There are many possible causes of panic attacks, but we can generalize them in to emotional causes, heredity, and diet causes.
Emotional Causes: Emotional causes will usually relate to a stressful and traumatic event.
For example, an extremely traumatic experience like drowning in water could cause panic attacks in that person whenever they are near water.
Knowing the emotional cause behind the condition will enable you to tackle the root cause more effectively.
Heredity: Another potential cause is heredity.
If any one in your family has a history of panic attacks then the chances are higher that you will as well.
But this is not a black and white issue though.
For example, your family might have a history of the condition, but your brother may not ever experience one in his life.
Diet Causes: Having a poor diet and vitamin deficiency can lead to various imbalances in your body and mind which can induce the unstable emotions associated with panic attacks.
Not being able to control your emotions sufficiently is a weakness which can bring them on more frequently.
In particular, a lack of Vitamin B is one of the root causes found in some people.
What To Do: When you know what the "triggers" are, you can then more effectively seek a suitable treatment.
The good news is that they are completely treatable and I myself have eliminated mine using a revolutionary technique.
It needn't be a long and tough road to recovery, it can actually be simple.