We'll have to wait for the facts, but let's not pretend that the "terrorist option" isn't at least plausible. However, in these kinds of cases, things that are reported as fact often turn out to be untrue. What the Houston Chronicle site is reporting is that the guy not only has a Middle Eastern name, but he is a lifelong Muslim. They also report that he "may" have made some incendiary chatroom comments. We'll see, but I think it's wise to withhold judgement until more is revealed. He survived the incident so I would expect much will be learned. I very much doubt one can cite PTSD as this guy was trained as a military psychiatrist and was unlikely to have seen much, if any, combat.