Feasibility and Acceptability of The Equus Effect: A Small Randomized Controlled Pilot Study of an Equine-facilitated Therapy
Phase: NA
Conditions: Social Skills, Emotional Dysfunction
Sponsor: VA Office of Research and Development

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Project Description 
 
Date:  04/07/2022 Revision of Original Protocol to Adjust for Covid Pandemic 
 
Project Title:  Feasibility and Acceptability of The Equus Effect: A Small Randomized Controlled Pilot 
Study of an Equine-facilitated Therapy 
 
Principal Investigator:  Steve Martino, Ph.D. 
 
Purpose 
We propose to pilot test an innovative equine-facilitated therapy called The Equus Effect (TEE) as a 
complement to Veterans’ existing VA mental health services to improve social functioning.  TEE aims to 
improve Veterans’ social functioning by developing their emotion regulation and interpersonal skills through 
therapeutic interactions with horses. In line with recommendations for pilot investigations, we will conduct a 
randomized pilot study to 1) evaluate the feasibility of study procedures, assessments, and outcomes, 2) 
demonstrate experimental and control interventions can be delivered with fidelity, and 3) examine the 
acceptability of the interventions. To accomplish these goals, we will enroll a transdiagnostic cohort of 40 
Veterans involved in VA mental health services with social dysfunction and emotion dysregulation.  We will 
randomize participants to receive either 1) TEE or 2) attention control (AC), both group interventions.  Each 
week, the 4-session TEE will include 1) mindfulness activities, 2) emotion regulation and interpersonal skills 
education, 3) experiential activities with horses incorporating opportunities to develop emotion regulation and 
interpersonal skills, and 4) between-session application of lessons learned from the equine activities. AC will 
have similar elements without equine features. Intervention outcomes will be measured at 4- and 16-weeks 
post randomization.  Specifically, using mixed quantitative-qualitative methods, we aim to: 
Aim 1:  Determine the feasibility of recruitment, randomization, retention, assessment procedures, and 
implementation of TEE and AC. Hypothesis: Rates of recruitment will be > 8 participants per month, and 
Veterans randomized to TEE will attend intervention sessions, remain in the study, and experience clinically 
significant changes in social functioning and emotion dysregulation at rates equal to or superior to AC. 
Aim 2:  Demonstrate TEE and AC can be delivered with fidelity. Hypothesis: Facilitators will deliver each 
intervention consistently and as intended across sessions.   
Aim 3:  Establish acceptability of TEE and AC by assessing intervention credibility and satisfaction and the 
usefulness of TEE as a complementary mental health intervention using mixed quantitative-qualitative 
methods. Hypothesis: Veterans will find TEE and AC credible and satisfying and Veterans and their mental 
health clinicians will qualitatively report the therapeutic benefits of TEE as a complementary and integrative 
health (CIH) intervention for mental health treatment.    
 
This small pilot project takes a bold step forward in proposing to investigate EFT with scientific integrity and 
has the potential to lend initial credibility to the therapeutic claims of this increasingly popular CIH. Should data 
indicate that TEE and methods to study its effects are feasible and acceptable, it will set the stage for a RR&D 
IIR proposal to test the efficacy of TEE in a multi-site randomized controlled trial. 
 
Background 
In 2016 the VA Office of Patient Centered Care and Cultural Transformation (OPCC&CT) launched the Whole 
Health initiative to change VA’s healthcare system from a traditional medical model focused on treating specific 
conditions to a more holistic personalized, proactive, patient-driven approach.1 With Whole Health, Veterans 
develop healthcare plans that center on achieving meaningful life goals and improving functioning, consistent 
with a psychosocial rehabilitation emphasis on recovery-oriented outcomes related to functioning in the 
community.2 A key component of Whole Health is the use of complementary and integrative health (CIH) 
approaches with traditional services. Currently, one facility in each of 18 VISNs are designated as VA Whole 
Health flagship sites, and many more VA facilities within each of these VISNs are implementing elements of 
the Whole Health system and expanding CIH options for Veterans.1 
One class of CIH is animal-facilitated therapy, such as the use of support dogs3 or interacting with 
horses.4,5 Among animals, horses confer unique therapeutic benefits.  As prey animals, they are extremely 
sensitive to the environment and have developed an ability to assess the emotional states, behaviors, and 
intentions of their herds, other animals, and predators,6,7 mirror body language,8 and immediately respond to 

Martino - 2 
 
subtle nonverbal cues.9  Through domestication, horses have transferred these skills to relationships with 
people and can sense a person’s emotions even when the person lacks emotional self-awareness.6,7  Like a 
mirror, they give immediate feedback about a person’s emotional state and nonverbal behavioral cues (e.g., 
pinning their ears back or walking away from someone who is angry or abrupt; moving tensely and putting their 
head up high when someone is anxious; relaxing with ears forward and approaching a person who is calm).9-11 
To gain a horse’s cooperation, a person must regulate emotional distress and present in a calm, patient, 
attentive, and confident manner.  As such, interactions with horses provide opportunities for people to reflect 
on and change behaviors that impede effective interpersonal connection, collaboration, and control and to 
apply these equine-facilitated experiences in their relationships with other people.12 
Equine-facilitated therapy (EFT) leverages these unique therapeutic benefits by having people interact with 
horses using unmounted activities (no riding), allowing horses to act naturally without the control of riders.13 
Typically, a horse specialist and a mental health provider work together with participants.  The horse specialist 
focuses on the participant’s physical safety and explains the horse’s behaviors, and the mental health provider 
focuses on the participant’s experience, behaviors, and emotional reactions. Most programs have participants: 
1) practice mindfulness activities (e.g., deep breathing, body scanning) to increase nonjudgmental self-
awareness of thoughts, emotions, and sensations, as well as to prepare for horse interactions; 2) learn 
didactically about horses and their therapeutic value; 3) participate in equine activities (e.g., handling, 
grooming, leading) to understand their internal experiences and explore and address mental health and 
interpersonal issues; and 4) debrief experiences and identify opportunities for application between 
sessions.4,5,14  EFT is increasingly available at the VA, with approximately 30 VA facilities currently partnering 
with EFT programs for Veterans.15  VA-partnered EFT availability is likely to grow in that the 2018 Military 
Construction and Veterans Affairs Appropriations Act included an amendment to expand funding by 5 million 
dollars for EFT within the VA.16 
EFT at the VA has been used to address a variety of diagnostic issues commonly experienced by 
Veterans, including PTSD, depression, anxiety, substance use and eating disorders, and relationship 
problems.5,17 Wide application of EFT may be due to its focus on the management of emotion dysregulation, a 
transdiagnostic phenomenon underpinning impaired functioning associated with many mental health 
conditions.18 In addition, EFT may be recommended when patients respond poorly to traditional mental health 
treatments; the complementary value of EFT is that the salient emotion-based learning with horses may 
catalyze progress on issues concurrently addressed in traditional mental health services.14 Finally, preliminary 
reports of EFT suggest it may help people reduce anger and aggressive behavior,12,19 improve mood,20 and 
reduce depression21,22 and PTSD symptoms,22,23 further supporting its transdiagnostic appeal.  None of these 
reports focus on social functioning as a main outcome, a surprising absence given that high quality social 
functioning depends on effective regulation of one’s emotions,24 a presumed key mechanism targeted by EFT.  
Research about EFT is in its infancy, despite increasing utilization of it in the VA.  Few peer-reviewed 
studies about EFT exist, and those that do are generally of poor methodological quality.4,5,17 Quantitative 
research has been limited by the lack of operationalized EFT interventions, independent fidelity assessment, or 
use of psychometrically established assessments, control conditions, randomization, or post-intervention 
follow-ups. In addition, qualitative research has not focused on discerning patients’ perceptions about effective 
and ineffective EFT components or how EFT works to improve functioning and well-being. Furthermore, 
clinicians’ perceptions of benefits catalyzed by EFT within traditional mental health services have not been 
studied, a clear limitation given the presumed complementary value of EFT.  Moreover, almost all the research 
on EFT has focused on school-age children and adolescents, not adults. Given VAs increasing embrace of 
EFT, carefully conducted research that aims to systematically develop and study EFT for Veterans is sorely 
needed to ensure that it works. 
 
Significance 
The proposed pilot study will advance knowledge in rehabilitation research by studying the feasibility and 
acceptability of conducting a randomized controlled trial of an EFT, called The Equus Effect (TEE), currently 
available to Veterans at VA Connecticut Healthcare System (VACHS).  TEE is a 4-session intervention that 
incorporates mindfulness strategies, emotion regulation and interpersonal skill development, and experiential 
equine activities to improve social functioning for a mixed diagnostic group of Veterans.  Data from the pilot 
study will inform development of a RR&D IIR proposal testing the efficacy of TEE in a multi-site randomized 
controlled trial. The proposed research aligns with the RR&D SPiRE Program Priority Areas for studying 

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promising non-pharmacological activity-based interventions to maximize functional recovery,25 OPCC&CT 
promotion of CIH within the Whole Health initiative,1 and the VA 2018-2024 Strategic Plan to ensure Veterans 
receive integrated care and support that emphasizes their well-being and independence.26 
 
Research Plan 
1.  Study design and overview. We will test the feasibility and acceptability of a randomized controlled trial 
design to study TEE to improve social functioning. We will enroll a transdiagnostic cohort of 40 Veterans with 
social dysfunction and emotion dysregulation who are receiving VA mental health services and randomize 
them to either weekly TEE or attention control (AC) sessions over 4 weeks. Social functioning will serve as the 
primary outcome; emotion dysregulation will serve as the secondary outcome. Following best practice 
recommendations for pilot investigations,27,28 we will use mixed quantitative and qualitative methods. Feasibility 
will examine performance of study procedures, assessment measures, and outcomes (Aim 1) and fidelity of 
TEE and AC (Aim 2). Acceptability will involve assessing TEE and AC credibility and satisfaction, as well as 
conducting key informant interviews with Veterans assigned to TEE and their clinicians (n = 20) to examine 
perceptions of the acceptability and usefulness of TEE and the ways in which it complements standard mental 
health care (Aim 3). Intervention outcomes will be measured at baseline and 4- and 16-weeks post-
randomization. 
2.  Study timeline. Year 1 will include start-up tasks and initiating the pilot trial.  Year 2 will involve completing 
the pilot trial, cleaning and analyzing data, and preparing manuscripts and the RR&D IIR RCT proposal to test 
TEE efficacy (see Table 1). 
 
Table 1. Study Timeline. 
 
Year 1 
Year 2 
Activities 
Q1 
Q2 
Q3 
Q4 
Q1 
Q2 
Q3 
Q4 
IRB 
X 
X 
 
 
 
 
 
 
Hire and train RA 
X 
X 
 
 
 
 
 
 
Develop AC 
X 
X 
 
 
 
 
 
 
Develop TEE and AC fidelity measure 
 
X 
X 
 
 
 
 
 
Recruit participants/provide TEE & AC 
 
X 
X 
X 
 
 
 
 
Complete assessments 
 
X 
X 
X 
X 
 
 
 
Enter and clean data 
 
X 
X 
X 
X 
X 
 
 
Analyze data 
 
 
 
 
X 
X 
 
 
Present findings 
 
 
 
 
 
X 
X 
 
Prepare manuscript and RR&D IIR RCT 
 
 
 
 
 
 
X 
X 
 
3.  Setting. All research procedures will be conducted at VA Connecticut West Haven and Newington 
campuses.  TEE and AC will be delivered off-site at the TEE location in Sharon, CT. 
4.  Participant eligibility criteria.  Inclusion criteria for Veterans are: 1) seeing a VACHS mental health 
clinician at least three times in the past 3 months with intent to remain in treatment during study enrollment; 2) 
age 18 and over; 3) social dysfunction (score > 2.5 on the Social Adjustment Scale–Self-Report or > 1.5 on the 
Inventory of Interpersonal Problems–32); 4) emotion dysregulation (score > 95 on Difficulties in Emotion 
Regulation Scale); and 5) consent to all study procedures, including audio recording of group intervention 
sessions. Exclusion criteria are: 1) psychotic disorder as self-reported by the Veteran and verified in the 
electronic health record or as determined by the Mini-International Neuropsychiatric Interview; 2) acute 
suicidality, 3) inability to read English or communicate in spoken English; 4) anticipated unavailability to the 
study during the next 16 weeks; 5) participation in any EFT in the past 24 weeks; and 6) unavailability of a 
landline or cellular telephone. Clinicians are eligible for study participation if 1) they have seen one of the 
Veteran participants assigned to TEE at least three times in the past 3 months at the participant’s baseline 
assessment, and 2) this Veteran received at least one TEE session and one psychotherapy/counseling 
session with the clinician prior to the key informant interview.  
 
Justification. Veterans must report a moderate level of impaired social functioning (primary outcome) for 
study interventions to demonstrate clinically significant changes in this area; proposed cut-offs exclude 
Veterans who report few or no problems with social functioning. We also included a cut-off of at least moderate 
emotion dysregulation (secondary outcome) given how TEE and most EFTs purport to lessen emotion 

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dysregulation as a key mechanism to improve social functioning.  Veterans must receive consistent mental 
health treatment from a clinician to enable qualitative examination of EFT’s complementary therapeutic value. 
Phone contact is necessary to coordinate transportation to Sharon, CT and arrange study assessments.  
5.  Randomization. Eligible Veterans will be recruited to form one TEE and one AC group every four weeks. 
We will use permuted block randomization (1:1 ratio), with variable block size, to maintain balanced 
assignment to conditions given potential differences in monthly recruitment.  The project coordinator will 
conduct randomization. 
6.  Recruitment and feasibility. Recruitment will begin at the end of Q2 in Year 1. In FY2018, VACHS served 
over 58,687 unique Veterans in Connecticut and southern New England, with 14,687 enrolled in mental health 
services.  Most Veterans are seen at our West Haven and Newington campuses. The West Haven campus 
has five outpatient mental health clinics, three intensive outpatient treatment programs, two residential 
psychosocial rehabilitation treatment programs, and the psychosocial rehabilitation Errera Community Care 
Center.  The Newington campus has two outpatient programs and two intensive outpatient treatment 
programs. We will recruit 8-12 Veterans per 4-week cycle to form a large enough cohort each month for block 
randomizing a sufficient number of Veterans to either TEE or AC.  Hence, recruiting 40 Veterans should take 
about 4 months; we have planned seven months in our timeline in case recruitment is slower than expected.  
Recruiting 40 Veterans should be quite feasible given the large number of Veterans in VACHS mental health 
services, the broad transdiagnostic eligibility criteria, and record of Veteran engagement in TEE thus far (> 200 
in the past 4 years). 
 
Direct-to-participant and clinician recruitment will occur via flyers, visits to clinic rounds, and email to 
clinicians at VA Connecticut sites, including Vet Centers in Connecticut. The study also will be presented to 
Veterans during community meetings at Errera Community Care Center programs located in West Haven and 
Newington.  In addition, clinicians and peer specialists will be provided with study cards that they can hand to 
Veterans if they feel the Veterans might be appropriate for study participation. If Veteran participants have 
more than one mental health clinician, they will be asked to identify which clinician they see as primarily 
providing them mental health psychotherapy/counseling, and the research assistant will invite that person to 
participate in the study.  The decision of Veterans’ clinicians to enroll in the study will not affect potential 
Veteran participants’ study eligibility, particularly because their clinicians will be approached for study 
participation after Veterans have already enrolled. The PI, project coordinator, and Co-Is will have monthly 
meetings to review the number of individuals assessed for eligibility and those who were found ineligible (with 
reasons), declined to participate (with reasons), randomized, started, completed, withdrew, and completed 
assessments at each timepoint. Quarterly/semi-annual reports of these numbers will be provided to the Data 
Safety Monitoring Board (DSMB).  
7.  Screening. We will seek waivers of written informed consent and HIPAA authorization for an initial phone 
screening. The research assistant (RA) will offer Veterans information about the study and invite interested 
parties to complete a brief phone screening on quickly obtained eligibility criteria (e.g., if they have received 
EFT in the past 6 months). Individuals who remain eligible will next attend an in-person meeting in which to 
learn more about the study in detail, including completing an additional screening to further determine inclusion 
and exclusion criteria (e.g., completion of psychiatric interview, social functioning, and emotion dysregulation 
assessments). If the potential participant is agreeable, the RA will invite individuals to provide written informed 
consent and then will complete the screening to determine eligibility.  Only individuals who meet eligibility 
criteria will be invited to continue in the study and participate in the baseline assessment. 
 
Given the vacillating COVID-19 pandemic conditions and Veteran preferences, the entire screening 
process can occur remotely, via phone or a VA-approved video conference platform, rather than in-person. If 
conducted in-person, participants will be required to wear a 2-ply face mask when in the room with research 
staff, and if they do not have one, one will be provided for them.  Likewise, research staff will utilize masks and 
social distancing during study visits and will sanitize the office between each in-person visit and at the end of 
the day.  
If conducted remotely, the consent form will be handled in one of two ways.  Preferably, research staff will 
use an e-consent approach with VA DocuSign. In advance of the next scheduled phone or video conference 
following the brief phone screening, research staff will send a DocuSign envelope (email containing links to the 
informed consent and HIPAA authorization documents).  The email will contain a reminder for the recipient to 
not sign the document prior to the scheduled contact time to review it and have questions answered.  During 
the remote visit, research staff will review the documents in the same manner as doing so in person. If the 

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potential participant agrees to participate in the continued screening and study, if found eligible, research staff 
will guide them to fill in the fields in the e-consent form (e.g., Last, First, Middle Initial name fields) and to 
electronically sign it and click “FINISH” to finalize the document.  While still on the phone/video conference 
platform with the participant, research staff will receive an email notification to log into DocuSign, verify that all 
fields are completed accurately, and sign as a witness.  The participant will be shown how to download a copy 
of the informed consent to their computer for their record or will be mailed a hard copy, if preferred.  
If VA DocuSign is infeasible to use with potential participants, the consent form will be mailed to subjects after 
participating in the phone screening to determine initial eligibility.  Upon receipt of the consent form, another 
remote encounter will occur with the potential participant to review it, and have it signed and returned to the 
research team, if the Veteran remains interested.  Once received, a member of the research team will meet 
remotely again with the participant to complete the screening, determine eligibility, and, if found eligible, have 
the participant finish the remaining baseline assessments. Remote sessions will not be recorded. 
8.  Intervention conditions.  Veterans will receive either TEE or AC, both closed group programs in which all 
members begin the group intervention at the same time. TEE and AC each will consist of four 4-hour weekly 
sessions over 4-weeks, with 4-6 Veterans attending per 4-week cycle. Activities in both conditions contain a 
mixture of indoor and outdoor activities; group facilitators and participants will wear 2-ply face masks indoors or 
outdoors as dictated by prevailing VACHS guidelines.  Masks will be provided to participants who do not have 
them. Jane Strong and David Sonatore, LCSW will conduct TEE sessions. They are Experiential Learning with 
Horses Instructors who trained at the Epona Equestrian Services Program in Tucson, AZ – an internationally 
acclaimed equine educational program that trains people in EFT. They have worked together for the past 
decade developing and delivering TEE to Veterans.  Peer specialists from VACHS or staff from the facility in 
Sharon, CT not delivering TEE will conduct AC sessions.  They have experience facilitating general support 
groups and will be trained by Dr. Martino to deliver the control intervention. 
TEE. Each session includes: 1) mindfulness-based activities; 2) didactics about emotion regulation and 
interpersonal skills; and 3) experiential learning activities with horses that provide opportunities to practice 
emotion regulation and interpersonal skills. At the end of each session, Veterans debrief about what they 
learned and identify how they might apply this knowledge to manage their mental health concerns and function 
better socially.  Ms. Strong and Mr. Sonatore have prepared a manual detailing the program’s major 
components and content and will co-facilitate its delivery to participants in this pilot study.  
AC. AC will exclude equine-related activities or discussions but maintain mindfulness-based activities, 
emotion regulation and interpersonal skills didactics, and experiential learning activities with between-session 
application. During the first five months of the study, Drs. Martino, Harpaz-Rotem, and Decker will develop and 
manualize AC to parallel the focus, content, and activities of TEE. Instead of experiential equine activities, AC 
will rely on team-building activities (e.g., scavenger hunt), which aim to enhance social relations by involving 
participants in collaborative tasks and providing opportunities for emotion regulation and interpersonal skills 
practice.29 Group leaders will practice the finalized curriculum with the research team in month 5 and then co-
facilitate it for Veterans randomized to this condition.  
TEE will occur at the horse stables and pastures/ring where the program occurs in Sharon, CT.  AC will 
occur at a cottage on the same property, but not in the stables and pastures/ring. Table 2 compares TEE and 
AC sessions. All TEE and AC sessions will be audio recorded, except for the experiential equine activities 
because of excessive logistical challenges.  
Veterans will have the choice to be transported by van to and from the intervention location by the Peer 
Specialists from VACHS or the Disabled American Veterans Department of Connecticut. If they choose to use 
van transportation provided for this study, they will first be screened by the driver for symptoms that could be 
consistent with COVID-19 infection.  Participants will only be permitted to enter the vehicle if they pass 
symptom screening.  During the drive, they will always wear 2-ply masks, which will be provided to those who 
do not have one. They will not be allowed to eat or drink while in the vehicle, and weather permitting, windows 
will be slightly open to allow for air circulation.  COVID-19 risk mitigation procedures for travel will be adjusted 
according to prevailing VACHS guidelines. 
Rationale for AC. For most Veterans, interacting with horses will be an unusual experience, and driving to 
the countryside and spending four hours in a bucolic setting may confer therapeutic benefits (e.g., stress 
reduction). Replicating TEE without horse-specific components will be essential to determine therapeutic gains 
specific to equine interactions. We elected not to include interactions with another large, familiar animal (e.g., a 
cow) as a more stringent test of “the equus effect” because of its impracticality, uncommonness as a 

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social/recreational activity, and the possibility that other animals could elicit different responses from different 
people (e.g., fear/hesitation vs. attraction/approach), making interpretation of potential condition differences 
difficult.  
    
Table 2. TEE vs. AC. 
 
Content/Activities 
Session Focus 
TEE 
AC (manual to be developed) 
 
 
 
1 
Mindfulness 
Joint fluidity/body scan in horse barn Joint fluidity/body scan in cottage 
Emotion regulation & 
interpersonal skills 
Fear and vulnerability/video, 
discussion w/ parallels to horses 
Fear and vulnerability; video, 
discussion; no horse parallels 
Experiential learning 
activity 
Setting healthy boundaries/ 
grooming, leading, yielding, backing 
up with horse  
Team building activity requiring 
disclosure and boundary 
management 
 
 
2 
Mindfulness 
Joint fluidity/body scan in horse barn Joint fluidity/body scan in cottage 
Emotion regulation & 
interpersonal skills 
Anger/Frustration/Agitation; video, 
discussion w/ parallels to horses 
Anger/Frustration/Agitation; video, 
discussion; no horse parallels 
Experiential learning 
activity 
Collaboration/ grooming, obstacle 
course with horse 
Team building activity requiring 
collaboration 
 
 
3 
Mindfulness 
Joint fluidity/body scan in horse barn Joint fluidity/body scan in cottage  
Emotion regulation & 
interpersonal skills 
Sadness and Grief; video, 
discussion w/ parallels to horses 
Sadness and Grief; video, 
discussion; no horse parallels 
Experiential learning 
activity 
Collaboration/ grooming, walk 
through labyrinth or trail with horse 
Team building activity requiring 
collaboration 
 
 
4 
Mindfulness 
Joint fluidity/body scan in horse barn Joint fluidity/body scan in cottage  
Emotion regulation & 
interpersonal skills 
Review of emotional states; video, 
discussion w/ parallels to horses 
Review of emotional states; video, 
discussion; no horse parallels 
Experiential learning 
activity 
Collaboration/ grooming, hooking up 
with horse in round pen 
Team building activity requiring 
communication in pairs 
 
9.  Assessments. Assessments will occur at screening, baseline, 4- and 16-weeks post-randomization. Dr. 
Martino will train the RA (blind to condition) to administer assessments. Assessments will be conducted either 
in-person or remotely, depending on COVID-19 pandemic conditions and the participants’ preference.  As with 
the screening process, if conducted in-person, research staff and participants will be required to wear a 2-ply 
face mask during study visits and social distance.  If the participants do not have a mask, one will be provided 
for them.  Research staff will sanitize the office between each in-person visit and at the end of the day. If 
conducted remotely, research staff will use either phone or a VA-approved video conference platform. 
Assessment sessions, regardless of mode of delivery, will not be recorded. The RA will schedule assessment 
sessions. Veterans will be instructed to not tell the RA their intervention assignments. 
 
Sample description. Demographics will be assessed with the 15-item Phen-X adult Demographic protocol.  
Military demographics and experiences will be assessed with the 11-item Phen-X Military Service 
Demographics measure. The Mini-International Neuropsychiatric Interview30 will assess psychiatric diagnoses. 
Outcomes. The primary outcome will be social functioning as measured by the Social Adjustment Scale–
Self Report (SAS-SR)31 and Inventory of Interpersonal Problems-32 (IIP-32).32 We chose the SAS-SR because 
it details social functioning in a range of role areas (e.g., work, social and leisure, family), contains skip-outs for 
nonapplicable items, and has been widely used in clinical trials and outcome research with participants with 
mixed psychiatric diagnostic characteristics.33 The overall SAS-SR score is 1 (no impairment), to 5 (highest 
impairment). We chose IIP-32 because it taps people’s interpersonal difficulties across role areas (e.g., hard to 
be assertive, too aggressive) and is reliable and valid when used with diagnostically mixed groups of 
psychiatric outpatients.32 The IIP-32 total score is 0 (no difficulties), to 4 (extreme difficulties). Both aspects of 
social functioning may be affected by TEE. Our secondary outcome is emotion dysregulation as measured by 
the Difficulties in Emotion Regulation Scale (DERS).34 DERS scores range from 36-180, with higher scores 
indicating more dysregulation. A total score of >105 falls between nonclinical mean scores (M=77.99-80.66)34 
and the mean of adults with extreme interpersonal and emotional dysregulation (M=128.03).35 

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Other outcomes will include mindfulness (Five Facet Mindfulness Questionnaire),36 psychiatric symptoms 
(Phen-X Cross-Cutting Symptom measure that assesses 13 psychiatric domains, including depression, anger, 
mania, anxiety, somatic symptoms, suicidal ideation, psychosis, sleep problems, memory, repetitive thoughts 
and behaviors, dissociation, personality functioning, and substance use),37 PTSD symptoms (PCL-5),38 coping 
skills (DBT Ways of Coping Checklist),39 and the Brief Pain Inventory (BPI).40 If a participant reports current 
suicidal ideation, the research assistant will contact the PI, Dr. Martino, or one of the co-investigators who will 
conduct a thorough assessment and, as warranted, either contact/escort the Vet to see their clinician and/or 
escort the Veteran to the psychiatry ER at VACHS.  If this event were to occur during remote assessment 
session, whoever is doing the assessment will contact the PI who will do a more detailed imminent risk 
assessment over the phone.  If the PI believes there is risk and is concerned for the study participant’s safety, 
911 will be called for a welfare check. 
Intervention Fidelity. Fidelity assessment will follow methods from the Yale Adherence and Competence 
System (YACS), a reliable and valid system for assessing fidelity of psychosocial treatments.41 YACS is a 
general rating system for evaluating the adherence (how often) and competence (how well) of therapists 
delivering psychosocial treatments. Items are developed to capture components of a treatment that are unique 
and essential (e.g., psychoeducation about unique therapeutic features of horses, experiential equine-
activities), essential but not unique (e.g., teaching emotion regulation or interpersonal skills), and antithetical to 
an approach (e.g., direct confrontation).  Independent raters trained in the system rate items along 7-point 
Likert scales (adherence = 1 [did not occur], to 7 [extensively]; competence = 1 [very poor], to 7 [outstanding]) 
to determine the fidelity of intervention delivery. YACS also includes therapist checklists completed after each 
session to indicate intervention elements conducted. Dr. Martino co-authored the last edition of the YACS,42 
trained many research groups in it as Education Director of the Yale Psychotherapy Development Center, and 
has modified and used it to assess the different psychotherapies in several studies. Drs. Martino, Harpaz-
Rotem, and Decker will develop a TEE/AC fidelity measure based on the YACS during months 4-9 of the 
study. Dr. Martino will train two to three independent raters to use the measure to reliably rate all recorded TEE 
and AC sessions.  We will use therapist checklists completed by TEE and AC group facilitators each week to 
document adherence to prescribed experiential activities. 
Intervention credibility and satisfaction. The credibility of and satisfaction with TEE and AC will be assessed 
with adaptations of the Credibility and Expectancy of Improvement Scale43 and the Client Satisfaction 
Questionnaire,44 respectively. 
Key informant interviews. Key informant individual 20/30-minute interviews will take place post-intervention 
to assess Veteran and clinician perceptions of the acceptability, usefulness, and satisfaction of TEE. Drs. 
Martino, Portnoy, and Fenton, and Ms. Strong and Mr. Sonatore will develop the Veteran and clinician 
interview guides to ensure questions and probes ascertain main topics. These interviews will be audio 
recorded using either Microsoft TEAMS (from a VA desktop or laptop) or a VA-approved audio recorder. 
Microsoft TEAMS is a HIPAA-compliant, VA approved platform for video conferencing and has transcription 
generating capacity. We will also gather some demographic and professional characteristics of clinician 
participants (i.e., age, sex, race/ethnicity, profession/discipline, professional status (e.g., staff, trainee), Veteran 
status, months treating Veteran, years providing clinical services, and major focus of mental health service 
provided to Veteran) to characterize the sample. 
10.  Data management. Quantitative assessment measure responses will be entered into VA REDCap to 
provide secure automated export procedures for data to be downloaded to Excel and common statistical 
packages (e.g., SAS) for data analysis. REDCap catches unclear characters, out-of-range variable and logical 
inconsistencies. The research assistant will check files monthly so that errors can be readily corrected. 
11.  Data analysis. 
Quantitative. To assess feasibility (Aim 1), we will use CONSORT reporting standards to diagram the 
number of Veterans screened, found eligible and ineligible (with reasons), consented, attended sessions, 
completed TEE and AC interventions, and retained through follow-up. We also will track rates of unanticipated 
study-related adverse events in both conditions and participants’ rate of completion of all outcome measures. 
Means, standard deviations, and median scores will be calculated for outcome assessments. The proportions 
of participants with clinically significant change in outcomes from baseline to 4- and 16-weeks post-
randomization will be calculated using each measure’s test-retest reliability and clinical cutoffs from the 
literature, or change of two standard deviations from the baseline mean when clinical cut-offs are not 
available.45  To assess intervention fidelity (Aim 2), we will determine the proportion of sessions that contain all 

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prescribed program elements and reach YACS-based proficiency and examine intervention discrimination. For 
acceptability (Aim 3), we will examine means, standard deviations, and median scores calculated for 
intervention credibility and satisfaction measures. 
Qualitative. To further assess acceptability (Aim 3), we will conduct, audio record, and transcribe verbatim 
key informant interviews assessing the acceptability, usefulness, and satisfaction of TEE and TEE’s effect on 
the Veterans’ use of traditional mental health services from the perspective of Veterans and their clinicians.  
We will use an established rapid content analysis approach commonly utilized VA-funded research.46 Analysis 
will occur throughout data collection, allowing for quick and accurate reduction of qualitative data and 
production of results useful for evaluating ongoing interventions.46 As transcripts become available, they will be 
reviewed and summarized by two members of the research team (Drs. Portnoy and Fenton). Discrepancies in 
the summary pairs will be discussed and resolved through consensus. We will then transfer the summaries into 
matrices and use matrix analysis methods to identify key themes related to the acceptability, usefulness and 
satisfaction of TEE.47 Matrices systematically note the similarities, differences, and trends in responses across 
interviews, thereby expediting synthesis and summary of findings. We will identify themes that are evident 
across multiple exit interviews. These cross-cutting themes will become the framework for our final analysis, for 
which we will use a hybrid deductive and inductive analytic approach48 in which the established themes will be 
evaluated against the data and new themes will be incorporated into the evolving coding scheme.49  

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