People frequently ask me why they have "out of the blue" anxiety. They'll just wake up in the middle of the night or in the morning and have a feeling of dread, which has no real reference to anything going on in their life at the time. Sometimes, not always, these episodes have to do with a history of trauma. A trauma is anything that has occurred to a person in their life that was emotionally overwhelming to such an extent that the person wants or needs to try to remove themselves by thinking "this can't be happening". The mind simply refuses to absorb what is happening because it is unthinkable. When that happens, there can be a kind of "hole" in our memory where the experience used to be; all that is left is a feeling of fear. That becomes a problem when something reminds us of that experience. The reminder may be obvious or not. Popular depictions of post-traumatic stress have familiarized us with the classic examples of the obvious. A war veteran is walking down a street when a car backfires, and he dives for the bushes thinking he's being shot at. The "reminder" puts him in the state of mind he was in when the trauma occurred. Usually, though, the reminders are much more subtle and much more difficult to connect to their origin in trauma. For example, a man has an argument with his wife, and finds himself having a panic attack. Thinking about it later, he finds himself thinking about the fights his parents used to have prior to their divorce in his childhood, and he realizes that his children (who he had feared might be listening to him and his wife) are about the same age as he was when his parents divorced. Just realizing this sort of connection helps, but it doesn't always eliminate the susceptibility to anxiety and panic. The mind seems to get stuck on these events and resist change, because the "learning" that occurred with the trauma is life or death in some sense. You can tell people that their chances of getting hit by lightning is only one in eight million, but if you are talking to a person who has been hit once by lightning, he or she says "yeah, I know. I'm that one. I'll be the one every time!" Talking with a therapist about such instances can help. There's no way to just flip the switch to off, but awareness of triggers diminishes one's susceptibility to panic, and gradually one can nip such occasions in the bud until they fade to a non-problem. Incidentally, the reason people wake up with anxiety is often a troubling dream triggered by something outside of their awareness that happened in the last couple of days, something which reminded them of a painful memory their dream was trying to process.