Jacob's Ladder: Is It ALL in His Head?

Okay, cinephiles! Just finished re-watching Jacob's Ladder (1990), and man, does that movie still mess with me. I keep coming back to this really simple, maybe obvious, question: How much of it is real? Like, is it just PTSD/shellshock at a truly horrifying level, or is there something genuinely supernatural going on? I'm leaning towards the former, honestly, and here's why. Think about the cinematography. It's all disorienting dutch angles and harsh lighting, especially in the hospital scenes and when those demon-thingies are crawling around. But it's consistent. It's Jacob's perception that's warped. If it were truly demons, wouldn't at least one other person notice something weird? Even Jezzie seems more concerned with his mental state than, you know, winged monstrosities. Also, the 'Ladder' itself, as explained by Louis in the hospital, points directly towards acceptance and letting go of his trauma. It's all about him processing what he went through, right? Then there's the whole 'Ladder' analogy. Louis explains it so clearly -- that his clinging to guilt and fear is what's holding him back from moving on to... well, whatever comes next. The moments where he seems to break through, like reuniting with his son Gabe at the end, feel more like moments of clarity breaking through the fog of his trauma than some kind of actual passage to an afterlife. Which, okay, maybe it's BOTH. But I think focusing on the psychological aspect is crucial to understanding the core of the film. So, yeah, that's my messy take. It's an awesome movie that keeps me thinking long afterward. Probably not watching it again before bed anytime soon lol... What are your theories? Am I completely off base?