Supporters of Army Sgt. Bowe Bergdahl hold up a poster of him during a rally in front of the White House on Tuesday. A new Washington Post story published Wednesday reports that he previously joined the Coast Guard, but was discharged within weeks. AFP PHOTO/Saul LOEBSAUL LOEB/AFP/Getty Images

Three years before Army. Sgt. Bowe Bergdahl disappeared from his small military outpost in eastern Afghanistan, he enlisted in the Coast Guard and left after 26 days due to psychological reasons, according to a new Washington Post story published Wednesday.

The story reports exclusively that Bergdahl received an “uncharacterized discharge,” which applies to individuals who are released from duty before completing 180 days of service. No reason was specified, but friends of Bergdahl told The Post that they were worried about his emotional health at the time.

Bergdahl’s fleeting time in the Coast Guard had not been reported previously. It raises anew questions about how he later was approved to join the Army and deployed with an infantry unit to a volatile area of eastern Afghanistan in 2009.

Bergdahl’s past in the Coast Guard also underscores how little is known about the only U.S. soldier who was held by the Taliban. He was recovered May 31 by U.S. Special Forces as part of a swap in which the United States released five Taliban officials. The move has infuriated some lawmakers and some current and retired U.S. soldiers, who have described Bergdahl as a deserter and say he should not have been swapped for senior Taliban.