© 1997 WILEY-LISS, INC. DEPRESSION AND ANXIETY 6:133–139 (1997) Research Articles MEASUREMENT OF PANIC DISORDER BY A MODIFIED PANIC DIARY Edwin de Beurs, Ph.D.,* Dianne L. Chambless, Ph.D., and Alan J. Goldstein, Ph.D. The psychometric characteristics of panic diary measures were investigated in a sample of 37 patients suffering from panic disorder with agoraphobia. Fol- lowing recommendations made in the recent consensus development conference on the assessment of panic disorder, daily ratings included not only the occur- rence of panic attacks but also fear of panic, expectancy of panic, and expected aversiveness of panic. These new measures were reliable and, on the whole, demonstrated good divergent and convergent validity. Further, adding such measures increased the incremental validity of panic disorder assessment. Depression and Anxiety 6:133–139, 1997. © 1997 Wiley-Liss, Inc. Key words: panic attack; self-monitoring; fear of panic; panic expectancy University of North Carolina at Chapel Hill, Chapel Hill, North Carolina Contract grant sponsor: NIMH; Contract grant number: R21- MH49851. *Correspondence to: Edwin de Beurs, Dept. of Psychiatry, Vrije Universiteit, Valeriusplein 9, 1075 BG Amsterdam, The Nether- lands. Received for publication 17 December 1997; Accepted 12 Janu- ary 1998 INTRODUCTION Panic attacks are the most striking feature of panic disorder. Consequently, assessment of panic frequency is considered essential for research on the psychopa- thology and the treatment of panic disorder (see Shear and Maser, 1994). For example, investigators often de- scribe the percentage of patients in a treatment trial who reported no panic during a posttreatment moni- toring period (e.g., Cross-national collaborative panic study, 1992). Although reporting panic frequency is es- sential, there are two reasons it is not sufficient. First, panic is but one feature of the disorder (see, e.g., American Psychiatric Association, 1994). Other defin- ing features include persistent concerns about having additional attacks and worry about the possible conse- quences of an attack, such as insanity or death. There- fore, merely measuring frequency of panic is inadequate for proper assessment of this disorder. Second, measur- ing panic frequency is a complicated endeavor. Attacks typically occur unpredictably, and their frequency may fluctuate considerably over time—hardly desirable properties from a psychometric perspective. The insta- bility of panic is especially marked for patients who suffer agoraphobic avoidance, the majority of panic suf- ferers who seek treatment (McNally, 1994). To some degree agoraphobic patients are successful in avoiding panic. Such patients may have a very low rate of panic before treatment and report increased panic only when their avoidance pattern is challenged by in vivo expo- sure (Cox et al., 1991; Craske and Barlow, 1988; de Beurs et al., 1993). For these patients, panic frequency per se is particularly deficient as the sole measure of their panic symptoms. Panic disorder experts who attended the recent con- sensus development conference on the assessment of panic disorder (organized by the National Institute of Health) concluded that it is essential for investigators to measure an additional characteristic of panic disor- der, so-called anticipatory anxiety (Shear and Maser, 1994); that is, apprehension about having another panic attack. Conferees further suggested that this construct be broken down in two components: (1) ex- pectancy of having a panic attack; and (2) thinking that an attack is a terrible thing (and therefore something to be anxious about). Theoretically, different treat- ment modalities might have differential effects on these two aspects of panic. For example, pharmaco- logical treatments might lower expectancy of panic while leaving patients frightened of what might hap- pen to them if they were to panic. On the other hand, cognitive–behavioral therapy might teach patients to view panic as less catastrophic, but have less impact on their expectancy of panic. To capture these concepts, new measures need to be added to ones now in use.