Living under a “seismic time bomb”: hyperarousal and insomnia severity in the context of anticipated earthquake threat

Background Sleep disturbances are well documented following large-scale disasters; however, less is known about insomnia severity among individuals living with anticipated seismic threat before a major earthquake occurs. Aim This study examined the associations among trauma-related symptom dimensions, emotional distress, and insomnia severity in a non-clinical sample of adults residing in Istanbul who had not experienced severe personal loss or major housing destruction due to a major earthquake. Method A total of 416 adults residing in Istanbul completed an online survey assessing depression, anxiety, stress, trauma-related symptom dimensions (intrusion, avoidance, and hyperarousal), and insomnia severity. Results Correlational analyses revealed positive associations among psychological distress, trauma-related symptom dimensions, and insomnia severity. No significant differences in insomnia severity were found across gender or age groups. In a simultaneous regression model, hyperarousal showed the strongest unique statistical association with insomnia severity ( β = 0.716, p < 0.001). A sensitivity analysis excluding the sleep-related IES-R Item 15 attenuated this association, with intrusion becoming the strongest predictor in the modified model. Exploratory mediation analyses showed no statistically significant indirect effects through depression, anxiety, or stress. Conclusion These findings suggest that hyperarousal was particularly strongly associated with insomnia severity within this sample living under anticipated earthquake threat. However, the cross-sectional design and overlap between IES-R hyperarousal and sleep-related content limit causal and construct-level interpretations.