The Congregation at Duke University Chapel

Value of our Faith from Empirical Studies

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Can we learn anything about the value of our faith from empirical studies of religion and health?

presentation at Adult Forum by
Dan G Blazer MD, PhD
JP Gibbons Professor Emeritus of Psychiatry and Behavioral Sciences
Duke University School of Medicine
April 3, 2016

Conflict of Interest


What I will and will not discuss

  • I will discuss three empirical studies from the extant literature which explore the association between religion/spirituality and health. This is an important discussion. There has been an explosion over the past 25 years of such studies.
  • I will not discuss the association between neurphysiological function (except tangentially in the imaging study) as reviewed in Andrew Newberg’s Why God Won’t Go Away or spiritual experiences as related to near death as popularized recently by Eben Alexander’s Proof of Heaven.

Why are we even having this discussion?

  • We live in an age where we value the empirical, that is, what we can see and verify.
  • We live in an age when we want tangible benefits for our efforts (Did I get my money’s worth when I bought that Honda? What do I get out of my beliefs or practices?)

Why are we even having this discussion?

  • We live in an age where some have asserted a clear association between religious (primarily Christian) beliefs and health beyond the health habits of some religious groups such as the Seventh Day Adventists. And others vehemently oppose such assertions.
  • We live in an age where we believe that good health is a right, an age where we have much hope for many different pathways to good health.

graph of increasing number of articles published on religion/spirituality and health

Some Definitions

  • Empirical - "capable of being proved or disproved by observation or experimentation."
  • Religion/spirituality - Some demarcate religion from spirituality, suggesting that religion implies a particular faith tradition which includes acceptance of a metaphysical or supernatural reality, whereas spirituality does not and is not bound to any particular religious tradition. The boundaries are blurred and depend on definitions from specific studies. For the studies I review, operational definitions (it means what it says) are used as probes for religion/spirituality.

A Note

  • When we discuss body/mind/brain, especially within the context of religion/spirituality, we traverse a wide range of disciplines – philosophy, theology, perspectives from many faith traditions, neuroscience, alternative approaches to traditional medicine, and individual case studies/reports as well as empirical studies.
  • Each of these methods contributes to the conversation. Empirical studies are valued because they are based on observations that can be replicated (from brain scans to epidemiologic studies). Yet they represent only one approach to understanding a complex yet deeply felt aspect of our health.

Why the Explosion of Empirical Studies of Religion/Spirituality and Health?

  • A long history of conflict with little empirical study (though empirical study will not answer many hotly contested questions, such as "Does God exist?" or "Is religious belief a delusion?")
  • For example, Freud stated that religion represents a "defense against helplessness" and concluded that "surely [such] infantilism is destined to be surmounted." ("The Future of an Illusion" as described in Pargament and Lomax, 2013.)
  • In other words, empirical clinical evidence (case studies), in his view, do not support the value of religion/spirituality.

Rapprochement Begins to Replace Conflict but Scholarship was Not Empirical

  • "aggression; ambivalence; the constant clash between love and hate;…A number of devout [religious] scholars are busy restudying these problems with the upmost care…and profound faith. The aid and insight which psychoanalysis provides them proves invaluable... to the...development of religious scholarship and the deeper understanding of the faith." Zilboorg (1962)

Entering a Stage of Empirical Study

  • "The contention that religion as an institution has been instrumental in fostering general well-being, creativity, honesty, liberalism, and other qualities is not supported by empirical data…there are no scientific studies which show that religion is capable of serving mental health."
  • This statement was written when such studies begin their quite dramatic rise.

Why the Explosion of Empirical Studies of Religion/Spirituality and Health?

  • We have become increasingly empirical in building an "evidence base" for the study and practice of medicine and psychiatry/psychology.
  • So questions such as, "Is regular attendance at religious gatherings associated with better health and longer life?" or "Is a spiritually enhanced psychotherapy as efficacious or more so than a non-enhanced therapy?" can be potentially answered IF we accept the assessments as adequate probes.

Three studies

  1. Participation (attendance at services, participation in activities such as prayer groups or service projects). Haywood, et al, 2012
  2. Salience (how important is religion/spirituality to you). Miller et al, 2012, Miller et al, 2013
  3. Interventional Intercessory prayer Benson et al, 2005


Participation: Haywood et al, AJGP, 2012

Cross-sectional analysis of clinical and interview data.
Four hundred seventy-six psychiatric patients with a current episode of unipolar major depression, and 167 nondepressed comparison subjects, ages 58 years or older (mean = 70 years, SD = 7).
Presence of depression was related to less frequent worship attendance, more frequent private religious practice, and moderate subjective religiosity. These results were only partially explained by effects of social support and stress buffering.

Participation: Haywood et al, 2012


  • This study is typical and straight forward in terms of a probe (How often do you attend religious services?).
  • The subjects were older adults
  • The setting was the Southern United States.
  • The study is cross-sectional



  • Studies of participation are the most easy to evaluate (you see what you get – difficult to honestly overgeneralize).
  • Always evaluate on the ability to control on potential confounders, especially health and functional status.
  • Such studies are much more solid if longitudinal in design
  • Studies of participation may reflect a range of characteristics about religion/spirituality.
    • Could reflect adherence and devotion to a particular faith tradition
    • Could reflect social pressures in some settings
    • Could reflect the value of social support that derives from religious communities
    • Could reflect lifelong habits
    • etc.




114 adult offspring (mean age 29) of depressed and non-depressed parents. 10 year follow-up. Religiosity measure included personal importance of religion or spirituality, frequency of attendance and religious affiliation.

Probes: "How important to you is religion or spirituality?"; "How often, if at all, do you attend church, synagogue, or other religious or spiritual services (from never to once a week or more)?"; and "How would you describe your current religious belief? Is there a particular denomination or religious organization that you are a part of?"

Sex, age, history of depression controlled.

85% Catholic, 15% Protestant. (other religious groups excluded). Often the case in this predominantly Christian country.

Outcome: Major depression at 20 year follow-up. Offspring that reported at year 10 that R/S was highly important had about 1/4 the risk of experiencing depression between years 10 and 20. Religious attendance and denomination did not predict outcome

Salience: Miller et al, 2012


The probe "How important is R/S?" is a valuable one despite its apparent simplicity and subjectivity. Consider the powerful predictive value of someone's subjective rating of their health as a predictor of mortality even in highly controlled studies. This is the same probe as used by the Gallop Poll to determine the pulse of the nation (54% felt religion to be very important).

Many US studies, such as this one, are confined to Christian groups (and may be characterized as Catholic, mainline, and evangelical though these boundaries are increasingly blurred).

In studies of older adults, religious attendance is more important than salience. (Haywood)

Salience: Miller et al, 2012


Younger generations are characterized as less active in structured religious activities but nevertheless continuing to view their spirituality as important.

Smith and Snell characterized the R/S of many adolescents and young adults in the US today as "moral therapeutic deism". Moral - being oriented to being "good and nice", therapeutic as being primarily concerned with one's own happiness, and deism as a view of God as distant and not normally involved in one's life. (Smith and Snell, 2009).

Therefore the distinction between Catholics and Protestants is probably much less today than in the past (Durkheim [1897] which I will discuss below)

Salience: Miller et al, 2012


  • Much more complex approaches to salience have been developed (multi-item scales).
  • Most probes of salience have attempted to be generic, cutting across all faith traditions. But does this reflect reality?
    • Salience for evangelical Christians
    • Salience for orthodox Jews
    • Salience for those practicing Islam
    • Salience for Buddhism
    • Salience for “new age” approaches to religion/spirituality (e.g. positive psychology and the human potential movement)

Salience: Miller et al, 2013 (2)


  • Studied same sample described above.
  • As noted above, religious or spiritual importance and church attendance were assessed. In this study, cortical thickness was measured on anatomical images of the brain acquired with MRI.
  • Salience but not frequency of attendance was associated with thicker cortices in the L and R parietal and occipital regions, the mesial frontal lobe of the R hemisphere, and the cuneus and precuneus in the left hemisphere independent of familial risk.

Salience: Miller et al, 2013


  • The effects of importance on cortical thickness were stronger in the high risk compared to the low risk group particularly along the mesial wall of the L hemisphere.
  • A thinner cortex at mesial wall of the L hemisphere was associated with a familial risk of developing depressive illness.

functional images of human brains

Salience: Miller et al, 2013


  • They conclude that associations between importance and cortical thickness is associated with religious beliefs and experiences, not overt behaviors.
  • Previous studies have shown an association between increased blood flow in various subregions of the prefrontal and parietal cortex and increased intensity of religious experience (such as meditation).
  • Perhaps religious salience is a protective factor against depression based in part on cortical thickness in specified regions.

Salience: Miller et al, 2013


  • Cautions in over interpretation
    • This study represents a new wave of studies that explore mechanisms of the association of salience with mental health.
    • Religious salience is probably the most difficult factor to assess among the variables that have typically been studied empirically. Even so, the single probe, "How important is R/S to you?" is a valuable one.
    • Does raise the question of whether religion/spirituality can be reduced to specific regions of the brain or whether such "feelings" supervene upon the entire substrate of the brain. Such a question does NOT assume that brain and soul are separate (Descartes Error). Almost all now recognize the embodied nature of "souls" and salience.


Intervention: Benson et al, Am Heat J, 2006


Patients in 6 US hospitals were randomly assigned to one of three groups:

  1. Intercessory prayer who knew they were being prayed for. (n = 601)
  2. Intercessory prayer but did not know they were being prayed for or not (n= 604)
  3. No intercessory prayer but did not know whether they were being prayed for or not (597)

Over 85% again were either Catholic or Protestant but some were Jewish or other. All agreed by informed consent.

Intervention: Benson et al, Am Heat J, 2006


  • Outcome any adverse event from coronary bypass graft (CABG)
  • Intervention - subjects were prayed for (if prayed for in the study) for 14 consecutive days, beginning the day before the CABG. Intercessory prayer is usually group and intentional prayer (such as a regular prayer group). Yet there are many other types of prayer that might be initiated.
  • Results 52% experienced some adverse event (included a variety of events from hypertension to mortality) over the 30 days following the bypass surgery. Intercessory prayer itself had no effect on whether complications occurred. Patients who were certain that intercessors would pray had a higher rate of complications than patients who were uncertain (yet CI of odds close to including 1.00).

Intervention: Benson et al, Am Heat J, 2006


  • Intercessors did not know the names of the subjects for whom they were praying (first name and first initial of last name and an anonymous site code were placed on the prayer lists for groups where intercessory prayer was used. No connection between the intercessors and the subjects. Such impersonal prayers are not typical.
  • The prayer was prescribed "for a successful surgery with a quick, healthy recovery and no complications" in addition to their usual prayer.
  • Intercessors from 3 Christian groups, 2 Catholic and one Protestant (could not find other groups to participate as the study was multiyear).

Intervention: Benson et al, Am Heat J, 2006


  • Intercessors received limited to no information about the subjects before, during or after the trial, including information about who else may be praying for the subject.
  • Subjects could pray themselves (and probably did). Family, friends and member of their faith community also prayed.
  • At enrollment, most subjects expected to receive prayers from others regardless of their participation in the study. (according to the authors, could be exposure to a large amount of non-study prayer). In other words, such studies are almost impossible to control empirically.
  • The results of this study are not likely to convince persons who believe in prayer that such prayers are not effective.



  • Measures of religion spirituality fall along a spectrum. Virtually all depend upon self report. Nevertheless, at one end of the spectrum are the measures which are more quantifiable (religious service attendance) and at the other end inquires such as, “How important is religion/spirituality to you?”.
  • All of these measures may have value. Yet they must be taken at face value and we cannot read more into the responses than what we observe.



  • The age of the respondent is a critical control variable given the changes in western society over the past 50 years in terms of views of religion/spirituality
    • Older adults are more likely to equate R/S with active participation, either private or public (service attendance, scripture reading, regular prayer)
    • Younger adults are more likely to equate R/S with an individualistic and subjective perspective which may not be easily equated with observable behaviors.



  • Studies of spiritual intervention must be thought through in terms of generalizability.
    • Studies of the effectiveness of prayer would be almost impossible to perform.
    • Studies of intervention using a "spiritually enhanced" type of therapy, if controlled well, could be of definite value. Yet they would need to be very carefully designed.



  • Must recognize that in some, perhaps most, faith traditions, there is no promise that faithfulness to that tradition improves health and relieves suffering.
    • The martyrs of many faith traditions
    • The apostle Paul’s thorn in the flesh
    • The tortured life of Job

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