Apostates
1Tim 4:1 Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons
By "latter times" he was referring to days since the New Covenant was in effect - namely from Acts 2 to the present. Thus Paul was writing in the "latter times". John also refers to this same thing saying, "Little children, it is the last hour; and as you have heard that the Antichrist is coming, even now many antichrists have come, by which we know that it is the last hour. They went out from us, but they were not of us; for if they had been of us, they would have continued with us; but they went out that they might be made manifest, that none of them were of us." 1John 2:18
People depart from the faith by deciding to follow the teachings of deceiving spirits and doctrines of demons. Most recently is the media's obsession with the "Gospel of Judas", a gnostic gospel rejected as heresy by the early Christians. The reason why some believe that gospel, which has little basis in actual historic facts, is simply because they prefer what it says over that of the other gospels. There have been many such deceitful teachings both then and now. In fact they serve a useful purpose in purging false Christians out of the Christian community.