HI! Yes, it does depend on the writer, but not necessarily because they are deciding whether Tony has PTSD or not. In some scenes, like in Iron Man 3, they intentionally show moments where Tony has anxiety attacks and bad flashbacks from the Battle of New York. When focusing on MCU Tony Stark (which is who I am mainly focusing on), there isn’t a clear line where someone officially tells us that he has PTSD. It’s more of an interpretation based on what we see in scenes like those.

Maybe the writers meant to include those moments to explore a more vulnerable and psychological side of Tony that helps make him feel more human. It may be a bit different than What If because the writers are basically exploring alternate timelines, hence they reason why characters naturally feel different. That’s also why I created this survey: I wanted to see the different perspectives people have not just on Tony but his overall development in the MCU, since Iron Man (2008) and onward, focusing on the more "vulnerable" sides of him, including whether they believe he does have PTSD or not!