A study published in the online journal PLoS ONE found aÂ key part of the brain atrophied more rapidly in Catholics and born-again Protestants than it did inÂ mainline Protestants.
This accelerated shrinkage was also found in people who reported a life-changing religious experience, as well asÂ those with no religious affiliation.
The reason, the researchers speculate, is the cumulative stress that comes with being a member of a religious minority. […]
Intrigued by previous research that linked smaller hippocampus volume with hyper-religiosity in some epileptics — as well as research on the effect of meditation on the hippocampus — the researchers decided to conduct a wider study of religious belief and brain shrinkage. […]
The researchers found no relationship between changes in hippocampal volume and a participant’s frequency of public or private religious activity. They did, however, find greater shrinkage in people who reported at the study’s outset that they had undergone life-changing religious experiences.
“Such experiences have the capacity to produce doubts regarding previously unquestioned convictions, potentially inducing cumulative stress even if the experience was subjectively positive,” Owen and her colleagues write. They add that “If the experience prompts a change in religious groups, existing social networks may also be disrupted” — another source of stress.
The researchers suspect low-level tension is also impacting the brains of non-mainline Protestants.
The study, funded by the National Institutes of Health and the Templeton Foundation, included at least two MRI measurements of the hippocampus region of 268 adults between 1994 and 2005.
It found an association between participants’ professed religious affiliation and the physical structure of their brain. Specifically, those identified as Protestant who did not have a religious conversion or born-again experience — more common among their evangelical brethren — had a bigger hippocampus. […]
The hippocampus is an area buried deep in the brain that helps regulate emotion and memory. Atrophy or shrinkage in this region of the brain has long been linked to mental health problems such as depression, dementia and Alzheimer’s disease. […]
Sociologists of religion, meanwhile, aren’t buying it. They say the researchers’ theory flies in the face of U.S. religious demographics. While it’s true that evangelicals are a minority, they’re a sizable one — 40% of the U.S. population, according to Gallup Polls — and not exactly a stressed-out minority, especially in the South.
“There are probably more born-again Protestants than non-born-again Protestants, and just about as many Catholics as either born-again or non-born- again Protestants,” said David Roozen, sociologist of religion at Hartford Seminary.
The study, Religious Factors and Hippocampal Atrophy in Late Life, is available online.