For us to evaluate the efficacy of our treatment programs, we are interested in your responses before and after treatment. We use two methods to evaluate the efficacy of our treatments: questionnaires and interviews with a member of the Anxiety Disorders Clinic. As part of standard clinic procedure, each person in the program completes an in-person interview with a staff member who will determine your suitability for treatment. If you have received this questionnaire packet, it is likely that your concerns will be appropriately addressed in the Anxiety Disorders Clinic. The purpose of the questionnaire packet is to assess the severity of your panic disorder; its impact on your functioning, and factors that may contribute to the onset or maintenance of your panic (e.g., depression, anxiety sensitivity). We will ask you to complete this questionnaire again when you have completed your treatment along with a brief telephone interview with a staff member of the Anxiety Disorders Clinic.