Although I don't have time to fully develop this topic right now, I wanted to throw out a brief paragraph on what I've been thinking about recently.  I just read this excellent article on falling away from the faith in Mission Frontiers magazine:

"Great is Thy Faithfulness": Some Reflections on the Loss of Faith by Ruth Tucker

Here's an excerpt that blew up some of my presuppositions:

Common Myths
In my research for Walking Away from Faith, I identified five common myths about people who lose their faith. Here is a list ready-made for challenge, including additions and deletions:

1. Those who lose faith are rebellious and angry.
2. Those who lose faith can be argued back.
3. Those with serious doubts should go to Bible college or seminary.
4. Those who walk away from faith do so to live a promiscuous lifestyle.
5. Those who lose faith were never sincere Christians to begin with.

It is simply not true that leaving the faith is prompted by the kind of rebellion we associate with a teenager who refuses to participate in family outings or church. The stories more often show initial hesitance and anguish and fear of alienating friends and relatives.

That people can be argued back to faith if we use the best apologetics is also false. In fact, many of those who lose their faith do so while seeking to argue others back to faith. These individuals are often enthusiastic and very bright Christians with a high degree of confidence—or as some would say, arrogance.

The notion that Bible colleges and seminaries offer secure protection from doubt and unbelief is not sustained by statistics. In fact, when the environment seeks to curb hard questions and doubt or to marginalize the doubter, such institutions can serve as an incubator for unbelief. The strictest regulations often foster an atmosphere of doubt.

That individuals walk away from faith in order to live a profligate lifestyle is not supported by the literature. Christians must be cautious about pointing the finger. They themselves are prominent among the Enron CEOs and elected officials who hire prostitutes—to say nothing of televangelists and megachurch ministers. It is true that some walk away from faith to feel more comfortable in gay or lesbian relationships. But many testify that they walked away because they could no longer live a lie—that they had tried to hide their unbelief but conscience got the best of them.

That people who walk away from faith were never really sincere Christians is an issue more closely related to theology than to character or sincerity. Theologically, the matter of losing faith is a topic that many people find troubling—especially those who hold fast to a belief in eternal security. From an Arminian perspective, the matter is easier to handle; people who lose their faith need to be re-evangelized and “saved” and brought back into the fold. For Reformed folks, on the other hand, a true experience of saving grace is a matter of God’s election and is something that cannot simply be undone.

Yet, apart from one’s theological perspective, there is surely the appearance of people losing faith—and not just the university student who abandons the faith of earlier years. Even among the most outwardly committed evangelists and ministers there are ones who have served faithfully for many years, only to walk away from it all. The theological implications are important, but it is also critical to consider this matter from a missiological perspective.