The purpose of this grant is to study the respiratory psychophysiology of panic disorder patients undergoing pharmacologic and cognitive/behavioral treatment. A number of recent findings point to complex respiratory parameters strongly correlate with self-rated anxiety, many panic patients are in a state of respiratory alkalosis, and carbon-dioxide (CO2) inhalation is becoming recognized as a reliable anxiety inducing method suggesting that some anxiety disorder patients are hypersensitive to CO2. At the same time cognitive/behavioral factors are increasingly acknowledged in the development and treatment of anxiety disorders. The biobehavioral model of panic is based on the success of cognitive/behavioral techniques (breathing retraining, interoceptive exposure, and cognitive restructuring) in normalizing the well documented complex biological and cognitive disturbances in panic disorder. A series of studies are proposed to investigate the differential biological and psychological effects of imipramine and the "Albany Panic Control Treatment" in panic; to assess the role of hyperventilation in anxiety; to investigate the pathophysiology of CO2 induced anxiety by establishing its specificity and dose dependent nature and by developing objective, reliable and specific respiratory parameters of CO2-panic; and to assess the importance of cognitive/behavioral factors in anxiety as they relate to respiratory physiology. Collaborative respiratory studies will involve patients with late luteal phase dysphoric disorder, and relatives of panic patients. The immediate goal is to systematically describe the complex ventilatory and cognitive changes and their pathophysiological role in panic anxiety. The long range goal is to apply this knowledge to other psychiatric disorders. Training is proposed in the general areas of neurosciences and behavioral medicine. Specific training will focus on the diagnosis, pathophysiology, and treatment of anxiety disorders, the respiratory physiology and cognitive/behavioral factors in anxiety and related psychiatric disorders, and statistics.