Cognitive behavioral therapy (CBT) is a brief, efficient, and effective treatment for individuals with depressive/anxiety disorders. However, CBT is largely underutilized within the Department of Veterans Affairs due to the cost and burden of trainings necessary to deliver all of the related disorder-specific treatments (DSTs). Transdiagnostic Behavior Therapy (TBT), in contrast, is specifically designed to address numerous distinct disorders within a single protocol in Veterans with depressive/anxiety disorders, including posttraumatic stress disorder. The proposed research seeks to evaluate the efficacy of TBT by assessing psychiatric symptomatology and related impairment outcomes in Veterans with depressive/anxiety disorders via a randomized controlled trial of TBT and existing DSTs in Veterans with major depressive disorder, posttraumatic stress disorder, and panic disorder. Assessments will be completed at pre-, mid-, and post-treatment, and at 6-month follow-up. Process variables also will be investigated.

Objective To examine efficacy of Transdiagnostic Behavior Therapy (TBT) on improving psychiatric symptomatology and related impairments in Veterans with major depressive disorder (MDD), posttraumatic stress disorder (PTSD), and panic disorder and agoraphobia (PD/AG) compared to disorder-specific treatments (DSTs) via a non-inferiority design. Patient satisfaction and predictors of feasibility (attendance and discontinuation) also will be assessed.

Recruitment Strategy and Feasibility of Recruitment Veterans will be recruited through the Primary Care Mental Health Integration, General Outpatient Mental Health, and CBT Clinic programs at the Ralph H. Johnson VAMC and all affiliated VA community-based outpatient clinics. IRB-approved study flyers will be distributed through each clinic/setting. Within these programs, all Veterans reporting symptoms of depression and anxiety meet with a mental health staff member to complete a clinical interview and self-report measures. If Veterans endorse symptoms consistent with a depressive/anxiety disorder, interest in participating in research will be assessed and, if agreeable, the Veteran will be referred to project staff. A research assessment will be completed with the project staff to first complete consent documentation and then assess inclusion/exclusion criteria (with a targeted sample of 306 VAMC patients), including a semi-structured clinical interview and self-report questionnaires focused on psychiatric symptomatology and related impairments (described later). Participants who meet inclusion/exclusion criteria will be randomized into a study condition and will be assigned to a project therapist. Because most VA Medical Center (VAMC) patients who meet study criteria likely will present with multiple depressive/anxiety disorders, principal diagnosis, or the most impairing of the diagnosable disorders, will be used to inform randomization. Principal diagnosis will be determined via diagnostic severity scores in the Anxiety Disorders Interview Schedule-5 (ADIS-5). To balance diagnoses across the two conditions, a stratified random assignment based on principal diagnosis will be used (MDD, PTSD, and PD/AG).

Procedures Eligible VAMC patients will be randomized into one of two treatment conditions: TBT or DSTs. Both treatment conditions will include 12 weekly 45- to 60-minute treatment sessions. The general format of sessions will involve: 1) brief check-in; 2) review of materials from previous sessions; 3) review of homework assignments; 4) overview of new materials and in-session exercises; and 5) assignment of homework for next session. Attendance and homework completion will be recorded.

Randomization Procedures Participants will be randomly assigned (1:1) to one of the two study arms (n = 108 per arm) using a permuted block randomization procedure. Randomization will be stratified by diagnostic group (PTSD, PD/AG, MDD) and block size will be varied to minimize the likelihood of unmasking. After determining eligibility and completing consent and baseline assessment materials, enrolled participants will be assigned to their treatment condition by the Research Project Therapist/Coordinator using a computer-generated randomization scheme.

Transdiagnostic Behavior Therapy TBT was developed as a streamlined protocol to address transdiagnostic avoidance via the use of four different types of exposure techniques (situational/in-vivo, physical/interoceptive, thought/imaginal, and positive emotional). From the transdiagnostic avoidance perspective, the four exposure practices are matched to the type(s) of avoidance experienced by patients based upon their cluster of symptoms/disorders. Per protocol, the first six sessions of TBT are designed to educate on, prepare for, and practice the four different types of exposure techniques. The next five sessions are focused on practicing and refining exposure practices as participants work through their lists of avoided situations/sensation/thoughts. The final session reviews treatment progress and relapse prevention strategies.

DSTs Control Condition Matching and Assignment To provide an evidence-based comparison for the TBT condition, DSTs will be used that are matched to the participant's most severe diagnosis, based upon the average of the ADIS interference and distress scores. If the scores are equivalent for two or more diagnoses, participants will be asked to list which diagnosis/symptoms that they find most impairing. DSTs will be included for each of the three targeted diagnoses, including PTSD (Cognitive Processing Therapy for PTSD), PD/AG (Cognitive Behavioral Therapy for PD/AG), and MDD (Cognitive Behavioral Therapy for MDD). Each of these DSTs have published manuals for administration and have received extensive support in the literature (Barlow, 2014). All three DSTs have been shown to improve comorbid symptomatology and therefore may be a more accurate comparison to TBT as compared to other available DSTs that may have less effect on comorbidity (e.g., applied relaxation for PD/AG).

Assessment of Psychiatric Symptomatology, and Treatment Satisfaction The battery of self-report questionnaires and a diagnostic interview will be completed pre-, mid-, and post-treatment and at the 6-month follow-up to track participants' progression through treatment and maintenance. To reduce the likelihood of missing data, all assessments will be scheduled separately from normal treatment sessions. Assessments of disorder-specific symptomatology, as well general symptoms of the depressive/anxiety disorders and related impairments, were chosen due to the transdiagnostic focus of the proposed study.

Inclusion Criteria:

• Participants must be Veterans
• Participants must be clearly competent to provide informed consent for research participation
• Participants must meet DSM-5 criteria for panic disorder, major depressive disorder, or posttraumatic stress disorder
• Participants must be 18-80 years old

Exclusion Criteria:

• recent history (< 2 months) of psychiatric hospitalization or a suicide attempt as documented in their medical record or reported during clinical interview
• acute, severe illness or medical condition that likely will require hospitalization and/or otherwise interfere with study procedures as documented in their medical record (e.g., active chemotherapy/radiation treatment for cancer),
• recent start of new psychiatric medication (< 4 weeks)
• diagnosis of moderate-to-severe traumatic brain injury in their medical record and/or endorsement of screener questionnaire
• additional comorbid psychiatric diagnoses that were not listed as exclusion criteria are permitted as long as they are considered secondary to the principal diagnosis of MDD, PTSD, or PD/AG as determined by the diagnostic interview
• ineligible Veterans will be referred for non-study-related treatments within mental health at the RHJ VAMC

Upon consultation with the local VA R&D and MUSC IRB committees after publication of primary research questions, the de-identified database will be made available to the public via the publishing journal's website (where applicable) as well as on (yet to be determined/selected) research community websites designed for the sharing of scientific findings and data.

starting 6 months after publication of the primary outcome papers