Response to hyperventilation and 5.5% CO2 inhalation of subjects with types of specific phobia, panic disorder, or no mental disorder

OBJECTIVE: This study tested the hypothesis that compared to other DSM-IV specific phobia types, situational specific phobias have more in common with panic disorder and agoraphobia. METHOD: Responses to hyperventilation and CO2 inhalation were compared across groups of patients with the four main DSM-IV specific phobia types, a group with panic disorder, and a group of comparison subjects with no anxiety disorder (N = 15 per group).