ASSESSING THE EFFICACY OF TREATMENTS FOR PANIC DISORDER AND AGORAPHOBIA .1. METHODOLOGICAL PROBLEMS

An assessment of the efficacy of treatments in panic disorder and agor aphobia (PDA) is complicated by methodological problems resulting from the complexity of these disorders. In this paper, commonly used anxie ty scales are discussed with regard to their relevance in the assessme nt of PDA. Although there are already many scales for assessing anxiet y and agoraphobia, a qualified instrument for measuring the severity o f PDA is still lacking. A survey of the instruments used in recent tre atment studies of PDA shows that rather inhomogeneous efficacy criteri a were applied. Most often, panic attack frequency was taken as a seve rity criterion, although this measure showed little power to different iate between treatments. To deal with the special features of PDA, a b attery of different scales was usually employed and non-standardized s cales were sometimes used additionally. A new rating scale designed to overcome the methodological problems associated with the assessment o f severity in PDA was introduced. The use of the psychiatrist-rated Pa nic and Agoraphobia (P & A) scale in patients with DSM-III-R panic dis order and/or agoraphobia (n = 235) shows that this scale has the highe st correlation with the psychiatrists' clinical global impression of P DA patients (r = 0.79, p < 0.0001), compared with other commonly used observer-rated anxiety scales. The self-rating version of the P & A ag ain had the highest correlation with a patient-rated clinical global i mpression (r = 0.82, p < 0.0001), whereas the other patient-rated anxi ety questionnaires correlated only moderately or poorly, By means of l ogistic regression, it was shown that the five subscores of the scale contribute independently and almost equally to the prediction of PDA s everity.