Quitting Twitter is always a bad sign. As we told you earlier today, Demi Lovato has left her gig opening for the Jonas Brothers and has checked into rehab. But for what? A source says that Demi is battling an eating disorder and that she has issues with cutting. Which makes sense since Demi had the blogosphere all atwitter after repeatedly appearing in public with mighty yikes-worthy slashes on her inner wrists. We hoped she just has a ferocious cat—not a cutting problem—but it appears that isn't the case. [People, WWTDD] After the jump, more stars we suspect are cutters.