The use of the Panic and Agoraphobia Scale in a clinical trial

A new scale for assessing severity in PDA (Panic Disorder with/without Agoraphobia) has recently been developed: the Panic and Agoraphobia Scale [P & A (Bandelow, 1995)]. The objective of this study was to test whether the scale is sensitive to changes during a treatment trial. Thirty-seven patients (mean age, 32.7; S.D., 6.3) with PDA were treated with imipramine (75-150 mg/day) for 8 weeks in an open prospective trial. Patients with concurrent agoraphobia were instructed in practising self-exposure to agoraphobic situations. The total scores on the P & A, the Hamilton Anxiety Scale (HAMA) and the Clinical Global Impression Scale (CGI) were used as the main efficacy criteria. Treatment results were excellent, as could be shown by a decrease in the average severity scores of the P & A observer-rated version from 28.9 (S.D., 8.1) to 13.3 (S.D., 11.8; rank statistic T(N) = 6.7; P < 0.0001). The largest effect size r(w) of all clinician-rated scales was seen with the observer-rated version of the P & A, although closely followed by the CGI and the HAMA. Among the self-rated scales, the P & A (self-rated version) also showed the largest effect size. All five subscores of the P & A showed significant improvements. The highest treatment effect sizes could be seen in the 'panic attacks' subscore, followed by the 'anticipatory anxiety' subscore. The new Panic and Agoraphobia Scale (P & A) is a useful tool for measuring treatment efficacy in panic disorder trials.