Why depression a universal symptom of post traumatic stress disorder?

PTSD depresion: Wrong! ptsd not always accompanied by depression, though depression frequently comes along or may precede or follows. People with already a mental issue suffers more risk of ptsd after a trauma. Drug users also suffers more ptsd after trauma, as they have a mental issue preceding the trauma.

It isn't universal.: I agree with dr. Dao. Someone who has suffered from ptsd is 7 x more likely to develop depression at some time over the general population. Depression and ptsd often co-occur. It is not universal, but when they coexist it is most often atypical depression. Sxs include exhaustion, amotivation, hypersomnia, increased appetite, weight gain & drop in sex drive.