Mental Health
Area-level deprivation and suicide by restrictable methods: trends in Japan, 2000-2022 Yoshikazu Komura* Yoshikazu Komura Naoki Kondo Aoi Kataoka Keisuke Fukui Tomoki Nakaya Yuri Ito
Background
As method restriction is known to reduce suicide rates, identifying suicide methods commonly used in deprived areas is critical for developing suicide prevention strategies that minimize area-based disparity in suicide risk. We examined national trends in suicide rates by potentially restrictable methods, focusing on disparities by area-level deprivation levels.
Methods
This serial cross-sectional study used national vital statistics data of Japanese residents from 2000 to 2022. Area-level deprivation at municipality level was estimated based on the Japanese Areal Deprivation Index 2000. Suicide rates by potentially restrictable methods—pesticide poisoning, jumping from a high place, and intentional collision with moving objects—and their differences by area-level deprivation were estimated.
Results
From 2000 to 2022, 609,029 suicides were recorded (average suicide rate = 21.0 / 100,000 person-year), with 74,448 (12.2%) suicides by the three potentially restrictable methods. The disparity in suicide rate by pesticide poisoning decreased over time, while the disparity in rate by jumping persisted (rate difference [/100,000 person-years] in deprived vs. non-deprived areas: by pesticide poisoning in 2000, 0.20; in 2022, 0.02: by jumping in 2000, 0.17; in 2022, 0.36). In contrast, suicide rates by intentional collision were higher in non-deprived areas than deprived areas (rate difference [/100,000 person-years] in deprived vs. non-deprived areas: by intentional collision in 2000, −0.15; in 2022, −0.24).
Conclusion
We found that suicide rate disparity by pesticide poisoning decreased over time, while disparity by jumping persisted. These findings suggested that pesticide restrictions in Japan, implemented in 1999, have contributed to reducing suicide disparity associated with area-level deprivation, and installing barriers at high places boosts the current reduction of suicide disparity associated with area-level deprivation in Japan.