… Have you looked?
There is an abundance of poems written by people who suffer from PTSD, especially veterans.
Here’s one that I enjoyed and can relate to:
It is a pretty “general” poem, and so may not be exactly what you’re looking for. It talks in particular about how isolating PTSD can be, and how it can make you feel numb or detached from your emotions and the people around you.
Most poems I was able to find about PTSD refer specifically to being in combat or to being raped, with the latter seeming much more abundant. My PTSD is neither combat nor rape related, so it is hard for me, personally, to relate to those. The feelings and symptoms are the same, or very similar, but the initial trauma is different.
Here is another poem that addresses this, but does not talk about the symptoms of PTSD directly:
[ tw: poverty, gang violence, murder, graphic descriptions of gun violence ]
tl;dr : this probably doesn’t answer your question, so do your own darn homework, but here are a couple cool videos anyway.