The proposed study will examine whether combined treatment with a clonazepam and paroxetine in patients with PD and comorbid depression will accelerate the onset of clinical response at both panic and depression symptoms. PD with comorbid major depression is a more severe disorder than PD alone. We will also examine whether the rapid and clinically meaningful benefits will be sustained until the end of the study, despite tapering off clonazepam at the midpoint of the study. If this study turns out to be the case combined SSRI-benzodiazepine treatment may become a standard initial therapeutic approach to PD and comorbid major depression.