Once you are under enough stress, almost anything can set off a panic attack. Suppose you are under a lot of stress, but still managing. If you add even more stress, your brain will begin to feel under siege. Your body will respond by releasing adrenaline as part of the fight or flight response. That will cause more anxiety, which will create a vicious feedback that will turn into a panic disorder.
Occasional anxiety is an expected part of life. You might feel anxious when faced with a problem at work, before taking a test, or before making an important decision. But anxiety disorders involve more than temporary worry or fear. For a person with an anxiety disorder, the anxiety does not go away and can get worse over time. The symptoms can interfere with daily activities such as job performance, school work, and relationships.