Judging my the comments to my last post, there seems to be some interest in the "religion as a basic human need" question, so I think this is worth spending some time on. Besides, I find the question of what leads people to religion and maintains their blind devotion to it a fascinating topic. This will be the first in a series of posts discussing the appeal of religion from a psychological perspective.
There are many psychological theories that consider human needs, and they run the gamut from instinctual drives (Freud) to more aspirational models (Maslow). Influential in psychology and probably even more so in other fields, Maslow posited a hierarchy of needs in which higher-order needs become relevant only after lower-order needs are met. He believed that most people will never satisfy their higher-order needs but that attention turns to these needs once lower-level needs are met. Starting from the bottom and moving up, these needs include (1) physiological needs (e.g., food/water, sleep, etc.); (2) safety needs (e.g., sense of security, stability, etc.); (3) love needs (e.g., belongingness to groups, family, etc.); (4) esteem needs (e.g., self-esteem and praise/recognition from others); and (5) self-actualization (i.e., reaching one's full potential).
This theory has been criticized on many grounds, but the most important criticism involves its limited applicability to western, mainstream, middle-to-upper class individuals. Nevertheless, it does appear that once physiological needs are out of the way, many people appear to meet the remaining needs through religion.