The proposed research takes a major step towards rectifying two profound deficits in research on spirituality and health: (1) the absence of a plausible causal mechanism by which spirituality can directly affect physical and mental health; and (2) the relative dearth of research on spiritual beliefs. It has been said that religion has three distinct aspects: believing, behaving and belonging. Beliefs should become the major focus of research on spirituality and health for two vital reasons. First, religions are fundamentally belief systems. Second, beliefs, unlike affiliation or behavior, are contained within the brain. Since they are stored and operate in the brain, they provide a plausible mechanism by which spirituality can directly affect health, as explained by Evolutionary Threat Assessment Systems (ETAS) Theory. The project will analyze data from the 2010 Baylor Religious Survey to test ETAS Theory-derived predictions about the association of spiritual beliefs with negative affect (psychiatric symptoms) and positive affect (happiness and optimism). These include hypotheses about belief in the Devil/Satan, life-after-death, God and guardian angels, trust in people, and meaning and purpose in life. The project will yield at least six peer-reviewed articles and several conference presentations; HCC will publicize the results via mainstream, online, and social media. The findings should spur further studies on spiritual beliefs and mental and physical health, and foster future research on the brain mechanisms by which they do so.