Abstract
IMPORTANCE: Rates of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are high among paramedics. OBJECTIVE: To evaluate the efficacy of a cognitive resilience training program for reducing the development of PTSD and MDD among early career paramedics compared with psychoeducation and standard practice. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial of paramedics training at 15 universities across England was conducted between October 2017 to October 2022 with 12-month follow-up. Data were analyzed from December 2023 to July 2025. INTERVENTION: Participants were randomized to receive internet-delivered cognitive training in resilience (iCT-R), psychoeducation, or standard practice. iCT-R, a guided online intervention that utilizes cognitive therapy tools to target predictors of PTSD and MDD identified in prospective research with paramedics, consisted of 6 modules delivered over 6 weeks with 6-monthly top-up sessions delivered by email. Internet-delivered psychoeducation, a supported online psychoeducation intervention, consisted of 6 topics (1 topic per week) with 6-monthly top-up sessions delivered by email. Standard practice was training as usual. MAIN OUTCOMES AND MEASURES: The primary outcome was rate of PTSD and MDD at 1-year follow-up, assessed by independent assessors blinded to intervention using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition). Secondary outcomes included measures of PTSD and depression symptom severity, resilience, rumination, anxiety, psychological distress, and well-being. Intent-to-treat analyses were conducted, with the primary outcome analyzed using mixed-effects logistic regression. RESULTS: Of 570 student paramedics enrolled (372 female [65.3%]; mean [SD] age, 23.67 [6.88] years), 195 were randomized to iCT-R, 197 to psychoeducation, and 178 to standard practice. For participants randomized to iCT-R, the odds of meeting criteria for PTSD or MDD at 12 months were significantly lower compared with psychoeducation (odds ratio [OR], 0.20; 95% CI, 0.05-0.73) and standard practice (OR, 0.25; 95% CI, 0.07-0.97). Providing iCT-R training to 18 to 24 paramedic trainees (number needed to treat) would prevent 1 case of PTSD or MDD. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, participants receiving iCT-R were approximately 5 times less likely to develop PTSD or MDD at 1-year follow-up compared with psychoeducation and 4 times less likely when compared with standard practice. These findings suggest that iCT-R appears to decrease the likelihood of developing PTSD and MDD in early career paramedics. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN16493616.