No idea.
There wasn’t any one thing, exactly*. All I know is that every time I came back home I was getting wilder and wilder, and that I was diagnosed with PTSD about a year before *I* thought I had any kind of problem. Did I have panic attacks & nightmares & shit during that year? Sure. But so did everyone I worked with. It was just considered a cost of doing business. Like hurting everywhere. Something to make fun of, and shrug off.
In retrospect? It was actually the getting wilder that was the biggest “tell” that something was wrong. Because my normal had reset / was resetting... emotions were blunting... and I was requiring bigger and bigger “oomph” to enjoy myself/feel anything, or blow off steam.
The “not exactly” part above? It’s something I’ve thought about a lot... and the only event that stands out as the first time everything changed? Was the first time I was in the field. Not in training, but actually working. Everything just clicked. Snapped into place. I felt alive. Like for the very first time. Like I had found my place in the world, where I was meant to be, where I belonged, where I was right... and it was f*cking amazing.
Coming back after that? Was just surreal. Like the world had lost its color, and I lost my place in the world.
Regret, remorse, pain, rage, loss, betrayal, sadness, fear... sure. Shrug. No shortage of those in life. But that wasn’t when everything changed.