Though it is impossible to know how many veterans are disputing their personality disorder discharges, Vietnam Veterans of America, an advocacy group, with help from the Yale veterans legal clinic, has sued the Defense Department seeking records they say will show that thousands of troops have been unfairly discharged for personality or adjustment disorder since 2001.

“We believe that many of the people who received personality disorder discharges were wrongly diagnosed and that in fact they were suffering from PTSD or traumatic brain injury,” said Thomas Berger, executive director of Vietnam Veterans of America’s health council.

Although the number of personality disorder discharges is small relative to the total number of troops who have served since 2001, Congress was concerned enough about the issue to hold hearings in 2007 after reading reports that troops with post-traumatic stress and other combat-related injuries were being discharged for personality disorder.

The Defense Department then tightened its requirements, partly to ensure that troops who had served in combat zones and had PTSD were not discharged for personality disorder. Personality disorder discharges subsequently declined, to 1,078 in 2010 from 4,264 in 2007, data obtained by Vietnam Veterans of America show.

But the Government Accountability Office said in 2010 that the Defense Department had not proved that it was in full compliance with its rules. And Captain Carlson’s case shows that the military continues to issue personality disorder diagnoses in questionable ways, according to veterans’ advocates and her lawyers, Stephen H. Carpenter Jr. and Daniel C. Russ.

Unlike the soldiers at Madigan, Captain Carlson has not been given a diagnosis of PTSD. But the personality disorder diagnosis could complicate her ability get a medical discharge for a back injury and other problems. Perhaps more significant, the diagnosis will be listed on her discharge papers, which employers typically review when they are considering veterans for a job.