A randomized clinical trial comparing an acceptance-based behavior therapy to applied relaxation for generalized anxiety disorder.

Generalized anxiety disorder (GAD) is a chronic anxiety disorder associated with high comorbidity (Bruce, Machan, Dyck, & Keller, 2001), reduced quality of life (Hoffman, Dukes, & Wittchen, 2008) and significant health care utilization (Hoffman et al., 2008). Meta-analyses reveal that cognitive behavioral therapies are efficacious for GAD (Borkovec & Ruscio, 2001; Covin, Ouimet, Seeds, & Dozois, 2008). However, GAD remains one of the least successfully treated of the anxiety disorders (Waters & Craske, 2005), with most studies finding that fewer than 65% of clients meet criteria for high end-state functioning at post-treatment (e.g., Ladouceur et al., 2000; Newman et al., 2011) and few studies examining the impact of treatment on quality of life. Several researchers have aimed to refine and expand existing models of GAD in an effort to more clearly identify causal and maintaining factors to target in therapy (see Behar, DiMarco, Hekler, Mohlman, & Staples, 2009, for a review). Recent randomized controlled trials informed by these models indicate that targeting intolerance of uncertainty (Dugas et al., 2010), and the interpersonal and emotion focused aspects of GAD (Newman et al., 2011) yield effects comparable to existing CBTs for GAD. A small pilot study found that targeting meta-cognition in GAD (Wells et al., 2010) produced better outcomes than applied relaxation, however, the very low rates of response to applied relaxation, coupled with the small sample size, indicate a need for further research to confirm this finding. Roemer and Orsillo (2002) developed a model of GAD informed by research and theory highlighting the potential roles of experiential avoidance (e.g., Hayes, Wilson, Gifford, Follette & Strosahl, 1996) and ruminative, self-critical processing (e.g., Barnard & Teasdale, 1991) in the development and maintenance of psychopathology. Supported by research comparing individuals with and without GAD, this model suggests that those with GAD have a problematic relationship with their internalized experiences characterized by a narrowed attention toward threat (Bar-Haim, Lamy, Pergamin, Bakermans-Kranenburg, & van IJzendoorn, 2007), and a critical, judgmental reactivity toward their emotional responses (e.g., Lee, Orsillo, Roemer, & Allen, 2010; Llera & Newman, 2010; Mennin, Heimberg, Turk, & Fresco, 2005) and thoughts (Wells & Carter, 1999). This reaction to internal experiences motivates individuals with GAD to engage in experiential avoidance (e.g., Lee et al., 2010) using a variety of strategies including worry, the central defining feature of GAD. Although worry decreases somatic arousal and helps to distract an individual from more emotional topics (see Borkovec, Alcaine, & Behar, 2004, for a review), rigid habitual efforts at experiential avoidance can paradoxically increase distress (e.g., Hayes et al., 1996), leading to a cycle of reactivity and avoidance that in turn affects behavior. Individuals with GAD are less likely to consistently engage in behaviors that are important to them (i.e., valued actions) and as a result experience a diminished quality of life (Michelson, Lee, Orsillo, & Roemer, 2011). This model led to the development of an acceptance based behavior therapy for GAD (ABBT; Roemer & Orsillo, 2009; Roemer & Orsillo, In press), a flexible treatment adapted from traditional CBT for GAD (e.g., Borkovec et al., 2004), as well as other acceptance-based behavioral therapies including Acceptance and Commitment Therapy (ACT; Hayes, Strosahl, & Wilson, 1999), Mindfulness-based Cognitive Therapy (MBCT; Segal, Williams, & Teasdale, 2002), and Dialectical Behavior Therapy (Linehan, 1993), that explicitly target these mechanisms1. Specifically, this ABBT aims to help clients to cultivate an expanded (as opposed to narrowed, threat-focused) awareness along with a compassionate (as opposed to judgmental) and decentered (as opposed to seeing thoughts and feelings as all-encompassing indicators of truth) stance towards internal experiences. These new skills reduce rigid experiential avoidance, as does the explicit promotion of an accepting and willing stance towards internal experiences. Behavioral avoidance and constriction are targeted by encouraging clients to identify and mindfully engage in personally meaningful actions. ABBT uses empathic validation, self-monitoring, formal and informal mindfulness exercises, encouragement of acceptance through psychoeducation and experiential exercises, and writing and behavioral exercises that apply these skills to personally meaningful activities (see Roemer & Orsillo, 2009; in press, for a more detailed presentation of the treatment). Data from an open trial (Roemer & Orsillo, 2007) and waitlist RCT (Roemer, Orsillo, & Salters-Pedneault, 2008) indicate significant effects on clinician-rated and self-report symptom measures of anxiety and depression, as well as self-reported quality of life and high rates of end-state functioning. Clients receiving ABBT report significant decreases in experiential avoidance (Roemer et al., 2008), distress about emotional responses, and intolerance of uncertainty (Treanor, Erisman, Salters-Pedneault, Orsillo, & Roemer, 2011) and significant increases in values-consistent behavior (Michelson et al., 2011). Moreover, both the time spent accepting internal experiences and engaging in valued activities significantly predict outcome (Hayes, Orsillo, & Roemer, 2010) providing support for the proposed mechanisms of action. However, studies are needed that compare this treatment to a credible, efficacious alternative therapy. Other acceptance- and mindfulness-based treatments have also been tested for GAD. A recent study comparing ACT to CBT (with behavioral exposures in both conditions) showed comparable effects of the two treatments, with the 14 individuals with GAD who received ACT demonstrating medium to large effects on outcome measures (Arch et al., 2012). Similarly, in a study of older adults with GAD, the seven individuals receiving ACT demonstrated large effect sizes on outcome measures, which were comparable to the nine individuals receiving CBT in this study (Wetherell et al., 2011). A recent meta-analysis demonstrated the promise of mindfulness-based interventions in reducing anxiety generally (Hofmann, Sawyer, Witt, & Oh, 2010), and two preliminary trials of MBCT suggest an effect of treatment on self-reported GAD symptoms (Craigie, Rees, Marsh, & Nathan, 2008; Evans et al., 2008), although outcomes fell short relative to other GAD treatment trials. Unlike ACT and ABBT, MBCT did not incorporate behavioral strategies, which may partly explain the more modest effects. While findings for ABBT are promising, previous studies were limited by absence of an active control condition and modest sample sizes. To more rigorously test ABBT, this study compared ABBT to an established and efficacious treatment, Applied Relaxation (AR). AR is an empirically supported treatment for GAD (Chambless & Ollendick, 2001) and is recommended in the NICE clinical guideline 113 (National Collaborating Centre for Mental Health and the National Collaborating Centre for Primary Care, 2011). This status comes from several methodologically rigorous studies that have examined the efficacy of AR. For example, randomized controlled trials demonstrated that AR was more efficacious than a nondirective, reflective listening therapy (Borkovec & Costello, 1993) and roughly as efficacious as cognitive therapy (Arntz, 2003; Ost & Breitholtz, 2000), cognitive behavioral therapy (Borkovec & Costello, 1993; Dugas et al., 2010), and worry exposure (Hoyer et al., 2009) in treating GAD. Further supporting the efficacy of AR, a meta-analysis by Siev and Chambless (2007) found that cognitive therapy and relaxation therapy were equivalent treatments for GAD. AR is also straightforward and relatively easy to learn, which increases the probability that therapists can deliver it with good adherence and competence. In the spirit of a comparative efficacy trial, we hypothesized that both ABBT and AR would lead to statistically and clinically significant change but that ABBT would be more efficacious than AR on measures of anxiety and quality of life. Additionally, because the processes targeted in ABBT are presumed to underlie many forms of psychopathology, we hypothesized that ABBT would be associated with greater decreases in depression and comorbidity than AR. Finally, we hypothesized that the treatments would be comparably credible and acceptable to participants.