in the DSM-IV-TR, an anxiety disorder marked by repetitive, sudden panic attacks which are correlated with (i) continual worry about having subsequent attacks, (ii) concern about the potential consequences of the attacks, (iii) substantial alteration in actions associated with the attacks, or (iv) a mixture of any or all of these. Panic disorder correlated with substantial avoidance is categorized as being with agoraphobia.

PANIC DISORDER: "Brian hasn't been diagnosed with panic disorder, but is fairly sure that's his problem."