By JOHN CHRISTOFFERSENNEW HAVEN, Conn. (AP) â¿¿ The military has failed to correct the wrongful discharges of thousands of Vietnam veterans suffering from post-traumatic stress disorder, an advocacy group says in a federal lawsuit. Vietnam Veterans of America on Monday joined a proposed class action lawsuit in Hartford against the Army, Navy and Air Force. The lawsuit, filed last year by a veteran, says the Vietnam veterans suffered PTSD before it was recognized and were discharged under other-than-honorable conditions that made them ineligible for disability compensation and other benefits. The lawsuit says the military has refused to review or upgrade the discharge statuses of thousands of Vietnam War-era veterans with service-related PTSD. "People did not understand PTSD during the Vietnam era," said John Rowan, national president of Vietnam Veterans of America. "Now that we do, these service members must not be denied the recognition and benefits they long ago earned." The U.S. attorney's office, which is representing the military in the lawsuit, said it's reviewing the matter and will respond in court. A Department of Defense spokeswoman said the agency is committed to addressing concerns related to PTSD and has taken numerous steps, including conducting PTSD assessments of service members at military treatment facilities. The initial lawsuit was filed by Vietnam veteran John Shepherd, of New Haven, who says he was diagnosed with PTSD in 2004 but has been repeatedly denied a discharge upgrade. Shepherd and the VVA, which has about 65,000 members, are represented by Yale Law School students who work at a veterans legal services clinic. The students say since 2003 the Army has approved fewer than 2 percent of applications by Vietnam veterans claiming PTSD to upgrade discharges, compared to 46 percent for all discharge upgrade applications in recent years. Some of the veterans denied had at least one medal or had a PTSD diagnosis from the Department of Veterans Affairs, according to the students, who analyzed the Army data.