Nb. Schmidt et al., EXTINCTION OF PANICOGENIC EFFECTS OF A 35-PERCENT CO2 CHALLENGE IN PATIENTS WITH PANIC DISORDER, Journal of abnormal psychology, 106(4), 1997, pp. 630-638
Inhalations of high concentrations of carbon dioxide (GO,) reliably pr
oduce panic attacks in patients with panic disorder The present study
evaluated whether cognitive-behavioral treatment (CBT) for panic disor
der would extinguish COL-induced panic and whether changes in panic an
d arousal-related cognitions were associated with the induction of pan
ic. Patients with panic disorder (N = 54) were assigned to 1 of 3 expe
rimental conditions: CBT with respiratory training (CBT-R), CBT withou
t respiratory training (CBT), or delayed treatment. Participants recei
ved 5 repeated vital-capacity inhalations of 35% CO2/65% O-2 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 tr
eated participants (CBT-R = 19%, CBT = 22%), compared with 64% of untr
eated participants, panicked. Forty-four percent of treated participan
ts , compared with 0% of untreated participants, reported no anxiety d
uring all posttreatment inhalations. Anxiety sensitivity as well as pa
nic appraisals regarding the likelihood of panic and self-efficacy wit
h coping with panic were significantly related to fearful responding t
o the CO2, challenge.