There was an eerie familiarity to the headlines that greeted North Texans on Thursday morning.A soldier on Fort Hood Army base had reportedly gone on a rampage Wednesday afternoon, killing or wounding 19 people before turning the gun on himself.In the immediate aftermath of such tragedies, in the scramble for facts and the search for explanations, we often find ourselves with more questions than answers.But with the facts now available, a narrative all too common among our nation’s servicemen and women is quickly beginning to take shape.During a press conference after the shooting, Lt. Gen. Mark Milley, the commanding officer at the military installation outside of Kileen, told reporters that the alleged gunman, identified as Spec. Ivan Lopez, had recently sought help for depression, anxiety and sleep disturbance.These are symptoms commonly associated with post-traumatic stress, a condition that afflicts between 7 to 8 percent of the population at some point in their lives, according to the U.S. Department of Veteran’s Affairs. PTS has received increased public attention in recent years because of its inordinate effect on veterans returning from the wars in Iraq and Afghanistan.As many as 11 percent of Afghanistan war veterans and a shocking 20 percent of Iraq war veterans are reportedly affected by the condition. Not to mention the impact on military families and communities. Milley said Lopez, who spent four months in Iraq at the end of 2011, had recently undergone a psychiatric evaluation but had not officially been diagnosed with PTS at the time of the shooting. Milley did confirm that Lopez had self-reported a traumatic brain injury, which studies have linked to PTS.But in a previously scheduled hearing before the Senate Armed Services Committee in Washington Thursday morning, Army Secretary John McHugh told committee members that while Lopez had served two deployments, including his stint in Iraq, Army records “show no wounds, no involvement — direct involvement in combat … or any injury that might lead us to further investigate a battle-related TBI or such.” McHugh added that Lopez had been “fully examined” last month, and “had no indication on the record of that examination that there was any sign of likely violence, either to himself or to other, no suicidal ideation.”Clearly, something was missed. Physical injury is common among those suffering from PTS, but it is not a prerequisite. It’s possible that Lopez’s exposure to situations he found difficult, whether in the waning days of the war in Iraq or elsewhere, could have been the catalyst for or exacerbated the deterioration of his mental state. (A study released this week found that as many as one in five military suffer from some form of mental illness before enlistment, raising questions about screening procedures.) And while he was undergoing treatment, questions about the adequacy of his care demand answers. The military has been rightly criticized in the past for its failure to properly diagnose, treat and de-stigmatize mental health issues resulting from military service, which have reportedly led to a record number of suicides in the last several years. In response, the Army and the National Institutes of Mental Health started a massive research initiative in 2009, seeking to better prevent violence and more effectively treat post-traumatic stress.But incidents like Wednesday’s shooting remind us that this work is only just begun. Military communities around the country are strong and resilient, even as they endure a disproportionate amount of hardship and loss. But there is something profoundly sad when such a tragedy is inflicted at the hands of another soldier, and most especially when there are reasons to believe it might have been prevented. In the coming weeks, the military will try to uncover any relationship between Lopez’s mental condition and his military service.It will try to determine if there was more it could have done to prevent the rampage and more that might be done to prevent future incidents. But every answer is likely to raise a new question, as the nation wades through its second tragic, mass shooting at Fort Hood in the last five years.