[Study on comorbidity between post-traumatic stress disorder and depressive symptoms in firefighters].

To analyze the epidemiological characteristics of comorbidity of post-traumatic stress disorder and depression symptoms among active firefighters, and explore its influencing factors. In November 2021, a cross-sectional study was conducted using a combination of convenience sampling and cluster sampling. Active firefighters were selected as the research subjects for a questionnaire survey. 1100 questionnaires were distributed, 1032 were collected, and 1021 were valid, with an effective response rate of 98.93%. The PTSD prevalence and characteristics of firefighters were assessed by using the PTSD Checklist Civilian Version (PCL-C) . The degree of depression was assessed by the Patient Health Questionnaire (PHQ-9) . The coping style was assessed by the Trait Coping Style Questionnaire, and the Social Support Rate Scale was used to investigate the degree of social support. Combined with the general information, the influencing factors of comorbidity of PTSD and symptoms of depression in firefighters were analyzed with binary logistic regression based on single factor analysis. Among 1021 firefighters, 379 had a PHQ-9 score of ≥5, and the prevalence rate of depression was 37.1% (379/1 021) . The prevalence rate of PTSD is 4.6% for 47 individuals with a total PCL-C score of ≥38, and the comorbidity rate of depressive symptoms among PTSD patients is 100%. Logistic regression analysis showed that injuries in the past six months, average/poor self-rated health status, and negative coping were all promoting factors for both the simple depression symptom group and the comorbidity group, while social support was the hindering factor (<0.05) . Two sets of values show that negative coping and social support have roughly the same degree of impact in both groups. The (95%) values of the two factors of being injured in the past six months and self-rated as average/poor health status have significantly increased in the comorbidity group. The (95%) values of being injured in the past six months has increased from 2.20 (1.24, 3.93) in the simple depression symptom group to 3.44 (1.30, 9.09) in the comorbidity group, and that of the self-rated as average and poor health status has increased from 4.91 (3.01, 8.00) to 6.56 (1.97, 21.87) and from 7.96 (2.25, 28.25) to 19.17 (4.75, 77.31) separately (<0.05) . The results indicate that firefighters with PTSD generally have comorbidity with depressive symptoms. The common influencing factor of being injured in the past six months is consistent with the pattern of PTSD symptoms triggered by depressive symptoms.