Long-Term Trajectories of Posttraumatic Stress Disorder Symptoms: A 20-Year Longitudinal Study of World Trade Center Responders

Objective The present study examined the 20-year course of posttraumatic stress disorder (PTSD) in World Trade Center (WTC) responders to address four questions: (1) How stable are symptoms of PTSD? (2) What is the average symptom trajectory? (3) How much do responders differ from the average trend? (4) How quickly do PTSD symptoms improve or worsen? Methods Data include 81,298 observations from n = 12,822 responders, spanning from July 2002 to December 2022. Fourteen percent meet PTSD criteria. PTSD symptoms were measured using the PCL-17. Retest correlations were calculated to estimate stability, growth curve models to estimate individual trajectories, and Kaplan-Meier curves to estimate the rate of clinically significant change. Results Retest correlations were high overall (range =.49, .84), lower in PTSD cases (range =.21, .78), and decreased as a function of time between assessments. The best-fitting growth model represented trajectories continuously rather than multiple classes. Symptom burden peaked in 2011 and declined modestly by 2022 (Cohen’s d = -0.28 and -0.59 in all responders and PTSD cases, respectively). Median time before clinically significant improvement in responders with PTSD was 8.88 years (95% CI = 8.01, 9.79). Conclusions In the longest and largest study of PTSD symptoms tracked continuously since exposure, illness course was characterized to find that, while symptoms were highly stable in the short term, symptoms changed significantly over two decades. Most responders experienced clinical improvement after nine years, but 10% had poor course and should be the focus of public health efforts. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement F.D.M. conducted analyses and drafted the manuscript. All authors provided revisions and approved a final version of the manuscript. Data collection was funded by CDC 2011-200-39361 awarded to B.J.L., U01OH011864 awarded to M.A.W, and by the SUNY Research Foundation. The analyses were partially funded by R21AG074705-01 awarded to F.D.M. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The IRB of Stony Brook University gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data not provided in the article because of space limitations are not publicly shared. All data and related documentation underlying the reported results will be made available after the de-identification of sensitive information and participant information. The authors will share the data with qualified investigators whose proposal to analyze the data has been approved by an internal review committee.