Reprinted from the March 2004 issue of Science and Theology News with permission.

Whether you prefer whirling with the dervishes, participating in liturgical services or meditating with Buddhists may depend on the level of serotonin in your brain, recent research indicates.

Participation in and receptivity to certain religious and spiritual practices may be linked to the density of one of 15 serotonin receptors in the brain, said Dr. Lars Farde, professor of psychiatry at Karolinska Institutet in Stockholm, Sweden, and co-author of, "The Serotonin System and Spiritual Experiences," published in the November issue of the American Journal of Psychology.

According to Farde, the receptor neurologists call 5-HT1A "is one of the most important because it serves as a marker for the entire serotonin system." He said the connection furthers the belief that brain function may impact openness to spiritual experiences.

Using a brain imaging technique called positron emission tomography, or PET, Farde and his team have been studying neurotransmitters like dopamine and serotonin for a number of years. Their past research was the first to demonstrate the correlation between higher brain function and personality.

Recently, the researchers became interested in the serotonin system because of its relationship to depression and anxiety, said Farde. In attempting to confirm the correlation between serotonin levels and anxiety, he said they were surprised to discover a connection between the density of the receptors and spiritual acceptance.

Using the "Temperament and Character Inventory," 15 mentally and physically healthy men ages 20 - 45 self-assessed a number of personality traits, including self-transcendence, which denotes religious behavior and attitudes. The scale includes yes-or-no questions like, "I have had supernatural experiences" and, "I believe in a common, unifying force."

"We looked at how they view the existence of a spiritual realm," said Farde. "You can take the extremes. The person who scores very low might be a technician who says they believe the things they see, the things they can measure, whereas they don't believe anything beyond that. The other extreme might be the new-age type, or the person who believes that nature has a soul and views the spiritual reality as more important than the reality seen by our eyes."

The participants also underwent PET scans to determine their serotonin levels. Analyzing the date from the two tests, the researchers discovered a strong linear correlation: the higher the scores for spiritual acceptance, the lower the density of the serotonin receptors.

"There is more to say that low serotonin is linked with people who are open to spiritual or supernatural experiences," explained Farde. "Whereas the higher levels go more with people who believe what they see with their eyes and are not so open to God or other aspects of religion."

Dr. Andrew B. Newberg, an assistant professor in the departments of radiology and psychiatry at the University of Pennsylvania, said this is an integral study in understanding the biology behind spirituality and religion.

"This is a big question that has been raised," said Newberg, who researches the connection between spirituality and the brain, or neurotheology. "We always talk about people that are predisposed to certain experiences, and the question is why."

According to Newberg, this research may be useful in a number of ways, including guiding people to practices that might better suit their disposition by understanding how people are spiritually different.

"This is helping us understand how religion and spirituality affect the global us and lead us to better knowledge to how people differ and religions differ - and how they affect people better than others or worse than others," Newberg said.

Farde also indicated that understanding the role of the brain in religion and spirituality may create more respect for plurality and the way we are religious beings. While the research does not explain whether a person has a belief system, Farde said, it might indicate why the person may be more attuned to a charismatic church as opposed to one with more order and tranquility.

" Because people are different in the way they perceive religion and spirituality, it adds to the difficulty of understanding and respecting each other, " Farde explained. "By understanding the genetic component, this data can support that differences may not be a matter of views or dogma but can also be related to the way we are created from the beginning."

Dr. Keith Meador, director of the Theology and Medicine program at Duke University, said that while the article is interesting, it points toward a lot more work to be done.

"The article is misinterpreted when it tries to make the direct relationship with spirituality," said Meador, explaining that the work lacks context. "By necessity, our brain is a vital part of the fullness of our understanding and expression of religion, but it has to be interpreted. It's that contextualization that gives it any meaning."

Meador added that there is a temptation to define perceptual phenomena as spiritual.

"The problem we find with a lot of the religion and health and spirituality findings and movement is the tendency to overinterpret without rightly contextualizing and being a bit more cautious about things."

Newberg said the study was worthwhile, but agrees that more research needs to be done.

"If we can learn more about the human brain through studies of these very complex spiritual and religious experiences people have, we can understand neurobiology and psychiatry better," said Newberg. "And if there are ways we can learn more about these experiences - how they happen, what they mean - religion and spirituality can be enhanced as well."

Farde and his colleagues are currently conducting an identical study in women that will be completed in three to six months