Clay Aiken, a former "American Idol" finalist, is being treated medically for panic attacks.

Aiken says he suffered panic attacks for years and now takes the antidepressant Paxil to control them, ABC News reported. The attacks do not occur while he is on stage.

The attacks are like "the walls are closing in on me and my heart races and I don't understand it," Aiken told ABC's Diane Sawyer in a segment on "Good Morning America."

The final part of Sawyer's three-part interview will air Thursday.