A study recently published found that, depending on religious affiliation, certain religious groups have greater amounts of hippocampus atrophies later in life as compared to those in mainline religions. The groups with the most hippocampus atrophy are born-again Christians, Catholics, and ironically no religious affiliation.
The hippocampus is involved with learning and memory, but high levels of stress can cause shrinkage and when a person undergoes a life-changing religious experience, the size of the hippocampus can shrink. Some of the reasons for this stress is a loss or change in friends, change of religious affiliation, being a member of a religious minority, and of course the profound religious experience one may have.
This study examined prospective relationships between religious factors and hippocampal volume change using high-resolution MRI data of a sample of 268 older adults. Religious factors assessed included life-changing religious experiences, spiritual practices, and religious group membership. Hippocampal volumes were analyzed using the GRID program, which is based on a manual point-counting method and allows for semi-automated determination of region of interest volumes. Significantly greater hippocampal atrophy was observed for participants reporting a life-changing religious experience. Significantly greater hippocampal atrophy was also observed from baseline to final assessment among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again. These associations were not explained by psychosocial or demographic factors, or baseline cerebral volume.
The men and women in this study were age 58 and over. This group included two groups of people who met the DSM-IV criteria for major depression and those who have never been depressed. Excluded from the study were people diagnosed with neurological and other psychiatric illnesses, significant cognitive impairment, and substance abuse. A baseline MRI was conducted at the beginning of the study and then another was done every two years, as well as religious, demographic, and psychosocial data done at the start and then every year until the end of the study.
In the final results of the study, there was more volume lost in the hippocampus for born-again Protestants, Catholics, and those with no religious affiliation in comparison to those who were never born-again.
These findings may reflect potential cumulative stress associated with being a member of a religious minority. Though religious factors have been associated with positive mental health studies have shown members of religious minority groups may also experience stressors related to these group affiliations . Greater hippocampal atrophy was also found to be longitudinally associated with reported life-changing religious experiences. Spiritual experiences not easily interpreted within an existing cognitive framework or set of religious beliefs have been shown in previous research to be detrimental to subjective well-being . Such experiences have the capacity to produce doubts regarding previously unquestioned convictions, potentially inducing cumulative stress even if the experience was subjectively positive. If the experience prompts a change in religious groups, existing social networks may also be disrupted. Thus, as possible sources of cumulative stress, both minority religious group membership and life-changing religious experiences may contribute to conditions that are deleterious for hippocampal volume.
Miller-McCune also mentioned in their report on this study, that meditation helps to prevent shrinkage of the hippocampus and while Buddhists are a minority religious group, they have less shrinkage in their brains. They also suggest that meditation may counteract these the tendency for the hippocampus to shrink.
I find this study interesting because after I left the Church and was still studying religion, mythology, psychology, and other subjects, I was like a sponge when it came to learning. Even after I suddenly had a profound experience in a Hindu class, my learning still did not stop. Upon leaving religion, I have had less problems learning than when I was in it. Ironically, I have also become healthier than I was, but we all grow older and I am a little more than a decade from age 58. I do find it fascinating that those who are born-again or are Catholic, have shrinkage in their hippocampus greater than those who are affiliated with mainline Protestantism. I was never born-again either, so that might make a difference also, but then again, I did have a vast amount of stress growing up in an abusive and Evangelical Fundamentalist family, so maybe I learned to compensate as a child. Who knows, but the findings of this study are interesting and are a lot of food for thought. Learning meditation from my Tao Buddhist son and taking up that in my life might not be such a bad idea.