A preview of this full-text is provided by American Psychological Association.
Content available from Journal of Consulting and Clinical Psychology
This content is subject to copyright. Terms and conditions apply.
Specificity of Treatment Effects: Cognitive Therapy and Relaxation for
Generalized Anxiety and Panic Disorders
Jedidiah Siev and Dianne L. Chambless
University of Pennsylvania
The aim of this study was to address claims that among bona fide treatments no one is more efficacious
than another by comparing the relative efficacy of cognitive therapy (CT) and relaxation therapy (RT) in
the treatment of generalized anxiety disorder (GAD) and panic disorder without agoraphobia (PD). Two
fixed-effects meta-analyses were conducted, for GAD and PD separately, to review the treatment
outcome literature directly comparing CT with RT in the treatment of those disorders. For GAD, CT and
RT were equivalent. For PD, CT, which included interoceptive exposure, outperformed RT on all
panic-related measures, as well as on indices of clinically significant change. There is ample evidence
that both CT and RT qualify as bona fide treatments for GAD and PD, for which they are efficacious and
intended to be so. Therefore, the finding that CT and RT do not differ in the treatment of GAD, but do
for PD, is evidence for the specificity of treatment to disorder, even for 2 treatments within a CBT class,
and 2 disorders within an anxiety class.
Keywords: generalized anxiety disorder, panic disorder, cognitive therapy, relaxation therapy, treatment
specificity
There has been extensive debate and controversy in recent years
regarding the utility of examining active ingredients versus com-
mon factors in psychotherapy. Wampold and colleagues (e.g., Ahn
& Wampold, 2001; Wampold et al., 1997) and Luborsky and
colleagues (e.g., Luborsky et al., 2002) have claimed that all forms
of psychotherapy are equivalent; what matters are the quality of
the therapeutic alliance and other factors common to all treatments
such as the presentation of a treatment rationale. Their assertions
are based on meta-analyses that combine treatments of all types
and disorders of all types, largely for adult patients. Researchers
have challenged their conclusions on the grounds that the fact that
all treatments for all disorders when combined do not differ from
each other does not imply that a particular treatment for a partic-
ular disorder is not superior (Chambless, 2002). Proponents of a
common factors approach to psychotherapy limit their contentions
to bona fide treatments, defined as “those that were delivered by
trained therapists and were based on psychological principles,
were offered to the psychotherapy community as viable treatments
(e.g., through professional books or manuals), or contained spec-
ified components” (Wampold et al., 1997, p. 205). This reasoning,
however, presupposes that a treatment can be, in and of itself, bona
fide, with no clinical referent: for the treatment of what?
Ahn and Wampold (2001) noted that “a familiar criticism of
meta-analysis” is that “aggregating across diverse studies yields
spurious conclusions” (p. 254). Certainly in conducting a meta-
analysis, the researcher paints with broad strokes. However, if the
findings are to be clinically useful, the researcher must consider
meaningful subsets in the data so as not to obscure potentially
important differences among treatments. It is our argument that
significant differences among treatments may exist for specific
disorders. For example, there are at least four studies in which
exposure and response prevention for obsessive–compulsive dis-
order (OCD) has proven more efficacious than relaxation therapy
(RT; see Chambless & Ollendick, 2001).
The primary goal of this article is to address this specific aspect
of the common factors approach by evaluating two efficacious,
active treatments across studies, but within particular domains of
psychopathology. A second goal, which forms the framework for
this investigation, is to review the treatment outcome literature
comparing cognitive therapy (CT) and RT for generalized anxiety
disorder (GAD) and panic disorder without agoraphobia (PD) to
determine the relative efficacy of each treatment for each disorder.
GAD and PD are related, and, until the introduction of the Diag-
nostic and Statistical Manual of Mental Disorders (3rd ed.; Amer-
ican Psychiatric Association, 1980), were not diagnostically dis-
tinct. In fact, even subsequent to the formalization of that
distinction, some studies evaluating cognitive–behavioral therapy
(CBT) and RT in treating anxiety have used mixed GAD–PD
samples (e.g., Borkovec & Mathews, 1988; O
¨st, 1988). By ana-
lyzing particular treatments in particular domains, it is possible
accurately to compare two specific active ingredients in psycho-
therapy, and by doing so within the context of two related anxiety
disorders, one executes a conservative comparison. Although the
absence of significant differences between treatments would not
necessarily imply that common factors account for all effects, the
presence of differences would support the notion that treatment
effects are influenced by specific therapy techniques.
Jedidiah Siev and Dianne L. Chambless, Department of Psychology,
University of Pennsylvania.
We wish to thank Arnoud Arntz and Lars-Go¨ran O
¨st for generously
sharing data to facilitate this meta-analysis. We are grateful, as well, to
Arnoud Arntz for suggesting this investigation.
Correspondence concerning this article should be addressed to Jedidiah
Siev, Department of Psychology, University of Pennsylvania, 3720 Walnut
Street, Philadelphia, PA 19104-6241. E-mail: jsiev@psych.upenn.edu
CORRECTED AUGUST 22, 2008; SEE LAST PAGE
Journal of Consulting and Clinical Psychology Copyright 2007 by the American Psychological Association
2007, Vol. 75, No. 4, 513–522 0022-006X/07/$12.00 DOI: 10.1037/0022-006X.75.4.513
513
This document is copyrighted by the American Psychological Association or one of its allied publishers.
This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
