Tommy,
Many people have panic attacks periodically, but not panic disorder. In my opinion, I think you fit this category, as your first attack can be deducted from the fact they you had been experimenting with amphetamines at the time. Also your next attack wasnt till 3 weeks later. You may be currently suffering from the "fear" of the attacks, but are not experiencing them.
To answer your question, mine began about 14yrs ago, and would persist to having them 2-3 times daily.
