This multicenter study builds upon the findings of a prior study comparing imipramine, placebo, CBT, and their combination in the treatment of PD patients with no more than mild agoraphobia. That study found response rates were as high with CBT or imipramine alone as with their combination. Given the added cost of combined treatments, it therefore seems reasonable to begin with monotherapy. Further, following general principles of medical practice, it would be reasonable to initiate treatment with the less invasive cognitive behavioral intervention. It is then important to learn what should be done following initial treatment.