There’s something in the blood in Mystic Falls! Paul Wesley (Stefan) tells TV Guide that the more his character feasts on the vital fluid, the more he’s pulled into his old Ripper ways.
"He gets deeper and deeper and the blood starts carrying him away,” Wesley says. "He commits to that lifestyle because the blood starts turning him into someone else."
“If I do this, if I give in, there’s no going back,” Stefan told Amber in Season 1, Episode 19, “Miss Mystic Falls,” before biting into her neck. While the younger Salvatore was able to come back after that one taste, who knows what a summer’s worth of bloodsucking will mean for him.
Somebody needs to give this guy a sanguine intervention stat!
Source: TV Guide