Introduction

Findings from the National Comorbity Survey indicate that the 12-month prevalence rate for panic disorder is 2.3% (Kessler et al., 1994). To meet Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV: American Psychiatric Association, 1994) criteria for panic disorder (with or without agoraphobia) a personmust experience an unexpected panic attack and develop substantial anxiety over the possibility of having another attack or its implications. The DSM-IV defines a panic attack as a discrete period of intense fear that is accompanied by at least four of 13 somatic or cognitive symptoms (e.g., palpitations, chest pain, fear of dying). The typical attack has a sudden onset, which builds to a peak rapidly and is accompanied by a sense of imminent danger or impending doom and an urge to escape. The worry about future attacks or its implications is the primary reason why panic-disorder patients use medical treatment facilities seven times more frequently than the general population (Siegal et al., 1990). Even those with panic attacks not meeting full diagnostic criteria for panic disorder (subclinical panic) have been found to manifest substantial disability in perceived physical and emotional health, occupational functioning, and incapacity for financial independence (Klerman et al., 1991). Compared to the general population, individuals with subclinical panic are also at higher risk for other comorbid mental disorders, particularly for major depressive disorder, alcohol, and other drug abuse.