Scientific American reported last week on another interesting if inconclusive study about the brain activity of the religious, “Religious Experiences Shrink Part of the Brain.” Specifically, the marked variation between believers (of a certain type) and non-believers in the volume of the hippocampus portion of the brain, the exact function of which is not totally clear, outside of its tie to emotion and memory function. Strangely, most of the report talks about the findings in terms of relative stress levels – which would be really interesting – before informing us that hippocampal activity didn’t correlate to stress levels… So it’s a chicken-egg thing – do emotional difficulties lead to a certain type of religious experience or do certain types of religious experiences (in this case, ones that ostensibly involve more demand/law) lead to emotional difficulties? Probably both. But it definitely begs some other questions about the relation of theology to conversion/bottoming-out experiences, ht JD:

The results showed significantly greater hippocampal atrophy in individuals reporting a life-changing religious experience. In addition, they found significantly greater hippocampal atrophy among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again.

The authors offer the hypothesis that the greater hippocampal atrophy in selected religious groups might be related to stress. They argue that some individuals in the religious minority, or those who struggle with their beliefs, experience higher levels of stress. This causes a release of stress hormones that are known to depress the volume of the hippocampus over time. This might also explain the fact that both non-religious as well as some religious individuals have smaller hippocampal volumes.

This is an interesting hypothesis. Many studies have shown positive effects of religion and spirituality on mental health, but there are also plenty of examples of negative impacts. There is evidence that members of religious groups who are persecuted or in the minority might have markedly greater stress and anxiety as they try to navigate their own society. Other times, a person might perceive God to be punishing them and therefore have significant stress in the face of their religious struggle. Others experience religious struggle because of conflicting ideas with their religious tradition or their family. Even very positive, life-changing experiences might be difficult to incorporate into the individual’s prevailing religious belief system and this can also lead to stress and anxiety. Perceived religious transgressions can cause emotional and psychological anguish. This “religious” and “spiritual pain” can be difficult to distinguish from pure physical pain. And all of these phenomena can have potentially negative effects on the brain.

The causal relationship between brain findings and religion is difficult to clearly establish. Is it possible, for example, that those people with smaller hippocampal volumes are more likely to have specific religious attributes, drawing the causal arrow in the other direction? Further, it might be that the factors leading up to the life-changing events are important and not just the experience itself. Since brain atrophy reflects everything that happens to a person up to that point, one cannot definitively conclude that the most intense experience was in fact the thing that resulted in brain atrophy. So there are many potential factors that could lead to the reported results. One might ask whether it is possible that people who are more religious suffer greater inherent stress, but that their religion actually helps to protect them somewhat. Religion is frequently cited as an important coping mechanism for dealing with stress.