03/28/2011 at 01:00 AM EDT
Libba Phillips' five-year search for her sister inspired Bringing Ashley Home, airing March 20 on Lifetime Movie Network.
Watching a movie about her five-year quest to find her troubled sister Ashley was "surreal," says Phillips, 43, of Bringing Ashley Home, which was prompted by PEOPLE's 2008 story about her. "I had to stop the movie a few times; it evoked such emotion." Phillips helps others search for missing loved ones with drug problems or mental illness through her nonprofit organization Outpost for Hope. But Ashley, who's been diagnosed with bipolar disorder, disappeared yet again in May 2008. "There's a lot I can't change about my sister," says Phillips, "but this movie was an answered prayer."