I was diagnosed with PTSD in 1990 after I was hit by a car. It took me eight years to acknowledge that I had a mental illness. It took me a lot more years after that to go for treatment.
My treatment of choice was not marijuana. At that time, it was alcohol. It wasn't because I wanted to get high or anything like that. It was just because I wanted to bury the thoughts and just pretend I didn't exist. That, from my experience in working with many, many people with PTSD, is often the root cause of being on marijuana or anything else. It's that they want to hide their feelings just for a little while and just escape for the time being. There are a lot of things at play, I believe. That's the way I felt about it.