I have this theory to explain how Miles ended up with a episode reset by the time of the next episode. So we do not see lingering effects of Hard Time. Look PTSD just doesn't disappear overnight or over a week long sessions of therapy. It takes years.
My theory is that Bashir doing brain scans of how the memories were placed in O'Brian's brain reminded him of some Vulcan memory erasure or something. So gets a well established or practiced Vulcan who can come in and sift through Miles brain for those artifical memories. Take them out like deleting files.
It is successful, O'Brian is monitored for a bit with perhaps a follow up.
Now would O'Brian woukd take this procedure? After all it is artifical, it never happened but he thinks he did.
DS9 - Hard Time review
DS9 - Hard Time review
I got nothing to say here.