Review
Efficacy of third wave cognitive behavioral therapies in the treatment of posttraumatic stress: A meta-analytic study

https://doi.org/10.1016/j.janxdis.2021.102360Get rights and content

Highlights

  • Effect of third wave therapies on posttraumatic stress symptoms was calculated.

  • Meta-analysis showed medium to large effects of third wave treatments in uncontrolled studies.

  • A small to large sized effect was observed for the subset of studies with a control group.

  • More rigorous studies of third wave treatments are needed.

Abstract

The purpose of the present study was to examine, via meta-analysis, the efficacy of third wave therapies in reducing posttraumatic stress (PTS) symptoms. A secondary aim was to identify whether treatment efficacy was moderated by treatment type, treatment duration, use of exposure, use of intent-to-treat samples, and treatment format (i.e., individual, group, both). Risk of bias was also assessed. A literature search returned 37 studies with a pooled sample of 1268 participants that met study inclusion criteria. The mean differences between pre- and post-treatment PTS symptoms were estimated using a random effects model (i.e., uncontrolled effect). Additionally, in a subset of studies that utilized a control condition, a controlled effect in which pre- to post-treatment PTS symptom changes accounted for symptom changes in the control condition was calculated. The overall uncontrolled effect of third wave therapies in reducing PTS symptoms was medium to large (Hedges’ g = 0.88 [0.72–1.03]). Treatment type, use of intent-to-treat analysis, inclusion of exposure, and format moderated the uncontrolled effect, but treatment duration did not. The controlled effect of third wave therapies was small to large in size (Hedges’ g = 0.50 [0.20−0.80]). Findings suggest that third wave therapies demonstrate enough promise in treating individuals with PTS symptoms to warrant further investigation. Implications and suggestions for future third wave research are discussed.

Introduction

Approximately 6.8 % of the U.S. population develops posttraumatic stress disorder (PTSD). PTSD is associated with severe dysfunction and substantial economic and social burden (Brady, Killeen, Brewerton, & Lucerini, 2000; Kessler, Chiu, Demler, & Walters, 2005). Two trauma-focused treatments designed to alleviate PTSD symptoms—cognitive processing therapy (CPT) and prolonged exposure (PE)—are empirically supported (Mendes, Mello, Ventura, De Medeiros Passarela, & De Jesus Mari, 2008; Monson et al., 2006; Rauch, Eftekhari, & Ruzek, 2012). For example, large effects sizes have been observed in meta-analytic studies when both CPT and PE were compared to control conditions for reducing PTSD symptoms (CPT: Hedges’ g = 1.24; Asmundson et al., 2019, and PE: Hedges’ g = 1.08; Powers, Halpern, Ferenschak, Gillihan, & Foa, 2010). However, these gold standard therapies have limitations—most notably, high rates of dropout (Imel, Laska, Jakupcak, & Simpson, 2013; Kehle-Forbes, Meis, Spoont, & Polusny, 2016) and hesitancy to enroll and comply with treatment (as described by Mulick, Landes, & Kanter, 2005). With this in mind, some practitioners may choose to use other treatments for PTSD, such as third wave cognitive-behavioral therapies.

While third wave cognitive-behavioral therapies may present a viable alternative when there are barriers to frontline treatments (e.g., client preference, clinician lacks training in trauma-focused therapy), there has been insufficient meta-analytic evidence as to their efficacy in treating posttraumatic stress (PTS) symptoms. The last review that was conducted of third wave therapies for treating individuals with PTSD was published over 12 years ago and did not include a meta-analysis to quantitatively summarize the efficacy of these therapies (Öst, 2008). Given these compelling reasons, the purpose of the present study was to use meta-analysis to examine the efficacy of third wave treatments in reducing PTS symptoms.

In the 1950s (i.e., the first wave), behavior therapists focused on the use of learning principles and restricted psychological assessment and intervention to publicly observable behaviors (i.e., overt behaviors; Wilson, Hayes, & Gifford, 1997). A shift took place in the late 1960s and early 1970s in which maladaptive cognitions were highlighted as being causally linked to emotional distress and psychopathology (Beck, Rush, Shaw, & Emery, 1979). In the late 1970s to early 1990s, the behavioral and cognitive models merged, thus resulting in what is typically described as “cognitive behavior therapy” (CBT; Öst, 2008). PE and CPT belong to the cognitive behavioral discipline of that era (for a review of the cognitive-behavioral waves see Hayes, 2004).

The term “third wave” first emerged in the literature in 2004 in an attempt to capture the growing family of therapies that are characterized by “a focus on second order and contextual change, an emphasis of function over form, and the construction of flexible and effective repertoires, among other features” (p. 639, Hayes, 2004). Third wave therapies (sometimes called “contextual therapies”) extend the previous frameworks by considering context and function of thought and behavior as central to conceptualizing psychological suffering. Whereas a cognitive therapist would teach a client to identify and alter the content of maladaptive thoughts related to emotional distress, a therapist from the third wave would argue that the content of one’s thoughts is not the problem; instead, the task of the therapist is to help the client change their relationship to their uncomfortable internal experiences (e.g., thoughts), while also encouraging the client to engage in value-driven behavior.

For example, in the case of an individual with PTSD, a therapist from the first wave would focus on weakening the association between a conditioned stimulus (e.g., crowded places) and a conditioned response (e.g., anxious arousal) by exposing the client to the threat stimulus in the absence of the feared outcome (e.g., decoupling via PE). A cognitive, or second wave, approach would emphasize identifying and challenging the maladaptive thoughts and beliefs associated with the feared stimulus (e.g., challenging the thought “If I go to the busy store, I will panic, have a heart attack, and die” with disconfirming objective evidence). A therapist delivering a third wave treatment would aim to identify the function of a specific problem behavior within a specific context for a specific client, and through techniques that increase acceptance of psychological phenomena (e.g., thoughts, feelings), mindful awareness of one’s experiences, and defusion from one’s thoughts, decrease psychological suffering (e.g., PTS symptoms).

Hayes (2004) defined the unifying features of “third wave” interventions as those that emphasize: “mindfulness, acceptance, defusion, values, relationship, spirituality” (p. 661). In accordance with this conceptualization of third wave therapies, Dimidjian et al. (2016) categorized the following therapies under the third wave umbrella: Acceptance and Commitment Therapy (ACT; Hayes, Strosahl, & Wilson, 1999), Dialectical Behavior Therapy (DBT; Linehan, 1993), Functional Analytic Psychotherapy (FAP; Kohlenberg & Tsai, 1994), Integrative Behavioral Couples Therapy (IBCT; Jacobson & Christensen, 1996), Mindfulness-Based Cognitive Therapy (MBCT; Segal & Teasdale, 2018), and Behavioral Activation (BA; Jacobson, Martell, & Dimidjian, 2001). Others have considered Metacognitive Therapy (Wells, 2008) part of the third wave (Hunot et al., 2013). Although a detailed description of the above therapies is beyond the scope of the current study, a brief overview of the third wave therapies that were used in the current meta-analysis is warranted (for more detail on these therapies, see Mulick et al. (2005) and Dimidjian et al. (2016)).

The therapy that is perhaps most synonymous with the third wave is ACT. The aim of ACT is not necessarily to reduce symptoms of psychopathology, but rather to reduce psychological suffering and improve quality of life more broadly. ACT is conceptualized as a transdiagnostic treatment. Modules of ACT focus on developing skills such as mindfulness, cognitive defusion, clarification of values, engagement in valued action, viewing oneself in context, and acceptance of negative psychological experiences (e.g., fluctuations in mood, ruminative thoughts). Though transdiagnostic, ACT protocols have been refined to more specifically address problems associated with PTSD (Walser & Westrup, 2007).

DBT, originally developed to treat individuals with borderline personality disorder, focuses on improving skills in four primary domains: emotion regulation, mindfulness, distress tolerance, and interpersonal effectiveness (Linehan, 1993). Given the high prevalence of trauma in individuals diagnosed with borderline personality disorder (BPD; Goodman & Yehuda, 2002), it is not surprising that DBT has been used and/or adapted to treat individuals with co-morbid PTSD and BPD. DBT in its entirety (i.e., full-model DBT) or DBT components (e.g., skills groups, but not one-on-one therapy or coaching calls) are sometimes delivered prior to exposure treatments for PTSD in order to better prepare the client for the emotional distress associated with exposure (Becker & Zayfert, 2001; Harned, Korslund, & Linehan, 2014).

Mindfulness-Based Cognitive Therapy was developed based on Mindfulness-Based Stress Reduction (MBSR; Kabat-Zinn, 1982). MBCT was originally intended to treat individuals suffering from recurrent depressive episodes. Mindfulness-based practices and interventions often involve bringing non-judgmental attention to unpleasant emotions, and thus, may help counter avoidance of trauma-related thoughts and memories in PTSD. Though sometimes used as an active control in controlled trials of exposure-based interventions for PTSD (King et al., 2013), MBCT has garnered some attention as a potential stand-alone treatment for PTSD (Jasbi et al., 2018; King et al., 2013).

Behavioral Activation is another treatment for those who suffer from depression that has gained popularity for also targeting PTS symptoms. Though some might categorize BA as purely behavioral, and thus “first wave”, there are components of BA that are consistent with “third wave” therapies (e.g., an emphasis on values-driven action). As described by Martell and Kanter (2011), in BA, thoughts and feelings are conceptualized as behaviors that can be intervened on with functional analysis (i.e., a process of identifying the contextual antecedents and consequences of problem behaviors). BA as a treatment for PTSD appears to have been born out of the presentation of co-morbid PTSD and depressive symptoms in primary-care settings, where BA is a common course of treatment (Jakupcak, Wagner, Paulson, Varra, & McFall, 2010). Although it can be delivered without adaptation for PTSD, BA and therapeutic exposure (BA-TE) is a trauma-specific adaptation that involves situational and imaginal exposures to trauma reminders (Gros, Price, Magruder, & Frueh, 2012).

The final treatment package of relevance to this meta-analysis is MCT. MCT was developed to treat anxiety pathology by reducing metacognitive beliefs (i.e., beliefs about thinking; second-order cognitions) surrounding worry and rumination. Though it has been debated as to whether MCT belongs under the second or third wave (Hofmann, Sawyer, & Fang, 2010), the focus on second-order cognitions and altering one’s relationship with thoughts aligns with the contextual nature of other third wave therapies. The model of MCT in treating individuals with PTSD proposes that second-order positive metacognitive beliefs (e.g., “I must worry in order to be prepared”) facilitate avoidance and threat monitoring, which increase PTSD symptoms. An adaptation of MCT for PTSD is detailed in Wells and Sembi (2004). Though the examples and prompts are specific to PTSD, the overall structure remains similar to the original MCT manual.

Researchers have attempted to summarize the efficacy of third wave therapies on various psychological outcomes via qualitative and quantitative synthesis. In a meta-analysis of third wave therapies, Öst (2008) found moderate effect sizes for ACT and DBT in treating a range of disorders (e.g., depression, substance use), although the methodology of several third wave treatment studies was noted as a significant concern (e.g., using waitlists as a control condition). Hunot et al. (2013) conducted a review of the efficacy of third wave therapies on acute depression. The authors concluded that though the existing evidence was of low quality, third wave therapies are as effective in treating acute depression as CBT.

Others have examined the efficacy of specific third wave therapies. Among meta-analyses to date, mindfulness-based therapies exhibited moderate to large effects in reducing anxiety and mood symptoms (Hofmann, Sawyer, Witt, & Oh, 2010), DBT appears effective in reducing suicidal and para-suicidal behavior among those with borderline personality disorder (Panos, Jackson, Hasan, & Panos, 2014), BA exhibited large effects in reducing depressive symptoms (Mazzucchelli, Kane, & Rees, 2009), and MCT holds promise in reducing symptoms of anxiety and depression (Normann, van Emmerik, & Morina, 2014). ACT has been subject to more reviews/meta-analyses than any other third wave therapy (e.g., A-Tjak et al., 2015; Öst, 2014; Powers, Vörding, & Emmelkamp, 2009; Ruiz, 2010; Ruiz-Jiménez, 2012). Results suggest that ACT holds promise for alleviating symptoms of a wide variety of presentations (e.g., mood and anxiety symptoms, chronic pain; A-Tjak et al., 2015; Öst, 2014; Powers et al., 2009; Veehof, Oskam, Schreurs, & Bohlmeijer, 2011). Although some of these third wave meta-analyses (e.g., Öst, 2014) have examined the effects of third wave therapies on “stress” generally, the efficacy of third wave therapies in reducing PTS symptoms has yet to be examined via meta-analysis.

In an early review of treatment studies that examined the use of third wave therapies to alleviate PTS symptoms, Mulick et al. (2005) concluded that third wave therapies hold promise, but much more research was needed before this class of interventions could be deemed effective for this specific symptom presentation. Specifically, there were relatively few published treatment studies (e.g., just two case studies of ACT in treating PTS symptoms) at the time that the review was published, and the authors were unable to arrive at empirically-driven conclusions about the efficacy of third wave therapies in the treatment of PTS. In a more recent review on a subdomain of third wave therapies, Banks, Newman, and Saleem (2015) investigated the effects of mindfulness-based treatments on PTS symptoms. The authors found that these therapies demonstrated some promise in reducing PTS symptoms, although they noted that the twelve studies used in their review lacked methodological rigor (e.g., small sample sizes, uncontrolled trials). The majority of the studies that they reviewed examined the effects of MBSR on PTS symptoms. While the authors suggest that MBSR may fall under the third wave category, others have argued that because it did not evolve from behavior analytic tradition, it is not of the third wave (Baer, 2005). Therefore, to date, it does not appear that the efficacy of third wave therapies, as a general class, in reducing PTS symptoms has been the subject of a quantitative review (i.e., meta-analysis).

Third wave therapies are becoming increasingly popular, with no indication that this trend is slowing (Hayes & Hofmann, 2017; Hofmann & Hayes, 2019). As the number of treatment manuals and training opportunities for third wave therapies rises each year (e.g., over sixty ACT-based manuals are currently listed by the Association for Contextual and Behavioral Sciences; “Treatment Protocols and Manuals,” n.d.), more clinicians have the ability to implement these treatments. In 2001, Corrigan warned that the practice of third wave therapies (ACT in particular) may be ahead of evidence in support of this class of treatments. While this criticism is nearly 20 years old, it remains a valid concern, particularly with respect to the treatment of PTSD. Given the strong theoretical rationale supporting the potential efficacy of third wave treatments in targeting PTS symptoms and evidence suggesting that clinicians are increasingly drawn to utilize these therapies, it is imperative to establish that these therapies are efficacious in reducing PTSD symptoms.

The purpose of the present study was to address this gap in the literature by quantifying the effects of third wave therapies on PTS symptom reduction via meta-analysis. It is important to note that the purpose of this study was not to compare third wave therapies to other established therapies for PTSD. This is in part because third wave therapies “borrow” skills and techniques from other cognitive behavioral therapies (e.g., exposure), and thus cannot be completely separated from established treatments. The primary aim of the study was to examine the uncontrolled effects (i.e., the effects of third wave treatments without comparison to a control treatment) of third wave therapies in reducing PTS symptoms. Due to the relatively few control trials comparing third wave therapies to inactive or active treatments, examining the controlled effects (i.e., the effects of an active treatment compared to a control treatment) was not the primary aim of this study. Rather, we examined controlled effects of third wave therapies only in the subset of studies for which there was a control condition. A final aim of the current study was to examine potential moderators in the efficacy of third wave therapies on PTS symptom reduction. Most notably, we examined whether the type of third wave treatment (e.g., ACT, DBT, MCT) explained variation in treatment effects. We also explored whether the use of exposure within the treatment moderated the treatment effects. For this study, exposure was conceptualized as trauma-relevant exposure to the memory or to external triggers (e.g., retelling of the traumatic memory, engaging in activities that were previously avoided because of trauma reminders). Given the strong evidence that exposure works to reduce PTS symptoms (Powers et al., 2010; Rauch & Foa, 2006), it was expected that treatments with an exposure component would be more efficacious than those without. Consistent with the dose-effect model of psychotherapy (Howard, Kopta, Krause, & Orlinsky, 1986; Stulz, Lutz, Kopta, Minami, & Saunders, 2013), it was expected that treatments with longer durations may lead to greater symptom reduction. Therefore, treatment duration was examined as a potential moderator. Additionally, given that meta-analytic evidence suggests that treatments for PTSD delivered individually or through a combination of individual and group therapy are more effective than group-based treatments (Haagen, Smid, Knipscheer, & Kleber, 2015), the format of treatment delivery (i.e., group, individual, or both) was examined as a potential moderator. Finally, because there was a range of data analytic methods used for missing data, we examined whether treatment effects differed depending on use of an intent-to-treat sample or a completer sample. It was hypothesized that there would be larger treatment effects in studies that used just a subset of the sample who completed the study.

Section snippets

Study selection

The literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Moher, Liberati, Tetzlaff, Altman, & PRISMA Group, 2009). The flow of screening processes to identify the studies that were included in this meta-analysis is depicted in Fig. 1. The literature search was conducted using PsycInfo and PubMed databases. Based on Dimidjian’s (2016) systematic review of third wave therapies, the following search string was used:

Study extraction and characteristics

The first and second authors screened initial studies (N = 1268) independently to determine whether they met study inclusion criteria. Disagreements were resolved by the third author. The two raters demonstrated a 96.2 % agreement, with adequate inter-rater reliability (Cohen’s Kappa = .73). Discrepancies between the two raters were generally due to a lack of clarity in an article’s abstract regarding whether a measure of PTS symptoms was included or disagreement regarding the delivery of 80 %

Discussion

The current study examined the effects of third wave therapies on PTS symptoms via meta-analysis. Results indicate that third wave therapies (i.e., ACT, BA, DBT, MBCT, MCT) had a medium to large effect on decreasing PTS symptoms, without comparison to a control group (i.e., uncontrolled effect). In the subset of studies with a control group, effects of third wave therapies were small to large in size (i.e., controlled effect). Both the uncontrolled and controlled effects exhibited significant

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