title: Extinction of panicogenic effects of a 35% CO2 challenge in patients with panic disorder.
abstract: Inhalations of high concentrations of carbon dioxide (CO2) reliably produce panic attacks in patients with panic disorder. The present study evaluated whether cognitive-behavioral treatment (CBT) for panic disorder would extinguish CO2-induced panic and whether changes in panic and arousal-related cognitions were associated with the induction of panic. Patients with panic disorder (N = 54) were assigned to 1 of 3 experimental conditions: CBT with respiratory training (CBT-R), CBT without respiratory training (CBT), or delayed treatment. Participants received 5 repeated vital-capacity inhalations of 35% CO2/65% O2 prior to and following either 12 treatment sessions or a 12-week waiting period. During pretreatment assessments, 74% of patients experienced a panic attack during at least 1 inhalation. At posttreatment, only 20% of treated participants (CBT-R = 19%, CBT = 22%), compared with 64% of untreated participants, panicked. Forty-four percent of treated participants, compared with 0% of untreated participants, reported no anxiety during all posttreatment inhalations. Anxiety sensitivity as well as panic appraisals regarding the likelihood of panic and self-efficacy with coping with panic were significantly related to fearful responding to the CO2 challenge.
authors.affiliation: Department of Medical and Clinical Psychology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA. SCHMIDT@usuhsb.usuhs.mil
authors.forename: N B
authors.initials: NB
authors.lastname: Schmidt
authors.forename: J H
authors.initials: JH
authors.lastname: Trakowski
authors.forename: J P
authors.initials: JP
authors.lastname: Staab
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001007:Anxiety / Q000209:etiology*; D001521:Behavior Therapy / Q000592:standards*; D002245:Carbon Dioxide; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016584:Panic Disorder / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide