A relative of mine grew up a Christian and became a believer as a child. During his teenage years he committed various forms of sin but not necessarily with regularity. Just occasional this and that. He became a thief with more regularity, stealing money from the wallets of family members plus occasional small time shoplifting. With that his conscience became seared, in his own words. While he was still behaving like this but better than during previous years he was instrumental in motioning me towards faith. So his own faith was not shipwrecked - yet. At one point during pre-college studies he was pressed on the matter of Christianity by other students who sensed his hypocritical walk and he came out a denier. A vague denial but a social one by nature and that shipwrecked his faith. Not in his mind, he was still thinking like previously. But in his heart, the problem was that he didn't bother to repent from what he had said, it was easier to just hang with his sinful buddies and have no witness in himself. It took several years of backsliding before his walk produced that act of denial though. Not a gradual descent either, more like back and forth without true repentance. I was in bible school when that happened and at one point he wanted prayer and I cast a demon out of him and he confessed some kind of sexual perversion. I'm not sure if he came back to the faith there and then or if he was still merely thinking in line with Christianity but it didn't take long before he was seeking God, including to get out of his problems with sin and to have his conscience restored, which he eventually succeded with.