The study of panic disorder using positron emission tomography.

Positron emission tomography (PET) is a brain imaging technique which safely provides quantitative, regional measurements of biochemical and physiological processes. Because of its capabilities, PET is well suited to the study of psychiatric disorders. Among psychiatric disorders, panic disorder is especially well suited for study. Since anxiety attacks can be precipitated by biological agents, blocked by anti-panic medications, and studied in a laboratory setting, PET can be used to investigate the elements necessary for the generation and treatment of anxiety attacks. Recently, we employed PET to identify several abnormalities in a sub-group of patients with panic disorder. Patients with panic disorder who were vulnerable to lactate-induced anxiety attacks had abnormal hemispheric asymmetries of parahippocampal blood flow, blood volume, and oxygen metabolism; abnormally high whole brain metabolism; and abnormal susceptibility to episodic hyperventilation. This article reviews the current concepts of panic disorder; it provides an introduction to the components, capabilities and limitations of PET; and it describes the strategy now being employed at Washington University to investigate the neurobiology of panic disorder.