked to its impact on self-perception (1).

Implications for mental health

Based on the study’s findings, psilocybin may have mechanisms responsible for treating mental health disorders like schizophrenia, anorexia nervosa, depression, and body dysmorphia disorder, which often involve distortions in how one perceived their bodies and selves. By altering the regions in the brain and mechanisms involved in these processes, psilocybin may help regulate these distortions and improve the overall mental health of patients. However, as promising as these results are, researchers note that further studies with larger sample sizes and varied sensory stimuli will be needed to fully confirm these findings and explore the therapeutic potential of psilocybin for.mental health treatment. 

The study was registered at clinicaltrials.gov under the identifier NCT03736980. No major side effects were observed throughout the research.

References

1. Duerler, Patricia, Silvia Brem, Gorka Fraga-González, Tiffany Neef, Micah Allen, Peter Zeidman, Philipp Stämpfli, Franz X Vollenweider, and Katrin H Preller. 2021. “Psilocybin Induces Aberrant Prediction Error Processing of Tactile Mismatch Responses—a Simultaneous EEG–FMRI Study.” Cerebral Cortex, July. https://doi.org/10.1093/cercor/bhab202.