I can tell you that this is a characteristic feature of obsessive anxiety diseases - taking probabilities backward.For example, for years and decades I am feared of separation with the family members. So every time my husband or daughter do not pick up the phone, I AUTOMATICALLY put MINOR chance that there is something really bad with them (compared to the chance of being in the toilet, on the meeting, in class, having phone dischared etc.) at the first place. Why? Because this result, however drastic, is a SOLID CHOICE. Other results, however beneficial, are vague. People with OCD and GAD often have zero tolerance to uncertain conditions. And the easiets way to get CERTAIN answer is to choose the worse one. cheap and easy way to get out of undertainity makes us depressed, but brain does not care

It is more important to our brain to be CERTAIN than not, and the price is a second issue.There is also another important condition which may divert a person, othervise healthy, into that downward spiral. it is a matter of trust in the world, let's say. Mine was undermined at the age of 3 or 4, and I can not repair that till right now, well over 40 (because I was consciously unaware about that, but all my behaviour and fears were just shouting about that. hope I can slowly rebuild that). But it should not be an early trauma - many of us survive childhood traumas and repair them, but traumatic situation may happen in any age. I can also see that at least for some of our fellows it is a trigger too - before BFS people sometimes admit a certain issues in their lives which seem undermine their basic trust in the life and world as a safe place. it could be anything if fact - death in the family, divorce, safety accident, moving to another country, job issues, even death of a pet or watching other people in acute suffering, - whatever that brain can interprete as 'things would never be the same' and 'I am deadly endangered' or 'same could happen to me'. We often can even not be aware of that, because we are not taught to cope with things like that or because we consider ourselves as strong enough to survive, or because we HAVE to be strong because there are other people depending on us.Psyhotherapy thererofre is the best way to cope with those parts of our overall condition triggers. CBT helps to rearrange that veird probability games, and speaking therapy (like Gestalt or Analysis or whatever else) often helps to reveal and heal that crack in reality and personal safety.Some of our symptomes need medication, but some need cognition and action plan and implementation. Post-traumatic stress disorder catch not only those who was at the war (however those are striken really badly and prominently compared to us) - it can happen to anybody. Think if you have any of such stress before starting to worry and google.