The pineal gland – a small endocrine gland located near the center of the brain – has long been suggested as playing an important role in spiritual experiences, with it often being linked with the mystical concept of the ‘third eye‘, an esoteric organ said to offer visions, clairvoyance and ultimately, enlightenment.
The 2nd century Roman surgeon and philosopher Galen stated that the pineal gland might be a valve that regulated the flow of ‘psychic pneuma’. French philosopher René Descartes would, some 1500 years later, put the pineal gland at the centre of his famous mind-body theories, claiming that it was the ‘seat of the soul’. And in the last couple of centuries, Western esotericism has blended theories of the pineal, the Hindu Ajna chakra, and the ‘third eye’ to promote it as a bridge between the physical world and the spiritual.
But does the legend hold up against scientific scrutiny? Psychedelics researcher Dr Rick Strassman asked whether the pineal gland could be a possible trigger for altered states of consciousness, through the secretion of the sleep-regulating hormone melatonin and/or the powerful psychedelic DMT. So could some people’s natural ability to enter altered states be directly associated with an abnormal pineal gland?
Enter a group of scientists in Brazil, who decided to investigate the pineal gland, and associated hormone levels, in 16 spirit mediums (the ‘medium group’, or ‘MG’), as compared to 16 healthy ‘non-mediums’ as control group (CG).
The experiments took place in Campo Grande, Brazil, from January 2018 to April 2019, with mediums selected through consultation with a regulatory organization for Spiritism in Campo Grande, the Spiritist Federation of Mato Grosso do Sul. All mediums and controls were female.
In pre-screening tests, it was found that subjects in the MG reported a significantly higher number of anomalous experiences than the subjects in the CG, but no significant differences were found in the subjects’ mental health.
As for their investigation of whether the pineal gland of the mediums differed from control group? They found no significant difference:
In the present study, no differences were found between the MG and the nonmedium CG in terms of pineal gland volume, nocturnal urinary aMT6s levels [6‐sulfatoxymelatonin (aMT6s) is the main metabolite is of melatonin, and thus morning levels in urine are correlated with melatonin production during the previous night], and self‐reported subjective sleep quality (PSQI). In other words, structurally and functionally normal pineal glands were found in mediums, that are individuals often considered to have psychotic‐like experiences. This picture contrasts sharply with the data available in the literature describing these aspects in individuals with psychotic disorder/schizophrenia. In patients with schizophrenia, there is a predominantly reduced pineal gland volume, reduced MLT production and higher frequency of sleep disturbance, when compared to healthy controls.
(It should be noted though, as the researchers point out in the passage above, that it could also be seen as strange that individuals having mediumistic experiences don’t have correlating changes in the pineal gland and associated secretions similar to other groups of people who experience dissociation.)
The results suggest, the scientists note, that any future research on “the conjectured relationship of the pineal gland with spiritual experiences, if any, should be done on other (yet unexplored) bases other than through the production of melatonin” – that is, further experiments could look into “the secretion of hallucinogenic tryptamines, and magneto receptors”.
In short: the spirit mediums seemed to have no abnormally sized pineal gland, or abnormal levels of melatonin secretion – though, the researchers warn, ” calculating the volume of pineal gland and melatonin level is obviously not enough to clarify the putative role of the pineal gland in spirit possession”.
The researchers do note however, in their conclusion, that their findings support the idea that mediumship should not be considered a form of mental illness:
In sum, the findings of the present study indicate that individuals with psychotic‐like symptoms linked to the cultural context (in this case, Spiritist mediums) have normal secretory and structural characteristics of PG, quite different from the picture usually found in individuals with psychotic disorder. Yet, an increase in MLT production does not appear to be a distinguishing feature of mediumistic experience. Additionally, mediums presented a fast recovery stress response pattern, indicating good emotional regulation, unlike patients with pathological dissociation. Hence, the main implication of this study is to reinforce the notion of mediumship as a nonpathological dissociative phenomenon. This underscores the importance of refining the differential diagnosis between nonpathological forms of spiritual possession versus psychotic and dissociative disorders, as evidence increasingly demonstrates that culturally well‐integrated mediums are often mentally and physically healthy. Thus, the correct differentiation between these conditions could avoid stigmatization and unnecessary treatments.