U.S. Defense Secretary Robert Gates says U.S. troops no longer have to disclose receiving treatment for combat-related mental health problems when applying for official jobs with security clearances.

Gates said during a visit to an army base in Texas Thursday in the southwestern U.S. that returning soldiers should no longer fear getting help for what doctors call post-traumatic stress disorder.

Gates called the mental illness caused by war an "unseen wound."

He said veterans can now answer "no" to what he calls the "infamous" question 21 on government security clearance applications. The question asks federal employees if they have sought treatment from a mental health professional.

Medical experts say many troops who fought in Iran and Afghanistan fail to get help for war-related mental illness fearing it could cost them a job.

Gates also said Thursday he is "appalled" at a video showing poor living conditions for soldiers at Fort Bragg, in the state of North Carolina. The video includes pictures of sewage in a barracks, peeling paint, and broken toilets. Gates said soldiers should not have to live in squalor. He said every commander has the duty to ensure decent living conditions for U.S. troops.

Some infornation for this report provided by Reuters, AFP and AP.