Depression, anxiety, and post-traumatic stress symptoms among wildland firefighters and local residents in recurrent wildfire areas

Abstract Background Recurrent wildfires are an emerging public health concern, yet little is known about their mental health impact on both wildland firefighters and local residents in low‑ and middle‑income countries. This study aimed to compare depression, anxiety, stress, and post‑traumatic stress symptoms between firefighters and residents living in a recurrent wildfire area in southern Thailand, and to identify factors associated with these outcomes. Methods A cross‑sectional survey was conducted among 108 wildland firefighters and 1,090 residents in communities surrounding Kuan Kreng Peat Swamp. Mental health symptoms were assessed using the Depression Anxiety Stress Scales‑21 and the Post-Traumatic Stress Disorder (PTSD) Checklist for DSM‑5, and bivariate analyses plus multivariable logistic regression were used to examine associations with sociodemographic characteristics and wildfire experiences. Results The prevalences of abnormal scores of depression, anxiety, stress, and PTSD symptoms were 14.8%, 21.8%, 5.9%, and 4.9%, respectively. The prevalences did not differ significantly between firefighters and residents. However, residents had higher median PTSD symptom scores, suggesting a greater subclinical PTSD burden. Experiencing actual or threatened death or serious injury was strongly associated with all four outcomes, with adjusted odds ratios of 2.68 for depression, 3.73 for anxiety, 3.13 for stress, and 8.20 for probable PTSD. A dose–response pattern was observed for wildfire‑related health concerns: compared with no concern, severe–extremely severe concern was associated with roughly two‑ to four‑fold higher adjusted odds of depression, anxiety, and stress, and more than five‑fold higher odds of probable PTSD. Shorter time since the most recent wildfire was linked to higher odds of depression and stress, and firefighters showed lower adjusted odds of depression than residents. Conclusions Wildland firefighters and residents in this recurrent wildfire area showed similarly elevated prevalences of screen‑positive depression, anxiety, stress, and PTSD, although residents reported a greater overall PTSD symptom burden. Individuals with life‑threatening wildfire experiences, recent exposure, and intense wildfire‑related health concerns represent key priority groups for screening and psychosocial support, underscoring the need for integrated mental health strategies within wildfire preparedness and recovery efforts in resource‑limited settings.