 The study aims on investigating the effect of fear augmentation during in-vivo exposure by adding interoceptive exposure e.g., hyperventilation in PDAG patients. By comparing the fear augmentation group with the therapist-guided CBT exposure, and by measuring autonomic arousal during and between exposure sessions, it will be possible to study the mechanisms of exposure based learning. A second aim is to disentangle effects of specific interoceptive exposure exercises e.g., respiratory vs. vestibular stimulation. Finally, by including patients without agoraphobic avoidance it will be possible to investigate whether interoceptive exposure alone will have any effect. This might open the door for early interventions for individuals after experiencing an initial panic attack to prevent the development of a severe panic disorder with agoraphobic avoidance. 