Question: What causes anxiety?
Answer: We don't know all the reasons why people develop normal anxiety. We certainly know that anxiety is hardwired into us. That's part of our biology. That can be very adaptive. It can allow us to be on top of our toes, or to flee certain situations -- such as avoiding a dark alley, and hear footsteps.
We know that people react differently to stressors and to traumas, and that somehow that's related to genetics, their temperament, how they solved things growing up, how they saw their parents or teachers handle stressors. And we certainly know that anxiety has something to do with how we view ourselves and the world around us.