Evaluating transdiagnostic treatment for distress and impairment in veterans: A multi-site randomized controlled trial of Acceptance and Commitment Therapy

Article Outline

• Abstract
• 1. Introduction
  • 1.1. Current treatments for returning veterans
  • 1.2. Transdiagnostic treatment
  • 1.3. Acceptance and Commitment Therapy (ACT)
• 2. Design and method
  • 2.1. Participants
  • 2.2. Assessment
  • 2.3. Treatment
    • 2.3.1. ACT
    • 2.3.2. Control
    • 2.3.3. Therapist selection, training and supervision
    • 2.3.4. Discontinuation
  • 2.4. Statistical methods
    • 2.4.1. Sample size
    • 2.4.2. Data analysis
• 3. Discussion and conclusions
• Acknowledgments
• References
• Copyright

Abstract 

Military personnel who engaged in the conflicts in Afghanistan and Iraq frequently present for mental health care because of the stresses of service and readjustment. Although excellent treatments are available to treat the typical presenting problems, there is a need for additional empirically supported treatment approaches for this population. Because these veterans have high levels of comorbidity, transdiagnostic treatment – treatment that applies to more than one diagnosis – may be an efficient approach for this group. Acceptance and Commitment Therapy (ACT) is one such approach that is well-known and has high face validity for veterans, but it has not been rigorously evaluated as a treatment for trauma-related mental health problems. Described herein is an ongoing multi-site randomized clinical trial of ACT as compared to a psychotherapy control. Challenges in designing an RCT to evaluate transdiagnostic treatment and in executing a multi-site psychotherapy trial are discussed.

Keywords: Randomized clinical trial, Psychotherapy, Veteran, Acceptance and Commitment Therapy

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1. Introduction 

A substantial number of military personnel who have deployed to the current wars in Iraq and Afghanistan have psychological health concerns. Common complaints include posttraumatic stress disorder (PTSD), other anxiety disorders, depression and substance use disorders [1], [2], and most individuals with one mental health diagnosis meet criteria for another disorder [2], [3]. In addition, traumatic brain injury has been called the “signature wound” of these conflicts [4], resulting in numerous individuals complaining of persistent postconcussive symptoms, which include cognitive (e.g., memory and attention problems), somatic (e.g., headaches, fatigue, dizziness) and affective (e.g., depression, irritability, anxiety) symptoms. Thus, the challenge for providers is finding the best way to manage the comorbid concerns of this new generation of veterans.

1.1. Current treatments for returning veterans 

At present, empirically supported approaches that can be used to treat returning veterans are disorder-specific. Exposure-based therapy [e.g., Prolonged Exposure] is a well-developed, empirically supported treatment for PTSD [5], which has been shown to effectively treat PTSD related to a variety of traumatic stressors [e.g., [6], [7]]. Cognitive Processing Therapy also has demonstrated efficacy for treatment of PTSD in veterans [8], [9]. These interventions have a demonstrated impact beyond PTSD, and thus address common comorbidities in this group as well [8].

As a group, depression, anxiety disorders other than PTSD, and adjustment disorders present more commonly than does PTSD among Veterans seeking care [2] and among active duty troops from the early phases of the wars in Iraq and Afghanistan [1]. Several well-established psychotherapeutic approaches can be used to effectively manage these conditions, including interpersonal therapy for depression and cognitive behavioral therapy for depression [10] and/or anxiety [11]. Frequently, these interventions show “spill-over” effects on disorders beyond the primary target of treatment [12].

Postconcussive symptoms are symptoms that follow traumatic brain injury. They include cognitive (e.g., attention/concentration problems), affective (e.g., depression, irritability), somatic (e.g., headaches, nausea), and sensory (e.g., light and noise sensitivity) symptoms [13]. In a population of OIF/OEF veterans exposed to more than one physically traumatic injury, 66.8% were diagnosed with persistent post-concussive symptoms (lasting longer than three months), and 54.2% were diagnosed with both PTSD and persistent post-concussive symptoms [14]. Treatment of postconcussive symptoms, which typically involves education about the nature and course of symptoms and may also include cognitive rehabilitative strategies, rarely has been studied [15]. Preliminary work indicates that empirically validated treatments for PTSD and depression may be as effective among patients with head injuries [16], [17], [18], [19]. It has been suggested that postconcussive symptoms are responsive to psychotherapy [20], but additional work is needed to establish this.

In spite of the strong existing interventions for many of the problems faced by returning Veterans, there remains a need for additional treatment approaches. Only up to half of patients will cease to meet diagnostic criteria for PTSD even after our best PTSD treatments [e.g., [7], [8]], and psychotherapy trials commonly show drop-out rates in the range of 20-30% [e.g., 21]. A significant proportion of therapists report not using the empirically validated approaches even when these therapists have been appropriately trained [22]. Finally, patients appear to adhere better to treatment, and therefore attain more symptom improvement, when they receive a preferred approach [23]. Given these concerns, we chose to evaluate a transdiagnostic approach in order to expand the treatment offerings for returning Veterans with deployment-related mental health problems.

1.2. Transdiagnostic treatment 

Transdiagnostic (or unified) treatment of emotional disorders is based on the idea that there are common factors that influence multiple types of psychopathological presentations and that interventions designed to target these commonalities would have broad applicability [24], [25], [26]. Evidence for such common factors comes from a number of sources, including high rates of comorbidity and the presence of higher order factors explaining variability among multiple disorders [27].

Transdiagnostic treatment has important advantages in its application to returning veterans. Comorbidity is common in this population. The typical treatment plan involves focusing on a single primary presenting complaint using a disorder-specific treatment approach. This approach is frequently successful because of the “spill-over” of disorder-specific treatment on co-occurring disorders, although the magnitude of change in the non-targeted disorder(s) is often attenuated [e.g., 8]. Also, disorder-specific treatment may not subjectively seem to address all of the presenting concerns, which could influence treatment adherence and satisfaction. Thus, an intervention that is effective for a broad range of symptoms may be a good complement to existing approaches. In addition, a transdiagnostic approach is ideal for patients for whom there is not a “perfect” disorder-specific approach, such as those who have subsyndromal but impairing symptoms of multiple disorders. In addition, transdiagnostic treatment reduces training burden because a clinician only has to receive training and supervision in a single approach to be able to treat a wide range of patients. This increases the likelihood that patients will receive empirically supported treatment and provides cost savings for healthcare systems [27].

1.3. Acceptance and Commitment Therapy (ACT) 

Acceptance and Commitment Therapy is a transdiagnostic structured psychotherapeutic intervention that applies mindfulness and behavioral techniques in helping clients to identify their values and goals and to act in a way that is consistent with them. ACT does not specifically target symptom reduction but rather encourages patients to engage in valued behavior regardless of the presence or absence of symptoms; however, reduction in symptoms is frequently observed as a byproduct of this shift. Published trials demonstrate the efficacy of ACT in managing depression, anxiety, stress, general distress, psychosis, substance use, smoking cessation, epilepsy, pain, weight control, and diabetes [28], [29], [30]. These studies are typically small and have been criticized for not having the same rigor as studies of empirically supported treatments [29]. In a recent large randomized controlled trial (RCT), Forman and colleagues [31] found ACT to be equivalent to cognitive therapy for psychiatric outpatients (N=101) with moderate-severe depression or anxiety. ACT has been successfully applied to PTSD in uncontrolled studies that demonstrate its safety and potential efficacy [32], [33], [34], [35], [36], [37] but has not been otherwise studies in veterans or military personnel.

In addition to this preliminary evidence about ACT's efficacy, there are several reasons why we elected to study ACT for the most recent generation of veterans. First, ACT has good face validity and is consistent with military culture. ACT asks individuals to move forward in accordance with their values regardless of limitations. Military training, doctrine and culture place considerable emphasis on the notion of the military as a values-based institution. Military personnel are taught to conduct missions and conduct their lives in accordance with core principles regardless of the challenges with which they are presented. Second, ACT has been shown to be acceptable to patients (mean attrition of 15.4% in 13 RCTs [29], [30]), which may be useful attribute in this population for whom there are many barriers to mental health care [1]. Third, ACT is already being disseminated, ahead of compelling evidence for its efficacy. Finally, as a transdiagnostic approach, ACT can be applied to a variety of presenting concerns.

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2. Design and method 

The trial described herein is a multi-site randomized controlled trial of ACT as compared to a general psychotherapy control.

2.1. Participants 

Each of 5 VA sites is projected to enroll 32 participants over 30months for a total sample size of 158 Veterans. In addition, 20 active duty participants will be recruited from a military hospital to provide preliminary information about the generalizability of VA data to active duty personnel.

Because a strength of ACT is its broad applicability, we opted to include multiple types of presenting problems in the study sample. Potential participants are referred by mental health providers in general and specialty mental health clinics, primary care clinics, and community-based Vet Centers. Criteria for inclusion are service in the wars in Iraq and Afghanistan (formally, Operations Enduring Freedom, Iraqi Freedom and New Dawn, or OEF/OIF/OND); ability to give informed consent; and a primary clinical concern of an anxiety disorder (including anxiety not otherwise specified), a depressive disorder (including depression not otherwise specified) and/or postconcussive symptoms. We exclude individuals who have a condition that may interfere with treatment, specifically moderate-severe cognitive impairment that has been determined by a neuropsychologist to hinder one's ability to meaningfully engage in treatment, uncontrolled severe psychopathology (psychosis, bipolar illness, urgent suicidality or self-injurious behavior), or untreated substance dependence in the past month. In order to appropriately attribute changes to the intervention, we exclude individuals who anticipate a change in their pharmacologic intervention during the period they would be in the study. Participants may stay on their current medications during the study but are asked to refrain from beginning or altering medication use during the study to the extent possible. Similarly, we exclude those who are currently in another psychotherapy focusing on the same target symptoms; patients may attend self-help groups or treatment for other types of problems (e.g., couples counseling). Finally, we exclude those who anticipate deployment or some other circumstance that would interfere with completion of all study procedures.

There are disadvantages to using this broad sample. At the end of the trial, we will not be able to draw conclusions about ACT's efficacy in any particular disorder, although we will collect disorder-specific data in hopes of being able to generate such hypotheses. There is also a risk that the benefits received by one group will be canceled out in the overall analysis by poor response in another group. Thus, there is a greater risk of erroneously concluding that the intervention is ineffective. Nonetheless, we believe that the typical ACT-trained clinician applies the approach broadly because of the transdiagnostic nature of the intervention. Thus, we believe that these concerns are outweighed by the need for ecological validity.

2.2. Assessment 

Participants are assessed before treatment, at mid-treatment, at the end of treatment and are followed for up to a year after completing treatment. The follow-up period may range from 3months to 12months depending on when an individual enrolled in the trial. For those who are recruited early in the enrollment period, there will be follow-ups at 3, 6, 9 and 12months after the end of treatment. For those who enroll later, there will be only be as many additional assessments as are possible in the follow-up period, with the final enrollees only completing the follow-up 3months after the end of treatment. This missing-by-design strategy was used to provide preliminary information about longer-term maintenance of treatment gains without extending the total study period. Study hypotheses are listed in Table 1.

Table 1. Study hypotheses.

Study inclusion/exclusion is based on (a) the Mini-International Diagnostic Interview [38] to establish psychiatric diagnoses and suicidality for inclusion and exclusion, (b) a screening instrument to establish exposure to traumatic brain injury in conjunction with the Rivermead Post Concussion Symptoms Questionnaire [Rivermead; 39], a 16-item measure of symptoms commonly experienced after head injury that is used to establish the presence or absence of postconcussive symptoms, and (c) the Montreal Cognitive Assessment [MoCA; 40] to determine whether or not neuropsychological evaluation is necessary to determine exclusion based on cognitive impairment.

The primary study endpoint is distress as measured by the Brief Symptom Inventory – 18 Global Severity Index (BSI-18 GSI; 41). The GSI is a composite of the three BSI-18 subscales (anxiety, depression and somatization) and acts as an index of current dysphoria [41]. This instrument has been shown to be sensitive to change in other treatment outcome studies [e.g., [42], [43]] and taps into three types of symptoms that we expect will be elevated in this sample.

The secondary outcomes of interest include anger as measured by the Dimensions of Anger Reactions [DAR; 44], a 7-item measure of the frequency, duration, intensity, expression, and perceived impact of anger; quality of life as measured by the WHOQOL-BREF [45], a 26-item quality of life measure that assesses physical capacity, psychological well-being, social relationships, and environment; functioning as measured by the Sheehan Disability Scale [46], a 3-item measure of impairment in work, social and family settings; and acceptability as measured by a composite of attrition (percentage completing less than 10 sessions), credibility [adapted from 47] and satisfaction (Client Satisfaction Questionnaire [CSQ-8; 48], an 8-item measure of satisfaction with services received).

In addition, we will conduct exploratory descriptive analyses to look for initial evidence of differences between key diagnostic subgroups, including PTSD (using the PTSD Checklist, Military Version [PCL-M; 49], a 17-item measure of PTSD severity), Major Depression (using the Patient Health Questionnaire depression items [PHQ-9; 50], a 9-item measure of depression severity), and postconcussive symptoms (using the Rivermead [39]).

2.3. Treatment 

Eligible participants are randomly assigned to a treatment condition using a web-based randomization tool that was developed for the study. Randomization is stratified by primary diagnostic type (anxiety, depression or postconcussive symptoms) and site. An effort is made to begin treatment within 2weeks of the initial assessment; a break longer than one month necessitates reassessment. A therapist meets one-on-one with a participant 12 times, ideally over a period of 6–10weeks, but a longer period is permitted with justification.

ACT is delivered using a manual that was developed by combining the work of Hayes and colleagues [51] with the clinical and research work of Walser and Westrup [52]. Thus, the manual uses both theoretical principles and core processes of the approach and clinical experience with trauma survivors.

ACT's philosophical origins are in functional contextualism and its overall framework is based on a behavioral principles and a behavioral understanding of human language called Relational Frame Theory [53]. ACT targets psychological problems that arise out of cognitive and behavioral rigidity and limit personal well-being. From the ACT perspective, this rigidity is the result of experiential avoidance (i.e., avoidance of unwanted internal experiences such as negative emotions), fusion with language (i.e., loss of perspective that thoughts are subjective rather then objective), excessive focus on the past or future, attachment to a particular sense of self, excessive focus on the elimination of negative internal experience and inaction with respect to personal values. ACT is designed counteract these maladaptive strategies using the following six core processes.

The manual contains 12 structured sessions and is designed to step a client through a series of exercises and metaphors while interacting with the client around their own struggles in a way that helps them to see willingness to experience internal events as an alternative to misapplied and excessive control of the same, while supporting them in efforts to make and keep commitments that are guided by personal values in the service of a vital life. Each session includes opening with a 5–10minute mindfulness exercise, reviewing homework assigned at the previous session, presenting and engaging new materials to include relevant exercises and metaphors and assigning new homework to be completed before the next session. To assist in appropriate implementation, examples of client/therapist dialog are provided throughout the manual. Also included in the manual is a therapist orientation that focuses on the importance of being aware of personal assumptions about internal experience (e.g., change of negatively evaluated emotions and thoughts as a means to health versus acceptance of the same) and the therapeutic relationship. From the ACT perspective, the therapist approaches the client from an equal, vulnerable, genuine and compassionate point of view. A brief content outline of the sessions is presented in Table 2.

Table 2. Content of ACT sessions.

As a control condition, we needed in a credible approach that could apply to any of the targeted conditions and would control for nonspecific psychotherapy, so that any observed differences can be attributed specifically to ACT rather than to good therapy in general. Present Centered Therapy (PCT) is such an approach. PCT is a supportive psychotherapy that focuses on current problems in one's life and the ways that symptoms may interact with those problems [54]. PCT was employed as a general psychotherapy control in a previous multi-site trial with Veterans. Pre-post effect sizes (in a highly chronic PTSD sample that had multiple comorbidities) were .62 for clinician-rated and .43 for self-reported PTSD severity; these effect sizes were lower than those associated with the active condition but were clinically meaningful. There was a lower dropout rate for patients receiving PCT than the active condition, and satisfaction was high with both approaches [7].

The PCT manual was refined to fit the needs of our sample; the length matches the length of the ACT intervention, and the problems common to this sample are referenced. The core elements of PCT are common to many supportive therapies. These include a review of presenting problems, psychoeducation about common types of emotional distress and problem solving. In the first session, the therapist provides education about anxiety, depression and/or postconcussive symptoms as relevant to the patient and draws connections between symptoms and current problems. Throughout the treatment, patients are encouraged to keep a daily record of stressors and problems, approximately matching the length of homework in the ACT condition. These records are reviewed each week with the therapist, and the therapist facilitates active problem solving of day-to-day difficulties.

If this trial is successful, it will be important to do noninferiority trials to compare ACT to empirically supported treatments, such as cognitive behavioral therapy. These will likely have to take the form of disorder-specific comparisons as different treatments are recommended for the disorders that may be represented in our sample. We anticipate that our disorder-specific data will provide information to direct such future efforts.

Study therapists have a master's or doctoral degree in clinical or counseling psychology, social work, or psychiatric nursing and were open to learning and employing the interventions. Therapists were initially trained to deliver both types of treatment during a week-long in person training. This training was conducted by the study supervisors, who are experts in ACT and PCT. After that training, the clinicians were instructed to carefully read both manuals and supporting materials and to complete two practice cases, one for each intervention, with intensive supervision involving supervisory review of all sessions and weekly individual discussions. Supervision during the trial involves weekly group supervision for each treatment approach as well as session by session review of audiotapes with individual feedback of 50% of the first 4 cases and 25% thereafter. Fidelity monitoring of audiotapes of a randomly selected 10% of sessions is conducted by an experienced clinician who is independent of treatment delivery.

Every effort is made to retain subjects in the study. Treatment is discontinued, however, if clinically indicated or for nonattendance. In the event that a patient does discontinue the treatment, the therapist assists the patient in locating appropriate alternative care.

2.4. Statistical methods 

We calculated the sample size to detect a difference in effect size between ACT and PCT of approximately d=.5 [i.e., (ACT effect size of ~1.0 ) – (PCT effect size of .3-.5)]; a smaller advantage over PCT would likely not be important because of the existence of other effective treatments for disorders represented in this sample. The study is powered to compare the mean change in the BSI-18 GSI over the treatment period between the ACT group and the control group using a two-sample t-test, assuming uniform allocation. With a sample size of 158 participants per group (79 participants per arm; equal allocation between the two treatment groups), and a type I error rate of 5%, the study will have 80% power to detect a difference as small as d=.50 in the mean change in BSI-18 GSI scores between the two treatment groups, even if up to 20% of participants are lost to follow up and provide no outcome data.

Analyses will incorporate the intent-to-treat principle; all randomized participants will be included in the analysis. No adjustments for multiple comparisons will be made for secondary analyses, and a p-value of .05 will be considered statistically significant. A number of covariates will be assessed to see whether there is a potential imbalance across treatments and whether there is an association with the outcome of interest. The variables will be included as covariates in the models if the test to assess the equivalence of the baseline variables between treatment groups is significant at p=.10 and the test to measure the association between the baseline variables and the outcome variable is significant at p=.15. The potential covariates to be assessed are demographic characteristics, nature of the head injury and neuropsychological functioning. Analyses will also be performed on the completers, namely, randomized participants who complete treatment (12 sessions).

To longitudinally assess change over time on continuous primary and secondary outcome variables, linear mixed effects regression modeling will be used to accommodate the dependencies of events over the 6-week evaluation period and over the follow-up period. Assuming a linear trend in mean response over time, the model will include treatment group (ACT vs control), time (in weeks), and a group-by-time interaction as the main fixed effects, and a random intercept and slope using a compound symmetry variance–covariance structure. The random effects in the model will account for differing initial values of subjects, individual variation in the rate of change of the response, and within-subject correlation. Other covariates will be added to the model if found to be unbalanced at baseline and also associated with the outcome. A significant treatment effect will be concluded when the p-value for the group-by-time interaction parameter in the model is ≤0.05. If the assumption of linearity is violated, the analysis will be conducted using response profiles. Sensitivity analyses using several alternate correlation structures [for example, unstructured, and AR(1)] in the mixed-effects regression models will be conducted in order to assess the effect of the correlation structure in the data. A Generalized Estimating Equations (GEE) model will also be used as the sensitivity analysis method. Mixed effects modeling will also be used to evaluate the treatment effects within the PTSD subgroup; the major depression subgroup; and the postconcussive symptoms subgroup, if appropriate (assuming a large enough sample size).

Descriptive analyses, including Fisher's exact test, 2-sample t-test, or the Wilcoxon Rank Sum test as appropriate, will be used to evaluate acceptability of the intervention and performance of ACT in active duty personnel compared to VA patients.

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3. Discussion and conclusions 

The years of conflict in Afghanistan and Iraq have created a new cohort of veterans, many of whom will struggle to make sense of their experiences in combat and suffer from related psychological symptoms. The Vietnam generation spurred several decades of research on posttraumatic stress and led to the development of excellent PTSD treatments. The current generation now challenges us to provide additional treatment options and to provide interventions efficiently so that everyone can access empirically supported care. Transdiagnostic interventions, which are broadly applicable yet have a relatively low training burden, are important to evaluate. We have described the design of a randomized controlled trial of one such intervention, Acceptance and Commitment Therapy. ACT is a compelling intervention that has received considerable attention in the past several years, with both high-profile popular coverage [55] and steeply increasing rates of empirical study [56]. Data on its efficacy in this group of veterans, however, are lacking.

This study has a number of strengths. This study will be the first large, multi-site RCT of ACT of which we are aware, and the first trial in OEF/OIF/OND Veterans. With very broad inclusion and few exclusions, the results of this trial will be readily generalizable to the population of returning veterans who seek treatment for mental health problems. ACT manuals are widely available and training is well developed, so dissemination will be straightforward. In many cases, ACT is already being applied without this level of empirical support, so this trial will provide a scientific grounding for choosing whether or not to continue use of this popular approach. The multi-site design permits collection of a large sample that will provide us with sufficient power to examine a range of outcomes. Multi-site trials also enhance generalizability because of the ability to examine variability in outcomes across sites.

This study has limitations. As we described, we have chosen to examine ACT in a broad, rather than disorder-specific, sample. As a result, questions will remain at the end of this trial about whether or not ACT is more effective when applied to some groups than others. We will also examine the impact of substance use in an exploratory way. Substance use disorders are commonly observed in this cohort of Veterans [e.g., [1], [2]], so we conjecture that there will be multiple participants for whom this is an issue. The impact of ACT on substance use problems is not well studied, but two studies preliminarily suggest a positive impact [e.g., [28], [57]]. We hope that our data will lead to informed hypotheses about more and less efficacious applications of ACT.

We expect challenges in the implementation of this study. One concern is maintaining protocol adherence across all sites. Our strategies for addressing this include centralized training and supervision, ongoing fidelity monitoring, and regular communications. We hold monthly calls for site PIs and for study therapists and maintain a website for the trial. We are also aware that recruitment can be challenging in the cohort of veterans of the wars in Iraq and Afghanistan. Our broad eligibility criteria will facilitate recruitment, but our staff also plan to work closely with mental health providers across multiple clinics to raise awareness of the study. We also hope that the strong acceptability of these interventions [7], [29] will help us to attract and retain participants.

It is our hope that this study will set the stage for future research on ACT. It will ultimately be important to understand the relative efficacy of the approach for different disorders and how it performs in comparison to gold standard treatments. It will be interesting to understand the mechanisms of change in this group. Finally, studies such as this one highlight the need for the development of measures to support transdiagnostic treatment, specifically measures of overarching distress, rather than disorder-specific symptoms that are responsive to intervention. In addition, we would benefit from additional development of measures of functioning. In ACT, symptom reduction is not a goal of treatment, but symptom reduction is the typical measure of treatment efficacy. Thus, we need more nuanced measures of the types of behavioral change that are the goal of ACT.

In summary, it is our goal to bring rigorous study to the application of ACT in veterans of the wars in Iraq and Afghanistan. It is our hope that this study will inform clinical practices in the nation's VA health care systems and military treatment facilities.

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Acknowledgments 

This work was supported by DoD Contract #W81XWH-10-2-0104 (A. Lang Initiating PI), VA Center of Excellence for Stress and Mental Health, DoD Contract #W81XWH-08-2-0159 (M. Stein, PI).

The ideas, attitudes, and opinions expressed herein are those of the authors and do not necessarily reflect those of the US Army, the Department of Defense, or any other branch of the US Government.

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