Peter's Facebook friends knew something was wrong months before he had a manic episode. He had been posting about expensive shopping trips and name-dropping celebrities he claimed to have partied with—seemingly out of character for the 26-year-old former dental student from Atlanta. When Peter (not his real name) ran away from home in April 2013, he unleashed a flurry of paranoid, all-caps status updates saying his family was out to get him. Meanwhile his sisters left messages on his Facebook wall begging him to come home.