A growing body of evidence suggests religion can be good medicine. New findings seem to emerge every other month: regular churchgoers live longer. Prayer helps heart patients. A strong faith can help people cope with depression, drug abuse -- even cancer.
The research represents a breach in the wall that usually separates religion and medicine.
The studies of the past decade have grabbed the attention of scholars at the world's most respected academic institutions, as well as doctors who are increasingly prescribing spirituality as a part of the healing process.
"Doctors can't just throw this stuff out," said Dr. Harold G. Koenig, director of Duke University's Center for the Study of Religion/Spirituality and Health. "They have to confront it. They can't just say religion is irrelevant to health. It is relevant."
The majority of research linking religion and health focuses not on whether a supreme being is at work but on how believing in God or belonging to a religious community influences physical and emotional well-being.
A Georgetown University professor reviewed 212 such studies and found that three-fourths showed religious commitment had a positive effect on health.
The news isn't surprising to chaplains, spiritual counselors and staff at Catholic and Jewish hospitals who've always incorporated spirituality into patient care.
"We've known it all along," said Steve Roberts, co-director of the Samaritan Counseling and Education Center in Colorado Springs, which offers spiritual therapy to individuals and churches. "We just haven't had the research."
A number of factors have fueled the research: doctors recognize that faith is central to the lives of many patients; a generation of baby-boomers is exploring its faith anew; there's a growing interest in alternative therapies and holistic healing -- which takes into account body, mind and spirit.
At Duke, Dr. Koenig and his colleagues don't try to establish the validity of faith healing; they investigate the healing or therapeutic power of people's religious faith. Some of their findings:
People who attend church regularly are hospitalized less often than people who never or rarely participate in church services.
People who pray and read the Bible have lower blood pressure.
People who attend religious services have stronger immune systems than their less-religious counterparts. Much of Mr. Koenig's research shows health benefits increase along with the level of one's religious involvement. Not only is someone who's active in church connected to a community that serves as an emotional support system, but it can come in handy for practical matters such as getting rides to the doctor.
Another commonly cited reason for religion's health benefits is that religious people tend to avoid alcohol and drug abuse, risky sexual behavior and other bad habits.
A study conducted in part by a University of Colorado professor attempted to take those kind of factors into consideration when weighing religion's impact on health.
The researchers used data from a national survey of more than 28,000 people that measured income, age and church attendance, among other things. The research team focused on more than 2,000 people who died between 1987 and 1995.
Their study, published in May in the journal Demography, found that those who go to church once or more each week live about seven more years than those who never attend.
A handful of controversial studies have looked at the potential impact of when a person or group prays for someone who is ill. At least two studies showed such prayer had no effect.
But others reached a different conclusion. A study published in October that looked at 990 patients admitted to a Kansas City coronary-care unit found that patients who were prayed for (without their knowledge) suffered 10 percent fewer complications than those who were not prayed for. The people who prayed came from a variety of Christian traditions.
How do you explain such a conclusion?
"The simple answer is God answers prayers," said Dr. William S. Harris, the study's lead author and a heart researcher at the Mid American Heart Institute, where the study was conducted.
Larry Dossey, executive editor of Alternative Therapies in Health and Medicine, said the real value in the recent flurry of research is the findings that faith has a positive effect -- even though everything isn't explained.
"Often in medicine, we know that something is efficient before we understand how it works," he said, citing aspirin and penicillin.
Mr. Dossey, like other researchers, hasn't found that any one religion works better than another when it comes to health matters. Because of that, he's received angry letters from people accusing him of heresy and blasphemy because his research doesn't affirm their particular faiths.
Mr. Dossey believes the power of prayer is in "plain old love, compassion and caring -- a deep sense of involvement with who it is you're praying for."
The question of whether God answers prayers is where science reaches its limit, he said.
"We're obsessed with wanting to explain things rationally in our culture," Mr. Dossey said. "But sometimes science bumps into obstructions that have persisted for centuries."