Post traumatic stress disorder sounds like it has always been in humans?

Probably: Called by different names in medical literature historically: "battle fatigue", "asthenia", "soldiers' heart", "shell shock". All have same factors of proximity, intensity, exposure to stressful events; all have resultant psychological and physical components. There have been gruesome events in the course of human history; no reason to believe that ptsd is a new response-just new understanding.

PTSD: It seems likely that, yes, ptsd has been around since the dawn of man. While the circumstances may have changed, our interpretation of the events that happen to us may cause long-standing and debilitating symptoms associated with ptsd.