I think that much of your thesis statement is directly contingent on what evidence you have accrued and what you plan to use. Your thesis statement should be enhanced and validated through your use of evidence. It has been my experience that only through a survey and analysis of this evidence that a thesis statement can emerge. Another element that has to be taken into account is what the demands of the task are and what has to be proven. I think that this is of critical importance in terms of being able to articulate a thesis statement. PTSD and how it impacts the lives of soldiers can be a powerful element and consulting the task requirement as well as analysis of your evidence can help to yield a very effective thesis statement.
That depends on your approach to the topic, or if there is a specific question about soldiers with PTSD that you are supposed to address. As for the topic of PTSD and the soldiers now returning from deployment in Afghanistan and Iraq, a thesis statement could look something like this:
American society is witnessing a rapid rise in the rates of PTSD among returning soldiers from Iraq and Afghanistan due to the type of guerrilla warfare and IED attacks faced by those soldiers, and the frustration and stress they experience by being under constant threat of attack by an elusive enemy practicing hit and run tactics.
i believe that you can use the lack of interest of shown by the government to point out the fact that ptsd is not taken being properly treated. that soldiers are actually "mere things" involved in a war.