title: The 35% CO2 challenge in panic disorder: optimization by receiver operating characteristic (ROC) analysis.
abstract: To test the power of the 35% CO2 test as a challenge for panic disorder (PD), and to set an ideal threshold of discrimination between patients and controls, we analysed by receiver operating characteristic (ROC) analysis the responses of 91 out-patients with PD and 46 controls who inhaled a 35% CO2/65% O2 gas mixture. ROC analysis confirmed that the CO2 challenge discriminates well between PD patients and controls, with 86% probability to classify them correctly on the basis of subjective anxiety after the test. A relatively modest increment in subjective anxiety (i.e. an absolute increment of 20 units, or a relative increment of 26% of subjective anxiety) proved to be the ideal threshold to separate the two groups of our sample.
authors.affiliation: Department of Neuropsychiatric Sciences, University of Milan School of Medicine, S. Raffaele Hospital IRCCS, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Battaglia
authors.forename: G
authors.initials: G
authors.lastname: Perna
mesh_terms: D000293:Adolescent; D000328:Adult; D000379:Agoraphobia / Q000145:classification / Q000175:diagnosis / Q000523:psychology; D001143:Arousal / Q000187:drug effects; D002245:Carbon Dioxide; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D011237:Predictive Value of Tests; D012372:ROC Curve
chemical_list: D002245:Carbon Dioxide