Posttraumatic Stress Disorder 551
be less effective when PTSD is associated with a severe mental illness like major depres-
sion, bipolar disorder, or schizophrenia (Mueser et al., 2008).
Cognitive therapy and CBT have been compared against attention placebo condi-
tions as well as other psychotherapies. Cognitive therapy and/or prolonged exposure are
significantly more effective than credible attention placebo conditions such as use of a
CBT self-help book (Ehlers et al., 2003), as well as progressive muscle relaxation (Marks
et al., 1998), and supportive counseling (Bryant, Moulds, Guthrie, Dang, & Nixon,
2003; Foa, Rothbaum, Riggs, & Murdock, 1991). However, cognitive therapy was not
significantly more effective than present- centered therapy (a problem- solving therapy
that focuses on the impact of trauma history on present coping style) in the treatment of
women with PTSD due to childhood sexual abuse (McDonagh et al., 2005).
A particular controversy in the PTSD treatment literature is whether EMDR is
an effective treatment, especially when compared to cognitive therapy. Although most
studies have failed to find a significant difference between EMDR and exposure alone
or exposure combined with cognitive restructuring or coping skills training (e.g., Lee,
Gavriel, Drummond, Richards, & Greenwald, 2002; Power et al., 2002), a more recent
comparison found that trauma- focused exposure tended to be more effective and to
produce more rapid change than EMDR, with the latter treatment equivalent to relax-
ation training (Taylor et al., 2003). The full EMDR treatment package contains a strong
focus on cognitive reprocessing of traumatic events and restructuring of trauma- related
thoughts. Lateral eye movement desensitization is the single therapeutic ingredient that
distinguishes the intervention most from cognitive therapy, and yet findings are mixed
on the efficacy of this key ingredient of EMDR (see Resick, Monson, & Rizvi, 2008, for
discussion). In their meta- analysis Davidson and Parker (2001) concluded that EMDR
was no more effective than exposure therapies and that eye movements or other alter-
nating movement is unnecessary because they show no incremental clinical benefit.
Until such controversies are resolved, we contend that the outcome literature for cogni-
tive therapy and CBT of PTSD is somewhat stronger and more consistent than it is for
EMDR.
Numerous psychotherapy dismantling studies have investigated various compo-
nents of cognitive therapy in order to isolate its effectiveness. In support of a basic
proposition of the cognitive model, cognitive therapy does produce significant reduc-
tions on symptom- related cognition measures, which suggests that change in trauma-
related appraisals and beliefs might mediate the effectiveness of cognitive therapy for
PTSD (e.g., Ehlers et al., 2005; Mueser et al., 2008). However, Foa and Rauch (2004)
found that prolonged exposure also led to significant reductions in trauma- related cog-
nitions and the addition of cognitive restructuring did not enhance change in negative
cognitions. Another important assumption of cognitive therapy is that focusing on the
traumatic experiences that caused PTSD is critical for achieving significant reduction
in PTSD severity. However, a randomized comparison involving 360 Vietnam veterans
failed to find a significant difference between trauma- focused group psychotherapy and
present- centered therapy that avoided any focus on trauma (Schnurr et al., 2003). Also,
the cognitive restructuring component of cognitive processing therapy proved to be as
effective as the full treatment protocol that included writing about the trauma (Resick,
Galovski, et al., 2008). It is unclear from these findings whether a concerted focus on
trauma is necessary for the effectiveness of cognitive therapy for PTSD.