There are several reasons panic attacks are thought to occur- it seems heredity has something to do with it.  When a study was done on adoptees of anxious biological parents, there seemed to be a higher risk for the adopted children to develop anxiety as well, implying nature may play a bigger role than nurture in this scenario.  (Rathus, Veenvliet, Maheu, 2014)

It is not known exactly why panic disorders occur, but genetics, life experience, major stress and life changes, and certain changes in the brain seem to all contribute to a panic disorder. Smoking, alcohol, and caffeine have all been reported to intensify panic disorders in some patients as well.

Panic attacks can sometimes be caused by other medical or physical problems, so it is important to see a doctor to rule out more serious issues.

Panic attacks are a result of your brains ‘flight or fight’ reflex, causing your body’s emergency system to kick in, and to react as if there was a serious threat. Because of this, your body protects itself, causing the physical symptoms one experiences during a panic attack.