The condition known as Gulf War syndrome is said to affect 25 percent of Gulf War veterans, and is characterized by memory loss, lack of concentration, fatigue, neuropathic pain and depression. The Defense Department has argued for years that it is not, in fact, a treatable physiological condition, but rather a "form of combat stress." But scientists have just proven the opposite: It's conclusively the result of brain damage due to exposure to sarin nerve gas.