Symptom-level architecture of chronic stress and its interconnections with depressive symptoms among firefighters: a network analysis

Chronic stress is common among firefighters and closely intertwined with depressive symptoms. However, the symptom-level organization of chronic stress and its specific connections with depressive symptoms remain insufficiently characterized in this population. This study aimed to characterize the network structure of chronic stress and identify its relatively central symptoms, as well as to examine cross-domain connections and bridge symptoms between chronic stress and depressive symptoms among firefighters. This cross-sectional study enrolled 5,323 Chinese firefighters, of whom 5,115 were included in the final analysis. The 14-item Perceived Stress Scale (PSS-14) and Patient Health Questionnaire-9 (PHQ-9) were administered to measure chronic stress and depressive symptoms, respectively. A standalone network of chronic stress and a combined network incorporating chronic stress and depressive symptoms were constructed. The expected influence (EI) of each node within the chronic stress network and the bridge expected influence (BEI) in the combined network were calculated. “Upset by something unexpected” showed the highest estimated EI (EI = 1.03) in the chronic stress network. In the combined network, “Felt nervous and stressed” (BEI = 0.29) in the chronic stress community and “Tired or little energy” (BEI = 0.28) in the depressive symptom community exhibited the highest BEI values. The strongest cross-community edge was also observed between these two symptoms. Our findings characterize the symptom-level architecture of chronic stress and its interconnections with depressive symptoms among firefighters. Central and bridge symptoms may represent clinically informative targets and help identify potential candidates for further investigation in longitudinal and intervention studies in this high-risk occupational group. Not applicable.