Behavioral Interventions 259
anxiety level was so extreme that the client refused to engage in any exposure or refused
to tolerate even the slightest amount of anxiety. In such cases relaxation training could
be taught to lower anxiety level so the individual would engage in exposure and other
behavioral experiments designed to modify the faulty appraisals and beliefs of threat,
vulnerability, and the need for safety. For the cognitive therapist, it is the deactivation
of the fear schemas that is considered essential for long- lasting reduction in anxiety and
not the acquisition of a relaxation coping strategy.
Despite these concerns with its conceptual basis, relaxation training continues to
be advocated as an effective intervention for inhibiting the physical tension of anxi-
ety (e.g., Bourne, 2000; Craske & Barlow, 2006). However, the empirical research
indicates that relaxation training has a far more limited role in treatment of anxiety
than once envisioned. Progressive muscle relaxation, for example, continues to be an
important therapeutic ingredient in CBT protocols for GAD (e.g., Brown, O’Leary, &
Barlow, 2001; see Conrad & Roth, 2007, for review of empirical status) and PTSD
(Foa & Rothbaum, 1998), but it appears to have less value for social anxiety (Heim-
berg & Juster, 1995) and OCD (Foa et al., 1998; Steketee, 1993), and has produced
mixed results, at best, for panic disorder (see D. M. Clark, 1997; Craske & Barlow,
2001, for reviews).
Progressive Muscle Relaxation
In 1938 Edmund Jacobson published his work on relaxation that was based on a rather
unique theory of anxiety. Jacobson argued that the core experience of anxiety is muscle
tension, which involves contraction or shortening of the muscle fibers. In order to reduce
this tension and subjective anxiety, progressive muscular relaxation (PMR) was intro-
duced as a method that eliminates tension by lengthening muscle fibers (Jacobson, 1968;
see also Bernstein & Borkovec, 1973). By systematically tensing and releasing various
muscle groups, Jacobson found that muscle contractions could be practically eliminated
and a state of deep relaxation induced. The only problem is his method of relaxation
was extremely time consuming, involving 50–200 sessions of training (see Wolpe, 1958;
Wolpe & Lazarus, 1966).
Jacobson’s relaxation procedure was adopted and refined by the pioneers of
behavior therapy as an incompatible response that could inhibit fear and anxiety.
Wolpe (1958) concluded from Jacobson’s writings that his relaxation method had
anxiety- countering effects, because individuals were taught to use differential relax-
ation in their day-to-day lives in which muscle groups not directly in use were relaxed.
This will lead to reciprocal inhibition of any anxiety- evoking stimuli encountered and
with repeated occurrences a conditioned inhibition of the anxiety response gradually
develops. However, Wolpe (1958) introduced two major modifications to improve the
efficiency and effectiveness of differential relaxation. First, he was able to drastically
reduce the number of relaxation training sessions to six 20-minute sessions and two
15-minute daily practice sessions at home (Wolpe & Lazarus, 1966). And second, in
subsequent sessions relaxation was paired with systematic graduated imaginal evoca-
tion of a fear stimulus in a treatment procedure called systematic desensitization. The
result was the introduction of a highly effective behavioral treatment for fears and
phobias.