Panic Disorder 325
effiCaCy of Cognitive therapy for paniC DisorDerCognitive behavior therapy for panic disorder falls within the American Psychological
Association’s well- established category of empirically supported treatments (Chamb-
less et al., 1998; Chambless & Ollendick, 2001). The American Psychiatric Associa-
tion Practice Guidelines for the treatment of panic disorder concluded that CBT was a
proven effective treatment for panic, with a 78% completer response rate that was at
least equal or superior to the effectiveness of antipanic medication (American Psychiat-
ric Association, 1998).
Numerous reviews of the clinical outcome research have concluded there is strong
support for the efficacy of CBT for panic disorder. After reviewing more than 25 inde-
pendently conducted clinical trials, Barlow and colleagues concluded that 40–90% of
patients treated with CBT are panic-free at end of treatment (Landon & Barlow, 2004;
White & Barlow, 2002). Other reviewers have also concluded that the effectiveness
of CBT for panic is strongly supported by the outcome literature (Butler, Chapman,
Forman, & Beck, 2006; DeRubeis & Crits- Christoph, 1998; Otto, Pollack, & Maki,
2000) and that treatment gains endure beyond termination more than with medication
(Hollon, Stuart, & Strunk, 2006). In the following section we provide a brief review of
selected key clinical outcome studies for CBT as well as dismantling studies that inves-
tigate the mechanism of change in the treatment package.
CBT Outcome Studies
Several meta- analyses have determined that CBT for panic is associated with superior
effect sizes. For example in a meta- analysis based on 13 studies Chambless and Peterman
(2004) obtained an average effect size of .93 for panic and phobic symptoms, with 71%
of CBT patients panic-free at posttreatment compared to 29% for the control conditions
(i.e., wait list or attention placebo). Furthermore, significant treatment gains were evident
in other symptom domains such as the cognitive symptoms of panic, generalized anxiety,
and, to a lesser extent, depression (see also Gould et al., 1995, for similar conclusions).
One of the earliest reports on cognitive therapy for panic disorder was a naturalistic
outcome study of 17 patients treated with a mean of 18 individual sessions of cogni-
tive therapy that focused on misinterpretations of the physical symptoms of anxiety,
exposure, and cognitive restructuring of panic- relevant fears (Sokol, Beck, Greenberg,
Wright, & Berchick, 1989). At posttreatment panic frequency declined to zero and was
maintained at 1-year follow-up, and significant reductions were achieved on the BAI
and BDI. In addition improvement was made in patients’ ability to reappraise their fears
in a more realistic manner. In a later randomized clinical trial in which 33 patients with
panic disorder were assigned to 12 weeks of individual cognitive therapy or 8 weeks
of brief supportive psychotherapy, Beck, Sokol, Clark, Berchick, and Wright (1992)
found that at 8 weeks the cognitive therapy group had significantly fewer self- reported
and clinician-rated panic attacks than the comparison group. In addition the cognitive
therapy group had less generalized anxiety and fear but not less depression, and 71%
were panic-free compared to 25% in the psychotherapy condition. At 1-year follow-up
87% of the cognitive therapy group remained panic-free.
In a major outcome study 64 panic patients were randomly assigned to an average of
10 weekly individual sessions of cognitive therapy, applied relaxation, imipramine only,