In continuation of prior work from our group (Broocks A, Bandelow B, Pekrun G, et al. Comparison of aerobic exercise, clomipramine, and placebo in the treatment of panic disorder. Am J Psychiatry 1998; 155(5):603-9.) it is the purpose of this trial to test the assumed superiority of a combined therapy of paroxetine and aerobic exercise compared to placebo or unspecific relaxation training in panic disorder. Participants were randomized to a 10 week treatment protocol of paroxetine 40 mg daily or placebo in combination with regular exercise or regular relaxation after having given informed consent and screening of in- and exclusion criteria.