Two new studies suggest this may be true. The first article is published in Scientific American and is by Anderw Newberg, author of Why God Wont Go Away.  Newberg is a pioneer in the field of studying the brain to understand the result of religious thinking. The research is by Amy Owen at Duke University. "The study, published March 30 in PLoS One, showed greater atrophy in the hippocampus in individuals who identify with specific religious groups as well as those with no religious affiliation. It is a surprising result, given that many prior studies have shown religion to have potentially beneficial effects on brain function, anxiety, and depression."
The Owen study used MRI to measure volume of the hippocampus, in the limbic system. This structure is involved in memory as well as emotion. Sample size inckluded 268 men and women, 58 and over, who suffered depression and were taken from a sample of elderly studied for depression. The study only looked at religious involvement and divided the group into those who were born again and who had life changing religious experiences. "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 Theory proposed by the authors is based upon the idea that those involved in struggle over their beliefs are involved in higher levels of stress. Stress results in shrinkage of the hippocampus. Such conflicts release a stress hormone. Newberg, elucidates upon the theroy in stating that
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.Newberg is less than enthusiastic about the findings, points out several flaws in the study, such as small sample size.
Thus, Owen and her colleagues certainly pose a plausible hypothesis. They also cite some of the limitations of their findings, such as the small sample size. More importantly, 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. (It is also somewhat problematic that stress itself did not correlate with hippocampal volumes since this was one of the potential hypotheses proposed by the authors and thus, appears to undercut the conclusions.) 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.There are more devastating criticisms to be made. First of all, the sample is taken from a study that was done on elderly and depression. Thus while people may have had a valid life changing experience at some point in the past, they were now depressed. That might either cause or indicate stress and would shrink the hippicamus. It masks the ability to determine the causal relationship between religious experience and shrinkage. Experiences do run low. In Wuthnow study the experience faded after one year. While Maslow speaks of some effects lasting a life time, there are those who need a renewed experience (and renewal is possible). More importantly, we are not told what constitutes "life changing religious experience." We don't know if the M scale was used or if some comparable scale was in sue, or were these experiences just subjectively judged as "religious" and "life changing" because they resulted in a conversion. So again they can't even prove they are talking about the kind of religious experiences that are associated with the most dramatic effects. Moreover, the article alludes several times to "Many studies have shown positive effects of religion and spirituality on mental health, but there are also plenty of examples of negative impacts." We are not told if the negatives are related to the actual experience or to some intervening variable such as persecution. Or even if they are among those with mystical experience or if that's the pile where any conversion is considered life changing.
This new study is intriguing and important. It makes us think more about the complexity of the relationship between religion and the brain. This field of scholarship, referred to as neurotheology, can greatly advance our understanding of religion, spirituality, and the brain. Continued studies of both the acute and chronic effects of religion on the brain will be highly valuable. For now, we can be certain that religion affects the brain--we just are not certain how.
The important point to to made is religious experience is so consistently positive and good that even clinicians in institutions encourage their patents to seek it for therapeutic effects. Wuthnow and Nobel both found numerious positive results (negative results--which were about stress and anxiety--were short term). 
*Say their lives are more meaningful,
*think about meaning and purpose
*Know what purpose of life is
*Score higher on self-rated personal talents and capabilities
*Less likely to value material possessions, high pay, job security, fame, and having lots of friends
*Greater value on work for social change, solving social problems, helping needy
*Reflective, inner-directed, self-aware, self-confident life style
*Experience more productive of psychological health than illness
*Less authoritarian and dogmatic
*More assertive, imaginative, self-sufficient
*High ego strength,
*relationships, symbolization, values,
*autonomy, authenticity, need for solitude,
*increased love and compassion 
This is just the tip of the iceberg. There's a huge body of empirical research going back 50 years demonstrating the positive effects of these experiences it's not logical assume they damage your brain. For years I've searched for examples of detrimental or pathological effects that resulted in transformation (dramatic postiive change for the better). It doesn't happen that way. No form of brain damage results of a really over all better life.
The Second study is in Science Daily "Selective Brain Damage Modulates Human Spirituality, Rsearch Reveals," (Feb. 11, 2010). There is no "by" line to the story, it just points to "cell press." So it's by a staff writer for a popular publication specializing in scinece news. The actual research is by Dr. Cosimo Urgesi from the University of Udine in Italy, in February 11 issue of the journal Neuron. This is not too impressive. It leads off with an ideological statment that is little more than pledging allegence ot materialism:
Although it is well established that all behaviors and experiences, spiritual or otherwise, must originate in the brain, true empirical exploration of the neural underpinnings of spirituality has been challenging. However, recent advances in neuroscience have started to make the complex mental processes associated with religion and spirituality more accessible."Neuroimaging studies have linked activity within a large network in the brain that connects the frontal, parietal, and temporal cortexes with spiritual experiences, but information on the causative link between such a network and spirituality is lacking," explains lead study author, Dr. Cosimo Urgesi from the University of Udine in Italy.In other words theoretically we assume that there's nothing more to spirituality than brain chemistry but it's been real hard to prove it. This study focuses on the phenomenon known as "self transcendence" (ST) as a measure of spirituality. Changes in ST among patience who had been treated for brain cancer so they changed the changes in ST made by brain lesions. The nature of ST was charted by scores obtained before and after on a test. Self transcendence is the sense of one's own unqieness as a person and one's place in relation to the rest of reality. The results are surprising:
The group found that selective damage to the left and right posterior parietal regions induced a specific increase in ST. "Our symptom-lesion mapping study is the first demonstration of a causative link between brain functioning and ST," offers Dr. Urgesi. "Damage to posterior parietal areas induced unusually fast changes of a stable personality dimension related to transcendental self-referential awareness. Thus, dysfunctional parietal neural activity may underpin altered spiritual and religious attitudes and behaviors."I would have expected the opposite. Make a lesion and it reduces ST but actually makes it stronger. So they are assuming that ST is the result of damage to the brain rather damage merely impairing it. That's grossly ideological because they are actually saying that our sense of self, the individuality that makes us who we are, the thing that gives us a sense of nobility and makes us human is a mistake, the result of brain damage. This fits with the trans human movement. People who now seek to be robots and who actually disregard their own human rights. That's just clearly wrong. All the positive steps we've taken as humanity since the Renaissance have come as a result of having a concept of self transcendence. If this finding is true than all of civilization is a huge mistake. Every postie step we have taken, including the development of brain science the understanding of neurology is a big accident not just an accident but a travesty, the result of brain damage. Doesn't imply that in some sense are true "design" if we can call it that would be to retard our sense of who we are to keep us from growing as people. Thus making the discipline of psycholgoy into a crime. So it undermines the very sciences that aruge for the finding. Of cousre the original research doesn't say if it's talking about positive or negative aspects associated with ST. Leading me to conclude this may just be a biased telling of the result, conditioned by ideological need.
 Andrew Newberg, "Religious Experiences Shrink Part of the Brain." Scientific American, May 31, 2011. on line copy: http://www.scientificamerican.com/article.cfm?id=religious-experiences-shrink-part-of-brain accessed 7/31/13
______________ and Eugene D'Aquili Why God Wont Go Away:Brain Science and The Biology of Belief. New York: Balantine Books, 2002.
 Robert Wuthnow, "Peak Experiences: Some Empirical Tests." Journal of Humanistic Psychology, 18 (3), 1978. 59-75.
 Metarock, "The M Scale and Universal Nature of Mystical Experience." The Religious A prori
website, http://religiousapriori.blogspot.com/2012/10/the-m-sacle-and-universal-nature-of.html accessed 7/31/13.
see also Ralph Hood Jr. “The Common Core Thesis in the Study of Mysticism.” In Where God and Science Meet: How Brain and Evolutionary Studies Alter Our Understanding of Religion. Patrick Mcnamara ed. West Port CT: Prager Publications, 2006, 119-235.
Google books on line version: URL http://books.google.com.cu/books?id=0bzj3RtT3zIC&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=true visited 8/20/2012
Lorraine S. Allman, et al. "Psychotherapists Attitudes Toward Clients Reporting Mystical Experiences." Psychotherapy, Vol 29, no 4, (Winter, 1992), 564-669, 564. on line copy
 Robert Wuthnow, Ibid.
 Kathleen D. Noble, ``Psychological Health and the Experience of Transcendence.'' The Counseling Psychologist, 15 (4), 1987, 601-614.
 findings of Wuthnow and noble summarized by the council on spiritual Practices, "State of Unitive Conscoiusness Research Summary. website URL:
Accessed 7/22/08 Science Daily "Selective Brain Damage Modulates Human Spirituality, Research Reveals," (Feb. 11, 2010).
http://www.sciencedaily.com/releases/2010/02/100210124757.htm accessed 7/31/13