Cox et al. (1991) compared the symptoms of panic in panic disorder patients to students with panic attacks and found that:
A) There was discontinuity between nonclinical and clinical panic, suggesting that panic disorder is a qualitatively discrete disorder
B) There was continuity between nonclinical and clinical panic, suggesting that that panic attacks and panic disorder differ in degree but not in kind
C) There was substantial evidence of both continuity and discontinuity
D) None of the above; no clear pattern emerged so conclusions were not possible