Study leader Ed Diener, an emeritus professor of psychology at the University of Illinois who is also a senior scientist with the Gallup Organization, analyzed data from the 2005-2009 Gallup World Poll, a survey of people in more than 150 countries.
"Circumstances predict religiousness," Diener says in a statement. "Difficult circumstances lead more strongly to people being religious and in religious societies and in difficult circumstances, religious people are happier than non-religious people. But in non-religious societies or more benign societies where many people's needs are met, religious people aren't happier -- everyone's happier."
The study, published in the Journal of Personality and Social Psychology, finds religious affiliation appears to boost happiness and wellbeing in societies that fail to provide adequate food, jobs, healthcare, security and educational opportunities.
The same trends can be seen in individual U.S. states, with more people reporting they are religious in poorer states with fewer social supports, Diener says.
Mississippi reports the highest (88 percent) and Vermont the lowest (44 percent) portion of people reporting that religion is an important part of their daily life, Diener says. Globally, 68 percent of people surveyed said they were religious.