Does religion shrink your brain?

Over the past couple of weeks we have looked at studies suggesting that religion rots your intelligence and that religion rots teens’ intelligence, and, not surprisingly, both theses fell apart. Now here is a different, more solid proposition.

In “Religious factors and hippocampal atrophy in late life,” Amy Owen and colleagues at Duke University found that in late life there was greater atrophy in the hippocampus (associated with memory) among individuals who have been “born again,” as well as those with no religious affiliation. Hippocampal volume change has been linked to depression, dementia, and Alzheimer syndrome. Of course, we’ve already been told that “many scientists view "outspoken religious commitment as a sign of mild dementia.", a charge aimed at genome mapper Francis Collins, who makes no secret that he is a Christian, but this is a serious look at the subject.

Unlike the earlier studies we’ve look at, Owen et al’s evaluation of the MRIs of 268 men and women aged 58 and over appears sound:

“These longitudinal associations were not explained by baseline psychosocial or psychiatric factors (social support, stress, and depression status), demographic factors, duration in the study, or total baseline cerebral volume. Frequency of public and private religious activity did not predict changes in hippocampal volume.”

The participants were originally recruited for the NeuroCognitive Outcomes of Depression in the Elderly study, and chosen because they answered some additional questions regarding their religious beliefs and affiliation. So the obvious bases were covered.

In “Religious Experiences Shrink Part of the Brain: A study links life-changing religious experiences, like being born again, with atrophy in the hippocampus” (Scientific American, May 31, 2011) neuroscientist Andrew Newberg, M.D. observes, “ It is a surprising result, given that many prior studies have shown religion to have potentially beneficial effects on brain function, anxiety, and depression.” He adds that the study is “unique” in that

“it focuses specifically on religious individuals compared to non-religious individuals. This study also broke down these individuals into those who are born again or who have had life-changing religious experiences.”

He might have added that “no religion” had the same effect on the hippocampus. The real winners in this study were people who were conventionally religious but had never had a spiritual or “born again” experience.

It’s well established that religious belief and practice are usually associated with better health. Mario Beauregard and I devoted an entire chapter of The Spiritual Brain to studies in this area (Chapter 8), and a number of books have unpacked them as well. There is also good evidence that “negative”religious beliefs are bad for one’s health. As we noted in TSB,

“One study found that ill elderly patients were more likely to die if they had a conflicted relationship with their religious beliefs. The researchers studied 595 patients of fifty-five or over at Duke University Medical Center and Durham VA Medical Center. They achieved a complete follow-up on 444 patients, including 176 who had died. Those patients who strongly agreed with statements like “wondered whether God had abandoned me; felt punished by God for my lack of devotion; wondered what I did for God to punish me; questioned God’s love for me; wondered whether my church had abandoned me; decided the Devil made this happen; and questioned the power of God” were significantly more likely to die (19–28 percent greater mortality during the two-year period after discharge from hospital). The authors concluded: “Certain forms of religiousness may increase the risk of death. Elderly ill men and women who experience a religious struggle with their illness appear to be at increased risk of death, even after controlling for baseline health, mental health status, and demographic factors.” (TSB, p. 237)”

So beliefs matter, whether positive or negative. But why should strong beliefs, pro or anti-religion, be worse for the hippocampus than lukewarm belief?

The authors suggest that one factor might be stress, noting that both extremes are minority positions. That makes intuitive sense because minority status entails more conflict over beliefs, independent of content. Newberg adds, among other thoughtful suggestions, that some

... 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.

That, of course, accords with religious history: The people who have encountered God are usually remembered not for a less stressful life but a more meaningful one.

(Note: Here’s a story, now available online, about a very old man who had a spiritual experience after a major assault on his brain.)

Next: No more religion means no more superstition. Right?
Previous:Does religion rot your intelligence? and Does religion rot teenagers' brains?

Denyse O'Leary is co-author of The Spiritual Brain.