In one of the books on prayers I read about medical schools in US. In 1990, 3 out of 125 medical schools have courses where spirituality was addressed. The no went upto 90 in 2008 in which spiritual lessons were given to correlated spirituality and health. The findings are that the people who practice live longer than those who do not practice it. they have lower incidence of all major diseases.
I belong to India where spirituality is practiced from the word go. (more than 10 thousand years as pe