Impact of Legislation of Suicide Prevention Act on Suicide Rates in the Republic of Korea: An Interrupted Time-series Analysis

Abstract Introduction Suicide is a global public health problem, and the Republic of Korea has one of the highest suicide rates worldwide. In 2011, the Act on the Prevention of Suicide and the Creation of Culture of Respect for Life (Suicide Prevention Act) was introduced in the Republic of Korea to promote necessary matters for suicide prevention policies. This study aims to evaluate the effectiveness of the Act in reducing suicide rates and identify the differential effects of the legislation by age and region. Methods We retrieved the suicide rates by sex, age, region, and district from the Korean Statistical Information Service (KOSIS). We investigated the impact of the Suicide Prevention Act on suicide rates between 1983 and 2021. We used interrupted time-series analysis to assess whether the trends of suicide rates changed following the introduction of the enactment and enforcement of the Suicide Prevention Act. Results The Suicide Prevention Act significantly impacted reducing suicide rates in South Korea. Suicide rates had steadily increased before the Act was introduced, but after enforcement, the trend reversed with decreasing rates in both men (β3=-1.600, P-value < 0.001) and women (β3=-0.097, P-value < 0.001). Age-stratified results showed the legal effectiveness in reducing suicide rates over 30 years old, but there was no change in 20–29 years old and 10–19 years old. The Act's effectiveness in reducing suicide rates varied regionally, with the law not significantly impacting suicide rates in Ulsan (β2=-0.128, P-value = 0.944, β3=-0.380, P-value = 0.220). At the district level, around 86.2% of the regions demonstrated a positive impact, with most districts having a considerable effect and others showing a slight result on suicide prevention methods. Conclusion Enactment and enforcement of the Suicide Prevention Act helped reduce suicide rates nationwide, suggesting that legal measures can be essential in implementing an integrated suicide prevention strategy. Further research should verify reasons and contexts in which the effects of suicide prevention regulations and guidelines appeared differently by age and region, as well as the mechanism of how the law could affect health indicators.