From what I have read, panic attacks are caused from a heightened flight or fight (adrenalin) response. When our ancestors lived closer to nature, the extra adrenalin could save their life. However, IMO, traumatic events (and they can just be stress from work, relationships, etc. in addition to a specific event like an accident) cause panic attacks. When I discussed the event from college, I woke up immediately having panic attacks for more than a month. It took me all morning to calm it down. I must have been dreaming about the event for a while after I talked about it. I certainly had obsessive thoughts replaying the event for a while. In college, I just filed that event in back of my mind, for about a month, I thought about it as I was going to sleep but other than that, did not suffer from any ill effects that I remember. I never told anyone about it and it would have been better to talk about it then but I was ashamed of what happened and just moved on with my life. I never had any panic attacks until my 40s. I think the lifetime accumulation of stress took its toll. I started taking sertraline (zoloft), gabapentin and xanax in my 50s for my anxiety. I also have processed a lot of what has happened by discussing it on here and with a therapist (I also am not seeing a therapist right now). I have not had a major panic attack in quite a while. I hope you can find a way to deal with your situation. It does take time to calm the fight or flight response down.