The Impact of Moderate Earthquakes on Antidepressant Prescriptions in Ulsan, South Korea: A Controlled Interrupted Time Series Analysis

BACKGROUND: In 2016, two consecutive moderate magnitude earthquakes occurred in Ulsan, South Korea. Therefore, we aimed to investigate the impact of earthquakes on the mental health of residents in Ulsan. METHODS: We used data from the 2015–2017 Korean Health Insurance Review & Assessment Service National Patient Sample. We conducted an interrupted time series analysis using location-based controls. Changes in the number of antidepressants, benzodiazepines, and zolpidem prescriptions in Ulsan were compared to controls. Overall changes in weekly prescriptions 1 year after the first earthquake, compared to a non-earthquake scenario, were estimated. RESULTS: In antidepressant prescriptions, the increase in trend after an earthquake was significantly higher than controls. However, the changes in benzodiazepines and zolpidem prescribing were not significant. Overall, the impact of the earthquake on weekly antidepressant prescriptions at 1 year was estimated as a 1.32 (95% CI, 1.18–1.56) rate ratio compared to the non-earthquake scenario. This corresponded to an increase of 1,989.7 (95% CI, 1,202.1–3,063.0) in the number of prescriptions. Among subgroups, the increase was highest among males aged 20–39 years. CONCLUSION: The moderate earthquake in Ulsan was associated with an increase in antidepressant prescriptions. The increase in the male group aged 20–39 was the highest. The impact may vary according to the context of the population.