Here is my take:
"Specifically, I argue that (1) atheism needs to be accurately measured as an individual-level exposure variable, with the aim of relating that variable to psychiatric outcomes, (2) there needs to be greater systematic investigation into the influence of atheism on psychiatry as an institution, and (3) the relation of atheism to mental health needs to be explored by examining atheistic theory and its practical application, especially as it relates to the human condition, suffering, and concepts of personhood."
1. Currently, there is no set definition or level of atheism. I believe Dr. Whitley is suggesting the need to categorize the term into sub-groups.
2. In the body of his text, Dr. Whitely explains that there are few studies dealing with atheism and mental health. He suggests further study.
3. Dr. Whitley examines atheistic leader from four countries who brutalized and killed it's own citizens. He is suggesting that further study in relation to atheism/mental health needs to be explored.