This study examines mental health challenges among World Trade Center (WTC) General Responders, who continue to experience significant psychological trauma from the WTC collapse. PTSD and depression remain common, and nearly six percent of the WTC Health Program (WTCHP) cohort now resides in Florida. Many identify as Hispanic, underscoring the need for linguistically appropriate services. Research shows that remotely delivered, clinician-supported mobile applications can reduce mental health symptoms.

PTSD Coach, developed by the Veterans Administration, is a free self-managed mobile app designed to help users manage PTSD symptoms through tools such as relaxation exercises, calming self-talk, and sleep hygiene practices. Reviews of the app have found it feasible, acceptable, and effective in reducing PTSD symptoms.

Clinician-Supported PTSD Coach was designed for individuals unlikely to use the app independently. This model pairs the PTSD Coach app with four remote 20-30-minute clinician sessions over eight weeks. Studies with Veterans demonstrate reductions in PTSD and depression, higher satisfaction, and increased treatment engagement compared with usual care. However, these interventions have not yet been tested with WTC General Responders or Hispanic populations.

This study will evaluate the feasibility, acceptability, and effectiveness of Clinician-Supported PTSD Coach in reducing PTSD, depression, anxiety, and sleep disturbances among English- and Spanish-speaking WTC General Responders in Florida. Participants will be randomly assigned to one of three conditions: (1) Clinician-Supported PTSD Coach, (2) Self-Managed PTSD Coach, or (3) Waitlist Control. Assessments at 8 and 12 weeks will measure symptom reductions and examine engagement, satisfaction, and barriers within the app-based conditions. It is expected that both interventions will reduce symptoms, with greater improvements in the clinician-supported condition.

This project addresses a critical gap in evidence-based mental health treatments for dispersed WTC Responders and responds to the WTCHP Scientific/Technical Advisory Committee's call for more research on mental health interventions. By focusing on Hispanic and Spanish-speaking Responders-an understudied group-this study may support the development of scalable, app-based interventions that can be deployed nationally to meet the mental health needs of WTC responders and survivors.

INTRODUCTION, BACKGROUND AND SIGNIFICANCE. The September 11, 2001 terrorist attacks on the World Trade Center (WTC) have had long-lasting impacts on the mental health of responders involved in rescue and recovery efforts. The World Trade Center Health Program (WTCHP) was established to monitor and treat health conditions related to the WTC disaster. This study addresses the mental health (MH) treatment needs of WTC responders, particularly those who have relocated to Florida after retirement and now represent an older WTCHP subgroup with a higher percentage of Latinos. The research evaluates a clinician-supported mobile application, Clinician Supported (CS) PTSD Coach, for reducing symptoms of Post-Traumatic Stress Disorder (PTSD), depression, anxiety, and sleep disturbances. The study also emphasizes inclusion of Spanish-speaking Hispanic responders to advance health equity through use of the Spanish version of the app and a Spanish adaptation of the intervention manual.

Background. Since its inception in 2011, the WTCHP, funded by CDC/NIOSH, has monitored and treated more than 120,000 responders and survivors with WTC-related conditions. Mental health conditions such as PTSD, anxiety, depression, substance abuse, and sleep disturbances are highly prevalent. PTSD is the most commonly certified psychiatric condition, with prevalence ranging from 3.8% to 29.6%. Despite the chronic nature of these conditions, there are few controlled studies of effective treatments. Most existing interventions are in-person and focus on highly exposed individuals. There have been virtually no controlled studies of app-based remote interventions for the large number of General Responders (GRs) with full or subthreshold PTSD, and none have focused on Spanish-speaking Hispanic GRs. This study addresses these gaps by testing a clinician-supported MH mobile application (CS PTSD Coach) among WTC GRs.

Florida Sub-Cohort. Florida has more than 5,496 registered WTC responders. This group is older, more often retired, and includes a higher proportion of Hispanic individuals compared with responders in other regions. The study focuses on this sub-cohort because of its unique vulnerabilities, including exposure to extreme climate events such as hurricanes that may exacerbate PTSD symptoms. Relocation of WTC responders from the New York Metropolitan Area to Florida is part of a broader migration trend, resulting in a growing number of WTCHP members in Florida and an urgent need for accessible MH services.

Preliminary data indicate that approximately 40% of Florida WTC responders show probable PTSD. There is interest in remotely delivered MH services, supporting the feasibility of the proposed intervention. The older age, higher retirement rates, and larger proportion of Hispanic individuals make this sub-cohort particularly relevant for studying the long-term MH effects of 9/11 exposure and the overlapping impact of aging.

Clinician Supported PTSD Coach Mobile App. The Clinician Supported (CS) PTSD Coach combines the self-managed PTSD Coach app with four 20-30 minute psychotherapy sessions delivered by a clinician over eight weeks. The app includes modules on psychoeducation about PTSD, self-assessment, symptom management, and accessing support. Preliminary studies with Veterans show that CS PTSD Coach can reduce PTSD and depression symptoms.

CS PTSD Coach was originally developed as a brief intervention for Veteran primary care patients with elevated PTSD symptoms who were unlikely to use a mobile app on their own. The clinician sessions provide instructions for app use, help set symptom-reduction goals, assign PTSD Coach activities between sessions, and assist participants in selecting and integrating app-based management strategies into daily life.

PTSD Coach is available at no cost from iTunes and Google Play and is accessible to nearly all U.S. smartphone users. The app is available in English and Spanish, making it suitable for the diverse WTC responder population. Its primary focus is PTSD symptom clusters: re-experiencing, persistent avoidance, negative thoughts or feelings, and hyperarousal (including sleep disturbance, startle, and irritability). The app provides psychoeducation on trauma and PTSD, symptom monitoring, and cognitive-behavioral coping tools such as relaxation exercises, calming self-talk, anger management, and sleep hygiene strategies. It has also shown benefits for depression and anxiety, which frequently co-occur with PTSD.

Significance.

The study is significant for several reasons:

1. Addressing Treatment Gaps: It responds to the WTCHP Scientific Technical Advisory Committee's recommendation for more MH intervention research and data on the effectiveness and utility of PTSD treatments among WTC responders.
2. Focus on Spanish-speaking Hispanic Responders: By specifically including Spanish-speaking Hispanic responders, the study advances health equity and addresses the needs of a group underrepresented in prior research.
3. Remote Intervention: The mobile-app format is well-suited for geographically dispersed WTC responders, especially those in Florida, and offers a scalable, accessible approach for individuals facing barriers to in-person MH care.

SPECIFIC AIMS. This study will assess the feasibility, acceptability, and efficacy of the PTSD Coach app among a multi-ethnic group of 9/11 GRs in Florida, focusing on two app delivery models: clinician-supported (CS) and self-managed (SM). There are four aims.

Aim 1 evaluates engagement with the app by analyzing usage data (frequency and duration of interactions and module use) by language group (English and Spanish) and collecting feedback on usability, barriers, and suggestions.

Aim 2 evaluates acceptability by examining user satisfaction and other indicators of positive responses to the app. Feedback on treatment acceptability and appropriateness will be gathered using standardized measures.

Aim 3 assesses the efficacy of CS and SM PTSD Coach in a randomized controlled trial (RCT). The primary outcome is reduction in PTSD symptoms; secondary outcomes are reductions in depression, anxiety, and sleep disturbances. CS and SM groups will be compared with a wait-list control to evaluate symptom changes post-intervention and at follow-up, to test whether CS is more effective than SM, and to explore potential moderators and mediators of treatment effects.

Aim 4 develops and delivers a Spanish-language version of CS PTSD Coach and evaluates its feasibility, acceptability, and efficacy for Spanish-speaking participants.

METHODS. Study Design. This two-year project is a three-arm randomized clinical trial (RCT) with: (1) CS PTSD Coach, in which participants receive clinician-supported use of the app focused on app navigation, symptom monitoring, and management strategies; (2) SM PTSD Coach, in which participants receive basic instructions on app use but no ongoing clinician support; and (3) Wait-list Control, in which participants receive no intervention until after follow-up, when they may choose CS or SM PTSD Coach. Participants will be assessed at baseline, immediately post-intervention at four weeks, and again four weeks later. Outcomes are feasibility, acceptability, and efficacy of PTSD Coach for reducing MH symptoms among WTC responders.

Recruitment and Randomization. Recruitment will use existing WTCHP General Responders Data Center resources and networks. Participants will be randomly assigned to one of the three conditions using a random number generator. The target sample is 120 participants, enrolled on a rolling basis to achieve sufficient sample size.

Measures and Data Collection. Validated measures will assess PTSD, depression, anxiety, and sleep disturbance symptoms. Data will be collected at multiple time points to evaluate symptom change and overall intervention effectiveness.

Analyses. Continuous data will be summarized with means and standard deviations or, when skewed, medians and interquartile ranges (IQRs). Categorical data will be summarized with frequencies (N) and percentages (%).

Feasibility will be assessed using objective app-use data to quantify frequency and duration of interactions and feature use, examine usage patterns (including peak engagement times and trends) by group and language, and identify the most frequently used modules. Usability will be assessed with the SUS to determine whether "good" usability is achieved.

Acceptability will be evaluated by analyzing satisfaction with PTSD Coach in both conditions and by language using the CSQ. Items rated as "good" or "excellent" will indicate endorsement. Additional feedback on acceptability of CS PTSD Coach will be collected using the AIM and IAM; items rated as "agree" or "completely agree" will indicate endorsement.

Efficacy of CS PTSD Coach will be examined using several approaches. Paired t-tests will test within-condition changes in psychological symptoms, reporting pre- and post-intervention means and standard deviations. Analysis of Covariance (ANCOVA) will compare changes in symptom scores across CS PTSD Coach, SM PTSD Coach, and wait-list control, adjusting for baseline scores and other covariates. Sample size calculations indicate that 40 participants per group, allowing for 10% attrition, will provide 80% power to detect differences between conditions.

An intent-to-treat analysis will include all randomized participants regardless of intervention completion. Missing data will be addressed using multiple imputation to maintain robustness and reduce bias.

Moderation and mediation analyses will further clarify intervention effects. Moderators (baseline PTSD severity, sex, race, ethnicity, and language [English vs. Spanish]) will be examined via interaction terms in ANCOVA models. Mediation analyses will follow the Baron and Kenny framework, using product-of-coefficients tests to assess whether intervention effects on PTSD symptoms are mediated by other variables.

EXPECTED IMPACT AND CONCLUSION. This study addresses critical gaps in MH treatment research for WTC responders, particularly those in Florida. By testing a remote, clinician-supported intervention, it has the potential to improve access to MH care for a geographically dispersed and ethnically diverse population. Findings may inform future research and clinical practice and enhance the well-being of WTC responders.

By leveraging innovative technology and focusing on an underserved population, this study aims to provide effective, accessible, and equitable MH care. The results will have important implications for the broader WTCHP cohort and contribute to ongoing efforts to support those affected by the 9/11 attacks.

Inclusion Criteria:

• World Trade Center General Responders (GRs) currently living in Florida.
• Any age.
• Must have a smartphone device capable of using the PTSD Coach app.
• Must be fluent in either English or Spanish.

Exclusion Criteria:

• Active or recent (past month) suicidal ideation or attempt.
• Low levels of distress as measured by the PCL-5 (score below 27).
• Severe alcohol use measured by an AUDIT score of 20 or above.
• Use of illicit or unprescribed drugs (except for cannabis) in the last 2 weeks, as indicated on the Modified ASSIST Measure.
• Presence of neurologic or neurodegenerative conditions associated with significant cognitive impairment (e.g., Parkinson's, Alzheimer's diseases) or current severe cognitive impairment measured using the Montreal Cognitive Assessment (MoCA).
• Current mental health treatment for PTSD.

Protecting the privacy of these World Trade Center General Responders is paramount. Sharing IPD could risk exposing sensitive personal information, even if anonymized, which might lead to re-identification.