Alleged mediums showed no differences in pineal gland or pituitary volumes, or in urinary 6-sulfatoxymelatonin levels, compared to nonmedium controls. During mediumistic experience, anxiety and heart rate increased to a level between reading and a stressful test, but 6-sulfatoxymelatonin levels did not differ across conditions. Salivary cortisol response to stress was attenuated. The normal neuroimaging and stress reactivity findings contrast with abnormalities typically seen in psychotic and dissociative disorders.
Alleged mediums who report regular communication with deceased personalities show no differences in brain structure, hypnotizability, dissociation, or empathy compared to non-medium controls. Magnetic resonance imaging revealed normal corpus callosum areas in the medium group, contrasting with abnormalities seen in psychotic and dissociative disorders. Both groups had intermediate hypnotic susceptibility levels, and the rostrum of the corpus callosum area did not correlate with hypnotizability. The medium group reported more anomalous experiences but scored similarly on dissociation, empathy, and mental health measures. The findings suggest that mediumship is not associated with the brain abnormalities or dissociative pathology found in clinical conditions.